View source for LIC-95-0079, Responds to Questions in NRC 950302 RAI & Addl Questions Raised by NRC During 950323 Telcon,To Assist Closure of NRR Review of Plant Revised Evaluation of Control Habitability

{{Adams
| number = ML20082J225
| issue date = 04/05/1995
| title = Responds to Questions in NRC 950302 RAI & Addl Questions Raised by NRC During 950323 Telcon,To Assist Closure of NRR Review of Plant Revised Evaluation of Control Habitability
| author name = Patterson T
| author affiliation = OMAHA PUBLIC POWER DISTRICT
| addressee name = 
| addressee affiliation = NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
| docket = 05000285
| license number = 
| contact person = 
| document report number = LIC-95-0079, LIC-95-79, TAC-M90495, NUDOCS 9504180178
| document type = CORRESPONDENCE-LETTERS, INCOMING CORRESPONDENCE
| page count = 54
| project = TAC:M90495
| stage = Other
}}

=Text=
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l                                Omaha Public Power District I                                  444 South 16th Street Mall                                .
Omaha, Nebraska 68102-2247                                  I 402/636-2000                                         i April 5,1995 LIC-95-0079 i
U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Station P1-137 Washington, DC 20555                                                                     J 1

==References:==
: 1. Docket No. 50-285
: 2. Letter from NRC (S. D. Bloom) to OPPD (T. L. Patterson) dated March 3, 1995

==SUBJECT:==
Response to Request for Additional Information (RAI) to Assist Closure of NRR Staff Review of Fort Calhoun Revised Evaluation of Control Room Habitability (TAC No. M90495)                                 .
l The purpose of this letter is to respond to questions in the Reference 2 RAI and to additional questions raised by the NRC during a telephone conference call on March 23, 1995.      These questions concern the analysis by Omaha Public Power          l District (0 PPD) of postulated toxic gas releases associated with ooeration of the cargill facility.
Attachment 1 of this letter contains the OPPD responses to the NRC questions.
Attachment 2 is a copy of a data source referenced in the responses. Please contact me if you have any questions.
Sincerely,
;    T. L. Patterson Division Manager Nuclear Operations TLP/tcm Attachments c:     LeBoeuf, Lamb, Greene & MacRae (w/o attachments)
L. J. Callan, NRC Regional Administrator, Region IV (w/o attachments)
S. D. Bloom, NRC Project Manager R. P. Mullikin, NRC Senior Resident Inspector (w/o attachments) 4 0 0$()                                                        l 9504180178 950405                                                                 ii PDR    ADOCK 05000285                                                                  }
p                   PDR                                                              ;

I LIC-95-0079 Attachment 1                                                                        l Page 1                                                                              l l                              Omaha Public Power District                            i Fort Calhoun Station Responses to NRC Requests for Additional Information                ,
NRC Ouestion 1-                                                                     i In your submittal related to the revision of control room habitability at the Fort  l Calhoun. plant, you indicated that there will be at least two minutes between the   '
time that the toxic gas is detectable by, smell by the operating crew and the time that toxic limit is reached. In order to determine this time interval, both these   ;
limiting values have to be known. For the upper limit you assumed the values from l Regulatory Guide 1.78 or IDLH values. What are the values assumed for detection.
by smell? Provide these values with references for the toxic chemical considered in your analysis.
1 OPPD Response:
For the Fort Calhoun Station control room habitability analysis, all of the odor -
threshold values of toxic chemicals assumed for detection by smell were derived from the paper "0 dor as an Aid to Chemical Safety: Odor Thresholds Compared with Threshold Limit Values and Volatilities for 214 Industrial Chemicals in Air and Water Dilution," Journal of Applied Toxicology, Vol. 3, No. 6,1983, pp. 272-290.
The following table provides the odor threshold values used in the Fort Calhoun     j Station analysis for the toxic chemicals considered.                                i Substance                 Air Odor Threshold foom: v/v or ul/1.) for aaseous olumes i in air Ammonia                   5.2                                                       j Carbon Dioxide            74,000*
Ethyl Alcohol             84 Hydrogen Chloride         0.77 Sulfur Dioxide             1.1 Gasoline                  2.7
  *The sensory detection level for carbon dioxide is several orders of magnitude greater than the toxic level thus the IDLH value of 10,000 ppm was used as the sensory level. Thus, there was no interval of time available between the sensory' value and reaching the IDLH value.

i I
LIC-95-0079
        ' Attachment 1 Page 2' From. Telephone Conference Call on March 23, 1995 NRC Ouestion 2:
l                                                                                     .              .
What period of time does the meteorological data provided in the submittal
.        . reflect, and what was the recovery rate for that period of time.                                  ;
        - OPPD Response:
                                                                                                             )
5         The meteorological data used for the Fort Calhoun Nuclear St'ation was obtained 'in a pre-processed form for the period from January 1, 1982 to December 31, 1991, and
;         is included in the plant IPEEE. The reported data was for'a tower elevation of'                    )
i         10 meters. In performing the modelling for the Cargill chemicals, the-average                      l I         wind speed for each ' stability class was used.         This methodology does not account' L         for certain conditions with very low wind speeds.                  Although it would .take an f         infinite. time, under very low : wind speeds the plume will reach the plant
;         regardless of stability class.               However, we are also conservatively including conditions in the final probability where the wind speed is higher than average-
:         and, consequently, the plant would not be impacted. The use of average wind speeds is consistent with the approach used in the rest of the analysis.
l         The meteorological data used was submitted to the NRC as part of the Semi-Annual
:         Radioactive Effluent Release Reports for the specified period. This information J-        was included per Regulatory Guide 1.21 as the " Joint Frequency Distribution Wind Direction vs. Wind Speed by Stability Class and MeteorologycData per Batch 1-        Release."    Regulatory Guide 1.21 requires that recovery-of ~ synthetic and actual i         data be a minimum of 90 percent per year. For those periods which did not meet i         that requirement, an explanation was provided in the appropriate semi-annual submittal.
NRC Ouestion 3:                                                                                    ;
:                                                                                                            i i         Provide the reference material for the failure rates and probability of scenario l         (maximum concentration or maximum duration accident).
1 j         OPPD Resoonse:
The failure rates for pressurized or single wall tanks were obtained from the
;         Handbook of Chemical Hazard Analysis Procedures (p. 11-36 of Attachment 2),
I         published by the Federal Emergency Management Agency (FEMA), the U. S. Department J         of Transportation (DOT), and the U. S. Environmental Protection Agency (EPA). In 4
accordance with . Regulatory' Guide 1.78, OPPD modelled a maximum concentration a         scenario and a maximum duration scenario. In the IPEEE for Fort Calhoun Station, the maximum concentration scenario is defined as a' catastrophic failure while the-maximum duration scenario is defined as a release' from a 2-inch orifice 'in the vessel. The FEMA / DOT / EPA document cites a tank failure rate of IE-04, with 10%
)         being instantaneous releases (maximum concentration) and 90% being releases ~from
'         1 inch orifices (maximum duration). Therefore, the chosen approach of using a'2-inch orifice for the maximum duration scenario is conservative.
i i   1

LIC-95-0079 Attachment 2 Handbook of Chemical Hazard Analysis Procedures t
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                                                                                                                                                                                                                                                                               .a._

FOREWORD Introduction The Federal Government has a long record of concem about hazardous materials and their potential impact on people and the environment. Over the years, several Federal agencies have pmvided training, technical assistance and guidance to State and local governments and industry in planning and response to emergencies involving hazardous materials. For example, the Federal Emergency Management Agency (FEMA) published the Planning                             I Guide and Checklist for Hazardous Materials Contingency Plans (FEMA-10) in 1981 to assist communities developing emergency response plans. The Department of Transporta-tion (DOT) has published several editions of the Emergency Response Guidebook to serve as          '
guidance for initial action to be taken by fire fighters, police, and emergency services personnel at the scene of transportation incidents involving hazardous materials. In 1985, the Environmental Protection Agency (EPA) published Chemical Emergency Preparedness Program (CEPP) Interim Guidance to provide technical assistance for a voluntary program focusing on airborne toxic chemicals under EPA's National Strategy for Toxic Air Pollutants.
l Government-wide guidance on emergency planning for hazardous material was introduced in 1987 after the passage of Title III of the Superfund Amendments and Reauthorization Act (SARA) with the publication of the National Response Team's Hazardous Materials Emergency Planning Guide (NRT-1). TW ctfort to coordinate Federal planning processes l
l conceming specific hazardous materials addressed by SARA was followed with the joint publication by EPA, FEMA and DOT of Techrdcal Guidancefor Hazards Analysis.
l       Handbook of Chemical Hazards Analysis Dr<>cedures This Handbook ofChemical Hazard Analysis Procedures has several objectives one of which is to expand NRT-1 and the Technical Guidance on Hazards Analysis document bv including information for explosive, flammable, reactive and otherwise dangerous chemicals. Al-though NRT-1 was aimed at addressing planning for all types of hazardous materials, SARA                 ;
Title III required local planners to focus on a specific initial list of acutely toxic chemicals         l (referred to as Extremely Hazardous Substances) due to their high inhalation toxicity when airborne, and this was the primary focus of the supplemental guidance document. By
)         introducing additional methodologies on how to plan for these and other dangerous chemicals, this handbook serves as a stepping stone from NRT-1 and the Technical Guidance on Hazards Analysis to a more comprehensive approach for emergency planning. If deemed necessary and appropriate by the National Response Team after distribution and field use of this handbook by emergency planning personnel, a further enhanced hazard analysis guide may be prepared in the future.
Because this handbook provides methods to investigate local hazards in greater detail than i          permitted by earlier guidance, results of calculations using air dispersion models may differ.
The Federal Govemment is continuing to evaluate these types of models and others to determine the degree of impact on calculations conceming the consequences of a chemical O
V release. For these reasons and because this handbook requires use of the accompanying software for full utilization, users should carefully assess accident scenarios selected for evaluation to ensure that computational procedures are appropriate for the chemical being l

i e
f studied. Difficulties encountered and suggestions or comments (both positive and nega        (.
should be submitted to DOT, FEMA, and/or the EPA. Be advised that workshops are b
  -          planned by these Agencies during 1989 to address comments, gather input on the handbook and the related software, and explain their functions. Similarly, DOT, FEMA and EPA are interested in receiving information on problems and experiences associated with use of the Technical Guidance on Hazards Analysis document and NRT-1.
Beyond providing additional methodologies for assessing the potential impacts of hazardous material releases, this handbook also expands the three-step hazards analysis approach (hazard identification, vulnerability analysis, and risk analysis) presented in NRT-1 and its supplement by introducing a four-step approach involving hazard identification, conseque analysis, probability analysis, and risk analysis. In addition, it provides a tutorial on i           hazardous chemicals, suggestions for applying hazard analysis results to writing and an emergency plan, and an expanded discussion of issues relating to sheltering-in-place (in-place protection) and evacuation. Because additional projects are underway concern-Ing these and other topics described in Chapter 14 and Appendix C of the handbook, sponsoring agencies are especially interested in comments on these sections. The workshops mentioned above will provide an opportunity for discussion and comment.
General comments on the handbook, its associated computer program named ARCHIE, and earlier planning aids are highly encouraged and may also be submitted in writing to:
Federal Emergency Management Agency Technological Hazards Division                                     J Federal Center Plaza 500 C Street, S.W.
Washington,DC 20472 U.S. Department of Transportation Research and Special Programs Administration                                l j
Office of Hazardous Materials Transportation DHM-50,400 7th Street, S.W.
Washington,DC 20590 U.S. Environmental Protection Agency Chemical Emergency Preparedness and Prevention Office
!                                           401 M Street, S.W., OS-120 Washington,DC 20460 i
l Alternatively, input to these agencies may be transmitted via use of the Hazardous Mate Information Exchange (HMIX) computerized bulletin board system operated and maintain by FEMA and the DOT. HMIX includes a Conference dedicated to ARCHIE where user may leave messages, questions or comments relating to the program or handbook, e viewpoints,    and receive responses to inquiries. HMIX may be accessed by modem and commercial phone line at:
(312) 972-3275

l
        ' An HMIX users manual and technical assistance can be obtained by calling:
                                           .1-800-PLAN-FOR Nationwide i
#                                                              or a
'.                                                 1-800-367-9592 in Illinois a
;         If you are unable to access HMIX to submit comments or questions relating specif the computer program, please send them in writing to:
ARCHIE Support (DHM-51/ Room 8104)
Office of Hazardous Materials Transportation i
Research and Special Programs Administration
;                                           U.S. Department'of Transportation 400 7th Street, S.W.
J
                                                   . Washington,D.C. 20590 4
Additional copies of this handbook maybe obtained by writing to:
Federal Emergency Management ' Agency Publications Office
,                                                       500 C Street, S.W.
ll Washington,D.C. 20472 i
l i
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1 J
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11.0 PROBABILITY ANALYSIS PROCEDURES y
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4        

==11.1 INTRODUCTION==

 /   t' The transportation and use of hazardous materials poses threats that are of concem to I             society, but which are not always fully understood in terms of their likelihood of occurrence 9              or viewed in perspective with regard to their relation to other threats. 'Ihe purpose of this chapter is to provide emergency planning personnel with the basic information, data, and t
procedures necessary to refine and evaluate individual hazardous material accident scenarios
     !        in terms of their annual probability or frequency of occurrence on at least an order of
 ;            magnitude basis, f"
As noted earlier in Chapter 9, this probability analysis step may be considered optional where community leaders (or individual facility operators) wish to prepare for every conceivable accident regardless ofits likelihood of occurrence and have the time, manpow-er, and resources to achieve their goals. More often than not, however, these individuals will find that time and resources are limited and that other threats or needs compete for attention, j
Prioritization of potential accidents in terms of annual probability as well as severity will permit attention to these threats (and it is eventually hoped all threats to public health and 9            safety) in a logical and orderly fashion and thereby reduce the chance that time and resources will be expended on emergency scenarios of exceedingly low credibility or significance.
Note, however, that assessment of hazardous material accidents or any other threats on a probabilitistic basis does not guarantee that all such hazards will be identified or that less likely events will not occur.
The chapter addresses seven prinuuy activities associated with hazardous materials, each with the potential to result in public emergencies. These include:
Bulk transponation by truck Bulk tmnsportation by rail Bulk transportation by barge or other marine vessel Transportation by pipeline Bulk storage, processing, or handling at fixed facilities Transportation of packages Transportation by air The overall approach presented in this chapter involves use of average national accident rates determined from historical records and relevant exposure data. While such rates may overestimate or underestimate average annual accident probabilities for any specific facility or transportation activity, they are not expected to be vastly in error in g           aggregate for any jurisdiction or facility. The ultimate goal, after all,is not exact estimation y
of accident probabilities, but their approximation at a level of accuracy sufficient for

1 I
emergency planning purposes. Appendix F to this guide presents the basis and rationale for the recommendations and procedures that follow, and additionally, discusses the use oflocal         j and other data and infonnation (where available) to further refine estimates where this may be desireable.
The actual computation of the annual accident probability associated with any specific activity involves using the frequency with which such accidents are known to occur in combination with a measure of the " exposure" of the community or otherjurisdiction to the          ;
potentially hazardous activity. For most transportation modes, for example, historical accident rates are presented in tenns of the number of accidents expected per mile of travel and exposures are expressed in terms of the number of trips made per year and the mileage of routes within the locality. Simple multiplication of these values provides the expected number of accidents per year involving the activity being considered. Further multiplication of this result by such factors as the fraction of accidents that result in loss of cargo to the environment and the fraction of accidents that result in a prespecified amount of cargo loss permits greater specificity in predictions. Worksheets for each activity facilitate computa-tions, and are provided in lieu of tabulated or generalized categorizations of accident             ;
probabilities to provide planning personnel with the option of using local data for greater accuracy. Planning personnel may use the predicted accident frequencies to determine an                 l appropriate " accident probability category" during the risk analysis step described in Chapter         l 13 of this guide.
An important point to be made is that the analysis methods presented herein provide              l their users with the annual accident probability expected for the entire area of concern and            l not for specific locations or subregions within the locality. Should it be desired to determine the probability of a release near a specific populated area, a specific body of water, or a specific environmentally sensitive habitat, it will be necessary for users to determine that fraction of the overall community or facility exposure associated with this special area and to adjust overall accident frequency predictions in an appropriate fashion.
Speci:1 Notes Wherever the term " spill" is used in the discussions that follow, readers are advised to interpret the term as referring to any release or discharge of a hazardous material in a manner capable of posing a threat to the public or the environment.
The procedures that follow permit the user to estimate the number of " spills / year" expected on average from individual activities or operations involving hazardous materials.
The average rebecurrence interval for a specific spill scenario can be determined by dividing the number "1.0" by the predicted frequency of spills per year. Thus, a spill frequency of 2 x 102 spills per year can be translated to mean that a spill can be expected to occur once every O
11-2

Iio                                                                                                                       ;
! 'I j.
i i!
i-
!         50 years on average. Where desired, readers may also sum the spill frequencies derived for                      i iI                                                                                                                        !
similar individual activities and then determine the reoccurrence interval associated with the ff        combination using the same methodology.
3                Thmughout this chapter, historical accident rates and other data are frequently                          ;
i                                                                                                                         '
presented in " scientific notation". Readers unfamilar with this method of representing very small (or very large) numbers are referred to Appendix A for guidance.
11.2 GENERAL SEVERITY OF ACCIDENTS CONSIDERED                                                                   h l                The types of accident scenarios that could theoretically be covered in this chapter range                j i         fmm minor spills of gasoline at service stations to major catastrophes that occur once every j          10 or 20 years on average on a worldwide basis. The primary focus, however, is somewhere j         between these extremes, and on the types of events which occur somewhere in the United i         States every week or month, but for which the risks to any one specific community might be .
)         low but nevertheless significant. In other words, we are not highly concerned with routine l         and common spills and discharges of relatively minor significance. Nor are we overly                            ,
j         concemed with extremely rare events.                                                                            ,
1 i                For a general perspective on hazardous materials accidents, consider that there are i
many thousands of hazardous materials releases which occur each year in transportation and                      ;
j    W    at fixed facilities, yet the vast majority arc of very limited consequence. Tables 11.1 to 11.3 j         give some idea of the total numbers of accidents reported each year and the relative
!        contribution made by various activities. More specifically, Table 11.1 addresses the number l        of evacuations in recent years that were of sufficient magnitude to warrant reporting. Table i
11.2 provides an estimate of the total number of accidents over a ten year period involving
!        hazardous material releases from transportation activities, while Table 11.3 focuses on major l        events by type of activity. Although the data presented in the latter table are somewhat
!        dated, they are nevertheless sufficient to demonstrate that only a small fraction of all j        accidents result in major consequences.
1 113 BULK TRANSPORTATION OF HA7ARDOUS MATERIALS BY HIGHWAY Bulk transportation of hazardous materials by highway involves the use of tank trucks j        or trailen and certain types of more specialized bulk cargo vehicles. In all, trucks transport j        more than sixty percent of the hazardous materials not carried by pipelines, with just under
[        fifty percent of this material being gasoline (OTA, July 1986). Average trip lengths are 28 l        miles for gasoline trucks and 260 miles for chemical trucks, implying that most gasoline
{'       shipments are very localized while chemical shipments may be regional or interstate. Since j        trucks carry hazanious materials the greatest number of miles near populated areas, and are j        also responsible for the largest number of shipments, it is not surprising that this mode of i
     }   transportation is also responsible for the greatest number of accidents.
j.-
j'                                                          11-3 L
^

4 TABLE 11.1 CHEMICAL ACCIDENTS REQUIRING EVACUATIONS Type of Accident              1980-1984        1984 Train derailment                               55             8 l
Railcar spill / fire                           23             5 Truck accident                                 35             5                 j Tnick spill / fire                             32             7 Chemical plant release                         43             5 Industrial plant release                      78             24                 )
.                                Pipeline                                       4             0                  j Ship incident                                  4
;                                                                                              1
                                                                                                                 )
'                                                                                                                l Waste site accident                            7              1 Other*                                         14             1 TOTAL                                         295            57
* Includes helicopter crash, plane crash, sewer gas episode, oil well explosion, swimming pool chlorine accident, pesticide spill in retail store, mine fire, two military missile silo accidents,
.           and two electrical transformer leaks.
l-                                                                                                               :
Source:                  Sorensen,1986 l
l TABLE 11.2 HAZARDOUS MATERIALTRANSPORTATION ACCIDENTS
.                                                     Number of Accidents
!                                    Mode                 Per Year              19731983 Average 2 Highway               10,000 - 15,000               10,289 Rail                       1,000                     975 5
Air                         200                      150 4
Water                        20                       26 Source:               iMaterials Transportation Bureau,1983 and Cheok et al,1985 j                               2OTA, March,1986
.                                                                    11-4 i

l
.)
TABLE 11.3 MAJOR HAZARDOUS MATERIALS ACCIDENTS
* Activity                 1964-1973 1953-1973 Chemical plants                              6         12 Oil refineries and storage                  10         13 Gas storage tanks                            1         2 Oil drilling rigs                            2         2 Pipelines                                    1         1 Fireworks plants                            0         2 Marine tankers, barges                      8         15 Railroad tank cars                          5         8 j                Trucks                                       3         8 TOTAL                                       36        63
  .
* 10 or more fatalities, 30 or more injuries, $3,000,000 or more in propeny damage Source:      Office of Radiation Programs,1980 f
4 0
4 11-5

N Tank trucks are usually tractor-semitrailer vehicles or smaller bobtail-type units. The tanks themselves are usually constmeted of steel or an aluminum alloy, but may also be stainless steel, nickel and other materials. Capacities are usually in the range of 3000-10,000 gallons, although slightly smaller and larger units are available. Intermodal tanks which consist of a tank within a protective rigid framework, one-ton tanks which are lifted on and off the transporting vehicle, and large gas cylinder bundles are also commonly used for bulk transport by highway.
Commodity breakdowns for trucks, as described in various data sources are not               I considered very accurate and vary widely. However, a one-month survey of cargoes in
; Virginia found a fairly close match (by percentage) to the average distribution of commodi-ties involved in accidents. The comparison for commodities involved in accidents in Virginia also matched national accident breakdowns fairly well (Urbanek and Barber,1980).
National involvement in accidents by type of commodity for the time period July                     l 1973-December 1978 was:                                                                             l Flammableliquids                          60.5 %
Combustible liquids                       16.3 %
Corrosives                                11.6 %
Flammable compressed gases                 3.2%
Oxidizers                                  2.1%
Poisons (liquid or solid)                  2.1%
Nonflammable compressed gases              1.9%
i Explosives                                 1.5%                                 !
Radioactive materials                      0.5%                                 l Fhnauable solids                           0.3%
l
;         Causes and En.nples ofPast Accidents Tmck accidents on roadways, regardless of the cargo involved, are generally due to:
Collisions with other vehicles Collisions with fixed objects such as bridges or overpass supports
* Running off the road Overrums due to excessive speed on curves These four events are most likely to result in a release of large quantities of hazardous materials, and are predominantly the result of human ermr. Smaller releases may arise due to defective or loose valves, fittings or couplings; weld failures; and various other structural    .
defects. (Note: Loading or unloading spills are considered separately in the category offb:ed facilities below and actually result in the majority of overall releases involving trucks.)
O 11-6

l l
:                                                                                                                                          1 i
The severity and consequences of discharges resulting from truck accidents can vary l           widely. Some examples include:
A tank truck carrying 11,000 gallons of gasoline blew a tire, struck a cement barrier which ripped open the side of the tank, and then burst into flames on Interstate 95 near Peabody, Massachusetts. State troopers closed down the highway while an emergency crew from Logan Intemational' Airport spread foam on the wreckage. The highway remained partially closed for several days, since one section had melted and needed to be replaced. 'Ihere were no injuries or deaths. (December 3,1985)
Littleton, New Hampshire, was spared a potentially catastrophic accident '
when a tank trailer loaded with 9,200 gallons ofliquefied propane jack-knifed
                        . on an icy hill and tipped on its side about 75 yards from a large storage tank of liquid propane and less than 100 yards frorn large fuel oil storage tanks.
No propane leaked from the truck, but a diesel fuel tank was ruptured: 1500 people residing within a half mile radius were evacuated until the propane was safely transferred to another vehicle the next day. (February 11,1982)
A truck pulling two tank trailers loaded with molten sulphur collided with a highway barrier on a toll bridge and burst into flames taking two lives and injuring twenty-six. Firemen encountered difficulty extinguishing the fire and rescuing victims. Visibility at the time was poor due to fog and the spilled sulfur had burned through water supply lines. (January 19,1986)
In Houston, a tank truck carrying liquefied anhydrous ammonia collided with l
'                        a car and fell from an elevated highway to a busy freeway. The truck exploded violently on impact releasing billowing clouds of ammonia. Four i
persons (including the truck driver) were killed, dozens of motorists were overcome by the fumes in a three-mile area, and at least 100 were treated at
'                        area hospitals. The vapors and fumes were so thick that police helicopters were initially repelled. 'Ihe city was forced to use all available ambulances and privately-owned hearses to transport the injured. (May 12,1976) l Although certain details are unclear, a tank truck carrying liquid propylene                                        ;
sprang a leak in the vicinity of a crowded campsite in Spain. Flammable                                             i gases spread from the truck, encountered a source ofignition, flashed back to-.                                     l
[                        the vehicle, and caused a BLEVE with a large fireball. The death toll from l                        burns was approximately 170. Numerous other people suffered moderate to                                             l severe burns but otherwise survived. (July 11,1978)
{l i                                                             11-7

Suggested Approach for Assessment ofAccident Potential Since we are concerned with accidents with the potential to cause major problems for a community or other jurisdiction and not those which are handled on a routine basis, it is best to focus on vehicular accidents rather than relatively minor leaks from valves, fittings, or open relief valves. Based on the information discussed in Appendix F, an average accident rate of 2 x 104 accidents / mile is considered representative of the general experience of trucks carrying bulk quantities of hazardous materials. If adequate local / state data are available for determination of individual accident rates for divided and undivided roadways, their use is recommended because the resulting rates will more accurately reflect accident probabilities underlocal conditions.
1 With respect to the fraction of truck accidents that result in a spill or discharge, the      j, available data suggest a consensus opinion on the order of 0.50 (50%) if all spills including          ;;
very minor valve and fitting leaks are considered. Omitting these, a spill appears to result from an accident in about C.15 - 0.20 (15% - 20%) of accidents. A value of 0.20 (20%) is therefore adopted for use for the sake of conservatism.
                                                                                                       ,j i   i Based upon available spill size distributions, and considering the likely causes of accidents, the following distribution is suggested for general use:                                        j
      .       10% cargo loss (thru 1" hole) or 1000 gal --- 60% of the time 9l;!I    l
      .       30% cargo loss (thru 2" hole) or 3000 gal --- 20% of the time                               .I
      -       100% cargo loss (instantly) or 10,000 gal --- 20% of the time                               !l
                                                                                                         !l These values cover the range of significant releases. If desired, a two point distribution               !I assuming that 3000-gallon spills occur 80% of the time and 10,000-gallon spills occur 20%               l of the time may be used to simplify consequence analysis procedures.
The suggested accident rates and other factors for truck accidents are summarized in Table 11.4. Worksheet 11.1 presents a simplified format for computing the annual average               j, probabilities of truck accidents resulting in spills of various amounts. A copy of the worksheet should be completed for each hazanlous material transported in bulk by truck within or through the community, or (if desired) groups of chemicals or materials posing similar threats in the event of a release may be analyzed together. Localinformation needed for the task includes:
Material (s) of concern
        -      Annual number of sh:pments
        -      Total capacity per shipment 11-8

.                                                                                                       i 1
,                                                                                                       i t
i TABLE 11.4 SUGGESTED FIGURES FOR TRUCK TRANSPORTATION Accident Rate:                               2 x 104 accidents / mile 1
Conditional Spill Probability                0.2 for significant spills                              i Spill Size Distribution:                     0.60 for 10% loss of cargo through 1" hole, or 1,000    j
;                                                gal                                                    i I
l                                               0.20 for 30% of cargo through 2" hole, or 3,000 gal O.20 for 100% of cargo, or 10,000 gal 4
Note:     Worksheet 11.1 demonstrates how these figures can be used to estimate annual accident probabilities and associated spill volumes for truck transportation.
J I
d h
a x
4 4
11-9

i WORKSHEET 11.1 ESTIMATING BULK TRUCK TRANSPORTATION RELEASE FREQUENCIES Hazardous Material (s):
Total Number of Annual Shipments:                A=                                                                                                                                      l (loaded trucks only)
L Length of Route of Concern:                      B=
(miles withinjurisdiction) l Total Number of Miles Per Year *:                C=AxB=
l Accident Frequency:                   D = C x 2 x 104 =                                                                                             (accidents / year)
I Spill Frequency:                                 E = D x 0.2 =                                                                                                 (spills / year)
Spills by Size +
l        10% loss of cargo (1" hole) or 1,000 gal:              Ex0.6=                                                                                                 (spills / year) 30% loss of cargo (2" hole) or 3,000 gal:                Ex0.2=                                                                                                (spills / year) 100% loss of cargo or 10,000 gal:                       Ex0.2=                                                                                                (spills / year)
Notes:
l         *If there are a number of different routes with varying numbers of shipments, multiply the i         number of shipments by the route length for each route individually and then sum. For example,100 shipments of 15 miles and 50 shipments of 7 miles would give (100 x 15) +
l         (50 x 7) = 1850 total miles.
          + The user may consider all three scenarios for consequence modelling and planning j         purposes orjust the largest spill.
9 l
11-10 l

!\                                                                                                                              ,
4 - p;
; i                .
Totallength of route within community                                                                  I
!l j               .
Type of roadways travelled (if specific rates by type of highway are available)
I
!             Note that it may be necessary in some cases to combine the number of shipments with the
!             length of route within the community to compute total mileage because there may be several l.
routes for the same material. A prime example is for gasoline which may be delivered to 4
several locations within any community orjurisdiction as well as driven through the locality.
j             Worksheet 11.1 provides further information on how this may be accomplished.                                      '
l                    AdditionalData/ Methodologies j                    Should more precise methodologies be desired or should special circumstances warrant j             attention, the reader can consider one of the techniques listed below. First efforts should be j             directed at obtaining more precise data either on a local, county, state or regional basis. The j             data specific to one carrier should not be broadly applied, however, as there can be major differences between carriers - even when they operate in the same area. His may occur due
!             to differences in truck design and upkeep, characteristics of the cargo, training of the drivers, enforcement of speed restrictions, and other factors.
l l[                   More detailed methodologies which take into account specific accident situations l             include:
!                 +                                                                                                             l Separate models to predict accidents on interstates, rural highways or urban 3                        arterials as a function of several input variables (Urbanek and Barber,' 1980).
                  =
Analyses of rail / highway grade crossing accidents (National Transportation
;                       Safety Board,1981). Note: There are only 60 or so of these each year, j                       nationwide, on average. Dey usually involve trucks carrying petroleum products and occur close to distribution / storage terminals, with very localized
;                       impacts.
1
                  +
l                       Breakdowns of rates by rural, urban, suburban and number of lanes (Smith l                       and Wilmot,1982).
j                       Risk assessments of transportation through tunnels (Considine,1986).                                    i
: j.
* Detailed considerations of the severities of various types of accidents for particular vehicle configurations (Clarke et al,1976).
l 4
i 11-11 I
i 4

Use ofResults in Consequence Analysis Each of the three accident scenarios denoted and evaluated above actually provides the user with two options, the first being assumption of a certain percentage of cargo loss through an orifice of a given size, and the second being assumption of a specific total amount of cargo loss. For example,in the first scenario considered, the user can assume that 10% of the total cargo of the vehicle is discharged through a hole having a diameter of one inch, or altematively, simply assume that 1000 gallons of presumably liquid cargo are released before the discharge is terminated for one reason or another under average accident conditions.
These results are based on generalized historical records of past accidents and provide one way in which the ultimate consequences of an incident can be evaluated by use of the analysis procedures discussed in Chapter 12 of this guide. Conversely, depending upon the type of hazardous materialinvolved and the desires of the user, these scenarios can be further refined for consequence analysis purposes, taking better advantage of locally available information.
Where the user wishes to assume a fixed percentage of cargo loss (this requiring knowledge of total cargo amounts) or a fixed amount of spillage for liquid cargos, the spill can be assumed to take place instantaneously, thus obviating need for use of discharge rate and duration estimation methods discussed in Chapter 12 and available in the computer program provided with this guide. It is cautioned, however, that the assumption of an instantaneous release in such situations may greatly overestimate resulting hazard zones from evolution of toxic or flammable vapors, fires, or explosions. Spill amounts presented in units of gallons of liquid can be converted to the units of pounds required by the computer j  program by use of the following expression:
I Amount in pounds = 8.34 x Amount in gallons x Liquid specific gravity Where a hole size is specified and cargo tank or compartment dimensions are known, it is alternatively possible (and recommended) to utilize available discharge rate and duration estimation procedures to obtain an ultimately more realistic indication of accident conse-quences. This is particularly advisable when the cargo is a compressed gas, a liquefied compressed gas, or an otherwise highly volatile material. The suggested percentage of cargo loss, when less than 100%, can be ignored,if necessary, in deference to the results obtained from the discharge models. (This is due to the fact that the aazard zone will be primarily determined by the release rate and the first ten or so minutes of the release; the ultimate release quantity is less significant.)
O 11-12 4

,y,,      . .
       'I g
j      11.4 BULK TRANSPORTATION HA ZARDOUS MATERIAIS BY RAIL 9
According to recent statistics, about 80 million tons of hazardous materials are shipped f       annually by rail in the U.S. (OTA, March 1986). The majority of these shipments are in a
[       single tank permanently mounted on a rail car. Exceptions include multi-tank tank cars (the units are usually ton containers), seamless steel cylinders (as for very high pressure service),
l i       and compartmented tank cars in which each compartment is treated as a separate tank. The j       sizes of these will range from a few hundred gallons in the case of a ton container to 45,000
     ;        gallons in so-called jumbo tank cars. Since 1970, however, the capacity of new tank cars has
     !        been limited to 34,500 gallon;,. 'fhere is abo occasional use of intermodal tanks, as
[           mentioned under truck transportation.
:i i                  The design, construction, inspec'. ion, ad ise of tank cars are regulated by both the l'         American Association of Railroads (AAR) .*d the Federal Railroad Administration (FRA) within the U.S. Department of Transponad u (USDOT). Carbon steel is used to constmet over 90% of the tanks, with aluminum for moc but not all of the remainder. Nickel or nickel l
   ;          alloy is found in acid service, and there are a small number of stainless steel cars (Wright and i          Student,1985). Safety relief valves (and vems) are required, unless otherwise specified.
j         Cars are usually classified into the categories of pressure tank cars, non-pressure tank cars, l          cryogenic liquid tank cars, and miscellaneous tank cars. Tanks may be lined, insulated, and
   ,          possibly fitted with heating coils. Some may have special thermal protection to prevent BLEVEs or other explosions in the event of exposures to pool fires or flame jets. Relatively recent regulathns have required shelf couplers - which limit potential for the puncturing adjacent cars in the event of a derailment or collision - for all new and old cars. Cars l
carrying liqut fied flammable gases or ammonia have been required to have head shields to further limit p.meture potential, and new housings for bottom outlets have also been adopted.
It has been estimated that 35% of all freight trains carry hazardous materials, but that only 7.5% of railroad accidents involve trains carrying these materials (von Herberg,1979).
This fipre corresponds to the percentage of all cars which carry chemicals and allied products or petroleum products versus the total number of cars on an annual basis (AAR, 1985).
A fairly extensive data base on commodity flows is available for railroads. The July 1986 OTA report provides the following breakdown on a tonnage basis:
Flammable liquids                          26%
Corrosive materials                        25 %
Combustible liquids /
nonflammable compressed gases            22% (less than 12% each)
Flammable compressed gases                  12 %
11-13

Poison B Poison A 3%
0.1%
9ll Radioactive materials                      0.03 %
Detailed breakdowns by state, ralhoad company, and other divisions are also available from various sources described in the OTA report.
Data on rail yards shows that the number of hazanlous me.terials cars handled by each ranges fmm 1-15 percent of the total throughput (Chemical and Engineering News, July 29, 1985). In one study, based on data through 1977,it was found that 36% of derailments and 73% of collisions occurred in such yards (Nayak et al,1983).
Causes and Examples ofPast Accidents i
For releases of hazardous materials from rail accidents, there are two types of events of concem. The most important for this analysis is the accident that involves a collision or a derailment, since these typically involve the largest spills or discharges. However, there is a second class of releases which may arise from fitting or seal leaks, relief valve leaks, and other releases associated with improper tightening of closures or defective equipment.
Harvey et al (1987) estimate that these account for 70% of the roughly 1000 releases each year. Rail accidents, like those for trucks, can result in virtually no adverse consequences up i
to very large losses of life, depending on the materials involved and the circumstances of the accident. Many of the more severe accidents occur in yards and on sidings (Wolfe,1984).
l  As for truck transportation, incidents arising during loading or unloading operations are j
addressed under fixed facilities.
AAR data (Wolfe,1984) showed that the materials most often involved in accidents with more than $100,000 of damage in 1981 were:
        . LPG                                                                                     I
        -     Acrylonitrile a     Fuel oil
        -     Vinyl chloride
        . Anhydrous ammonia The same source found that there were less than 30 accidents each year with this level of damage.
Examples of past accidents involving the rail transportation of hazanlous materials are given below. These particular incidents include some of the most severti that have occurred in recent times.
1 O
d 11-14

u 3,
a I
t                    In Waverly, Tennessee the derailment of two propane cars was treated l                      casually as crews worked to clear the track and right the cars. As this was
              }
              ~
being done, some 40 hours after the derailment, propane began lea one car, reached a source of ignition, flashed back to the car, and caused an
             ;                      explosion and fireball. He town center looked like a battle scene after the i                       explosion with 16 dead, 54 requiring hospitalization for burns, and 42 i                       requiring outpatient care. (February 24,1978)
Over 240,000 people were evacuated for all or part of a week in Mis Canada after a derailment involving 11 propane cars,1 chlorine car and cars loaded with other chemicals. The wreckage produced a series of explosions, launched missiles more than half a mile, and prompted fears massive chlorine release. No fatalities or major injuries occurred partly d to the quick accident response of authorities, a welly executed emergen evacuation plan, and various fortuitous circumstances. (November 10,19 4
A white cloud of toxic smoke towered a thousand feet over the comm Miamisburg, Ohio and covered an area about a mile wide and 10-15 mi long at one point after a derailment caused a car containing white ph
[;                       to fail and ignite. The intense heat and difficulties in     re controlling the fi forced authorities to wait four days for the blaze to burn itself out Eleven persons were hospitalized after exposure to the toxic smoke, with a total of 273 being treated for skin, eye, and lung irritations. The 40,000 (or
[                           U.S. (July 8,1986) evacuees were the largest number ever resulting fm Suggested Approach for Assessment ofAccident Potential j
104 per train mile be used for mainline                       -
x track. To c as s, it is assumed that 0.20 (20%) of the cars will be damagedaain an accident (b presented about   6 x 10'per in  Nayak,1979). The overall rate therefore becomes 0.2 x 3 x 1 car-mile.
and a 20% damage estimate to obtain about 3 x 1                           -
ngs e
with mainline and yard track.also pose a risk, but these                             risks are co mainline and yard accidents, as no data are availa events.
e 11-15
\

With respect to the distributions of spill amounts in accidents, the available data suggest use of:
        .      3,000 gallons or 10% of cargo (thru 2" hole)- 50% of the time
        .      10,000 gallons or 30% of cargo (thru 2" hole) - 20% of the time
        -      30,000 gallons or 100% loss of cargo - 30% of the time The higher weighting of the last category partially accounts for the potential for more than one car to release part of its contents in an accident.
Table 11.5 summarizes the accident rates and other factors suggested for use, while Worksheet 11.2 outlines the procedure for determining the annual average probability of an f  accident involving spills of various amounts. A copy of the worksheet should be completed i
for each hazardous material transported in bulk by rail within or tlarough the community. (As
. for trucks, groups of chemicals posing similar hazards may be considered together.) Local
;  information that will be required to accomplish the effort includes:
Material (s) of concern
        .      Annual number of cars
        .      Total capacity per car
        .      Total miles of mainline track within community l       -      Total miles of yard track travelled by a typical car Railcar trips and associated mileage involving loaded vehicles are of primary concem as i  these pose the greatest risk. Nevertheless, it is important to realize that the residual materials within tank vehicles considered " empty" can also pose a hazard under certain circumstances.
If local data on accident rates or spill frequencies are available, they can be directly substituted for the rates and other factors listed in Table 11.5.
AdditionalData/ Methodologies 4
l           Should a more detailed evaluation be desired or required, readers can consider use one j   of the techniques listed below. However, any effort to improve the specificity of accident predictions should probably first involve the determination and use of individual state or railroad company accident rates for specific routes.
More detailed evaluations of rail transportation can also include consideration of several different factors (alone or in combination) in the analysis. Examples of these include:
          . Detailed review of accident severity to determine the overall likelihood of puncture, crush, impact and fire scenarios (Clarke et al,1976)
O 11-16

j i
         \                                            TABLE 11.5 SUGGESTED FIGURES FOR RAIL TRANSPORTATION Mainline accident:
6 x 10Vcar-mile Yard accident ate:
3 x 104/ car-mile i             Spill size distribution:
0.5 for 10% cargo loss through a 2" hole, or 3,000 gallons 0.2 for 30% cargo loss through a 2" hole, or 10,000 gallons 0.3 for complete loss of a cargo load, or about '
30,000 gallons on average Note:
Worksheet 11.2 demonstrates how these figures can be used to estimate annual accident probabilities and associated spill probabilities for rail transportation.
6 11-17

4 WORKSIIEET 11.2 ESTIMATING BULK RAIL TRANSPORTATION RELEASE FREQUENCIES l
1 Hazardous Material (s):
l Number of Cars Per Year:                                A=
(loaded cars only)
Number of Car-Miles in Yards:                           B=                                                      l (miles per trip injurisdiction)               -)
;                                                                                                                              i
;              Number of Car-Miles on Mainline:                        C=                                                      !
(miles per trip injurisdiction)                l l              Accident Frequency:            D = (A x B x 3 x 1P) + (A x C x 6 x 1@) =                  (accidents / year)
)              Spill Frequency:                                        E = D x 0.15 =                       (spills / year)
!              Spills by Size
* d l                         10% loss of cargo (2" hole) or 3,000 gal:  Ex0.5=                      (spills / year) 30% loss of cargo (2" hole) or 10,000 gal: Ex0.2=                      (spills / year)               l i
100% loss of cargo or 30,000 gal:           E x 0.3 =                  (spills / year) 4 Notes:
l
                           *The user may consider all three scenarios for consequence modelling and planning purposes orjust the largest spill.
9 11-18

l t
l
            . Detailed consideration of specific types of accidents and associated leak sizes.
(Note: One study in Finland considered 14 types of accidents and four categories of leaks, including valve leaks, broken valves, moderate breaks and punctures, and large breaks.) (Lautkaski et al,1979)
            .      Separate consideration of different classes or quality of track (FRA,1988, gives some the additional information needed for this type of evaluation)
             . Separate consideration of mainline, yard, and sidings                                l 1
Use ofResults in Consequence Analysis Each of the three accident scenarios denoted and evaluated above actually provides the user with two options, the first being assumption of a certain percentage of cargo loss through an orifice of a given size, and the second being assumption of a specific total amount   j of cargo loss. For example, in the first scenario considered, the user can assume that 10% of    )
the total cargo of the vehicle is discharged through a hole having a diameter of two inches, or 4      alternatively, simply assume that 3000 gallons of presumably liquid cargo are released before    )
the discharge is terminated for one reason or another under average accident conditions.         )
These results are based on generalized historical records of past accidents and provide one      !
('
i i
way in which the ultimate consequences of an incident can be evaluated by use c.f the analysis procedures discussed in Chapter 12 of this guide. Conversely, depending upoa the type of hazardous materialinvolved and the desires cr the user, these scenarios can be further  ]
refined for consequence analysis purposes, taking better advantage of locally available          j information.
Where the user wishes to assume a fixed percentage of cargo loss (this requiring knowledge of total cargo amounts) or a fixed amount of spillage for liquid cargos, the spill
,       can be assumed to take place instantaneously, thus obviating need for use of discharge rate and duration estimation methods discussed in Chapter 12 and available in the computer program provided with this guide. It is cautioned, however, that the assumption of an instantaneous release in such situations may greatly overestimate resulting hazard zones from
.        evolution of toxic or flammable vapors, fires, or explosions. Spill amounts presented in units of gallons of liquid can be converted to the units of pounds required by the computer          l program by use of the followmg expression.
I Amount in pounds = 8.34 x Amount in gallons x Liquid specific gravity Where a hole size is specified and cargo tank or compartment dimensions are known, it is alternatively possible (and recommended) to utilize available discharge rate and duration estimation procedures to obtain an ultimately more realistic indication of accident conse-quences. This is particularly advisable when the cargo is a compressed gas, a liquefied 11-19

                                                                                                       ~
t t
i I
e compressed gas, or an otherwise highly volatile material. The suggested percentage of cargo loss, when less than 100%, can be ignored, if necessary, in deference to the results obtained from the discharge models.
11.5 BULK TRANSPORTATION OF IIAZARDOUS MATERIAIS BY MARINE VES.
SELS l
A large portion (about 550 million tons in 1982 according to the OTA) of the                   j hazardous materials shipped annually in the United States is transponed by barge or other              1 marine vessel on coastal and inland waterways. Extensive regulations cover safety proce-               l
,     dures, cargo documentation, vessel constmetion and cenification, hazardous material transfers, and the handling of explosives or dangerous cargos within or near waterfmnt facilities. Individual shipments can be vastly larger than those conveyed by rail or truck due         l to the size differences among these conveyences.
The primary types of marine vessels used for bulk transportation of hazardous goods are bulk liquefied gas carriers, chemical tankers, oil tankers and tank buges, but bulk cargos         i may also be found in smaller tanks placed on the decks of vessels or '.n standard intermodal cargo containers. Some barges are self-pmpelled but most are designed to be pushed by a tugboat singly or in arrays called " tows". Marine transponation generally involves volumes of 300-600 thousand gallons in barges, though some such vessels are of far larger capacity.           '
Tank ships can have capacities that are ten times or more greater (OTA, July 1986).
Commodity flow data are compiled fairly rigorously for marine transportation. Crude petroleum, petroleum products, and chemicals and liquefied gases constitute a large fraction of all shipments in and out of most major pons. Petroleum products include alcohols, crude oil, refined fuels, solvents and residuals. Typical chemicals include sulfuric acid, benzene, toluene, sodium hydroxide, inorganic speciality products, and fertilizers. The most fmquent-ly transported liquefied gases are propane and butane, but anhydrous ammonia, chlorine, propylene, butylene and butadiene are also frequently transported by water, as are many other bulk commodities.
Causes and Examples ofPast Accidents Marine transportation is generally at slow speeds and involves many precautions and traffic controls. Hence, it has the lowest accident rate per ton-mile and the lowest number of accidents. However, the large energies involved when these massive vessels strike each other or other objects can result in severe consequences at times in terms of cargo loss. As with other modes of transport, sma!! releases can result from problems with gaskets, flanges, valves or even the tanks themselves. The separation from population limits the consequences of small releases, however.
i 11-20

7 .
b i
i I
fM A few examples of accidents involving marine transportation of hazanious materials include:
i8..
: l.                   . A total of 23,000 gallons of leaded and unleaded gasoline spilled into the southem approach to Cape Cod Canal when a barge ran aground. The Army Corps of Engineers and the Coast Guard responded with divers and marine safety personnel to assess the damage after the tugboat called for assistance.
         ,                The Coast Guard expected the sea current to dissipate the spill. Environmen-
';      i                 tal damage was said to be minimal. There were no deaths or injuries.
I                  (August 18,1986)
!                    . A collision in the Houston Ship Channel between a tug and barges and a grain l
ship resulted in an explosion and fire involving one 33,000 gallon tank of butadiene. Two burning barges were towed to sea where they burned for five      1 days. (August 7,1980) a
                     . A 565-foot long tanker carrying two million gallons of gasoline rammed an unlighted oil drilling rig in the Gulf of Mexico. The tanker caught fire and    )
had to be abandoned. (August 21,1980).
A barge carrying 400,000 gallons of acrylonitrile struck the Galveston Causeway railroad bridge and ignited. Resultant explosion caused one end of     i
 .i                       the barge to sink and release an unknown amount of chemical into the water.
(January 3,1982) le Up to 40,000 pounds of hydrobromic acid spilled into the Mississippi waterway after a collision between two ships. Violent reactions between the acid and water required evacuation of 3000 people on the adjacent shore.
(July 22,1980)
Suggested Approachfor Assessment ofAccident Potential Based upon the information and data presented in Appendix F, and given the understanding that harbors and inland waterbodies are of greater concern than shipping
.              activities on the open ocean and/or otherwise distant from coastlines (in terms of the
;              distances typically associated with spill effects that may pose a threat to human life and
,              health), accident rates and other spill characterization factors are presented below for:
Collisions in lakes, rivers, and intercoastal waterways Groundings in lakes, rivers, and intercoastal waterways Collisions and groundings in harbors and bays Collisions / casualties while vessels are moored / docked 11-21 i

An accident rate of 105/ mile of travel is suggested for use for collisions in the first category to cover both the lower expected accident rates on certain slow speed waterways and the higher ones for congested, highly utilized routes. Based on Gulf Intercoastal Waterway (ICWW) statistics, a grounding casualty rate of 5 x 104/ mile is suggested for the serious type of grounding which could lead to a release. Note that this is also a "per mile" rate. The harbor / bay area grounding and collision rate given below is "per transit", while the moored collision rate is "per pon call." (There are two transits per port call.) The suggested rate for groundings and collisions in a harbor area is 105/ transit, while the suggested casualty rate for moored or docked vessels is 2 x 104 per pon call.
i If no distinction is being made with regard to vessel type and construction, it should be assumed that 0.15 (15%) of accidents result in actual loss of cargo to the environment.
Alternatively, it can be assumed that accidents involving single-hulled vessels result in cargo loss 0.25 (25%) of the time and that accidents involving double-hulled and bottomed watercraft result in cargo loss 0.05 (5%) of the time.
The recommended distribution of spill amounts is:
10% loss of cargo in one tank /companment -- 35% of the time 30% loss of cargo in one tank /companment -- 35% of the time Full loss of cargo in one tank / compartment -- 30% of the time This distribution is weighted toward more severe events than the spill distributions presented earlier, because the earlier distributions are heavily influenced by minor fitting leaks.
Table 11.6 summarizes the accident rates and other factors suggested for use, while 4
Worksheet 11.3 outlines the procedure for determining the annual average probability of an accident involving spills of various amounts. A copy of the worksheet should be completed for each hazardous material or group of similar materials transported in bulk by waterbome vessels through the community or other jurisdiction of concem. local information that will be required to accompliin the effon includes:
Material (s) of concern Maximum tank capacity of vessels carrying this material Total number of lake, river, or intercoastal waterway miles in the area, Total ships traveling this route in a year,
              ' Total cargo barges / tankers entering and exiting the bay ama or harbor, 4
Total barge / tanker port calls, 11-22

1 TABLE 11.6                                                                       l SUGGESTED FIGURES FOR MARINE TRANSPORTATION Accident Rates:                                 105/ mile for collision on lakes, rivers and inter-coastal watenvays I                                                    5 x 104/ mile for groundings on sr.me l
l                                                    10'/ transit for collisions and groundings in harbors / bays                                                             l I
,                                                   2 x 10d/ port call for collisions / casualties while                       l l                                                   mwrd Conditional SpillProbabilities:                 0.15 if using one rate regardless of vessel j                                                   0.05 for double-hulled / double-bottomed vessels 0.25 for single-hulled vessels e SpillSizeDistribution:                          0.35 for 10% loss of one tank or compartment I
l                                                   0.35 for 30% loss of one tank or compartment 0.30 for 100% loss of one tank or compartment l
Note:     Worksheet 11.3 demonstrates how these figures can be used to estimate annual accident probabilities and associated spill probabilities for marine transportation, l
1 l
l0 11-23

WORKSHEET 11.3 l
ESTIMATING BULK MARINE TRANSPORTATION RELEASE FREQUENCIES IIazardous Material (s):
Length of Lake, River,ICWW                  A=
Route *:                                             (miles withinjurisdiction)                    l Annual Number of Trips on Route *:          B=
(loaded trips only)
Annual Number of Transits of Har-           C=
bor/ Bay *:                                          (loaded transits only)
Annual Number of Dockings*:                 D=
(loaded dockings only)
Accident Frequency: E = (A x B x 1.5 x 108) + (C x 1&S) + (D x 2 x 104)=
1 1
Spill Frequency *:
F = E x 0.15 =                   (spills / year)
(all vessels)
OR F = E x 0.25 =                   (spills / year)                        )
(single hull)
F = E x 0.05 =                   (spills / year)
(double hull)                                                           !
1
:      Spills by Size-                                                                                   l 10% loss of one tank or compartment:         F x 0.35 =                  (spills / year) 30% loss of one tank or compartment:         F x 0.35 =                  (spills / year) 100% loss of one tank or companment:         F x 0.3 =                 (spills / year) i Notes:
           *If applicable
           +1f it is known how many vessels are single-hulled and how many are double hulled, this worksheet can be completed twice; the first time'for single-hulled vessels and the second for double-hulled.
The user may consider all three scenarios for consequence modelling and planning purposes orjust thelargest spill.
11-24 4

n Total river miles in the area,
         =
Number of barges / tankers traveling the river route in a year.
When totaling barge / tanker port calls or harbor transits, remember to count only those involving actual carriage of hazardous materials. Empty vessels may pose some risk of fire or explosion, but are not as important as loaded vessels. Also, note that all of the data listed above may not be needed for every location. For example, a community located on a river and not having a harbor or bay area only needs the total river miles and number of ships traveling the river. In this case, only moving collisions and river groundings would be of interest.
Nonimpact casualties, such as fim/ explosions, hull and machinery damage or break-downs, and structural failture have a very low likelihood of occurrence. It is not considered necessary to include them in the analysis.
AdditionalData/ Methodologies A more detailed and accurate analysis may be performed if one chooses to derive the appropriate casualty rates and conditional probabilities for a specific harbor or water route 7 using local data. An accident rate may be derived by combining a measure of vessel movements with the number of past accidents reported for the type of movement being looked at. 'Ihe movement measure may consist of: 1) the total waterbody, river, or waterway miles traveled; 2) the total port calls made; or 3) the total harbor transits. Counts should be made only for loaded hazardous material tankers and barges. The number of accidents is then divided by the total number of transits or miles, as appropriate, for a similar period of time to determine the accident rate.
Conditional spill probabilities and spill distributions are derived in a similar fashion.
The probability of a spill is obtained by dividing the number of spill accidents by the total number of accidents that occurred for a specific type of movement. A spill amount distribution from local or national data can then be applied to determine the percentage of the spills expected in various size ranges.
Several other means exist for estimating the probability of marine casualties and spills but they are generally highly technical, time-consuming, and occasionally quite expensive.
The reader is directed to the reference list at the end of the chapter for further information.
9 11-25 l

~ -
Use ofResults in Consequence Analysis Due to the special nature of the discharges from marine vessels, and difficulties in estimating discharge rates and durations when there is water outside the cargo tank rather than air,it is recommended (in the absence of more specific information or assumptions) that all discharges be assumed to take place instantaneously for emergency planning purposes.
Spill amounts available in units of gallons ofliquid can be converted to units of pounds by use of the following expression:
Amount in pounds = 8.34 x Amount in gallons x Liquid specific gravity l
11.6 TRANSPORTATION OF HAZARDOUS MATERIALS BY PIPELINE Pipelines in the United States primarily carry petroleum liquids, such as crude oil, gasoline and natural gas liquids, and energy gases which include natural gas and liquefied petroleum gas (LPG). To a much smaller extent, pipelines also transport ethane, ethylene, liquefied natural gas (LNG), anhydrous ammonia, carbon monoxide, sour (hydrogen sulfide containing) gas, and many other chemicals. The majority of these pipelines are between a limited number of suppliers and users, as opposed to natural gas transmission lines. IAw pressure gas distribution lines found within many cities and towns are not the focus of this section.
Pipelines are generally constructed out of steel, although some cast iron is still in me and plastic, nickel alloys, stainless steel, carbon steel and other materials are also used.                '
Diameters also vary tremendously, from 2 to 4 inches to 36 inches and over. The more hazardous materials tend to be conveyed in lines at the smaller end of the size range.
Pressures also span a wide range, and can be several thousands of pounds per square inch or more in the highest pressure lines encountered.
In order to reduce failures caused by corrosion, pipelines are frequently coated and/or cathodically protected. Lines may also be insulated, heated, double-piped for additional protection and control, and protected with leak detection and shutdown systems.
Causes and Examples ofPast Accidents Pipeline failures may be a result of:
          -      Internal corrosion -- especially on two-phase flow lines and those in sour service
          -      Extemal corrosion -- from defects in protective systems, in cased crossings 1.cncath roads and railway lines 11-26

i
!                                                                                                                                                                 1 l
i                                                                                                                                                                .
!
* Extemal impact -- due to farm or construction machinery                                                                                      -
t                                                                                                                                                                :
!
* Structural failures or mechanical defects -- as a result of defective ~ seams or                                                               l
}                 welds
            . Natural hazards - from seismic events, subsidence, etc.
l 1     Operating ermrs and construction defects are also potential causes of pipeline incidents.                                                                  l i     Leaks may also occur at valves and pump stations.
!             While there are over a thousand leaks reported each year, many of these are very small                                                             i i     and have minor or no consequences to the public. For instance,1984 data show the j.-   following number of incidents and deaths resulting from pipeline failures (Transportation l     Systems Center,1985):
i l
l                                                     No.of failures                    No.of deaths i               Gas pipelines                                967                              35 i
j               Liquid pipelines                             188                              0                                                                  I These rates are not particularly consistent from year to year. In 1983, there were 1575 gas l     pipeline failures, but only 12 deaths resulted. There were also 6 deaths from liquid pipeline j     failures.
!             The following three examples illustrate typical accidents involving pipeline transport of .                                                        !
l     propane and natural gas. No injuries occurred in these' accidents because of their remote l     locations.
j-          -
In Port Hudson, Missouri, propane escaped fmm a pipeline, flowed into a j                 sparsely inhabited valley, ignited, and exploded with a blast equivalent to 50 i                 tons of TNT. No fatalities or injuries occurred because the area was so
;                 sparsely inhabited. (September 12,1977) l
[           .
In Prattville, Alabama, a natural gas pipeline exploded into two fireballs, and i                 shot flames 600 feet high. Two houses were scorched; 200 people were
:                 evacuated, but no one was hurt. (July 12,1986) j           -
A natural gas pipeline explosion ignited a 200-ft flame jet and left a huge crater: 60 ft across and 20 ft deep. No one was injured but an unmanned metering station at the accident site was destroyed. (November 2,1985) l 11-27
    =     =    w-      ry  - y wew w-,,,
                                               .-v7 e-w          w.    , -           .-   ,    -  m---       - -,--ya-- .p4 tt -'rp ti-
                                                                                                                                                     ^*tr+*tw-

l l
l 1
Another typical pipeline accident did not have so fortunate an outcome as the above three.
In Jackson, Louisiana, a natural gas pipeline explosion resulted in 50-foot high flames. The blaze was battled by firefighters for several hours. The five i          dead and twenty injured were gas company employees repairing the pipeline.
(November 26,1984)
Suggested Approach for Assessment ofAccident Potential l        Based on the information presented in Appendix F, an accident rate of 1.5 x 10$/mi-yr i is suggested for lines of unknown size or lines less than 20" in diameter. For pipelines with diameters greater than or equal to 20", a rate of 5 x 104/mi-yr is proposed.
1 l        The followmg spill size distribution, incorporating the limited data available , is                   j suggested for analyzing pipeline releases of hazardous materials:                                           i For liquid pipelines: discharge computed using consequence analysis proce-dures of Chapter 12 assuming a complete line break along the route of the                          )
pipeline --- 20% of the time For gas pipelines: discharge computed using consequence analysis proce-dures of Chapter 12 assuming complete line break along the route of the                            l pipeline -- - 20% of the time                                                                      !
l For either gas or liquid pipelines: I hour release through 1" hole - - - 80% of the time Table 11.7 summarizes these rates, and Worksheet 11.4 demonstrates the procedures for their use.
The application of this material requires localinformation on:
Material of concem Length of pipeline within jurisdiction
      . Pipeline diameter Flow rate (capacity) of pipeline Presence (or not) of a leak detection and emergency shutdown system .
Should a pipeline be a very short segment between two facilities, it is possible to include it with one of the facilities, rather than analyzing it separately.
9 11-28

9                                            TABLE 11.7 SUGGESTED FIGURES FOR PIPELINE TRANSPORTATION Accident Rates:
1.5 x 10Vmi-yr with diameters less than 20" ofif diameteris not known 5.0 x 104mi-yr lines with diameters greater than or equal to 20" Spill Size Distribution:
0.20 for 15 min. (or 1 hour if no emergency shutdown) at the capacity flow rate through an orifice equal to the pipe size 0.80 for 1 hour release through 1" hole Note:
Worksheet 11.4 provides guidance on how to utilize these rates and probabilities for estimating releases of hazardous materials from pipelines.
s 11-29

l i
WORKSHEET 11.4 ESTIMATING PIPELINE RELEASE FREQUENCIES                                            i Hazardous Material (s):
Length of Pipeline of Unspecified          A=
Diameter:                                         (milesin jurisdiction)                                  l Length of Pipeline < 20" in Diameter:      B=
(miles in jurisdiction) 1 C=
^
Length of Pipeline;t20" in Diameter:
(milesin jurisdiction)
Spill Frequency: D = (A x 1.5 x 105) + (B x 1.5 x 105) + (C x 5 x 104) =              (spills / year)     .
l
;                                                                                                            l l
Spills by Size
* l l     1 hour release through 1" hole:               D x 0.8 =                  (spills / year)
Complete line break calculated according      D x 0.2 =                  (spills / year) to procedures given in Chapter 12:                                                                     j 1
Note:
l         *The user may consider both scenarios for consequence modelling and planning purposes or just the scenario posing the greatest threat to public safety. If several pipelines have j         been grouped by diameter, the line posing the greatest threat should not automatically be 1
assumed to be the line with the largest diameter within any group. Rather, the various 4
pipelines should be individually evaluated using the consequence analysis procedures described in Chapter 12 to determine the actual worst case scenario, if this is desired.
4 4
0 11-30

1 AdditionalDatalhiethodologies w-The main alternative to the approach given above is the specific consideration of M[@Z    pipeline design and the operating environment to more precisely determine the failure rate Mw     associated with each potential cause of failure (Technica,1983).
   .ll5          Use ofResults in Consequence Analysis
   ,i W              For pipelines conveying compressed (but not liquefied gas), the consequence analysis f     procedures described in Chapter 12 and incorporated into its associated computer program are fully capable of estimating the rate and duration of gas release from either full line breaks f
p       or smallerleaks.
l~            Due to the complexity of the problem, the computer program's liquid pipeline T:
  #       discharge model is only capable of addressing fullline breaks. It will be necessary to consult with the pipeline owner or operator for assistance in estimating discharge rates and durations
[,      for outflows from one inch diameter holes if these scenarios are considemd worthy of analysis.
g 11.7 j f            HANDLING AND TRANSFER OF HAZARDOUS AfATERIALS AT FIXED FACILITIES A broad range of facilities may pose potendal risks associated with the release of hazardous materials. These can include: large refineries, chemical plants, and storage unninals; more moderately sized industrial users, warehouses, and isolated storage tanks for water treatment; small quantity users / storage as may be found in high school and college laboratories, florists, greenhouses, hardware and automotive stores, paint stores, etc.
As a result of this broad spectrum of potential spill sources, virtually no accurate data exists to determine the magnitude of this problem. Marine terminals and loading / unload activities for rail cars and trucks are somewhat more widely reported and are considered within this overall category.
FEMA has a database that identifies the number of chemical and petroleum facilities b county. These facilities are broken down i no chemical and allied products, petroleum and coal products, and rubber and miscellaneous plastic products. No accident information is maintained, however. As of 1981, there were 16,000 chemical process industry plants with 20 or more employees and 6,000 plants with 100 or more employees. Los Angeles and Cook (Illinois) counties each have over 200 plants. The number of counties with between 11 and 50 plants is 160; all the rest have ten or fewer plants. About 50% of all the counties in the U.S. have no chemical process industry plants (Check et al,1985). (This is not to say that
{%                  '
d 11-31 I
i l

there are no facilities handling hazardous materials in these counties.) McGraw Hill has published a map of the plant locations and a booklet entitled " Census of the Chemical Process Industries."
Causes and Examples ofPast Accidents Releases from fixed facilities may arise from: storage tank or container ruptures or leaks, piping ruptures or leaks, releases through safety and relief valves, fbr-induced releases, other equipment failures, malicious or deliberate actions, overfills and overflows of storage tanks, t.uman errors, open valves, failed loading hoses, or improper hose connections.
These may generally be grouped into three categories for large facilities:
i
          . Transfer, loading and unloading activities                                                                            j
          -     Processing activities                                                                                                 j
          -     Storage tanks and their spill control systems Smaller facilities may not have any processing activities.
Transfer areas include pipelines, pumps, valves, and control instrumentation needed to achieve the movement of material within a facility. The loading / unloading area involves the most handling operations and the largest potential for human error in most facilities. 'Ihis is where the raw materials are brought in and products and by-products are removed, and temporary connections are frequently used. The storage area may be for raw materials, intermediates, products, or by-products. The greatest volumes are contained here, so spill sizes can be quite large. The processing area has equipment for raw material conversion into products. This is the area that will only be found in a plant, while handling and storage activities may take place at warehouses, water treatment facilities, greenhouses, and numerous other types of miscellaneous facilities.
Examples of a broad spectrum of accidents are given below. These cover events which start with a release of hazardous materials, as well as those where a fire propagates into a hazardous materials release.
            . A natural gas pipeline rupture at a Texas refinery caused t: series of explosions and fires. Two hundred firefighters worked nearly six hours to control the blaze fed by three other propane pipelines. Two refinery workers were killed; a town of 1,200 people was evacuated. Damage to the complex was predicted "into the millions." At least three similar explo-sions had occurred in the area in the prior five years.
11-32
: m.                                                                                         ,
l j
l e
a i      . Lightning struck a power pole in a chemical plant, then jumped to a tank of m            dilute hydrochloric acid, damaging a tank valve. A cloud of gas floated fr Re across several nearby neighborhoods. Hundreds of residents were forced to evacuate their homes; three plant workers were injured. (August 1,1980) j l
A refrigeration line at an ice cream plant in Burbank, California ruptured f(        .
spilling 300 gallons of anhydrous ammonia. Firefighters sprayed water to
{y control the fumes until the main valve could be shut off and the leak j      $1            stopped. Eleven people were hospitalized and 60 residents were forced to K@
leave the surrounding area. (November 13,1984)                                  1 l
      @           . In Covington, Kentucky a chlorine gas cylinder ruptured at a swimming
[$             pool jammed with about 300 swimmers. More than 140 people were
      $              hospitalized; no senous mjunes were reported. (June 21,1981) 4                                                                                                  ,
;k                . At least 11 people were injured and 100 persons evacuated from a                l is                   one-square mile area East Los Angeles after 100 gallons of chlorine             I jj                 overflowed fmm a storage tank. (March 1,1982) y               . A 25,000 ton storage tank in Portland, Oregon, discharged 3-5 tons of           !
f
;P                    anhydrous ammonia due to a valve malfunction. An area three miles downwind was evacuated while response personnel used water fog to u                knock down vapors and had tra spill vacuumed. (February 5,1982) x
~
dR              . Falling equipment sheared oft a pipe leading to a tank of hydrofluoric acid.
There were 66 serious injuries and roughly 3000 people were evacuated i                amund the Texas City oil refinery. Water fog was used to help control the 4   i                 vapor cloud and the tank contents were transferred to adjacent rail cars.
!                     (October 31,1987)
>                  . More than 16,000 south Chicago residents were evacuated fmm the vicinity
, y                   of a bulk storage and terminal when a silicon tetrachloride storage tank E                   sprang a leak. The escaping liquid, on the order of 150,000 gallons, reacted I                   with the moisture in die air to form hydrogen chloride, resulting in a dense, corrosive, choking plume that stretched 5-10 miles downwind at times. It i                  required 8 days for authorities to stop the leak, neutralize the spillage, and transfer remaining tank contents to other containers. Approximately 100 people were hospitalized during the incident. (April 26,1974) 4 9
11-33 i

i
            . A truck driver delivering sodium hydrosulfide to a Chicago leather company was directed to the wrong valve and began unloading the sodium hydrosulfide cargo into a tank of chromic acid. The reaction of the two chemicals released a deadly gas, hydrogen sulfide. Over 170 persons working inside the four-story tannery were overcome by the gas; a total of
;                 eight died and twenty-nme were mjured. (February 14,1978)                                  ,
 .                                                                                                           1 I
           'Ihere is one last tyy: of accident that merits special attention for fixed facilities,           i whether they be small or large. This is the potential for external events to cause releases, with earthquakes being of particular concem. Any natural disaster can cause releases as wen as affect responses. For instance, transportation and access to the facility may be restricted, water lines for fire protection may be broken, and resources may not be adequate to cover all situations simultaneously. Within any one site, an earthquake may impair the integrity of               ;
containment (e.g., dikes) and/or may cause multiple containers / tanks to fail, thereby exceeding the capacity of dikes, curbs, or other types of containment. Jurisdictions                    l particularly prone to such natural events as major earthquakes and floods should consider a more formal analysis of facility risks, taking into account the presence or lack thereof of             !
appropriate protective measures for these threats.
Suggested Approachfor Assessment ofAccident Potential                                         ,i Based upon the information presented in Appendix F, the approach suggested for getting a handle on fixed facility accident scenarios is to consider three basic types of release events for plants; one or two release scenarios for facilities such as water treatment plants, laboratories and industrial facilities; and one release scenario for warehouses and other facilities storing hazardous materials. It has been shown that very little specific historical information exists upon which to base accident rates. Hence, the best general approach is to I
look at equipment failure rates. The increasing use of physical barriers to limit spills, drainage systems to channel spills, and venting and scrubbing systems to control releases all help to render this simplified accident estimation procedure more meaningful.
For example, a large facility may be coarsely modelled as having storage operations, 3    loading / unloading operations, and processing operations. These can respectively be repre-sented by storage tank failures and leaks, hose failures, and piping and process vessel failures. The rates suggested for each of these are:
Storage tank - double walled         104/ tank-year Storage tank - single walled         10'/ tank-year Pressure vessels                     104/ vessel-year Inplant piping                       1.5 x 104/ft-year O
11-34

  $f k               Loading hoses                       10d/ operation or g                                                   lO2/ hose-year
  .g MI    While these certainly do not cover all potential release scenarios, they do capture some of the more likely ways to lose large volumes of material. The only piping of prime concem is that i    of relatively large diameter and long segments. In other words, a 100-foot expanse of 8" pipe
   =    should be counted during assessment of failure potential if it contains hazardous materials, but not 10 or 20 foot sections between vessels. As shown in Table 11.8, the spill size is generally taken to be a function of the specific release scenario.
For the middle category of industrial users, water treatment plants, laboratories, etc.,
the main focus shoulo be on storage tank or container failures. Piping failures or loading.
hose failures may be considered if there is a significant amount of piping (say over 100 feet) or if there are frequent loading / unloading operations (say 10 or more per year). The rates to be used are the same as those listed above and summarized in Table 11.8.
Storage of hazardous materials, such as in warehouses or greenhouses, may also result in failures of storage containers, but the greater threat here is'probably from a fire which:
spreads to the storage area and results in release, ignition, explosion, and/or combustion of stored materials (with attendant evolution of potentially toxic smoke). We occurrence rate of such fires is suggested to be 105/yr resulting in a release of 10% to 100% of the stored volume of hazardous materials -- as summarized in Table 11.8. His is one area in which                        I more specific local data and information would be particularly helpful for better definition of scenarios and estimation of their likelihood. Worksheet 11.5 summarizes the overall l       recommended procedure recommended for analysis of fixed facilities.                                           ,
l                                                                                                                     1 l                 The data required for an analysis that generally focuses on the larger and/or more likely           !
l       (yet significant) events at fixed facilities are:
I Material (s) of concem
                  . Number, dimensions, capacities, and contents of storage containers or tanks
                  . Number, dimensions, capacities, and contents of other vessels with large inventories of hazardous material (such as columns, separators, reaction vessels)
                  . Size, length, and operating conditions of piping systems
                  . Number of unloading and loading operations per year, materials involved, and transfer flowrates l
l                                                         11-35 l
l l
l

e
!                                                                                                                             I i
i l
TABLE 11.8                                                             i' SUGGESTED FIGURES FOR FIXED FACILITIES                                                      )
ITEM                     ACCIDENT RATE                                   SPILL SIZE 1
l Chemical Plants Double-walled storage tank                1.0 x 104/ tank-year     100% of time - total amount of typical contents releasedinstantaneously Single-walled storage tank or             1.0 x 10d/ tank-year     90% of time - release of contents through 1" hole pressure vessel                                                    until leak can be plugged or otherwise terminated 10% of time -- total contents released instantaneously                                         '
Piping                                    1.5 x 10*/ foot-year     90% of time - release through 1" hole in wall of pipe until leak can be plugged or otherwisc l
terminated 10% of tmic- complete rupture of pipe                  l Loadmg hose                            10d/ loading or unloading or 100% of time - release through full ho:: diameter 108/ hose-year       at loading / unloading rate until flow can Le terminated Industrial Users, Laboratories, Water Treatment Plants Storage tank / container                   1.0 x 10d/ tank-year    90% of time -- as above for single-walled storage tank or vessel 10% of time -- as above for single-walled storage tank or vessel Piping (if more than 100 ft)               1.5 x 104/ foot-year     90% of time -- selease through 1" hole in wall of pipe until leak can be plugged or otherwise terminated 10% of time - complete rupture of pipe Loading hose (if used more than 10           10'/ operation or       100% of time -release through full hose diameter times /yr)                                    108/ hose-year        at loading / unloading rate until flow can be terminated Warehouses and Other Storage Facilities Storage containers (drums, cylinders,            10$/ year          90% of time - release of 10% of total stored etc.)                                                               volume 10% of time - 100% loss of total stored volume (i.e., all containers combined) h 11-36

E          . . - .
1 l
l              -
l        -                                                                                                                   l t                                                WORKSHEET 11.5 s-     C                       ESTIMATING FIXED FACILITY RELEASE FREQUENCIES
'                                                                                                                             1 Hazardous Material (s):
i i UN4              Number of Process Vessels / Single-Wall               A=
StorageTanks:
l %=f.?c:
B=
[$              Number of Double-Walled Storage Tanks:
C=
 . i$
l N Length of Pipe:                                                                              (feet)        !
! yr               Annual Number of Loadings /Unloadings:                D1=
l    <&
     -t                 (or number of hoses)                             D2=
Spill Frequencies
* Process Vessels / Storage Tanks:                 E = A x 104 =                   (spills / year)
        ~
Double-Walled Storage Tanks:                     F = B x 104 =                   (spills / year) l                        Piping:                                          G = C x 1.5 x 104=                (spills / year)   I I                        Loading / Unloading Hoses:                       H = DI x 10d =                   (spills / year)
OR H = D2 x 102 =                      (spills / year) l 1
n            Spills by Size *+                                                                                          i
                                                                                                                              \
   .(        \'
     .\ /           Process Vessels / Storage Tanks 10% of contents (1" hole):                       Ex0.9=                    (spills / year) l                        100% of contents:                                (E x 0.1) + F =                    (spills / year)
Piping release through 1" hole:                              Gx0.9=                     (spills / year) release through full pipe diameter for time needed for shutdown or until associated tank is emptied:                      G x 0.1 =                  (spills / year) l                   Loading / Unloading Hoses release through full hose diameter l                        at transfer rate for time needed for
!                        shutdown:                                        H=                 (spills / year)
Notes:
* Assumes that the consequences of releases will be based on the tanks, piping and loading
!                          hoses which give the worst consequences. If desired, individual components or smaller groupings may be evaluated by completing the worksheet separately for each grouping.
l                          +The user may consider all these scenarios for consequence modelling and planning purposes, or just the largest spill in each category.
l N./
11-37 I
l

                                                                                                  '95 The more of this data available, the better. A first cut analysis could start with just the storage tanks / containers and any other large vessels, adding loading activities and piping only if the more information is desired or needed. Tanks of similar size and contents may be grouped together for probability analysis purposes, as may pipelines.
AdditionalDatalhiethodologies In addition to the multi-tiered approach discussed above, there are a number of more detailed analysis procedures that are appropriate for fixed facilities. These generally require more complete risk assessments which can be time consuming and expensive, and which mandate the complete cooperation of plant / facility management in order to obtain accurate and complete results. Numerous data sources discuss the merits and requirements of such analyses. Some starting points might include CONCAWE: 1982, Atherton et al: 1980, Simmons: 1974, COVO: 1982, and literally dozens of other reports and hundreds of articles.
Use ofResults in Consequence Analysis                                                         \
The choice of consequence procedures to be utilized for any given potential source of          ,
hazardous material discharge or spillage depends on the type of container or tank involved and the nature of the particular hazardous material contained therein. Although Chapter 12 of this guide and its related computer program provide a wide variety of analysis tools to          g assist users in evaluating individual accident scenarios, the large number of diverse situations that may be encountered at many fixed facilities does not permit the provision of detailed guidance for each and every case. Rather, emergency planning personnel need to apply the following guidelines with some degree of flexibility and common sense.
The first objective of a consequence analysis for a fixed facility should be evaluation of threats posed by storage tanks or process vessels that contain significant amounts of hazardous materials. Releases from short lengths (10-20 feet) of piping attached to these containers are included in the vessel failure rates. Each container of this type should be evaluated individually. If a length of piping between containers can result in simultaneous discharges from more than one container, this fact should be considered in the analysis. To the extent possible, the analysis should utilize available information on the operating conditions of each vessel in terms of typical and maximum amount of contents, operating temperature, pressure, and so forth. Any container of a substance with the potential for runaway polymerization, decomposition, or other unusual reactivity hazard should be given special consideration and attention. (However, the frequency of such events cannot be estimated rsing general historical data.)
                                                                                                  $)i 11-38

I e
OT RW
   }V u
Most intraplant or facility piping systems will be attached to one or more storage or 7              process vessels and should consider the amount of contents of such vessels. In addition, y           larger lines of significant diameter and length may require analysis via use of pipeline i         discharge models to the extent that is feasible, or altematively, the use of tank discharge models. Although the procedures of Chapter 12 permit evaluation of full line breaks and leaks from small holes in compressed gas pipelines, only full line breaks can be considered for liquid pipelines. Consequently, assistance will be required from facility owners or
         ?        operators for analysis of smaller liquid leaks if this lower consequence but higher probability scenario is to be addressed. If shutdown capability is not known, a reasonable release I
duration may be assumed to be 15 minutes.
:                                                                                                                                                      l Loading hose failures commonly involve transfers to and from transportation vehicles.
It will be necessary in many (but not all) such cases to assume a discharge rate equivalent to                                                i the cargo transfer rate through the hose, though the actual rate of discharge may be somewhat higher (especially initially). 'Ihe potential duration of discharge should be determined by investigation of the presence of emergency shutdown systems, available response foxes, and the likely time needed for them to terminate the release by various means at their disposal. In
      ;         no case, however, should the total amount of discharge exceed the total contents of the storage tank and the transponation vehicle. While evaluating such situations, pay special attention to situations in which manually activated emergency shutdown systems may be                                                          !
present but not approachable due to the hazardous propenies of the material being released.
Obviously, a truck driver may be reluctant or unable to approach a vehicle to pull an emergency shutoff vahe lever if his vehicle is venting large amounts of a highly toxic, i
flammable, and/or explosive gas or liquid. In the absence of such information, a recom-mended release duration is 5 minutes.
Evaluation of consequences from small containers or cylinders stored in warehouses, I              laboratories, and a wide variety of other commercial or public facilities will require consideration on a case by case basis where greater specificity is desired than that given in Table 11.8 and Worksheet I1.5, giving due consideration to the nature of potential accidents and their likely outcome. Gas cylinder leaks can generally be evaluated in a direct and straightforward manner using the procedures of Chapter 12 and its related computer program.
Note, however, that one of the most common major problems in this general type of facility is not leakage from one or more containers but a fire in the facility that involves the hazardous materials stored therein and produces large quantities of toxic smoke that may adversely impact downwind areas. Given the diversity of substances that may be involved, there is no simple manner in which the downwind area possibly requiring evacuation or other protective action can be precisely estimated in such events. Rather the general emergency plan must be sufficiently flexible to permit on scene decisions during an actual emergenc and the rapid initiation of evacuation or protective action activities.
11-39

                                                                                                 'E-i 11.8 TRANSPORTATION OF PACKAGED HAZARDOUS MATERIALS It has been estimated that there are up to 700,000 vehicles and vessels used to carry hazardous materials in small packages in the United States (OTA, March 1986). Such packages may be cylinders, drums, barrels, cans, boxes, casks, bottles, or other similar containers, and are defined as having a capacity of less than 110 gallons or 1000 pounds.
They may be transported by air, water, rail (usually in box cars), truck or van. Non-bulk transportation of hazardous goods is estimated to represent 50% of the total tons shipped by truck and 80% of the total truck spills (OTA, July 1986). Up to 8% of the marine                   l transportation of hazardous materials involves dry cargo barges carrying portable tanks or drums.
i Commodity flow information for such shipments is very limited due to the large number and variety of shipments that take place and a lack of reporting requirements. Thus, there is also a lack of accident rates or spill amount distributions which can be applied on a general basis. But the small amounts of materials involved usually (not always) imply limited consequences in the event of a release.
Causes and Examples ofPast Accidents The causes of releases from small packages include:
          -     Improperly tightened or faulty fittings, valves, and closures
          -     Dropping packages (while loading / unloading or in transit)
* Puncturing packages (again while handling or in transit)                             j
          -     Improper blocking and bracing which allows packages to move, fall or fail from impact or crushing while in a vehicle a     Fires
           . Freezing, getting wet, or other severe environmental exposure Examples of some incidents involving small packages are given below. These particular examples cover transportion as well as loading and unloading incidents.
l
!
* Ten employees were treated and released when a container of arsenic l                 trichloride was found ruptured as a truck was being unloaded. (July 19, 1985) 11-40

Et                                                                                                                  ,
: k.                                                                                                                  l l
A drum loaded with pesticide began leaking its contents as it was being transponed on a flatbed truck near Cologne, Germany. The small spill formed a large gas cloud which was toxic and corrosive. Traffic had to be halted for a considerable time to allow clean-up crews to neutralize the situation. (May 15,1985)
                .       A container loaded with drums of phosphorous was being lifted by crane from a barge to the dock when it ignited after an adjacent obstruction punctured a drum through the container walls. The crane driver submerged the entire container in the water away from the barge. De phosphorous reignited when the container was placed on the dock; by then the fue department had arrived and extinguished the fue with dry powder. No deaths or injuries resulted. (May 15,1986)                                       a.
{
                  -      In a Houston port, a freight container explosion from improperly packaged aluminum phosphide killed a dock worker. When inspectors from the Marine Safety Office opened the container, boxes of high explosives were found, even though the aluminum phosphide had warning labels marked, "Do not store with high explosives." (January 20,1986)
* Amid heavy tourist traffic, a truck driver noticed that water was leaking g                     from his cargo, drums containing nuclear reactor sludge. Funher inspection j
at a busy truck stop showed that the hole in the drum had been patched with
(
electrician's tape. (November 14,1979),
b.y m n.                                  a
                                                                                                             /j          l 1
Suggested Approachfor Assessment ofAccident Potiniiil ~ ' ~~Jw'"
The available accident data covers accidents per unit of handling for a package                      l
!          (without designation of spill or nonspill events) (Kloeber et al,1979), and there are a few data sources (ICF,1984) which give release fractions for transit as well as at asrociated terminals. He methods needed to take advantage of these data, however, require more information than can be obtained by emergency planning personnel with a reasonste amount of effort in the vast majority of cases.
The approach suggested is to identify particular shipments of concem which were discovered during initial data collection efforts and to only analyze those selected materi-als/ shipments which involve sufficient volumes of materials to pose major hazards. The basic approach is to then utilize the basic accident rates for rail, marine, or highway transport as dictated by the type of transportation taking place, and to combine the resulting annual l
 '          accident rate with the fraction of accidents expected to result in a spill or discharge. As a fust pass on estimating the spill size distribution, consider using:
11-41 I
4
                                ,~-    +

l
!l                     .
loss of one container (or group of containers, such as 12 bottles in a box)
                             -- 90% of the time I
i                      -
Full loss of cargo (all containers) --- 10% of the time
:                     AdditionalData/ Methodologies 3
Should more precise estimates be needed, one of the more detailed methodologies
{
L should be utilized (for example, see ICF,1984, and the references contained therein).
ll
!    L Use ofResults in Consequence Analysis '
Given the relatively small amounts of hazardous materials transported in individual j
j-packages and the' manner in which most fail, the best course of action for consequence analysis purposes is to assume that the amount of cargo specified directly above is released
     ;          instantaneously to the envimnment.
r                                                                                                                                                               1 113 TRANSPORTATION OF HAZARDOUS MA TERIALS BY AIR I
l-j The transportation of hazardous materials by air is generally limited to small packages, but this category of accidents also applies to crop dusters applying pesticides. The materials transported by air are usually of high value or of high priority time-wise. He annual tonnage shipped is between 200 and 300 thousand tons, but this involves a very large number of l              shipments. One study (OTA, March 1986) reports that in an evaluation of the air cargo -
;              packages at 39 major airports,5% involved hazardous materials.
As demonstrated at the beginning of this chapter, there are relatively few hazardous materials incidents each year involving this mode of transportation.- One source (Hazardous F
Materials Intelligence Report, May 31,1985) found that there were only 6 incidents in 1984 i              which resulted in dmb, injury or more than $25,000 of property damage on a nationwide j              basis. The accidents N 'o concentrate in the vicinity of airports, as might be expected.
i j                    There are nrm            i regulations covering the transportation of hazardous goods by air, j
including quantity restrictions and detailed regulations involving packaging. Many incidents i-which occur have been shown upon investigation to involve violations of these regulations.
In terms of emergency tesponse planning, there is little that can be done to accurately determine a community's potential vulnerability to this type of accident, and admittedly, j
there is a question of whether planning should go beyond the development 'of communica-tions links with airport facilities that handle hazardous materials, and the identification of f
f i
11-42 Y
a e
J-4
                                                      -r    < a . - - . ,                             + -. . . - , ,, w, =          , --:e- e-aw-,e-ar , mw. m w

q                                        ..                                       --- . - _. . . - -___ - _
i i                                                                                                  i E
47 (y              a l~1            h    those locations where hazardous materials may be found on airport property. This observa-tion follows from both the very low frequency of serious incidents and the extremely             ;
!       c      1 i
p       ?
incomplete data available on commodity flows.
AT                                                                                                            .
4R d#
Crop dusters present a special case. Although accident rates and specific consequences cannot be predicted in advance due again to a rarity of serious incidents,it is a good idea for l
j           jurisdictions in which these aircraft wc+k to give some thought to how to respond to a crash.
h t en Note that these planes usually carry pesdcides and herbicides that may be highly toxic when concentrated. 'Ihe crash site and surrounding areas may be highly contaminated. Crashes in T             or near bodies of water may threaten water supplies or cause environmental damage.
M R;g          11.10 

==SUMMARY==

l
        ~ sy                                                                                                          )
The preceding sections have presented methodologies for estimating the annual             j iX            probability of hazardous material releases from fixed facilities and transportation systems.
iF Individual worksheets have been provided for truck, rail, marine, pipeline and fixed facility   l K          activities and operations. At the very least, a separate worksheet will need to be completed jd            for each material or group of materials of concem and/or each facility of concem. Even if y          accident probabilities are not computed, the worksheets and related text can be valuable for w
a          the identification and refinement of individual accident scenarios, The most critical local information needed for completion of worksheets involves Lg             exposure data -- i.e., the number and length of shipments, the number and capacity of storage  l EK
       -4 tanks or process vessels, and so forth. When obtaining this information, it is usually sufficient to obtain the correct order of magnitude -- great expenditures of resources or very  i
!         y           precise counts are not warranted. Should information be unavailable, it may be necessary to    l make a best estimate, with advice from other knowledgeable individuals. This is surely 4           better than eliminating any potentially significant accident scenario from consideration.
       -W l      'T                    Another important point is that no one event can result in all possible potential
       ]
79 consequences simultaneously. In other words, if a rail car or tank truck experiences a BLEVE, it cannot then also have major downwind toxic vapor dispersion hazards as these Q              require non-ignition of the cloud. Also, not all ignitions of flammable vapors result in explosions. The percentage of events which result in various consequences is very dependent on the material involved, the quantity released, and the reason for the release. General L                     percentage breakdowns cannot be given.
11.11 REFERENCES Association of American Raihoads. " Railroad Facts,1985 Edition," August 1985.
(
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f I
l  Athenon, J.G. et al. "The Bulk Storage and Handling of Flammable Gases and Liquids,"
London: Oyez Publishing Limited,1980.                                                           ~
i i
Chemical and Engineering News. " Emergency plans urged for rallyard chemicals," July 29,              ,
1985,p.6.
;  Cheok, M.C., G.D. Kaiser and G.W. Parry. " Development of a Methodology for Compren-i sive Hazard Analysis - A Feasibility Study," prepared by NUS Corp. for the Federal              - '
Emergency Management Agency, June 1985.
Clarke, R.K. et al. " Severities of Transponation Accidents," Sandia Laboratories, NTIS SLA-74-0001, July 1976.
CONCAWE. " Methodologies for Hazard Analysis and Risk Assessment in the Petroleum Refining and Storage Industry," CONCAWE Repon No.10/82, Den Haag, December 1982.                  :
Considine, M. " Risk Assessment of the Transponation of Hazanious Substances Through            ;
Road Tunnels," Recent Advances in Hazanious Materials Transponation Research, An Intemational Exchange, State-of-the-An Report 3, Transponation Research Board, Washing-          ;
ton, DC,1986, pp.178-185.
Considine, M., G.C. Grint and P.L. Holden. " Bulk Storage of LPG - Factors Affecting Offsite Risk," Institution of Chemical Engineers Symposium Series No. 71, pp. 291-320.
COVO Steering Committee. Risk Analysis of Six Potentially Hazardous Industrial Objects in the Rijnmond Area, a Pilot Study, Boston: D. Reidel Publishing Co.,1982.
Federal Railroad Administration. " Accident / Incident Bulletin, No.156, Calendar Year 1987,"      !
July 1988.                                                                                         I Harvey, A.E., P.C. Conlon and T.S. Glickman. " Statistical Trends in Railroad Hazardous             '
Materials Transponation Safety - 197J to 1986," Publication R-640, Association of American Railroads, Washington Systems Center, September 1987.
i
* Hazardous Materials Intelligence Repon, May 31,1985.
ICF,Inc. " Assessing the Releases and Costs Associated with Tmck Transpon of Hazardous         ,
Wastes," prepared for the U.S. Environmental Protection Agency, NTIS PB84-224468,1984.
Kloeber, G. et al. " Risk Assessment of Air Versus Other Transponation Modes for Explosives and Flammable Cryogenic Liquids, Volume I: Risk Assessment Method and Results," prepared by ORI, Inc. for Materials Transponation Bureau, NTIS PB80-138472,          _
December 1979.
5 i
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e
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[ Lautkaski, R., T. Mankamo and M. Karkkainen. " Chlorine Transponation Risk Assessment,"
g           Revised Edition, Nuclear Engineering Laboratory, Report 27, Technical Research Centre of l    M           Finland, September 1979.
K4          Materials Transportation Bureau. " Annual Repon on Hazardous Materials Transponation,
      .D          Calendar Year 1983."
      $gft        National Transponation Safety Board. " Railroad / Highway Grade Crossing Accidents Involv-
     .?g          ing Trucks Transponing Bulk Hazardous Materials," NTIS PB82-113432, September 1981.
y F           Nayak, P.R., D.B. Rosenfield and J.H. Hagopian. " Event Probabilities and Impact Zones for l}            Hazardous Materials Accidents on Railroads," prepared by Arthur D. Little, Inc. for the
       @          Federal Railmad Administration, DOT /FRA/ORD-83/20, November 1983.
M q          Office of Radiation Programs. "The Consequences and Frequency of Selected Man-Originat-l      J:         ed Accident Events," U.S. Environmental Protection Agency, NTIS PB80-211303, June A           1980.
       ]          Office of Technology Assessment. " Transportation of Hazardous Materials," OTA-SET-340,    .
     %            Washington, DC: U.S. Government Printing Office, July 1986.
l                  Office of Technology Assessment. " Transportation of Hazardous Materials: State and Local I (g               Activities," OTA-SET-301, Washington, DC: U.S. Government Printing Office, March 1986. I e
i           Simmons, J.A. " Risk Assessment of Storage and Transpon of Liquid Natural Gas and s               LP-Gas," prepared by Science Applications, Inc. for the U.S. Environmental Pmtection Agency, NTIS PB-247 415, November 1974.
Smith, R.N. and E.L. Wilmot. " Truck Accident and Fatality Rates Calculated from Califomia Highway Accident Statistics for 1980 and 1981," prepared by Sandia National Laboratories for U.S. Department of Energy, S AND-82-7066, November 1982.
Sorensen, J.H. " Evacuations Due to Chemical Accidents: Experience fmm 1980 to 1984,"
     "             prepared by Oak Ridge National Laboratory, ORNI/rM-9882, January 1986.
Technica. " Ethane and Ethylene Pipelines Between Mossmorran and Grangemouth, Assess-ment of Residual Risk," Production No. 9, London, January 1983.
              ?
Transponation Systems Center. " Transportation Safety Information Report,1984 Annual Summary," U.S. Department of Transponation, DOT-TSC-RSPA-85-1, April 1985.
Urbanek, G.L. and EJ. Barber. " Development of Criteria to Designate Routes for Transpon-ing Hazardous Materials," prepared by Peat, Marwick, Mitchell and Co. for the Federal Highway Administration, NTIS PB81-164725, September 1980.
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'         J' Wolfe, K.E. "An Examination of Risk Costs Asmated with the Movement of Hazardous Materials,'' submitted to the Transportation Research Forum's 26th Annual Pmc October 22-24,1984.
i Wright, C.J. and PJ. Student. " Understanding Railroad Tank Cars," Fue Comman November 1985, pp.18-21 and December 1985, pp. 36-41.
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