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SodPQ-eHS-t-Z 

CONSEQUENCES OF ACCIDENTS INVOLVING COMMERCIAL EXPLOSIVES 

July 5, 1990 

a 
P.3 

TABLE OF CONTENTS 

age 

1.0 Introduction 1 

2.0 Background 1 

2.1 Characteristics of Explosive Materials 2 

2.2 Past Incidents Involving Commercial Explosives 3 

3.0 Existing Classification Systems 3 

3.1 DOT Standards 4 

3.2 ATF Standards 5 

33 Other Standards 7 

4.0 Comparison of Methodologies for Determining Affected Distances 

for Commercial Explosives 7 

4.1 Approach 7 

4.1.1 Explosive Materials Selected 7 

4.1.2 Damage Criteria 8 

4.1.3 Assumptions 8 

4.1.4 Quantities Modeled 8 

4.2 Methodologies for Determining Explosive Distances 9 

4.2.1 Scaling Law for Explosives 9 

4.2.2 ATF 11 

4.23 ARCHIE 15 

4.2.4 "K-Factor" Methodology 16 

43 Results 18 

43.1 High Explosives 18 

43.2 Low Explosives and Blasting Agents 23 

5.0 Findings 27 

References 28 
P.4 

TABLE OF CONTENTS 

(Continued) 

Page 

APPENDICES 

Appendix A: Test Methods Used in Qassification of Commercial Explosives A-l 

A l Screening Tests A-l 

A.2 Standard Tests A-6 

A.2.1 Explosiveness by Shock Initiation A-6 

A.2.2 Ignitability and Violence of Deflagration A-9 

A.2.3 Occurrence and Violence of Decomposition and Deflagration 

Due to External Heating A-10 

A.Z4 Field Combustion Tests for Unstable Substances A-ll 

Appendix B: Damage Criteria/Overpressure Data B-1 

B.1 Damage Criteria B-1 

B.2 Effects of Varying Overpressure B-9 

Appendix C: Differences in Methodology C-1 

4 
P.5 

LIST OF EXHIBITS 

Page 

1 K-Factors as a Function of Peak Overpressures 10 

2 Table of Distances - High Explosives & Blasting Agents 12 

3 Table of Distances - Low Explosives 13 

4 Sample Printout of ARCHIE Modeling Results for 250 Pounds of Tetryl 17 

5 Affected Distances for Commercial High Explosives, Determined 

Using Four Different Methods (Peak Overpressure - 0.5 psi) 19 

6 Affeaed Distances for Commercial High Explosives, Determined 

Using Four Different Methods (Peak Overpressure = 1.0 psi) 20 

7 Affected Distances for Commercial High Explosives, Determined 

Using Four Different Methods (Peak Overpressure - 2.0 psi) 21 

8 Affected Distances for Commercial High Explosives, Determined 

Using Four Different Methods (Peak Overpressure = 3.0 psi) 22 

9 Affeaed Distances for Low Explosives, Determined Using the 

ATF Table of Distances for Low Explosives 24 

10 Affeaed Distances for Low Explosives, Analyzed as High Explosives, 

Assuming Detonation 25 

11 Affeaed Distances for Blasting Agents, Analyzed as High Explosives, 

Assuming Detonation 26 

A-l Screening Tests Used in the Classification of Commercial Explosives A-2 

A-2 Assessment Criteria in the Combustibility Test A-4 

A-3 Method of Grading in the Ignition Point Test A-5 

A-4 An Example of Hazard Grading with Respea to Impaa Sensitivity A-7 

A-5 Summary of Standard Tests Used to Evaluate Hazards Associated 

with Explosives A-8 

B-1 Human Injury Criteria B-2 

B-2 Property Damage Criteria B-4 
P.6 

UST OF EXHIBITS 

(continued) 

Page 

B-3 Lethality Curves B-7 

B-4 Lethality and Injury Curves B-7 

B-5 Air-Blast Criteria for Personnel Standing in the Open B-8 

B-6 Consequence Distance Versus Overpressure for Four High Explosives 

(Amatol 60/40, Amatol 50/50, Lead Azide, and Metriol Trinitrate) B-10 

B-7 Consequence Distance Versus Overpressure for Four High Explosives 

(PLX, SUver Azide, Tetryl, and TNT) B-ll 

C-1 Comparison of Results of Consequence Analysis (Overpressure 0.5 psi) C-2 

C-2 Affeaed Distances Determined by K-Faaor Method for Two Commercial 

High Explosives, Using Several TNT Equivalents C-5 

fc 
P.7 

CONSEQUENCES OF ACCIDENTS INVOLVING COMMERCIAL EXPLOSIVES 

1.0 Introduction 

When the Superfund Amendments and Reauthorization Aa (SARA) was enacted in 1986, a list of 

extremely hazardous substances was published under Section 302 of Title III. Section 302 requires a facility 

that has an extremely hazardous substance (EHS) above its threshold planning quantity (TPQ) to notify the 

State Emergency Response Commission (SERC) that it is subjea to the requirements for emergency planning. 

The original list of EHSs was created using only acute toxicity criteria. The purpose of the list was to 

identify those substances that, if accidentally released, could cause death or serious irreversible health effects 

off-site. However, toxicity is not the only hazard posed by chemicals. SARA states that the Administrator 

may revise the list, but such revisions "shall take into account the toxicity, reactivity, volatility, dispensability, 

combustibility, or flammability of a substance." 

EPA is currently contemplating a rulemaking addressing the hazards of commercial explosives. The 

Agency is aware that the Bureau of Alcohol, Tobacco, and Firearms (ATF) already has a rule on this issue 

(ATF P5400.7, ATF: Explosives Law and Regulations). However, the ATF regulation does not require 

reporting of the presence of commercial explosives to local emergency planning authorities. Therefore, EPA 

is considering a rule that would mandate reporting to the Local Emergency Planning Committees (LEPCs) 

to enable proper planning for the hazards associated with explosives. The purpose of this report is to compare 

the quantity-distance relationship found in the ATF rules to quantity-distance relationships used by other 

generally accepted methodologies. This report is intended to be used as technical support for any future listing 

of commercial explosives on the Section 302 list 

2.0 Background 

EPA originally developed the EHS list as part of the Chemical Emergency Preparedness Program 

(CEPP) which was designed to increase public awareness of chemical hazards in communities and focus effort 

on emergency planning. EPA believed that communities needed a starting point and intended that the list 

draw attention to the chemical substances and facilities that pose the most immediate concern from an 

emergency planning and response perspective. EPA recognized and emphasized that there are tens of 

thousands of compounds and mixtures in commerce that may pose a hazard under specific circumstances and 

that this list only deals with lethality or serious irreversible health effects associated with acute toxicity. The 

Agency chose lethality because it represents the most immediate concern in an emergency situation. 

Several commenters to the rulemaking for the EHS list noted that physical/chemical hazards such as 

flammability or explosivity may also lead to serious consequences, including death and irreversible injury. In 

an official inquiry to the Agency in 1987, Senator Frank Lautenburg also noted concern for hazards other than 

toxicity and asked that EPA focus on other hazards. The Agency agreed and noted its intent to evaluate 

hazards other than toxicity in the future. 

^ 
P.8 

A Physical/Chemical Criteria Workgroup (P/C Workgroup) was formed at EPA to address the concerns 

raised by Senator Lautenburg and others and to focus on the problem of identifying materials which are 

hazardous based upon their physical/chemical properties and could thereby be candidate EHSs. The 

Workgroup initially considered the hazards referred to in the Aa and determined that they fell into two 

general categories: hazards related to toxic properties and hazards related to physical/chemical properties. 

The charaaeristics of reactivity, volatility, dispersibility, combustibility, and flammability, mentioned in the Act, 

are related to a variety of physical/chemical properties; the Workgroup chose to focus on the physical/chemical 

properties that lead to the greatest potential hazards to people. Hazards associated with physical/chemical 

properties are primarily based on two phenomena that can cause serious personal injury or death. These 

phenomena are the result of the release of energy from highly reactive or flammable chemicals and are 

identified as overpressures from blast waves and thermal radiation from fires. Overpressures result from nearly 

instantaneous energy release, or detonation, while thermal energy is released during combustion, which occurs 

more slowly. Since explosive chemicals are highly reactive substances that can detonate and create 

overpressures, and flammable chemicals can burn and produce thermal radiation, the Workgroup focused on 

explosives and flammable chemicals as chemicals of concern. 

The workgroup eleaed to segregate the chemicals for review into separate categories for flammables, 

explosives, and reactrves for purposes of analysis and possible regulation even though it was recognized that 

there may be overlap of the consequences; e.g., the detonation of a flammable material may yield the same 

results as the detonation of a commercial explosive. However, the workgroup wanted to determine which 

parameters distinguish extremely hazardous explosives from all other explosives, extremely hazardous 

flammable substances from all other flammables, and so on. This report focuses on commercial explosives. 

In this instance, the workgroup decided to investigate the various methodologies used in analyzing the 

consequences of explosives and to compare the results using these methodologies with the Table of Distances 

used in the rulemaking by ATF. Separate documents will address the consequences of accidents involving 

flammable materials, non-commercial explosives, and other reactive chemicals. 

2.1 Characteristics of Explosive Materials 

An explosion is defined as a sudden and violent release of energy (Lees 1980) accompanied by high 

pressure gases. The more rapid the release and the greater the available energy, the more violent the 

explosion (U.S. DOT 1988). Most of the available energy from an explosion is converted into some form of 

mechanical energy, manifesting itself in the form of blast waves, fragmentation, and ground shock. Of these 

damage effects, blast overpressure contributes the greatest damage in chemical explosions. The remaining 

portion of the explosive energy remains in thermal form and is of concern because of its fire hazard. 

Explosive materials typically are classified as either "high" or "low" explosives. "High" explosives are 

defined by ATF as those materials that detonate if ignited, shocked, or subjeaed to heat or friction. 

Detonations result from exothermic chemical reactions that proceed at supersonic velocities, generating large 

volumes of high pressure gas and heat instantaneously, even though no confining vessel or structure exists. 

In an explosion caused by a high explosive, the rate of energy release is particularly rapid and the shock wave 

has a very short duration. Some examples of high explosives are TNT, dynamite, gunpowder, and 

nitroglycerine. In contrast, "low" explosives deflagrate, or burn at subsonic velocities. A deflagration generates 

lower pressures and is less destructive than a detonation. A deflagration reaction propagates through the 

unreaaed material via a diffusion mechanism rather than a shock wave. However, under the right conditions 

(e.g., confinement) some low explosives may detonate; conversely, some high explosives may burn if ignited. 

An example of a low explosive is blade powder. (Note that although the Bureau of Alcohol, Tobacco, and 

3 
P.9 

"*!________ 

Firearms considers black powder a low explosive, the Department of Transportation regulates it as a Qass A 

explosive.) 

The Physical/Chemical Criteria Workgroup investigated several possible approaches to charaaerizing 

explosive materials, including accident histories and quantitative physical/chemical properties. As the following 

sections demonstrate, none of the approaches investigated provided satisfaaory distinctions. The accident data 

on explosives are not comprehensive enough to provide any clear cut means of placing certain commercial 

explosives into extremely hazardous categories (a review of the data is presented in Section 2.2). A review of 

the literature associated with explosions revealed that an explosion usually results in both a thermal and 

pressure (Le., blast) wave. Typically, the damage associated with the pressure wave is far greater such that the 

thermal wave can be ignored (Brasie and Simpson 1968). Blast waves from accidental explosions can cause 

damage to people and property by subjecting them to transient crushing pressures and winds. Relatively 

simple concepts have been used effectively to correlate blast wave properties with damage. These concepts 

are discussed in Section 4.2,1. 

2.2 Past Incidents Involving Commercial Explosives 

The Acute Hazardous Events Data Base (AHE/DB) was developed by EPA to provide a historical 

perspective on accidents that release hazardous substances in the United States (EPA 1988). The 1988 version 

of the data base includes data on 5,827 events that occurred between the 1960s and 1987 (the majority of the 

incidents appear to have occurred in the 1980s). The AHE data base lists approximately 36 incidents resulting 

in fires or explosions that may have involved commercial explosives.1 This data base does not appear to 

provide clear evidence that commercial explosives should be considered extremely hazardous based solely on 

their accident history. It does show that commercial explosives have been involved in accidents that resulted 

in death and injury in the past 

A recent accident not included in the AHE/DB occurred in Kansas City, MO, on November 29,1988. 

In this incident, six fire fighters were killed in an explosion of a blend of ammonium nitrate and fuel oil 

(ANFO). About 59,000 pounds of ANFO, a blasting agent, were stored in two trailers at a construction site. 

The trailers exploded in a fire caused by arson. 

3.0 Existing Qassification Systems 

The Bureau of Alcohol, Tobacco and Firearms (ATF) and the Department of Transportation (DOT) 

are the two principal regulatory groups that oversee explosives. Explosives and explosive mixtures generally 

are not distinguished in any classification schemes. Most organizations recognize that a "mixture" containing 

an explosive substance can be just as hazardous as a "pure" explosive substance. Therefore, the classification 

of explosives by ATF, DOT, and others is not based directly on chemical properties, rather it is based on 

empirical data obtained from tests performed on the substance or mixture. These standardized tests typically 

are performed by the Bureau of Mines and other agencies and are described in Appendix A. The number of 

1

 The identities of the substances involved are not always known. In some cases the substances reported 

may be considered commercial explosives under certain conditions but not under others. For these reasons, 

the total number of incidents involving commercial explosives is an estimate. 

3-

q 
P.10 

chemicals and chemical mixtures classified as explosives is unknown (White 1989, Dowling 1989, McCune 1989, 

Schultz 1989). 

3.1 DOT Standards 

The DOT regulates the transportation of explosives and defines an explosive as "any chemical 

compound, mixture, or device, the primary or common purpose of which is to function by explosion, Le., with 

substantially instantaneous release of gas and heat.." (49 CFR 173.50). Explosives are further defined by the 

DOT according to the following classifications: 

• Class A — Detonating or otherwise of maximum hazard: 

Type 1: Solid explosives which can be caused to deflagrate by contaa with sparks 

or flame but cannot be detonated by means of No. 8 test blasting cap.2 Example: 

black powder. 

Type 2: Solid explosives which contain a liquid ingredient and which when 

unconfined can be detonated by means of a No. 8 test blasting cap; or which can 

be exploded in at least 50% of the trials in the Bureau of Explosives' Impaa 

Apparatus under a drop of 4 inches or more, but cannot l>e exploded in more than 

50% of the trials under a drop of less than 4 inches. Example: commercial 

dynamite containing a liquid explosive ingredient 

Type 3: Solid explosives which contain no liquid ingredient and which can be 

detonated by means of a No. 8 test blasting cap; or which can be exploded in at 

least 50% of the trials in the Bureau of Explosives' Impaa Apparatus under a 

drop of 4 inches or more, but cannot be exploded in more than 50% of the trials 

under a drop of less than 4 inches. Examples: commercial dynamite containing 

no liquid ingredient, TNT, amatol, tetryi, picric acid, urea nitrate, pentolite, and 

commercial boosters. 

Type 4: Solid explosives which can be caused to detonate when unconfined, by 

means of contaa with sparks or flame; or which can be exploded in the Bureau 

of Explosives' Impaa Apparatus, in more than 50% of the trials under a drop of 

less than 4 inches. Examples: lead azide, fulminate of mercury. 

TVpe 5: Desensitized liquid explosives are explosives which may be detonated 

separately or when absorbed in sterile absorbent cotton, by a No. 8 test blasting 

cap; but which cannot be exploded in the Bureau of Explosives' Impaa Apparatus 

under a drop of less than 10 inches. Example: desensitized nitroglycerine. 

Type 6: Liquid explosives that can be exploded in the Bureau of Explosives' 

Impaa Apparatus under a drop of less than 10 inches. Example: nitroglycerine. 

2 A No. 8 blasting cap is one containing two grams of a mixture of 80% mercury fulminate and 20% 

potassium chlorate, or a cap of equivalent strength (49 CFR 173.53). 

- 4 -

IC 
P.11 

Type 7: Detonators and initiating devices. 

Type 8: Any solid or liquid compound, mixture, or device which is not specifically 

included in any of the above types, and which under special conditions may be so 

designated and examined by the Bureau of Explosives. Example: shaped charges. 

Type 9: Propellant explosives, class A (solid chemicals or solid chemical mixtures 

which are designed to function by rapid combustion of successive layers) which 

detonate in their package in one out of five test trials, when ignited. 

• Class B — Flammable Hazard: 

Those explosives that in general function by rapid combustion rather than 

detonation and include some explosive devices such as special fireworks, flash 

powders, some pyrotechnic signal devices and liquid or solid propellant explosives 

which include some smokeless powders. 

• Class C — Minimum Hazard: 

Certain types of manufactured articles which contain Class A, or Qass B 

explosives, or both, as components but in restriaed quantities, and certain types 

of fireworks. 

Qass A explosives are considered by DOT to be more hazardous than Qass B explosives, which in turn are 

considered to be more hazardous than Qass C explosives. In general, Class A explosives will detonate while 

Qass B and C explosives will deflagrate. Anyone wishing to transport materials classified as class A, B, or C 

explosives is subjea to the requirements specified in the DOT regulations for packaging, labeling and proper 

transport 

DOT also regulates transportation of blasting agents, defined as materials designed for blasting that 

have been tested in accordance with a series of specified tests and found to be so insensitive that there is very 

little probability of accidental explosion. 

3 J ATF Standards 

The manufacture, processing, use, distribution, and storage of explosive materials is regulated also by 

the Bureau of Alcohol, Tobacco, and Firearms (ATF) as set forth in 27 CFR Part 55. The ATF defines an 

explosive material as follows: 

"Any chemical compound, mixture, or device, the primary or common purpose of 

which is to function by explosion. The term includes, but is not limited to, dynamite 

and other high explosives, black powder, pellet powder, initiating explosives, 

detonators, safety fuses, squibs, detonating cord, igniter cord, and igniters." 

Explosive materials have been divided into three classes by the ATF for purposes of regulating storage: 

- 5 -

U 
• High Explosives: those explosives which can be detonated by means of a blasting 

cap when unconfined (e.g., TNT, dynamite). 

• Low Explosives: those explosive materials which can be caused to deflagrate when 

confined (e.g., black powder, safety fuses, and DOT Qass B explosives). 

• Blasting Agents: any material or mixture consisting of a fuel and oxidizer that is 

intended for blasting and not otherwise defined as an explosive, provided that the 

finished produa cannot be detonated by a No. 8 blasting cap when unconfined 

(e.g., ammonium nitrate/fuel oil (ANFO) and certain water gels). 

Note that blasting agents are very insensitive and unlikely to explode; however, in the event that they do 

explode, the consequence may be a detonation, with accompanying overpressure, as for high explosives, rather 

than a deflagration (intense fire), as for low explosives. For example, an explosion of the blasting agent ANFO 

killed six fire fighters in Kansas City, MO (see Section 2.2). 

The ATF regulations contain a table, called the Table of Distances," (see Exhibit 2) which must be 

used by explosive materials handlers to determine acceptable minimum separation distances for storing and 

handling high explosives and blasting agents. The table also states the maximum quantities of explosives 

allowed in any one location. Locations that contain explosives must be separated from: 

• Inhabited buildings, including structures or other places not directly related to 

explosives operations where people usually assemble or work; 

• Public highways; 

• Passenger railways; and 

• Other locations which contain explosives. 

For example, if a site has from 40 to 50 pounds of high explosives in one magazine, there can be no 

unbarricaded inhabited building (e.g., a home) within 300 feet (91 meters) of that magazine. A separate table 

is provided for determining separation distances for the storage of low explosives (see Exhibit 3). These 

distance requirements differ from those for high explosives because the consequences of an accident involving 

low explosives are likely to result from thermal radiation rather than overpressure. In all instances, the 

separation distances increase as the quantity of explosives stored increases. 

The original Table of Distances was published in 1910 based on the work of a special committee of the 

Association of Manufacturers of Powder and High Explosives. This committee gathered and evaluated 

information on a number of explosions ranging from small amounts of explosive materials to one million 

pounds. Since then, the table has been revised periodically to incorporate information obtained from past 

accidents. The explosions studied have covered a period of almost fifty years and have occuned in 

manufacturing, transportation, and storage, both in the United States and abroad. The last revision to the 

table was in 1985. The table is designed to cover manufacture and permanent storage of explosive materials 

and is not applicable for the incidental handling or temporary storage of explosive materials being transported. 

ll 
P.13 

33 Otiier Standards 

Other agencies such as the Occupational Safety and Health Administration (OSHA), Mine Safety and 

Health Administration (MSHA), Department of Defense (DOD), the International Maritime Organization 

(IMO), and others regulate certain aspects of the explosives industry. For example, DOD regulates the storage 

of munitions and military explosives, OSHA regulates worker safety at explosives manuCaauring sites, and the 

IMO is concerned with international shipments of hazardous materials. 

4.0 Comparison of Methodologies for Determining Affected Distances for Commercial Explosives 

4.1 Approach 

The Agency's Physical/Chemical Criteria Workgroup compared the results of several methods for 

estimating the consequences of explosions and evaluated the effea of quantity exploded on the distance 

affeaed at various overpressure levels. The approach used for this comparison was to obtain published safe 

storage distances from the Table of Distances (see discussion of ATF standards) for varying quantities and 

types of explosive materials and compare them to distances derived from other widely recognized explosives 

consequence methodologies such as the K-factor and the Automated Resource for Chemical Hazard Incident 

Evaluation (ARCHIE) computer program. 

4.1.1 Explosive Materials Selected 

For this analysis, commercial explosives have been grouped into three categories: high, low, and blasting 

agents, in the same way ATF has classified explosives for storage purposes. The analysis has been performed 

using explosive materials representing each of the three categories as follows: 

High Explosives 

• Amatol (60/40) (Ammonium nitrate/TNT) 

• Silver azide (CAS number 13863-88-2) 

• Amatol (50/50) (Ammonium nitrate/TNT) 

• Metriol trinitrate (Trimethylolethane trinitrate) 

• PLX (Picatinny Liquid Explosive: Nitromethane, CAS number 75-52-5, with 5 percent ethylene 

diamine, CAS number 107-15-3) 

• Tetryl (N-Methyl-2,4,6-tetranitroaniline, CAS number 479-45-8) 

• TNT (2,4,6-Trinitrotoluene, CAS number 118-96-7) 

• Lead azide (CAS number 13424-46-9) 

Tnw Rtplnstves 

• Blade Powder (usually mixture of 75 percent potassium nitrate, 10 percent sulfur, and 15 percent 

charcoal (Meyer 1987)) 

Blasting Agents 

• Ammonium Nitrate Fuel Oil (ANFO) (94 percent ammonium nitrate, 6 percent fuel oil) 

These explosive materials have been chosen based upon the availability of chemical/physical property data and 

known commercial use. Single examples of low explosives and blasting agents were used due to the small 

number of materials regulated as such for which data are available. 

- 7 -

.£ 
4.1.2 Damage Criteria 

The next step in the consequence analysis is the identification of credible accident scenario(s). For 

high explosives, only one scenario is likely: a quantity of explosive is somehow detonated. Damage from 

accidents involving explosives is a function of the peak overpressure resulting from the blast wave. This is 

discussed further in Section 4.2.1 below and in Appendix B. In the analysis which was used to determine the 

threshold planning quantities for acutely toxic materials, lethality was chosen as the endpoint In the case of 

explosions, human deaths and injuries may be caused directly by blast waves or indirectly by flying glass or 

other objects. Very high overpressures are needed for fatality as a direa result of an explosion; various 

sources dte threshold levels for fatality of 14.5 pounds per square inch (psi) to 120 psi (see Appendix B). 

However, much lower overpressures may cause property damage that might lead to human injury or death. 

For this analysis, EPA considered blast overpressures of 0.5 psi, 1.0 psi, 2.0 psi, and 3.0 psL An overpressure 

of 0.5 psi can cause shattering of glass windows (Brasie and Simpson 1968, US Air Force 1983, US DOT 1988, 

Lees 1980). An overpressure of 1.0 psi can cause partial demolition of houses, and is the threshold for skin 

laceration from flying glass (Lees 1980). An overpressure level of 2.0 psi can lead to the partial collapse of 

walls and roofs of houses and shattering of non-reinforced concrete or cinder block wall panels (Brasie and 

Simpson 1968, Air Force 1983, U.S. DOT 1988, Lees 1980). Overpressures between 2.0 and 3.0 psi can cause 

eardrum rupture (Lees 1980). Overpressure of 3.0 psi can cause a steel frame building to become distorted 

and pull away from its foundations (Lees 1980); it can also hurl a person to the ground (Brasie and Simpson 

1968). 

Appendix B contains more detailed background information on blast overpressures and their effects. 

The results of consequence analysis at different overpressures are presented in Section 4.3.1 and graphically 

in Appendix B. The results show that, as would be expeaed, if a higher overpressure is chosen, the blast effea 

extends over a shorter distance. However, the affeaed distance does not change linearly with overpressure; 

the rate of decrease in distance is considerably greater between overpressures of 0.5 psi and 1.0 psi than 

between 1.0 psi and 10 psi or 2.0 psi and 3.0 psi (see Section 4.3.1 and Exhibit B-6). 

4.13 Assumptions 

The following assumptions were made in the consequence analysis: 

• Explosions occur at ground level; and 

• The area surrounding the explosion is charaaerized by flat open terrain. 

In actuality, potential reflections of the blast or shock wave from building walls or the sides of other obstacles 

and surfaces may cause damage to be somewhat more erratic than that predirted using these assumptions; in 

fact, damage may be increased, especially if there are obstades parallel to the shock wave front However, the 

above assumptions are used widely in performing consequence analyses for explosive materials. 

4.1A Quantities Modeled 

The following quantities of material were utilized in the analysis: 50,100,250,1,000 and 5,000 pounds. 

These amounts were chosen to provide a wide range of values in the analysis. 

H 
P.15 

42 Methodologies for Determining Explosive Distances 

4.2.1 Scaling Law for Explosives 

Damage from explosions is primarily a function of the peak overpressure resulting from the blast wave 

and is not dependent upon one specific physical or chemical property. It is a function of an empirically 

derived function, known as the scaling law: 

D = (K)(W1/3) 

where: D = Required, or potentially affeaed, distance, ft 

K = Protection faaor depending upon the degree of risk assumed or permitted; the relationship 

between the peak overpressure and the K faaor is shown in Exhibit 1 (e.g., using this 

exhibit, a K-faaor of 11 (Kll) corresponds to a peak overpressure level of 8 psi) 

W =TNT equivalent weight, lb 

The TNT equivalent weight is the weight of TNT that would yield the same peak pressure or impulse at a 

given distance as the total weight of explosive material under consideration. 

The scaling law relates peak overpressure, explosive weight, and distance for the purpose of evaluating 

the effects of blast waves. Blast waves generated during an explosion of a given material are compared to 

those which would have resulted from an explosion involving TNT (Le., TNT is used as a reference material): 

This approach is used because of the large amount of experimental data available on blast waves from TNT 

explosions and on damage produced by TNT explosions. This relationship is applicable to any explosion 

provided the equivalent weight of TNT is known. The scaling law is the basis for the consequence analysis 

methodologies discussed below. 

There are several limitations of the scaling law using TNT equivalent weights that need to be 

recognized (U.S. DOT 1988). They are: 

• Not all of the acddentally-released material may be involved in the explosion. Part 

of the material may disperse without reacting and part may reaa at a different 

time or location from the initial explosion. As such, measured TNT yields of 

explosive materials depend upon acddent conditions, duration, and failure mode; 

• Of the portion of released material that reacts in the explosion, part may detonate 

and part may deflagrate, with the latter contributing little energyto the blast 

Predicting whether a detonation or a deflagration (or a combination) will occur is 

very complex. The outcome depends on the materials' properties and on the 

conditions of the acddent; 

• The blast charaaeristics of the released material may be different from those of 

a TNT charge with an equivalent energy. For example, measured overpressure 

amplitudes are generally lower and durations are longer for low explosives than for 

TNT because of slower reaction rates; and 

-9 

15 
EXHIBIT 1. K-FACTORS AS A FUNCTION OF PEAK OVERPRESSURES 

6 8 u n 

K-fACTOR (FT/US.*" . 

Source: U.S. Air Force. 1983. "Explosives Safety Standards," Air Force Regulation 127-100. 20 May 1983. 

-10 -

Id 
~

!mWk 

m TNT yields are only available for materials which have been tested. New 

chemicals would require testing before consequence analyses could be 

performed (See Appendix A). 

As the above limitations indicate, the TNT yield of a material is not an absolute property such as density or 

molecular weight Instead, it depends upon the test conditions under which it is measured (See Appendix A 

for information on some of the tests used; e.g., the lead block test and the ballistic mortar test). These 

limitations, however, do not present a serious problem in the use of the scaling law equation since the 

dependence of blast parameters on yield is low due to the cube-root exponent in the equation. The prediction 

of a hazard distance is not very sensitive to the TNT equivalent weight Further, the limitations of the 

equation will generally lead to a worst-case estimate and, hence, a conservative analysis. The TNT method 

of analysis has been used effectively over many years despite the limitations mentioned above. 

The scaling law is accepted widely and well established in the published technical literature. It has 

been adopted by several government agendes, including the Bureau of Alcohol, Tobacco, and Firearms, the 

Department of Defense, and the U.S. Air Force, and private companies for related uses, including hazards 

assessment and emergency response and planning. It is used in some of the existing classification systems for 

commercial explosives which are described above in Section 3.0. No other methods of estimating blast wave 

effects have been found. 

EPA seleaed the following commonly used methodologies for comparison with the ATF standards: 

• ARCHIE: A computerized hazard assessment model developed for DOT, FEMA, and 

the EPA; and 

• K-Factor. Use of the scaling law, as described above. 

The discussion of methodologies begins with a description of the ATF standards and distances 

obtained using the Table of Distances. Following the ATF section are descriptions of the ARCHIE and the 

K-factor methods and a comparison of results obtained using each. Appendix C provides an analysis of the 

quantitative differences in results. 

4.2.2 ATF 

The primary purpose of the ATF regulations is to control the distribution of explosive materials to 

authorized persons. As part of this goal, the ATF regulations specify a set of standards to be used in the safe 

storage of explosives. The standards are set forth in tabular form in two tables: (1) the Table of Distances" 

for high explosives and blasting agents as shown in Exhibit 2, and (2) a second table for low explosives as 

shown in Exhibit 3. The distance requirements in these tables are designed to ensure that explosives stored 

in accordance with the regulations will not present an off-site hazard. The original Table of Distances is based 

upon the scaling law and was developed by the Institute of Makers of Explosives (IME) (Dowling 1989). Since 

the equation that the table is based upon is known, additions may be made to the table depending upon the 

needs of the analysis. For example, the table for high explosives (Exhibit 2) has several columns representing 

different overpressures and damage criteria. In calculating the safe distance to an unbarricaded inhabited 

building (fourth column), an overpressure of 0.4 psi is used. In contrast, in determining the safe distance to 

a barricaded inhabited building (third column), an overpressure of 4.5 psi is used, and distance requirements 

11 

tf 
P.18 

* i _-"*•< 

EXHIBIT 2 

TABLE OF DISTANCES - HIGH EXPLOSIVES & BLASTING AGENTS^/ 

QUANTITY OF EXN.OSIVES 

flai l 

• wr 

2 

S 

10 

20 

30 

40 

SO 

75 

100 

125 

150 

200 

250 

300 

400 

500 

600 

700 

too 

900 

1.000 

1.200 

1.400 

1.800 

1.100 

2.000 

2.500 

3.000 

4.000 

5.000 

1.000 

7.000 

1.000 

S.000 

10.000 

12.000 

14.000 

16.000 

18.000 

20,000 

25.000 

30.000 

35.000 

40.000 

45.000 

50,000 

55.000 

60,000 

65,000 

704100 

75.000 

80,000 

85.000 

90.000 

95.000 

100,000 

110.000 

120.000 

130.000 

140,000 

150.000 

160.000 

170.000 

180.000 

190.000 

200,000 

210.000 

230.000 

750 001 

.75.000 

f M n 

MtM f 

5 

10 

20 

30 

40 

50 

75 

100 

125 

ISO 

200 

250 

300 

400 

500 

600 

700 

too 

900 

1.000 

1.200 

1.400 

1.600 

1.800 

2.000 

2.500 

3.000 

4.000 

5.000 

6.000 

7.000 

8.000 

9.000 

10.000 

12.000 

14.000 

16.000 

16.000 

20,000 

25.000 

30.000 

35.000 

40.000 

45.000 

50.000 

55.000 

60.000 

65.000 

70.000 

75.000 

80.000 

85.000 

90,000 

95.000 

100.000 

110.000 

120.000 

130.000 

140.000 

150.000 

160.000 

170.000 

"180.000 

190.000 

200,000 

210.000 

230.000 

250.000 

275 000 

M0.000 1 

laMMM 

tortc s M 

70 

90 

110 

125 

140 

150 

170 

190 

200 

215 

235 

255 

270 

295 

320 

340 

355 

375 

390 

400 

425 

450 

470 

490 

505 

545 

SM 

635 

605 

730 

770 

WO 

835 

MS 

175 

115 

NO 

040 

975 

1.055 

1.130 

1.705 

1,275 

1,340 

1.400 

1.460 

1.515 

1.565 

1.610 

1.655 

1.695 

1.730 

1.780 

1.790 

1.615 

1435 

1.855 

1.175 

1.890 

1.900 

1.935 

1.965 

1.990 

2.010 

2.030 

2.05* 

2.100 

2.155 

2.m 

1 U7J 

lilli-t i 

Makam-

» 1 H 

140 

I M 

220 

250 

2N 

300 

340 

310 

400 

430 

470 

510 

540 

590 

640 

(80 

710 

750 

780 

too 

ISO 

900 

940 

910 

1.010 

1.090 

1.110 

1.270 

1.370 

1.460 

1.54. 

1.600 

1.670 

1,730 

1.750 

1.770 

1.100 

i.tto 

1.950 

2,000 

2.006 

2.000 

2.000 

2.000 

2,000 

2.000 

2.000 

2.000 

2.000 

2.000 

2.6U 

2.000 

2.000 

2.000 

2.000 

2.000 

2.000 

2.000 

2.000 

2.000 

2.000 

2.000 

2.000 

2,010 

2.030 

2.055 

2,100 

2.155 

:.2i | 

2-210 

MITMCtt IB TOT 

fvMlc Mgtaraiv 

cit x m i 

urnu * « 

30 

35 

45 

50 

55 

60 

70 

75 

to 

IS 

IS 

105 

110 

120 

130 

135 

145 

ISO 

155 

160 

IIS 

170 

175 

110 

its 

190 

195 

210 

225 

235 

.45 

250 

255 

260 

270 

275 

2M 

285 

290 

315 

346 

300 

3M 

400 

420 

44. 

455 

470 

415 

500 

510 

520 

530 

540 

545 

550 

555 

560 

565 

570 

510 

590 

600 

605 

610 

-2. 

635 

690 

670 

690 

MtMTtUtH 

60 

70 

M 

100 

110 

120 

140 

150 

160 

170 

m 210 

220 

240 

200 

270 

290 

300 

310 

320 

UO 

340 

350 

360 

370 

m 300 

420 

450 

470 

4H 

500 

510 

520 

540 

55S 

5M 

570 

5M 

630 

US 

720 

760 

too 

MO 

iU 

110 

940 

970 

1.000 

1.0H 

1.040 

1.0M 

1.0M 

1.0M 

1,100 

1.110 

1.120 

1.130 

1.140 

1.180 

1.180 

1.2M 

1.210 

1-220 

1-24fl 

1,271 

1.3M 

1.340 

1.3M 

TfSMc VMMH flf M l 

t k a M M VMMii/ta r 

lan. 

CMM 

51 

M 

11 

93 

103 

110 

127 

139 

ISO 

159 

175 

I N 

201 

221 

231 

253 

2M 

271 

2N 

3M 

111 

338 

351 

3M 

371 

4tt 

432 

474 

513 

541 

Stt 

MS 

124 

MS 

M7 

m 7M 

7M 

113 

171 

4M 

NI 

1.1B6 

1.0M 

1,104 

1.141 

1,173 

UOO 

1-238 

1X3 

1X3 1.317 

1.344 

1.3M 

1.392 

1.4)7 

1,479 

1.521 

1.557 

1.593 

1.629 

1.682 

1.695 

1.725 

1.755 

1.7*} 

1.M0 

1.M0 

>.9» 

2.N0 

MftS-Tt* 

am* 

102 

120 

i n 

IM 

200 

220 

254 

270 

300 

310 

350 

371 

402 

442 

471 

SM 

532 

SM 

571 

600 

tit 

672 

702 

732 

7M 

811 

8M 

941 

1.020 

1.002 

1.144 

1.2M 

U 4 I 

1.2M 

1,374 

1.4M 

1.512 

1.572 

1.628 

1.752 

l.ltt 

1.962 

2.000 

2.0M 

2.0M 

2.000 

2.0M 

2.0M 

2.0M 

2.0M 

MM 2.000 

2.0M 

2.000 

2.000 

2.000 

2.0M 

2.0M 

2.000 

2.000 

2.0U 

2.0M 

2.0M 

2,000 

2.000 

2.AM 

2.0M 

2.0M 

2JM 

2.0M 

IMMKI M 

Macittot 

•art. 

c a M 

1 

1 

10 

11 

12 

14 

15 

11 

11 

11 

21 

23 

24 

27 

29 

31 

32 

33 

39 

36 

39 

41 

43 

44 

45 

40 

52 

M 

61 

65 

ii 

72 

75 

71 

12 

17 

90 

M 

N 

105 

112 

119 

124 

129 

135 

140 

145 

IM 

155 

I M 

I N 

170 

175 

IM 

I U 

195 

205 

215 

225 

235 

245 

255 

265 

275 

215 

295 

315 

335 

3M 

M5 

•akarrtf * t 

12 

11 

20 

22 

24 

21 

M 

32 

M 

M 

42 

41 

a 54 

M 

62 

64 

M 

70 

72 

76 

62 

M 

M 

M 

N 

104 

116 

122 

I M 

I M 

144 

I M 

IM 

164 

174 

IM 

IM ' 

I N 

210 

224 

238 

240 

2M 

270 

2M 

290 

300 

310 

320 

3M 

340 

3M 

3M 

370 

3M 

410 

4M 

4M 

470 

490 

510 

530 

5M 

570 

5M 

6M 

670 

720 

77_ 

A separate table is provided by ATF for determining required distances between blasting agents and 

explosives or other blasting agents. 

12 

l<3 
P.19 

EXHIBIT 3 

TABLE OF DISTANCES - LOW EXPLOSIVES 

P( 

Over 

0 

1,000 

5,000 

10,000 

20,000 

30,000 

40,000 

50,000 

60,000 

70,000 

80,000 

90,000 

100,000 

200,000 

ounds 

Not Over 

1,000 

.5,000 

10,000 

20,000 

30,000 

40,000 

50,000 

60,000 

70,000 

80,000 

90,000 

100,000 

200,000 

300,000 

From 

Inhabited 

Building 

75 

115 

150 

190 

215 

235 

250 

260 

270 

280 

295 

300 

375 

450 

Distances (ft) 

From Public 

Railroad & 

Highway 

75 

115 

150 

190 

215 

455 

250 

260 

270 

280 

295 

300 

375 

450 

From 

Above Ground 

Magazine 

50 

75 

100 

125 

145 

155 

165 

175 

185 

190 

195 

200 

250 

300 

Source: ATF P 5400.7 (11/82), "ATF: Explosives Law and Regulations," Bureau of Alcohol, Tobacco, and 

Firearms, Department of the Treasury. 

-13 

\°» 
-*• -*»• 

are lower. Barricades, by ATF definitions, can be natural barriers, such as hills or dense timber, or artifidal 

barriers, such as mounds or walls of earth. Such barricades must be high enough that a straight line from the 

top of the barricaded magazine (explosives storage building) to the eave line of another magazine or building, 

or "to a point 12 feet above a railway or highway, will pass through the barricade. Presumably, a barricaded 

building could withstand higher overpressures (Le., overpressures that might occur closer to the explosion site) 

than an unbarricaded building. Data are provided for four overpressure levels.3 However, distances based 

on various other overpressures can be calculated since the equation for the table is known. 

The differences between the scaling law and the table for high explosives are the following: 

• The ATF assumes that all high explosives and blasting agents have roughly 

equivalent explosive energies and therefore does not calculate an explosive 

weight based upon TNT equivalents (W = M^^, rather than W = 

[Mchem

 x %TNT]) for each high explosive material; and 

where: 

W = TNT equivalent weight 

Mchem = Total mass of the explosive material 

% TNT = TNT equivalent (fraction) 

• The Tables provide specific distances for ranges of weights, resulting in some 

degree of error, especially at the endpoints. For example, the distance 

determined using the table for a high explosive weighing 4,000 pounds is 

the same as the distance for one weighing 5,000 pounds. 

The Table of Distances for low explosives (see Exhibit 3) was originally developed by the Department 

of Defense and adopted by ATF for application to the private seaor. It is designed for use with materials that 

deflagrate rather than detonate. The distances are based on levels of heat flux produced by a fireball rather 

than blast overpressures. The heat flux level used for determining distances is 4 calories per square inch; no 

exposure time is specified. When the table was developed, this heat flux was considered to be a level at which 

people could avoid injury by moving away. To calculate distances, the following equation (empirically derived) 

is used for inhabited buildings and public railroads and highways (Moran 1989): 

D = 8W W 

where: 

D = Required, or affeaed, distance in feet 

W = Weight of material in pounds. 

For determination of distance to magazines, the equation isD = 5W w (Moran 1989). Because the table 

of distances for low explosives is based on thermal radiation, the ARCHIE and "K-fattor" methodologies 

discussed below, which are based on blast overpressures, do not give comparable results. None of the models 

3

 In determining the safe distance to a barricaded public highway, an overpressure of 4.5 psi is used; 

for unbarricaded public highways and barricaded passenger railways and high volume public highways, an 

overpressure of approximately 1.75 psi is used; for unbarricaded railways and high traffic public highways, an 

overpressure of between 0.6 and 0.7 psi is used; and for unbarricaded inhabited buildings, an overpressure of 

0.4 psi is used. 

-14 -

30 
P.21 

reviewed that give thermal radiation results (e.g., models for pool fires and BLEVEs) appear to be applicable 

to explosives that deflagrate (Le., low explosives). However, as low explosives such as black powder may 

detonate under some conditions, it may be appropriate and conservative to carry out consequence analysis for 

these materials using the same methods as for high explosives (i.e., the K-factor method and the ARCHIE 

model for condensed-phase explosions). 

4.2.3 ARCHIE 

The Automated Resource for Chemical Hazard Inddent Evaluation (ARCHIE) computer program 

was developed for FEMA, DOT, and EPA to provide emergency planning personnel with the tools necessary 

to assess the vapor dispersion, fire, and explosion impacts assodated with hazardous materials acddents. 

Contained within the program are several methods for evaluating the consequences of an explosion, depending 

upon the type of material involved Model "K", the Condensed-Phase Explosion Model, was used for this 

analysis. The model is based upon the scaling law discussed earlier and is appropriate for use with commercial 

explosives. The Condensed-Phase Explosion Model differs from the scaling law in that the TNT-equivalent 

weight is calculated as a function of heat of combustion and empirically derived yield factors, rather than as 

a function of an empirically derived TNT equivalence. (See Appendix C for a brief discussion of heat of 

combustion and heat of explosion.) In addition, the curve relating K to overpressure has been approximated 

by a logarithmic expression. The ARCHIE manual presents the following equation for determining distance: 

X = (M-rNT^Xexp (3.5031 - 0.72411n(Op) + 0.0398(lnOp)2)) 

where: X = Required distance, ft 

MTNT = Adjusted equivalent mass of TNT, lb 

- [McteBx[(AH0/1155)xYt]] 

Mchem ~ Original mass of explosive material 

AHC = Lower heat of combustion of explosive material, kcal/kg 

Yf = Yield faaor 

Op = Peak overpressure, psi 

1155 = Heat of explosion of TNT, kcal/kg 

The ARCHIE manual recommends using a yield faaor of one for condensed-phase explosions (Le., 

it is assumed that all of the energy is available for the explosion). 

The following expression, from the above equation, gives an approximation of the K-faaor at a given 

overpressure: 

exp (3.5031 - 0.7241 ln(Op) + 0.0398(lnOp)

2

) 

The primary limitation of this method is that it attempts to estimate TNT equivalence, an empirically 

derived parameter, with heats of combustion using yield faaors, another empirically derived parameter. Note 

also that the heat of explosion given for TNT, 1155 kcal/kg, is higher than the heat of explosion reported 

elsewhere, 1011 to 1090 kcal/kg (Kirk-Othmer 1980, Meyer 1987). In addition, the equation approximating 

the curve relating overpressure to K is imprecise at the endpoints. 

15-

oli 
While the ARCHIE manual presents the above equation for estimating the K-faaor, it appears, based 

on an analysis of the model results for several chemicals, that the model actually uses seleaed values of the 

K-faaor corresponding to specific consequences rather than the equation for the K-faaor and, therefore, the 

results produced by the computer model are somewhat different from the results obtained from the equation. 

The model results are presented as distances (or ranges of distances) to 14 damage levels. Apparently the Kfaaor for the overpressure related to each of these damage levels is included in the model. 

Exhibit 4 presents a sample printout of ARCHIE model results for 250 pounds of tetryl (heat of 

combustion 5,262 BTU/lb). The expeaed damage levels presumably correspond to the overpressures and 

expeaed damage presented in the ARCHIE manual, Le., "Windows usually shattered; some frame damage" 

corresponds to overpressures of 0.5 psi • 1.0 psL An overpressure of 0.5 psi would be reached at 368 feet from 

the explosion; an overpressure of 1.0 psi would be reached at 212 feet (See Appendix B for more information 

on the effects of various overpressure levels.) 

4.2.4 "K-Factor" Methodology 

The K-faaor methodology is equivalent to the straight usage of the scaling law. The scaling law is 

represented by the following equation: 

where: 

D = (K)(W1/3) 

D = Required, or affeaed, distance, ft 

K = Protection faaor (see Exhibit 1) 

W = TNT equivalent weight, lb. 

As described in Section 4.3.2, W in the above equation is equal to the TNT equivalent weight of the 

material of concern as follows: 

W = [M^ x %TNT] 

where: 

Mchem = Total mass of chemical 

%TNT = TNT equivalent; the ratio of the quantity of TNT to the quantity of explosive 

material that will have an equivalent effect 

The %TNT, or TNT equivalent, varies and is derived for each explosive material from empirical tests and 

actual acddents involving TNT and other explosive materials. 

The parameter K in the scaling law is referred to as the protection faaor. It is a function of the peak 

overpressure and is independent of the material of concern. The value of K at a given overpressure is 

determined from the graph shown in Exhibit 1. 

16 

SQ 
P.23 

* **HHf_i_—W—v 

EXHIBIT 4. SAMPLE PRINTOUT OF ARCHIE MODELING RESULTS FOR 250 POUNDS OF TETRYL 

(HEAT OF COMBUSTION 5,262 BTU/LB.) 

CONDENSED-PHASE EXPLOSION EFFECTS 

DISTANCE FROM EXPLOSION EXPECTED DAMAGE 

(feet) 

6895 Occasional breakage of large windows under stress. 

972 Some damage to home ceilings; 10% window breakage. 

363 - 629 Windows usually shattered; some frame damage. 

363 Partial demolition of homes; made uninhabitable. 

93 - 363 Range serious/slight injuries from flying glass/object. 

219 Partial collapse of home walls/roofs. 

167 - 219 Non-reinforced concrete/cinder block walls shattered. 

75 - 194 Range 90-1% eardrum rupture among exposed population. 

189 50% destruction of home brickwork. 

140 - 167 Frameless steel panel buildings ruined. 

122 Wooden utility poles snapped. 

101 - 122 Nearly complete destruction of houses. 

83 Probable total building destruction. 

50 - 69 Range for 99-1% fatalities among exposed populations 

due to direct blast effects. 

Note: The explosion is assumed to take place on or near the ground. 

Note that the distances provided by the ARCHIE model are in feet Since the Agency has used meters as the 

unit of measure in its evaluations, the values here should be divided by 3.25 for purposes of comparison. 

17 

^ 
43 Results 

4.3.1 High Explosives 

• 

Exhibit 5 presents the faaors used and the results for analysis of eight high explosives using the 

ARCHIE equation, the ARCHIE model, and the K-faaor method at an overpressure of 0.5 psi, and the ATF 

table of distances for overpressure levels of 0.4 psi (the level used for development of the table) and 0.5 psi. 

Exhibits 6, 7, and 8 show the results at overpressures of 1.0 psi, 2,0 psi, and 3.0 psi, respectively. Distances 

for 0J, 1.0, 2.0, and 3.0 psi are not included in the ATF Table of Distances; the ATF distances at these 

overpressures were estimated from the K-faaor for purposes of comparison. Distances from the ATF Table 

of Distances (based on 0.4 psi) are also included in these exhibits for comparison. The analyses were carried 

out for 50,100,250,1,000, and 5,000 pounds of each high explosive material The exhibits show the heat of 

combustion used for ARCHIE modeling and the TNT equivalent and K value used in carrying out the distance 

calculations using the K-faaor method. A yield faaor of one was used for ARCHIE modeling in all cases, 

as recommended for condensed-phase explosions. Affeaed distance in meteis based) on each of the methods 

is shown. 

TNT equivalents are not taken into account in using the Table of Distances (Le., all materials are 

assumed to have the same explosive potential); however, the TNT equivalent is taken into account in the Kfaaor method. Therefore, the Table of-Distances gives greater distances than the K-faaor method for 

materials with TNT equivalents less than one, while the K-factor method gives greater distances than the Table 

of Distances for materials with TNT equivalents greater than one. (It should be noted that the TNT 

equivalent is an experimentally-derived quantity, not a physical property, and values may vary, depending on 

the test used. See Appendix C for additional discussion of the effea of varying TNT equivalents on the 

distances calculated.) 

The equation presented in the ARCHIE manual for calculating distance (see Section 4.2.3) does not 

give results that are consistently higher or lower than the K-factor method or the Table of Distances. This 

equation is based on a calculated K-faaor, which may be significantly different at a given overpressure from 

the K-faaor value read from the graph, and a TNT equivalent weight calculated from the heat of combustion 

of the material For an overpressure of 0.5 psi, the K-factor calculated using the ARCHIE equation is 56, 

compared to about 70 from the graph. At 1.0 psi, the equation gives 33, while the graph shows 43. At 2.0 

psi, a K-faaor of 20 is calculated from the equation, compared to 26 from the graph, and at 3.0 the calculated 

value is 16 and graph value is 20. The TNT equivalent used in the K-faaor method is based on empirical tests 

comparing the substance to TNT. In all the cases considered, the TNT equivalent calculated from the heat 

of combustion using the ARCHIE method is greater than TNT equivalents reported in the literature. Because 

both the calculated K-factor and the calculated TNT equivalent may affea the results of the ARCHIE 

equation, but in opposite ways (the lower K-factor would tend to lead to lower distances and the higher TNT 

equivalents to higher distances), no dear-cut comparisons can be made between the ARCHIE equation and 

the other methodologies. 

i 

The ARCHIE model yields greater distances than the K-faaor method, probably because heat of 

combustion rather than heat of explosion is used to calculate an approximate TNT equivalent Heats of 

combustion for explosives are generally higher than the heats of explosion, so the calculated TNT equivalent 

used by the ARCHIE model tends to be greater than the TNT equivalents from the literature (which are based 

on test results) that were used in the K-factor calculations. The K-factors used by the ARCHIE model (as 

I 18-

S* 
EXHIBIT 5. AFFECTED DISTANCES FOR COMMERCIAL HIGH EXPLOSIVES, DETERMINED 

USING FOUR DIFFERENT METHODS 

(Peak Overpressure = OS psi) 

Explosive 

Material 

Amatol 60/40 

, 

Amatol 50/50 

jfl~' 

Lead Azide 

Netriol 

Trinitrate 

PLX 

Silver Azide 

Tetryl 

TNT 

Amount 

(lbs) 

50 

100 

250 

1000 

5000 

50 

100 

250 

1Q00 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

Heat of 

Combustion 

(kcal/kg) 

1658 

; 

1990 

630 

2642 

2830 

1037 

2925 

3620 

TNT 

Equivalent * 

1.28 

1.24 

0.40 

1.38 

1.31 

0.88 

1.21 

1.00 

Overpressure 

(psi) 

0.5 

0.5 

0.5 

0.5 

0.5 

0.5 

0.5 

0.5 

K Value 

70 

70 

70 

70 

70 

70 

70 

70 

ARCHIE 

Model 

93 

117 

159 

252 

431 

99 

124 

169 

268 

458 

67 

85 

115 

183 

312 

109 

137 

185 

295 

503 

111 

140 

190 

301 

515 

80 

100 

136 

216 

369 

112 

141 

192 

305 

521 

120 

152 

206 

327 

559 

ARCHIE 

Equation 

71 

89 

121 

192 

329 

75 

95 

129 

204 

349 

51 

65 

88 

139 

238 

83 

104 

142 

225 

384 

85 

107 

145 

230 

393 

61 

76 

104 

164 

281 

86 

108 

146 

232 

397 

92 

116 

157 

249 

427 

Affected Distance (m) 

K-Factor 

85 

108 

146 

232 

396 

84 

106 

144 

229 

392 

58 

73 

99 

157 

269 

88 

110 

150 

238 

406 

86 

108 

147 

233 

399 

75 

95 

129 

204 

350 

84 

106 

143 

227 

389 

79 

99 

134 

213 

365 

ATF (0.5 psi)** 

79 

99 

134 

213 

365 

79 

99 

134 

213 

365 

79 

99 

134 

213 

365 

79 

99 

134 

213 

365 

79 

99 

134 

213 

365 

79 

99 

134 

213 

365 

79 

99 

134 

213 

365 

79 

99 

134 

213 

365 

. 

ATF (0.4 psi)+ 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

* Sources of TNT equivalents: NTIS 1971, NASA 1988, Kirk-Othmer 1980. 

** Estimated for purposes of comparison 

• The value of K corresponding to an overpressure of 0.4 psi is between 80 and 90. 

8l 
g 

EXHIBIT 6. AFFECTED DISTANCES FOR COMMERCIAL HIGH EXPLOSIVES, DETERMINED USING 

FOUR DIFFERENT METHODS 

(Peak Overpressure = 1.0 psi) 

Explosive 

Material 

Amatol 60/40 

Amatol 50/50 

/.-

. ••* 

Sl'eY.'' i -..•. 

..ead Azide 

Metriol 

Trinitrate 

PLX 

Si Iver Azide 

Tetryl 

TNT 

Amount 

(lbs) 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

Heat of 

Combustion 

(kcal/kg) 

1658 

> 

1990 

630 

2642 

2830 

1037 

2925 

3620 

TNT 

Equivalent * 

1.28 

1.24 

0.40 

1.38 

1.31 

0.88 

1.21 

1.00 

Overpressure 

(psi) 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

K Value 

43 

43 

43 

43 

43 

43 

43 

43 

ARCHIE 

Model 

54 

68 

92 

145 

248 

57 

72 

97 

155 

264 

39 

49 

66 

105 

180 

63 

79 

107 

170 

290 

64 

81 

109 

174 

297 

46 

58 

78 

124 

213 

v 65 

82 

111 

176 

300 

70 

88 

119 

188 

322 

ARCHIE 

Equation 

42 

53 

72 

114 

195 

45 

56 

76 

121 

208 

30 

38 

52 

83 

141 

49 

62 

84 

133 

228 

50 

63 

86 

136 

233 

36 

45 

62 

98 

167 

51 

64 

87 

138 

236 

55 

69 

93 

148 

253 

Affected 

K-Factor 

52 

66 

90 

142 

243 

52 

65 

89 

141 

241 

36 

45 

61 

97 

165 

54 

68 

92 

146 

250 

53 

67 

90 

143 

245 

46 

58 

79 

126 

215 

51 

65 

88 

140 

239 

48 

61 

83 

131 

224 

Distance (m) 

ATF (1.0 psi)** 

48 

61 

83 

131 

224 

48 

61 

83 

131 

224 

48 

61 

83 

131 

224 

48 

61 

83 

131 

224 

48 

61 

83 

131 

224 

48 

61 

83 

131 

224 

48 

61 

83 

131 

224 

48 

61 

83 

131 

224 

, 

ATF (0.4 psi)+ 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

* Sources of TNT equivalents: NTIS 1971, NASA 1988, Kirk-Othmer 1980. 

** Estimated for purposes of comparison. 

+ The value of K corresponding to an overpressure of 0.4 psi is between 80 and 90. 

tr 
s> 

EXHIBIT 7. AFFECTED DISTANCES FOR COMMERCIAL HIGH EXPLOSIVES, DETERMINED USING 

FOUR DIFFERENT METHODS 

(Peak Overpressure = 2.0 psi) 

Explosive 

Material 

Amatol 60/40 

Amatol 50/50 

^ 

Lead Azide 

:vH>.3l 

"r-nitrate 

PLX 

Silver Azide 

Tetryl 

TNT 

Amount 

(lbs) 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

Heat of 

Combustion 

(kcal/kg) 

1658 

- ' 

1990 

630 

2642 

2830 

1037 

2925 

3620 

TNT 

Equivalent * 

1.28 

1.24 

0.40 

1.38 

1.31 

0.88 

1.21 

1.00 

Overpressure 

(psi) 

2.0 

2.0 

2.0 

2.0 

2.0 

2.0 

2.0 

2.0 

K Value 

26 

26 

26 

26 

26 

26 

26 

26 

ARCHIE 

Model 

32 

41 

55 

88 

150 

34 

43 

59 

93 

159 

23 

30 

40 

64 

109 

38 

48 

65 

102 

175 

39 

49 

66 

105 

179 

28 

35 

47 

75 

128 

39 

49 

67 

106 

181 

42 

53 

72 

114 

195 

ARCHIE 

Equation 

26 

33 

44 

70 

121 

28 

35 

47 

75 

128 

19 

24 

32 

51 

87 

30 

38 

52 

82 

141 

31 

39 

53 

84 

144 

22 

28 

38 

60 

103 

31 

40 

54 

85 

146 

34 

42 

58 

91 

156 

Affected Distance (m) 

K-Factor 

32 

40 

54 

86 

147 

31 

40 

54 

85 

146 

22 

27 

37 

58 

100 

33 

41 

56 

88 

151 

32 

40 

55 

87 

148 

28 

35 

48 

76 

130 

31 

39 

53 

84 

144 

29 

37 

50 

79 

136 

ATF (2.0 psi)** 

29 

37 

50 

79 

136 

29 

37 

50 

79 

136 

29 

37 

50 

79 

136 

29 

37 

50 

79 

136 

29 

37 

50 

79 

136 

29 

37 

50 

79 

136 

29 

37 

50 

79 

136 

29 

37 

50 

79 

136 

ATF (0.4 psi)+ 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

Sources of TNT equivalents: NTIS 1971, NASA 1988, Kirk-Othmer 1980. 

Estimated for purposes of comparison. 

The value of K corresponding to an overpressure of 0.4 psi is between 80 and 90. 

5 
4 

K 

EXHIBIT 8. AFFECTED DISTANCES FOR COMMERCIAL HIGH EXPLOSIVES, DETERMINED 

USING FOUR DIFFERENT METHODS 

(Peak Overpressure = 3.0 psi) 

Explosive 

Material 

Amatol 60/40 

Amatol 50/50 

Lead Azide 

Metriol 

Trinitrate 

r*t " 

Silver Azide 

Tetryl 

TNT 

Amount 

(lbs) 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

50 

100 

250 

1000 

5000 

Heat of 

Combustion 

(kcal/kg) 

1658 

f 

1990 

630 

2642 

2830 

1037 

2925 

3620 

TNT 

Equivalent * 

1.28 

1.24 

0.40 

1.38 

1.31 

0.88 

1.21 

1.00 

Overpressure 

(psi) 

3.0 

3.0 

3.0 

3.0 

3.0 

3.0 

3.0 

3.0 

K Value 

20 

20 

20 

20 

20 

20 

20 

20 

ARCHIE 

Model 

25 

31 

42 

67 

114 

26 

33 

45 

71 

122 

18 

23 

31 

48 

83 

29 

36 

49 

78 

134 

30 

37 

51 

80 

137 

21 

27 

36 

57 

98 

30 

38 

51 

81 

138 

32 

40 

55 

87 

148 

ARCHIE 

Equation 

20 

25 

34 

54 

92 

21 

27 

36 

57 

98 

14 

18 

25 

39 

67 

23 

29 

40 

63 

108 

24 

30 

41 

65 

111 

17 

21 

29 

46 

79 

24 

30 

41 

65 

112 

26 

33 

44 

70 

120 

Affected 

K-Factor 

24 

31 

42 

66 

113 

24 

30 

41 

65 

112 

17 

21 

28 

45 

77 

25 

32 

43 

68 

116 

25 

31 

42 

67 

114 

22 

27 

37 

58 

100 

24 

30 

41 

65 

111 

22 

28 

38 

61 

104 

Distance (m) 

ATF (3.0 ps 

22 

28 

38 

61 

104 

22 

28 

38 

61 

104 

22 

28 

38 

61 

104 

22 

28 

38 

61 

104 

22 

28 

38 

61 

104 

22 

28 

38 

61 

104 

22 

28 

38 

61 

104 

22 

28 

38 

61 

104 

. 

) * * ATF (0.4 psi)* 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

97 

119 

160 

251 

431 

Sources of TNT equivalents: NTIS 1971, NASA 1988, Kirk-Othmer 1980. 

Estimated for purposes of comparison. 

The value of K corresponding to an overpressure of 0.4 psi is between 80 and 90. 
"••"•'^fifc 

estimated using the scaling law) are very close to the values read from the graph for use in the K-faaor 

method. The ARCHIE model gives greater distances than the ATF Table of Distances in cases where the 

calculated TNT equivalent is greater than one (Le., where the heat of combustion of the explosive is greater 

than 1155 kcal/kg, the heat of explosion of TNT dted by ARCHIE), and smaller distances where the TNT 

equivalent is less than one (Le., where the heat of combustion is less than 1155 kcal/kg). 

Comparison of distances affeaed at different overpressure levels shows a greater decrease in distance 

between 0.5 psi and 1.0 psi than between 1.0 psi and 2,0 psL The decrease is even smaller between 2.0 psi and 

3.0 psi. (Graphs of affeaed distance versus overpressure are presented in Appendix B.) For a given weight 

of explosive, affeaed distance is directly proportional to the K-faaor. The K-faaor is not linearly related to 

overpressure (see Exhibit 1), but decreases more rapidly with increasing overpressure at lower overpressures 

than at higher overpressures. Therefore, the overpressure chosen has a greater effea on the distance at lower 

overpressures (e.g., between 0.5 psi and 1.0 psi) than at higher overpressures (e.g., between 2.0 psi and 3.0 psi 

or at higher). 

43.2 Low Explosives and Blasting Agents 

Black powder was chosen as an example of a low explosive for analysis. Black powder was analyzed 

both as a low explosive (assuming that the material deflagrates) and as a high explosive (assuming that the 

material detonates). Exhibit 9 presents the distances calculated for the deflagration of five quantities of black 

powder, based on the equation used in developing the ATF Table of Distances for low explosives. Distances 

are reported in meters for comparison to the distances calculated for high explosives. The results for 

deflagration were obtained from the following equation, used for the derivation of the ATF Table of Distances 

for low explosives (see Exhibit 3): 

D = 8W W 

where: 

D = required, or affeaed, distance, ft 

W = weight of material, lb 

(The table itself was not used because of the wide ranges of quantities presented.) 

Black powder was also analyzed as a high explosive (assuming a detonation) using the ARCHIE model 

for condensed phase explosions, the equation presented in the ARCHIE manual, and the K-faaor method. 

Analysis was carried out for overpressures of 0J, 1.0, 2,0, and 3.0 psi for five quantities of black powder. 

Exhibit 10 shows the results of the analysis as well as the heat of combustion used for ARCHIE modeling and 

the TNT equivalent and K-value used, for the K-factor method. 

Comparison of Exhibits 9 and 10 shows that the Table of Distances for low explosives gives much 

shorter distances than the ARCHIE and K-faaor methods. This result is to be expeaed because the Table 

of Distances assumes a deflagration rather than a detonation and is based on thermal effects, while the 

ARCHIE and K-faaor methods assume a detonation and are based on blast overpressures. 

Ammonium nitrate fuel oil (ANFO), the most commonly used blasting agent, was analyzed as a high 

explosive at overpressures of 0.5, 1.0, 2.0, and 3.0 psL Results are presented in Exhibit 11. Analysis was 

carried out using the ARCHIE model, the ARCHIE equation, the K-factor method, and the ATF Table of 

Distances for high explosives. Faaors used for the analysis are also included in the exhibit Results for 

-23-

-i 

%°\ 
EXHIBIT 9. AFFECTED DISTANCES FOR LOW EXPLOSIVES, DETERMINED USING THE ATF 

TABLE OF DISTANCES FOR LOW EXPLOSIVES 

(Assuming Deflagration; Results Based on Thermal Radiation) 

Low Explosive: Black Powder 

Amount Affeaed 

(lbs) Distance 

(meters) 

50 9 

100 11 

250 15 

1000 24 

5000 42 

1 

-24 -

3o 
CP 

EXHIBIT 10. AFFECTED DISTANCES FOR LOW EXPLOSIVES, 

ANALYZED AS HIGH EXPLOSIVES, ASSUMING DETONATION 

(Overpressure OJ, 1.0, 2.0, and 3.0 psi) 

Heat of 

Combustion 

(kcal/kg)** 

Affected Distance (m) 

Explosive 

Material 

Amount 

(lbs) 

TNT 

Equivalent 

Overpressure 

(psi) K Value ARCHIE ARCHIE K-Factor 

Model Equation. 

Black Powder 

(0.5 psi) 

50 

100 

250 

1000 

5000 

684 0.50 0.5 70 69 

87 

118 

188 

321 

53 

66 

90 

143 

245 

62 

79 

107 

169 

290 

Black Powder 

(1.0 psi) 

50 

100 

250 

1000 

5000 

684 0.50 1.0 43 40 

50 

68 

108 

185 

31 

39 

54 

85 

145 

38 

48 

66 

104 

178 

K 

Black Powder 

(2.0 psi) 

50 

100 

250 

1000 

5000 

684 0.50 2.0 26 24 

30 

41 

65 

112" 

19 

24 

33 

52 

90 

23 

29 

40 

63 

108 

Black Powder 

(3.0 psi) 

50 

100 

250 

1000 

5000 

684 0.50 3.0 20 19 

23 

31 

50 

85 

15 

19 

25 

40 

69 

18 

22 

30 

48 

83 

* Source of TNT equivalent for black powder: NTIS 1971. 

** Heat of detonation for black powder (NTIS 1971); heat of combustion not available. 
EXHIBIT 11. AFFECTED DISTANCES FOR BLASTING AGENTS, 

ANALYZED AS HIGH EXPLOSIVES, ASSUMING DETONATION 

(Overpressure 03, 1.0, 2.0, and 3.0 psi) 

Explosive 

Material 

Heat of 

Amount Combustion TNT Overpressure 

(lbs) (kcal/kg)+ Equivalent * (psi) K Value ARCHIE 

Model 

ARCHIE 

Equation 

Affected Distance (m) 

K-Factor ATF ATF (0.4 psi)' 

ANFO 

(0.5 psi) 

50 

100 

250 

1000 

5000 

626 0.77 0.5 70 67 

85 

115 

182 

312 

51 

65 

88 

139 

238 

72 

91 

123 

196 

334 

79 

99 

134 

213 

365 

97 

119 

160 

251 

431 

r ANFO 

(1.0 psi) 

50 

100 

250 

1000 

5000 

626 0.77 1.0 43 39 

49 

66 

105 

180 

30 

38 

52 

83 

141 

44 

56 

76 

120 

205 

48 

61 

83 

131 

224 

97 

119 

160 

251 

431 

ANFO 

(2.0 psi) 

£ 

50 

100 

250 

1000 

5000 

626 0.77 2.0 26 23 

30 

66 

63 

109 

19 

24 

32 

51 

87 

27 

34 

46 

73 

124 

29 

37 

50 

79 

136 

97 

119 

160 

251 

431 

ANFO 

(3.0 psi) 

50 

100 

250 

1000 

5000 

626 0.77 3.0 20 18 

23 

30 

48 

83 

14 

18 

25 

39 

67 

21 

26 

35 

56 

96 

22 

28 

38 

61 

104 

97 

119 

160 

251 

431 

* Source of TNT equivalent: average of values from NTIS 1971, NASA 1988, Kirk-Othmer 1980. 

** The value of K corresponding to an overpressure of 0.4 psi is between 80 and 90. 

+ Heat of combustion for pure ammonium nitrate (Kirk-Othmer 1980); heat of combustion for ANFO not available. 

J 
-*°**m 

ANFO are similar to results for high explosives. ATF uses the Table of Distances for high explosives for 

blasting agents. Although blasting agents are much less likely to detonate than high explosives, the 

consequences, in the event of a detonation, might be expeaed to be similar to the consequences of a 

detonation of high explosives. (See, for example, the description of the Kansas City ANFO explosion in 

Section 2.2.) 

5.0 Findings 

In general, the ATF Table of Distances, the ARCHIE model, the ARCHIE equation, and the K-faaor 

method give results for high explosives and blasting agents that are of the same order of magnitude. As all 

three methods are based on the scaling law, similar results would be expeaed. In some cases, however, the 

results differ significantly, apparently because of the approximations made (Appendix C discusses the 

differences in more detail.) 

It is not clear that any of the three methods can be considered to have more validity or to give more 

conservative results than the others. However, it should be noted that the ATF Table of Distances is widely 

used and accepted, and that the Institute of Makers of Explosives and the Department of Defense favor the 

ATF method (Sawyer 1989, Dowling 1989). 

For low explosives, the ATF Table of Distances gives distances that are much shorter than the 

distances obtained using the ARCHIE and K-faaor methods. If it is determined that it is reasonable to treat 

black powder and other low explosives as materials with the potential to detonate, then the ARCHIE and Kfaaor results should probably be considered reasonable. In this case, the Table of Distances for high 

explosives would be used, rather than the table for low explosives. This would be consistent with ATF 

treatment of blasting agents, which, like low explosives, are much less likely to detonate than high explosives, 

but may have consequences similar to high explosives if they do detonate. 

27 

3B> 
REFERENCES 

ATF 1982. "ATF: Explosives Law and Regulations," P 5400.7, Bureau of Alcohol, Tobacco, and Firearms, 

Department of the Treasury, November 1982. 

Brasie, W., Simpson, D. 1968. "Guidelines for Estimating Damage Explosion," AIChE Symposium on Loss 

Prevention in the Process Industries, February 18-23,1968. 

Dowling, T. 1989. Telephone conversation between Tom Dowling, Institute of Makers of Explosives, 

Washington D.C and ICF Incorporated. June 12,1989. 

EPA 1988. "Acute Hazardous Events Data Base (1988)," Prepared for the Office of Policy Analysis, Office 

of Policy, Planning, and Evaluation, U.S. Environmental Protection Agency, Prepared by Industrial Economics, 

Incorporated, Cambridge, Massachusetts, 31 August 1988. 

Kirk-Othmer 1980. "Encyclopedia of Chemical Technology," Third edition, volume 9, John Wiley & Sons, Inc. 

1980. 

Lees, F. 1986. "Loss Prevention in the Process Industries: Hazard Identification, Volume I," Butterworth & 

Co. (Publishers) Ltd, 1980 (Reprinted 1986). 

McCune, L, 1989. Telephone conversation between Larry McCune, Bureau of Alcohol, Tobacco and Firearms, 

Explosives Technology Branch and ICF Incorporated. June 13,1989. 

Meyer, R. 1987. "Explosives," third, revised and extended edition, Sponsored by WASAGCHEMIE, 

Essen/Germany. 1987. 

Moran, P. 1989. Telephone conversation between Paul Moran, Department of Defense Explosives Safety 

Board, Washington, D.C and ICF Incorporated, November 1,1989. 

NFPA. "Fire Protection Handbook," 16th edition, National Fire Protection Assodation. 

NASA 1988. "Ignition and Thermal Hazards of Seleaed Aerospace Fluids," RD-WSTF-0001, National 

Aeronautics and Space Administration, Lyndon B. Johnson Space Center, White Sands Test Facility, Post 

Office Drawer MM, Las Cruces, New Mexico, Oaober 14,1988. 

NTIS 1971. "Engineering Design Handbook Explosives Series Properties of Explosives of Military Interest," 

AD-764 340 (AMCP 706-177), Headquarters, U.S. Army Materiel Command, Washington D.C, January 1971. 

Sawyer, R. 1989. Telephone conversation between Ray Sawyer, Department of Defense Explosives Safety 

Board, Washington D.C and ICF Incorporated. June 13,1989. 

Schultz, C 1989. Telephone conversation between Charlie Schultz, Department of Transportation and ICF 

Incorporated. July 5,1989. 

28 

M 
P.35 

REFERENCES (Continued) 

U.S. Air Force. 1983. "Explosives Safety Standards," Air Force Regulation 127-100. 20 May 1983. 

U.S. DOT. 1988. "Hazard Analysis of Commerdal Space Transportation," U.S. Department of Transportation, 

Office of Commerdal Space Transportation Licensing Programs Division. May 1988. 

White, L. 1989. Telephone conversation between Larry White, Bureau of Alcohol, Tobacco and Firearms and 

ICF Incorporated. June 13,1989. 

-29 

4 35 
P.36 

APPENDIX A 

TEST METHODS USED IN CLASSIFICATION OF COMMERCIAL EXPLOSIVES 

y* 
P.37 

APPENDIX A 

TEST METHODS USED IN CLASSIFICATION OF COMMERCIAL EXPLOSIVES 

Al SCREENING TESTS 

The extent and type of experimentation and testing carried out by users/handlers of explosive 

substances vary depending on the nature of the hazard. Some commonly used screening tests are presented 

in Exhibit A-l. These screening tests are performed on samples in a condensed phase to examine the tendency 

of a material to ignite because of an external source of a flame, to determine if the sample ignites upon 

indirect heating, and to determine the violence of decomposition when a substance catches tire or is heated 

indirectly (Yoshida 1987). 

A.1.1 Current Internationally Recognized Screening Tests 

Sealed Cell Differential Scanning Calorimetry (SC-DSC) 

This test is employed to estimate the decomposition initiating temperature and heat of decomposition. 

During this test, the sample is heated at a constant rate simultaneously with an inert sample which does not 

absorb or release heat when heated. The cell is sealed because it enables testing samples of materials which 

evaporate or sublime before or during the decomposition. 

The DSC operation is carried out at a heating rate of 10°C per minute. Heat supplied or removed 

to keep the temperatures of the sample and the reference substance is recorded and the difference (between 

that recorded for the sample and that for the reference substance) is plotted as millicalories per second versus 

the sample temperature to obtain a thermogram. The amount of heat released as the result of the 

decomposition is calculated using the equation: 

M x AH = KA 

where, M = sample weight (mg) 

AH = change in energy per unit weight (mcal/mg) 

K = apparatus constant, and 

A = peak area computed from the area of the chart 

Bundes Anstalt far Materiaprufung (BAM) Ignitability Test 

This test is employed to determine the tendency of a substance to catch fire from an external ignition 

source. This is carried out in four different ways, cesium-iron spark ignition test, safety fuse test, small gas 

flame test, and red-hot iron rod (at 800°C) test (Yoshida 1987). 

A-l 

3D 
EXHIBIT A-l 

SCREENING TESTS USED IN THE CLASSIFICATION OF COMMERCIAL EXPLOSIVES 

P.38 

Test Purpose 

Sealed Cell Differential Scanning 

Calorimetry (SC-DSC) 

BAM Ignitability Test 

Combustibility Test 

Ignition Point Test for Powdered 

solid samples 

Exothermidty Test 

Drop Hammer (drop weight) Tests 

Decomposition initiating temperature 

and heat of decomposition 

Tendency of a substance to catch 

fire from an external ignition source 

Ignitability and combustibility of solids 

Temperature at which dry sample 

ignites on a hot surface in air 

Minimum temperature at which a substance 

can undergo exothermic decomposition 

Impaa sensitivity of substances 

A-2 

3% 
In each of these test methods, the spark or the heated source is brought into contact with the sample 

(3 ml) to see if ignition or explosion occurs. The substances can be classified as: easily ignitable (if the sample 

ignites within one second), ignitable (if it ignites after more than one second elapses, and difficult to ignite 

(if the sample doesn't ignite). 

Combustibility Test 

This is a screening test popularly used in large chemical firms in Switzerland and West Germany to 

determine the ignitability and combustibility of solids. In this test, 5 ml of the sample is piled on an asbestos 

sheet and a red hot platinum wire is brought into contact with a corner of the sample for 5 seconds. If the 

sample does not ignite, the wire is inserted into the sample and left there for 5 seconds. If the sample 

decomposes and releases gases, a match stick is used to test the ignitability of the gases. The criteria used for 

the assessment of the observations made during this test are summarized in Exhibit A-2. 

Ignition Point Test for Powdered Solid Samples. 

This test is carried out to determine the temperature at which dry sample ignites on a hot surface in 

air. During this test, 100 mg samples are placed on hot steel plates attached to hot aluminum blocks 

maintained at temperatures of 240, 270, 300, 330, 360°C. The criteria used for the assessment of the 

observations made during the test are presented in Exhibit A-3. 

Exothermicity Test for Piled Powders 

This test is employed to measure the minimum temperature at which a substance can undergo 

exothermic decomposition. During this test, a 2 gram sample in a test tube is placed in an aluminum block 

which is used for heating. A 2 gram sample of powdered graphite in a tube is also placed in the same block 

as a reference substance. Temperatures of the sample and the reference substance are recorded, and any gas 

that is generated due to decomposition is tested for combustibility. The aluminum block is heated linearly 

up to 550°C. 

The assessment of the results are carried out as follows: 

1. If the sample temperature exceeds that of the reference 

temperature, it is concluded that an exothermic reaction has taken place. 

2. If the temperature difference between the sample and the reference substance reaches 30°C 

in 3 minutes, it is concluded that spontaneous exothermic decomposition has occurred. 

A-3 

S<? 
P.40 

EXHIBIT A-2 

ASSESSMENT CRITERIA IN THE COMBUSTIBILnY TEST 

Type of Reaction Grade 

After the start of 

ignition the flame 

does not spread 

Not ignited 

Fire extinguished immediately 

after ignition 

Localized burning or reddening 

with almost no flame 

propagation 

The flame spreads 

Reddening of the substance 

without sparks or slow 

decomposition without flames 

Firecracker type burning or 

slow and mild burning with 

visible flame 

Rapid burning with flame or 

decomposition without burning 

SOURCE: Yoshida, 1987 

A-4 

40 
P.41 

EXHIBIT A-3 

METHOD OF GRADING IN THE IGNITION POINT TEST 

Observed Results Qass 

No reaction at 360°C (But reaaion may occur at a higher temperature) 1 

Reaction occurs at 360°C 2 

Reaction occurs at 330°C 3 

Reaaion occurs at 300°C 4 

Reaction occurs at 270°C 5 

Reaction occurs at 240°C 6 

SOURCE: Yoshida, 1987 

A-5 

iri 
P.42 

Drop Hammer Sensitivity Tests 

There are various versions of drop hammer tests (or, drop weight tests) such as: BAM drop hammer 

test, U.S. Bureau of Mines (USBM) drop hammer test, Japanese Industrial Standards (JIS) Test. All these 

tests are aimed evaluating sensitivity of an explosive substance to mechanical impact. 

These test methods use dropping hammers (or, weights) ranging between 25 grams and 10 kg, and 

these weights are dropped on samples from heights ranging between 50 cm to 330 cm. The results are 

evaluated based on the frequency of observation of events such as burning, fire or sparking, production of large 

amount of smoke, or detonation. An example of hazard grading with respect to impact sensitivity is shown 

in Exhibit A-4. Based on the results of the screening tests, more detailed (and therefore more expensive) tests 

may be required. These tests are used to evaluate characteristics such as: detonability, deflagration-todetonation transition (DDT). The following section describes briefly the detailed tests that are currently used. 

A2 STANDARD TESTS 

The standard tests used for detailed evaluation of hazards assodated with explosives are presented in 

Exhibit A-5 (Yoshida 1987). 

A2.1 Explosiveness by Shock Initiation 

BAM 50/60 Steel Tube Test 

This test is used to determine if a substance has the potential to detonate. A sample size of 910 ml 

is packed in a steel tube, and the booster charge is placed at the center of the top. The booster charge which 

is used for firing consists of 95% RDX which is a high performance explosive. The assessment of the results 

consist of evaluating the potential for detonation based on the degree of shattering of the steel tube, as 

indicated below: 

YES: Complete shattering 

PARTIAL: More than 50% of the tube shatters 

NO: Less than 50% of the tube is shattered 

The description of the test (Yoshida 1987) also indicates that the rate of propagation of detonation 

can also be measured, however, it is not very dear how it is carried out. 

United States Bureau of Mines (USBM) Card Gap Test 

This test is employed to determine if a liquid has the potential to explode and measure initiation 

sensitivity of liquids to detonation shocks. A shock wave caused by the detonation of a high powered explosive 

is applied through a card gap to a liquid sample. The booster charge is made up of pentolite (50/50 

PETN/TNT) Air is blown because the detonability of liquids containing air bubbles is measured by this test. 

Velocity measurements are continuously carried out using a continuous velocity probe. Condusions are drawn 

based on the measured value of velocity of propagation, formation of a hole in the witness plate, and nature 

of fragmentation of the sample tube. 

A-6 

*% 
EXHIBIT A-4 

AN EXAMPLE OF HAZARD GRADING WITH RESPECT TO IMPACT SENSITIVITY 

Reaction observed Number of +'s Grade 

Fire, sparks, or fairly large 

amount of smoke 

0 - 1 

2 - 5 

6-10 

1 

2 

3 

Detonation 10 or more 

Source: Yoshida, 1987 

4

 The noise is 10 dB higher than the standard value. 

- A-7 

4*> 
P.44 

EXHIBIT A-5 

SUMMARY OF STANDARD TESTS USED TO EVALUATE HAZARDS ASSOCIATED 

WITH EXPLOSIVES 

Purpose Test 

Explosiveness by Shock Initiation BAM 50/60 Steel Tube Test 

USBM Card Gap Test 

Trauzl Lead Block Expansion Test 

Ballistic Mortar Test 

Ignitability and Violence of 

Deflagration 

BAM Red Glowing Steel Dish Test 

IMCO Burning Rate Test 

TNO Deflagration Test 

USBM Three inch DDT Test 

Occurrence and Violence of Decomposition 

and Deflagration due to External Heating 

Dutch Pressure Vessel Test 

US Pressure Vessel Test 

Field Combustion Tests for Unstable 

Substances 

Bonfire tests 

Burning Trials 

Bonfire and Fast Cookoff Tests 

External Fire Tests 

Violence of Spontaneous Decomposition 

During Storage 

US SADT Test 

BAM Heat Accumulation Storage 

Test 

Kotoyori's Spontaneous 

Ignition Tester (SIT) 

Source: Yoshida, 1987 

A-8 

4+ 
-'-"rlWff 

Trauzl Lead Block Test 

This test is used to estimate the explosion power of unstable substances. As the name suggests, a 

sample is placed in a lead block, and detonation is initiated using a cap. The explosion power is measured 

based on the size of the cavity produced in the lead block. 

The assessment criteria used are: 

HIGH: The volume of the cavity formed in the block is greater than 75 ml/10 gms 

of sample 

MEDIUM: The volume of the cavity is between 30 and 75 ml/10 gms 

LOW: The volume of the cavity is less than 30 ml/10 gms 

Ballistic Mortar Test 

This test is used to measure the explosive power of explosives. The sample is placed within the bore 

hole of a suspended mortar. A projectile is placed in the hole and detonation of the sample is initiated with 

a charge. The projectile is shot forward and the mortar swings backward due to the reaction. The maximum 

angle of the swing is used to estimate the explosive power. 

The assessment criterion consists of comparing the angle of deflection produced by the sample to that 

produced by a reference substance such as TNT and a ballistic mortar ratio is calculated, as shown below: 

Ballistic Mortar Ratio = (1-Cos 6^/(1-Cos 9,) 

where, 9S = angle of deflection caused by the sample, and 

6 r = angle of deflection caused by the reference substance 

.V_-.2 Ignitability and Violence of Deflagration 

BAM Red Glowing Steel Disk Test 

This test is carried out to test the ignitability as well as the deflagration potential of the sample. As 

the name suggests the sample of material being tested is tested is dropped on a red hot dish. A small quantity 

of sample (0.5 gms) is thrown into the hot dish which is maintained at 700°C. If there is no ignition, a larger 

quantity (5 gms) is thrown in. The assessment consists of making observations on the immediacy of the 

ignition, time delay before the ignition starts, the general mode of burning, and formation of any residues upon 

combustion. 

IMCO Burning Rate Test 

This method is suggested by the Chemical Group of the Organization for Economic Cooperation and 

Development (OECD-CG) and the International Maritime Consultive Organization (IMCO) for evaluating 

combustibility of granular or paste-like materials and oxidants. In this test method, the oxidant is mixed with 

a combustible material such as wood or cellulose powder. 

A-9 

-\5 
The oxidants used as references are sodium chlorate, sodium nitrate, and anhydrous sodium 

dichromate. The maximum rate of combustion advancement (cm/min) for each mixing ratio of fuel with 

oxidant versus % combustible in the mixture is plotted. Comparison is carried out with the results obtained 

from testing the reference oxidants under identical conditions. Based on the comparison, the oxidants are 

classified as follows: 

Group I: Oxidants stronger than sodium chlorate 

Group II: Oxidants stronger than sodium nitrate 

Group III: Oxidants stronger than anhydrous sodium dichromate 

TNO Deflagration Test 

This test, developed by the Dutch Organization for Applied Scientific Research (TNO) is used to 

measure the rate of propagation of deflagration and this rate is then used to estimate the violence of the 

deflagration. The sample is held upright in a glass tube and the substance at the top of the tube is ignited. 

The velotity of deflagration is measured using thermocouples located at various points in the tube. 

The assessment of the deflagration potential is carried out using the following criteria: 

HIGH: Velocity of deflagration propagation greater than 3 mm/sec 

MEDIUM: Velodty of deflagration propagation between 0 and 3 mm/sec 

LOW: No ignition of sample 

USBM Three inch DDT Test 

This test is carried out to evaluate the deflagration-to-detonation transition (DDT) of a substance 

under confinement. The US Bureau of Mines developed this test on behalf of the U.N. Committee for 

Transport of Dangerous Goods. In this test, a powdered sample is packed tightly inside a tube. The igniting 

agent used is composed of ammonium perchlorate, aluminum, and polyurethane. The assessment criteria are 

based on the extent of fragmentation of the pipe and the caps. 

A23 Occurrence and Violence of Decomposition and Deflagration Due to External Heating 

Dutch Pressure Vessd Test 

This test is carried out to determine the violence of decomposition of unstable substances (peroxides) 

when they are subjected to external heating. A small quantity of the sample (10 grams) is placed in a pressure 

vessel having an orifice and equipped with a rupture disk and the vessel is heated externally. The gases 

evolved as a result of decomposition escape through the orifice until the pressure in the vessel sufficiently in 

which case the rupture disk bursts. The violence of decomposition is measured based on the pressure vessel 

limiting orifice diameter (PVLD) which causes bursting of the rupture disk. 

The assessment criteria used for the peroxides are: 

HIGH: PVLD > 9.0 mm 

MEDIUM: 3.5 mm < PVLD < 9.0 mm 

LOW: PVLD < 3.5 mm 

A-10 

4& 
P.47 

US Pressure Vessel Test 

This test is used to measure the energy of decomposition of organic peroxides when subjected to rapid 

external heating. The prindple of this test is similar to the TNO test described above except for differences 

such as the heating is electrical (as opposed to gas heating), and the sample is placed in an aluminum cup and 

then placed in the pressure vessel. 

The assessment of the peroxides is carried out using the parameter, maximum orifice diameter (PVT 

value) at which the bursting occurs. The criteria used for rating different peroxides are given below: 

HIGH (3): 14 < Orifice Diameter < 20 mm 

MEDIUM (2): 1 < Orifice Diameter < 14 mm 

LOW (1): Orifice Diameter < 1 mm 

A2.4 Field Combustion Tests for Unstable Substances 

These are tests such as Bonfire Tests, Burning Trials, Bonfire Cookoff and Fast Cookoff Tests and 

are conducted to determine the degree of hazard when explosives are exposed to fire. In the Bonfire Test, the 

material being tested is exposed directly to fire by burning fire wood which is piled around it. In the Fast 

Cookoff Test, the sample is heated rapidly by placing it over a container of fuel oil which is ignited. 

Reportedly, these tests are used by the Canadian and Japanese governments to make transportation decisions. 

It is not very dear what assessment criteria are employed to evaluate the results. However, it is also reported 

that substances were cleared for transportation if "no explosion occurred", or "if the vessel did not burst" when 

the test was carried out in a vessel. 

A-ll 

4-1 
P.48 

REFERENCE 

Yoshida, T. 1987. Safety of Reactive Chemicals. Amsterdam: Elsevier. 

A-12 

Hg> 
P.49 

APPENDIX B 

DAMAGE CRITERIA/OVERPRESSURE DATA 

tf 
Appendix B 

Damage Criteria/Overpressure Data 

This appendix contains background on blast overpressure damage criteria and its effects. Also 

contained within this appendix are graphs illustrating the effea of varying overpressures on consequences. 

B.l Damage Criteria 

Blast waves from acddental explosions can cause damage to people and property by subjecting them 

to transient crushing pressures and winds. Relatively simple concepts have been used to quite effectively 

correlate blast wave properties with damage. The concept states that damage is primarily a funaion of either 

the peak overpressure, the impulse or some combination of these factors. Peak overpressure is most 

commonly used. 

Criteria for peak overpressures causing personal injury are given in Exhibit B-1, including injury from 

direa blast effects and from flying glass. Guidelines for peak overpressures required to produce property 

damage are presented in Exhibit B-2. These data are largely based on empirical observations. There seems 

to be general agreement between sources on the data presented in Exhibit B-2; however, the same is not true 

for the data presented in Exhibit B-1. According to Exhibit B-1, lung damage may occur at overpressures of 

10 psi. According to other sources, threshold lung damage may not occur until peak overpressures reach 30 

to 40 psi (Grelecki, Richmond 1968). The values for corresponding fatalities also vary. According to the 

Exhibit, the lowest overpressure dted for fatality from direa blast effects is 14.5 psi. According to another 

source, a 1% mortality rate is probable at 27.0 psi. Others dte values in the range of 35 to 120 psi as the 

threshold overpressure value for fatalities, 20.5 to 180 psi for a 50% fatality rate, and 29 to 250 psi for a 99% 

fatality rate (Grelecki, Richmond 1968, Lees 1980). 

Exhibits B-3 and B-4 show how lethality and injury vary with both overpressure and the duration of 

the blast wave. Exhibit B-5 shows similar data as a function of both pounds of TNT and range in feet. 

Exhibits B-3 through B-5 present potential injury levels resulting from direa exposure to blast 

overpressures in an open area. They do not take into account injuries resulting from property damage 

presented in Exhibit B-2. For example, substantial injury and possible deaths may result from the shattering 

of concrete walls at 2.0 to 3.0 psi. In planning with regard to injury to personnel, the following guidelines have 

been recommended (Brasie and Simpson 1968): 

• Personnel in areas subjea to overpressures greater than about 2 psi are 

likely casualties from fragmentation or self-impact against objects. 

• Personnel beyond the under 1 psi overpressure range should be reasonably 

safe inside a reinforced structure away from windows or, if outdoors, lying 

on the ground. 

B-1 

So 
P.51 

EXHIBIT B-1. HUMAN INJURY CRITERIA 

(Indudes Injury from Flying Glass and Direct Overpressure Effects) 

Overpressure 

(psi) 

0.6 

1.0 - 2.0 

1.5 

2.0 - 3.0 

2.4 

2.8 

3.0 

3.4 

4.0 - 5.0 

5.8 

6.3 

Injury 

Threshold for injury 

from flying glass* 

Threshold for skin 

laceration from flying glass 

Threshold for multiple 

skin penetrations from 

flying glass (bare skin)* 

Threshold for serious wounds 

from flying glass 

Threshold for eardrum rupture 

10% probability of eardrum 

rupture 

Overpressure will hurl 

a person to the ground 

1% eardrum rupture 

Serious wounds from flying 

glass near 50% probability 

Threshold for body-wall 

penetration from 

flying glass (bare skin)* 

50% probability of eardrum 

rupture 

Comments 

Based on studies 

using sheep and dogs 

Based on Army data 

Based on studies 

using sheep and dogs 

Based on Army data 

Conflicting data on 

eardrum rupture 

Conflicting data on 

eardrum rupture 

One source suggested an 

overpressure of 1.0 psi 

for this effea 

Not a serious lesion 

Based on Army data 

Based on studies 

using sheep and dogs 

Conflicting data on 

eardrum rupture 

Source 

(Fletcher, Richmond, and 

Yelverton 1980) 

(Lees 1980) 

(Fletcher, Richmond, and 

Yelverton 1980) 

(Lees 1980) 

(Lees 1980) 

(Lees 1980) 

(Brasie and Simpson 

1968) 

(U.S. DOT 1988) 

(Lees 1980) 

(Fletcher, Richmond, and 

Yelverton 1980) 

(Lees 1980) 

* Interpretation of data tables presented in reference. 

B-2 

5( 
EXHIBIT B-1. HUMAN INJURY CRITERIA 

(Indudes Injury from Flying Glass and Direct Overpressure Effects) 

(continued) 

Overpressure 

(psi) 

Injury Comments Source 

7.0 - 8.0 

10.0 

14.5 

16.0 

17.5 

20.5 

25.5 

27.0 

Serious wounds from flying 

glass near 100% probability 

Threshold lung 

hemorrhage 

Fatality threshold for 

direa blast effects 

50% eardrum 

rupture 

10% probability of fatality 

from direa blast effects 

50% probability of fatality 

from direa blast effects 

90% probability of fatality 

from direct blast effects 

1% Mortality 

29.0 99% probability of fatality 

from direa blast effects 

Based on Army data 

Not a serious lesion 

(applies to a blast of 

long duration (over 50 

msec); 20-30 psi required 

for 3 msec duration waves) 

Fatality primarily from 

lung hemorrhage 

Some of the ear injuries 

would be severe 

Conflicting data on 

mortality 

Conflicting data on 

mortality 

Conflicting data on 

mortality 

A high inddence of severe 

lung injuries (applies to a 

blast of long duration (over 

50 msec); 60-70 psi required 

for 3 msec duration waves) 

Conflicting data on 

mortality 

(Lees 1980) 

(U.S. DOT 1988) 

(Lees 1980) 

(U.S. DOT 1988) 

(Lees 1980) 

(Lees 1980) 

(Lees 1980) 

(U.S. DOT 1988) 

(Lees 1980) 

B-3 

5% 
Overpressure (psi) 

0.03 

EXHIBIT B-2. PROPERTY DAMAGE CRITERIA 

Damage 

Occasional breaking of large glass 

windows already under strain 

' 

Source(s) 

(Lees 1980) 

P.53 

0.04 

0.10 

0.15 

0.30 

0.4 

0.5 - 1.0 

0.7 

1.0 

1.0 - 2,0 

1.3 

2.0 

Loud noise (143dB). Sonic boom 

glass failure 

Breakage of windows, small, under strain 

Typical pressure for glass failure 

"Safe distance" (probability 0.95 no 

serious damage beyond this value). Missile 

limit Some damage to house ceilings. 

10% window glass broken. 

Minor struaural damage 

Shattering of glass windows, occasional 

damage to window frames. One source 

reported glass failure at 0.147 psi 

Minor damage to house structures 

Partial demolition of houses, made 

uninhabitable 

(Lees 1980) 

(Lees 1980) 

(Lees 1980) 

(Lees 1980) 

(McRae 1984, Lees 1980) 

(Brasie and Simpson 1968, 

Air Force 1983, 

U.S. DOT 1988, 

Lees 1980) 

(Lees 1980) 

(Lees 1980) 

Shattering of corrugated asbestos siding (Brasie and Simpson 1968, 

Failure of corrugated aluminum/steel paneling Air Force 1983, 

Failure of wood siding panels (standard U.S. DOT 1988, 

housing construction) Lees 1980) 

Steel frame of clad building slightly 

distorted 

(Lees 1980) 

Partial collapse of walls and roofs of houses (Lees 1980) 

B-4 

3*5 
EXHIBIT B-2. PROPERTY DAMAGE CRITERIA 

(continued) 

• .. '^Sv i 

Overpressure (psi) Damage Source(s) 

2.0 - 3.0 

2.3 

2.5 

3.0 

3.0 - 4.0 

4.0 

4.8 

5.0 

5.0 - 7.0 

7.0 

7.0 - 8.0 

Shattering of non-reinforced concrete or cinder 

block wall panels (1.5 psi according to 

another source) 

Lower limit of serious structural damage 

50% destruction of brickwork of house 

Steel frame building distorted and 

pulled away from foundations 

Collapse of self-framing steel panel buildings 

Rupture of oil storage tanks 

Snapping failure - wooden utility tanks 

Cladding of light industrial buildings 

ruptured 

Failure of reinforced concrete structures 

Snapping failure - wooden utility poles 

Nearly complete destruction of houses 

Loaded train wagons overturned 

Shearing/flexure failure of brick wall panels 

(8-12 inches thick, not reinforced) 

Sides blown in of steel frame buildings 

Overturning of loaded rail cars 

(Brasie and Simpson 1968, 

Air Force 1983, 

U.S. DOT 1988, 

Lees 1980) 

(Lees 1980) 

(Lees 1980) 

(Lees 1980) 

(Brasie and Simpson 1968, 

U.S. DOT 1988, 

Lees 1980) 

(Lees 1980) 

(McRae 1984) 

(Brasie and Simpson 1968, 

Lees 1980) 

(Lees 1980) 

(Lees 1980) 

(Brasie and Simpson 1968, 

Air Force 1983, 

U.S. DOT 1988, 

Lees 1980) 

(Air Force 1983) 

(Brasie and Simpson 1968, 

U.S. DOT 1988) 

B-5 

5* 
P.55 

EXHIBIT B-2. PROPERTY DAMAGE CRITERIA 

(continued) 

Overpressure (psi) Damage Source(s) 

9.0 Loaded train box-cars completely demolished (Lees 1980) 

10.0 Probable total destruction of buildings (Lees 1980) 

30.0 Steel towers blown down (Brasie and Simpson 1968, 

Air Force 1983) 

88.0 Crater damage (McRae 1984) 

B-6 

55 
EXHIBIT B-3. LETHALITY CURVES 

(For a 154 Ib Person in Free Stream Situations) 

kPa P* 

Maximum 

incident 

overpressurt 

10,000 

5.000 

2.000 

1,000 

soo 

200 

U.9 

9 9 * lethality —— — 

SO* Lethality — - - — 

I H lethality -

0.2 0.4 1.0 2 4 710 20 40 100 200 1000 

(Juration of positive incident overpressure, mutt 

5000 

EXHIBIT B-4. LETHALITY AND IN JURY CURVES 

(For a 154 lb Person in Free Stream Situations) 

kPa 

10* 

103 

Maximum 

incident 

QSHTpntrw rt 

10* 

10 

0.1 

I S lethality 

P« 

1.000 

100 

10 

0.1 

0.01 

Threshold lung damage -»«*«»•» 

S0H Eardrum rupturt * " 

95H Eardrum protection with muffs ~~S~~= 

95H Eardrum protection w/o muffs —. — .—. 

•+• •+• •4- •+• 

Notes: msec = milliseconds 

kPa = kilopascals = 6.895 psi 

psi = pounds per square inch = 0.1450 kPa 

Source: U.S. DOT 1988. 

0.2 10 10 100 

Duration of positive incident overpressure 

— I — 

1000 

, msec 

•+• 

10,000 

B-7 5fc 
EXHIBIT B-5. AIR-BLAST CRITERIA FOR PERSONNEL STANDING IN THE OPEN 

100 

RANGE IN FEET 

10,000 

Source: U.S. DOT 1988. 

B-8 

an 
_.' _VV "V. -J-r.] ^gMfT^. 

The values presented in the Exhibits may be used to relate damage or injury criteria to safe distances 

for emergency planning, using the scaling law described in the text 

Note that although glass is reported to shatter at an overpressure level of 0.5 psi (see Exhibit B-2), 

there is evidence that human injury from flying glass is unlikely at this leveL Lees (1980) dtes a report stating 

that risk of injury from flying window glass is negligible for an explosion that gives a peak overpressure of 0.6 

psi or less. Lees also dtes a report giving the skin laceration threshold for flying glass as 1-2 psi and the 

serious wound threshold as 2-3 psi (see Exhibit B-1). Fletcher, Richmond, and Yelverton (1980) carried out 

experiments on the effects on sheep and dogs of glass fragments from windows shattered by various blast 

overpressures. Their results (briefly dted in Exhibit B-1) appear to agree reasonably well with the data 

reported by Lees. Their data indicate that the threshold for injury from flying glass is about 0.6 psi. Multiple 

injuries from skin penetration (Le., ten or more) may occur for bare skin at overpressures of 1.5 psi or higher. 

Flying glass may penetrate the body-wall at 5.8 psi or higher if the skin is bare. The authors point out that 

the skin and body-wall thickness of men and sheep are approximately the same (Fletcher, Richmond, and 

Yelverton 1980); therefore, the data reported should be roughly applicable to humans. 

B.2 Effects of Varying Overpressures 

To determine the effea on distance of choosing different overpressure levels, analysis was carried out 

at four different overpressures for the eight high explosives studied. K-faaor methodology was used, and 

calculations were carried out for a quantity of 100 pounds of each material at overpressures of 0.4, 0.5, 1.0, 

10, and 3.0 psi. 

Exhibits B-6 and B-7 present graphs of distance versus overpressure for the commerdal explosives. 

The exhibits indicate that higher overpressures occur at lower distances (i.e., closer to the explosion site), and 

overpressure falls off as distance increases. This is as expeaed from the scaling law. Distance and K are 

directly proportional in the scaling law. Therefore, as K increases, so does the affeaed distance. However, 

as K increases, overpressure decreases (as is indicated by Exhibit 1 in the main text of this study). 

The decrease in distance affeaed with increase in overpressure appears to occur more rapidly at low 

overpressures than at higher overpressures; note that the distance decreases much more sharply between 0.4 

and 0.5 psi than between 1.0 and 2.0 psi or 2.0 and 3.0 psi (see Exhibits B-6 and B-7). 

B-9 

SB 
w 

I 

I— 

© 

u 

o 

c 

o 

n 

5 

U 

o 

u 

150 

140 

130 -

120 -

110 -

100 -

90 -

80 -

70 -

60 

50 

40 -

30 -

20 

EXHIBIT B-6 

OVERPRESSURE VERSUS DISTANCE FOR 100 POUNDS OF FOUR HIGH EXPLOSIVES 

(Amatol 60/40, Amatol 50/50, Lead Azide, and Metriol Trinitrate) 

0.0 0.4 

Amatol 60/40 

1.2 1.6 

Overpressure (psi) 

Amatol 50/50 O 
o 

c 

o 

* i 

£ 5 

T3 

U 

u 

u 

150 

140 -

130 -

120 -

110 

100 -

90 -

80 -

70 

60 H 

50 

40 -

30 -

20 

D 

0.0 

PLX 

EXHIBIT B-7 

OVERPRESSURE VERSUS DISTANCE FOR 100 POUNDS OF FOUR HIGH EXPLOSIVES 

(PLX, Silver Azide, Tetryl, and TNT) 

0.4 0.8 

-1 r 

1.2 1.6 2.0 2.4 2.8 3.2 

+ Silver Azide 

Overpressure (psi) 

Tetryl TNT 

R TJ 

b> 
P.61 

REFERENCES 

Brasie, W., Simpson, D. 1968. "Guidelines For Estimating Damage Explosion," AICHE Symposium on Loss 

Prevention in the Process Industries, February 18-23,1968. 

Fletcher, E.R., Richmond, D.R., Yelverton, J.T. 1980 (May 30). "Glass Fragment Hazard from Windows 

Broken by Airblast." Washington, D.C: Defense Nuclear Agency. Report Number DNA 5593T. 

Lees, F.P. 1980. Loss Prevention in the Process Industries, Vol. 1. London: Butterworths. 

U.S. Air Force 1983. "Explosives Safety Standards," AF Regulation 127-100, 20 May 1983. 

U.S. DOT 1988. "Hazard Analysis of Commerdal Space Transportation," Office of Commerdal Space 

Transportation Licensing Programs Division, U.S. Department of Transportation. May 1988. 

NFPA. "Fire Proteaion Handbook," 16th edition, National Fire Protection Association (NFPA). 

McRae, T. 1984. "The Effects of Large Scale LNG/Water RPT Explosions," McRae, T.G., et.al., Lawrence 

Livermore National Laboratory. April 27,1984. 

Grelecki, C. "Fundamentals of Fire and Explosion Hazards Evaluation," C Grelecki, Hazards Research Corp., 

AICHE Today Series. 

Richmond, D. 1968. "The Relationship Between Seleaed Blast-Wave Parameters and the Response of 

Mammals Exposed to Air Blast." Richmond DR, Damon EG, Fletcher ER, Bowen IG, White CS., Ann. N.Y. 

Acad. Sd., 1968. 

Eichler, T., Napadensky, H. 1977. "Accidental Vapor Phase Explosions on Transportation Routes Near 

Nuclear Plants," HT Research Institute, Prepared for Argonne National Laboratory. April 1977. 

Wiekema, B. J. 1984. "Vapor Cloud Explosions - An Analysis Based on Acddents," Journal of Hazardous 

Materials, 8 (1984). 

B-12 

U 
P.62 

APPENDIX C 

DIFFERENCES IN METHODOLOGY 

WL 
P.63 

Appendix C 

Differences in Methodology 

An attempt was made to learn the reason behind the differences in results between the three 

methodologies used in the consequence analysis (i.e., ARCHIE, K-Factor, and ATF). Theoretically, all three 

methodologies should yield very similar results since they each are based upon the scaling law. However, the 

results do vary considerably. 

Exhibit C-1 presents the differences in distances calculated for high explosives using the equation from 

the ARCHIE manual and the ARCHIE model (see Section 4.2.3 of the text), the K-factor method (see Section 

4.2.4), and the ATF Table of Distances (see Section 4.2.2). The differences are presented as percentages. The 

first column of percent difference shows the difference between distances calculated by the ARCHIE equation 

and the K-factor method. The percent difference was calculated as follows: 

% difference = (K-factor distance - ARCHIE equation distance. x 100 

ARCHIE equation distance 

The second column of percent difference shows the difference between distances resulting from the ARCHIE 

model and the K-factor method. The percent difference was calculated as follows: 

% difference = (ARCHIE model distance - K-factor distance', x 100 

ARCHIE model distance 

The third percent difference column shows differences between distances calculated using the ARCHIE 

equation and those found using the ATF table of distances, calculated as follows: 

% difference = (ATF distance - ARCHIE equation distance) x 100 

ARCHIE equation distance 

For the fourth column, the percent difference between the distance determined using the K-factor method and 

the distance from the ATF Table of Distances was calculated as follows: 

% difference = (ATF distance - K-factor distance _ x 100 

-. . K-factor distance 

The fifth column shows the percent difference between the distances calculated using the ARCHIE model and 

those calculated from the ARCHIE equation. The difference was calculated as follows: 

% difference = rARCHTF model distance - ARCHIE equation distance) x 100 

ARCHIE model distance 

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In an attempt to determine the sources of the major differences, the results from ARCHIE (using the 

equation presented in the ARCHIE manual) and from the K-factor were analyzed further. The scaling law 

is made up of two components: (1) "K" which relates overpressure and distance, and (2) "W which defines the 

amount of material which is involved in the explosion. ARCHIE and the K-factor methodology arrive at these 

two components in different ways, as described below: 

• Calculation ofK 

ARCHIE: K = exp (3.5031 - 0.72411n(Op) + 0.0398(lnOp)

2

) 

K-Factor: K = Function of Op (read from graph) 

where: Op = peak overpressure 

The difference between the two methods is that the K-factor method uses 

the empirically derived K-factor at a given overpressure from the graph 

shown in Exhibit 3 of the text, whereas ARCHIE uses the above equation 

to approximate the K-factor. (Note that ARCHIE uses this equation in the 

manual; the model itself appears to use K-factors at selected overpressures 

from the graph.) At an overpressure of 0.5, the K-factor value from the 

graph is about 70, while the K-factor from the ARCHIE equation is 56. The 

K-factor used by the ARCHIE model was calculated to be 73 at 0.5 psi. The 

difference between the ARCHIE model and ARCHIE equation results 

(about 24 percent) is due entirely to the different K-factors used. 

• Weight of the material 

The methods differ in the method used for determination of the TNT 

equivalent weight of the explosive material. ARCHIE calculates the 

equivalent weight as a function of the material's heat of combustion 

compared to the heat of explosion of TNT and its "yield factor" (assumed to 

be one for condensed-phase explosions), whereas the K-Factor methodology 

uses empirically derived TNT equivalents: 

ARCHIE: W = Adjusted equivalent mass of TNT, lb 

= [MchenJc[(AHyil55)xYg] 

ft-Factor: W = [Mche„jc %TNT] 

where: 

Mchem = Original mass of explosive material 

AHC = Lower heat of combustion, kcal/kg 

Yf = Yield factor (assumed to be one for condensedphase explosions) 

1155 = Heat of explosion of TNT (kcal/kg) 

C-3 

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The TNT equivalent weight determined using the ARCHIE method, based on heat of combustion, 

is generally greater than the equivalent weight used in the K-factor method, based on TNT equivalents 

reported in the literature. Differences between the K-factor results and the ARCHIE model results are 

primarily due to the differences in TNT equivalents, although at 0.5 psi overpressure, the ARCHIE model also 

uses a slightly higher K value (73) than the value used in the K-factor analysis (70). 

Heat of combustion, used in the ARCHIE method to estimate TNT equivalents, represents the total 

combustion energy of a substance and depends only on the composition of the material. Heat of explosion 

is the heat liberated during its explosive decomposition; its magnitude depends on the thermodynamic state 

of the decomposition products. Experimental values of heat of explosion may differ from theoretical values, 

as composition of the explosion products may be different and may vary with the loading density (Meyer 1987). 

TNT equivalents found in the literature, used in the K-factor method, may vary, several different 

values may be reported for the same substance. Exhibit C-2 presents results of calculations by the K-factor 

method for silver azide and tetryl, using various reported TNT equivalents and also, for comparison, TNT 

equivalents estimated by the ARCHIE method (i.e., heat of combustion (kcal/kg)/1155). Note that although 

the two reported TNT equivalents for silver azide differ by nearly a factor of two, the calculated distances 

differ by a much smaller factor because the distance is proportional to the cube root of the TNT equivalent. 

The TNT equivalent calculated from the heat of combustion for silver azide is very close to one of the 

reported values; however, the calculated TNT equivalent for tetryl is considerably higher than the values 

reported in the literature. The distance calculated using this TNT equivalent is significantly higher than the 

distances calculated from reported TNT equivalents. 

C-4 

<dc 
EXHIBIT C-2 

AFFECTED DISTANCES DETERMINED BY K-FACTOR METHOD FOR TWO COMMERCIAL HIGH 

EXPLOSIVES, USING SEVERAL TNT EQUIVALENTS 

(Overpressure OS psi, K Value 70) 

K-Factor Results Using Reported TNT Equivalents* Results Using 

Calculated Calculated 

TNT Distance Distance Distance Distance Distance TNT 

Equivalent 1 2 3 4 5 Equivalent 

(ARCHIE) (01) (tn) (m) (m) (m) (ARCHIE) 

Explosive 

Material 

Amount 

(lbs) 

Heat of 

Coo-bustion 

(kcal/kg) 

Reported TNT Equivalents 

Silver Azide SO 

100 

250 

1000 

5000 

1037 0.88 0.45 0.90 75 

95 

129 

204 

350 

60 

76 

103 

163 

280 

76 

96 

130 

206 

352 

Tetryl 50 

100 

250 

1000 

5000 

2925 1.21 0.96 1.15 1.25 1.31 2.53 84 

106 

143 

227 

389 

78 

98 

133 

210 

360 

82 

104 

141 

224 

382 

85 

107 

145 

230 

393 

86 

108 

147 

233 

399 

107 

135 

183 

291 

498 

Sources of TNT equivalents: NTIS 1971, NASA 1988, Kirk-Othmer 1980. 

2 

_-.