Industrial Fire Protection Engineering - Robert G. Zalosh (Wiley, 2003)

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INDUSTRIAL FIRE

PROTECTION

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INDUSTRIAL FIRE

PROTECTION

ENGINEERING

Robert G. Zalosh

Center for Firesafety Studies, Worcester Polytechnic Institute,

Worcester, MA, USA

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Copyright2003 John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex PO19 8SQ, England

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Library of Congress Cataloging-in-Publication Data Zalosh, Robert G.

Industrial fire protection engineering / Robert G. Zalosh. p. cm.

Includes bibliographical references and index. ISBN 0-471-49677-4 (alk. paper)

1. Industrial buildings – Fires and fire prevention. 2. Fire protection engineering. I.

Title.

TH9445.M4 Z35 2002

628.922 – dc21 2002069032

British Library Cataloguing in Publication Data

A catalogue record for this book is available from the British Library ISBN 0-471-49677-4

Typeset in 9.5/11.5pt Times by Laserwords Private Limited, Chennai, India Printed and bound in Great Britain by TJ International, Padstow, Cornwall

This book is printed on acid-free paper responsibly manufactured from sustainable forestry in which at least two trees are planted for each one used for paper production.

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PREFACE

This work was made possible in part by a grant from the Society of Fire Protection Engineers Educational and Scientific Foundation.

The material in this text was compiled and presented while the author was teaching a course in Industrial Fire Protection at the Worcester Polytechnic Institute (WPI) center for Firesafety Studies. The course is intended for graduate students who have an undergraduate education in engineering or the physical sciences, and who have already studied combustion chemistry, fire dynamics, and the basics of automatic fire suppression systems. However, a keen interest in industrial fire protection and an inquisitive, analytical psyche are perfectly acceptable substitute prerequisites for readers of this text.

Neither this nor any other textbook can replace consensus codes and standards for the majority of industrial fire protection applications. On the other hand, codes and standards often do not suffice for the probing practitioner or pathfinder in industrial fire protection. Many of the author’s students and his current and former colleagues at WPI and at Factory Mutual Research Corporation fall into this category. Their work and encouragement have made this text possible.

Publisher’s Note: Whilst all efforts have been made to identify and contact holders of copyrighted material it is possible one or two items may not be acknowledged. If anyone is aware of an item in this book so affected the publisher would welcome their comments.

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1 INTRODUCTION

AND PERSPECTIVE

1.1 Engineering approach to industrial fire protection

The prevailing impression among many employees, regulators, and ‘captains of industry’ has been that industrial firesafety can be achieved through common sense, enforcement of prescriptive codes and standards, and guidance from local fire chiefs. Indeed, these methods should suffice in a simple workplace producing simple and unchanging products or services. However, today’s industrial facilities are rarely simple and unchanging. A more effective approach to industrial firesafety is needed to deal with the complexities and changes that exist in modern industrial facilities.

The approach to industrial fire protection espoused in this text is an application and elaboration of the performance-based approach espoused by the Society of Fire Protection Engineers (SFPE, 2000). It involves engineering analyses of generic industrial hazards and fire/explosion protection measures. Engineering analyses are systematic studies incorporating pertinent scientific principles and data. In this case the pertinent science stems from combustion and fire science, as well as the relevant physical and chemical principles governing the design and operation of the fire protection systems. Relevant data includes generic fire/explosion incident data, test data, and plant-specific operating experience. This information is to be evaluated along with the applicable codes and standards, expert opinion, and a general understanding of the relevant facility, products, and/or processes.

The three steps involved in an engineering determination of suitable protection measures for an industrial fire or explosion hazard are: (1) scenario identification; (2) consequence analysis; and (3) alternative protection evaluation. Scenario identification for an actual or hypothesized fire or explosion entails a description of the pre-fire/explosion situation, ignition sources, combustible materials ignited, and surrounding materials vulnerable to fire spread and fire or smoke or blast damage. Consequence analysis entails estimates of the extent of fire spread and damage with and without the installed or proposed fire or explosion protection. If these consequences are acceptable to the facility stakeholders, then another scenario can be considered, as indicated in Figure 1.1. If the consequences are not acceptable, then alternative protection should be evaluated. Acceptance criteria depend upon the stakeholder specific objectives and the designated scope of the analysis, as well as cost constraints. Alternative protection evaluation entails estimates of the extent to which the ignition and fire/smoke/blast damage potential can be reduced by alternative installed protection measures. Figure 1.1 is a flowchart of the three steps in the analysis, and the input to the first two steps. Explanations and examples of the three steps follow.

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Scenario identification Process and facility description Hazard analysis methods Specific objectives Loss history Consequence analysis No STOP Alternative protection evaluation Acceptable consequences? More scenarios? Test data Fire dynamics Scope

Figure 1.1. Flowchart for scenario identification, consequence analysis, and alternative protection evaluation

1.1.1 FIRE/EXPLOSION SCENARIO IDENTIFICATION

Guidelines for developing and analyzing fire scenarios are described in Fire Safety Aspects of Polymeric Materials, Volume 4: Fire Dynamics and Scenarios (National Academy of Sciences, 1978), and in Chapter 8 of the SFPE Engineering Guide to Performance-Based Fire Protection (2000). In accord with those guidelines, the following items should be identified to characterize the fire scenario through the time of self-sustained burning.

Pre-fire situation – The industrial process or operation, including start-up, maintenance, and shutdown, is the starting point in pre-fire situation considerations. A thorough review would consider potential mishaps as well as normal operations. Three techniques for systematic reviews of mishaps are the Failure Modes and Effects Analysis (FMEA), the What If Analysis, and the Hazards and Operability Study (HAZOP), described in various hazard evaluation references such as the Center for Chemical Process Safety’s Guidelines for Hazard Evaluation Procedures (1992). Other elements to be evaluated in the pre-fire situation are: facility services (HVAC, electrical, gas, water, telecommunications, waste removal), building geometry and construction features, installed fire protection systems, and the fire protection interest and training of plant

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management, operating, and emergency response personnel. This background information is used in assessing the potential for fire initiation, fire spread, damage, and extinguishment.

Ignition sources – Equipment and personnel representing potential ignition sources should be identified. Quantitative descriptions to characterize the strength of the ignition source are helpful in establishing time-to-ignition and the potential effectiveness of various prevention measures. Quantification in the case of exposure fires would entail a description of flame size, heat release rate, and proximity to target material. In the case of electrical ignition sources, strength charac-terizations would include arc/spark/short energy or energy release rate.

Ignited material – The first material to be ignited depends on the flammability properties of target materials, their size, configuration, and proximity to the hypothesized ignition source. Quantitative ignitability criteria for a variety of combustible materials can be found, for example, in Chapter 6 of Drysdale (1985). An attempt should be made to determine if these criteria are satisfied in the hypothesized ignition scenario. Examples are presented in several chapters of this text.

Flaming or smoldering combustion – Some combustible materials may burn with or without a flame. Sometimes a material may smolder for a period of time before suddenly bursting into flame. Solids with low thermal conductivities, such as expanded plastics and rubbers, certain cable insulations, and combustible dust layers are often prone to smoldering combustion. The occurrence of smoldering versus flaming combustion is an important aspect of the fire scenario because heat release rates and flame spread rates are much lower during smoldering. Furthermore, smoke composition, particle size, and detectability differ considerably in flaming and smoldering combustion. Descriptions of fuel, ignition, and ventilation conditions conducive to smoldering combustion are available in Chapter 8 of Drysdale (1985) and in Chapter 2-11 in the SFPE Handbook (1995).

Fire spread and heat release rates for first ignited material – The rate of fire spread over the ignited material is a key factor determining the severity of the hypothesized fire. Data and analyses for surface flame spread rates are presented in Chapter 7 of Drysdale (1985), and in Quintiere’s review in the SFPE Handbook (Chapter 2-14, 1995). Fire heat release rates depend both upon flame spread rates and mass burning rates as well as the effective heat of combustion (defined as the theoretical heat of combustion multiplied by the burning efficiency) of the ignited material. They are highly configuration dependent. Heat release rates for an assortment of materials and configurations have been compiled by Babrauskas in the SFPE Handbook (Chapter 3-1, 1995). Values for representative materials are listed in Tables A.3 and A.4 in Appendix A. Additional compilations are presented in Chapters 5 and 6 for warehouse commodities, and Chapters 7 and 8 for flammable liquids.

Fire spread to second material – Fire spread across a gap between the first ignited material and some adjacent combustible can occur via radiant or convective heating or via direct contact with burning fuel that may have dripped (for a thermoplastic polymer for example), flowed out of its container (flammable liquid), collapsed, generated windblown firebrands, or splattered as a result of ineffective extinguishment attempts. Flame radiation heat fluxes can be calculated by methods summarized in Appendix A. Fire plume and ceiling layer heat fluxes can be evalu-ated with engineering correlations presented in Chapters 3 and 5 and in several chapters of the SFPE Handbook. Target material ignition potential can be evaluated as described in Chapter 6 of Drysdale (1985), and in Chapter 7 of this text for the case of flammable liquids.

Example – A chronic fire hazard in semiconductor and electronics manufacturing plants has been the use of plastic and plastic-lined wet benches or tubs with electric immersion heaters

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Figure 1.2. Clean room wet benches.2002 Factory Mutual Insurance Company, with permission

for heating various process liquids. These tubs, which are situated in clean rooms as shown in Figure 1.2, are used for cleaning, etching, and plating circuit boards and semiconductors in the wet bench. They often contain nonflammable liquids such as acids or precious metal solutions. Many fires have occurred when the liquid level fell below the heater while the heater remained energized in close proximity to the tub wall. The resulting rapid increase in heater surface temperature ignited the tub wall, and flame often spread to plastic exhaust hoods, ducting, and adjacent tubs. Although most of these fires have not been very extensive, the surrounding area is often susceptible to smoke damage and contamination, which usually occur before ceiling or duct sprinklers actuate. Several incidents of this nature are described in Factory Mutual Data Sheet 7-7 (1997) and in Semiconductor Safety Association papers such as Lotti (1986).

A key aspect of the pre-fire situation for this hazard is the heater and liquid-level controls. A typical arrangement would involve a liquid temperature sensor, often in the form of a high temperature limit switch, for heater control. When the liquid level falls below this sensor, it is measuring air/vapor temperatures which do not increase much above ambient room temperature, even though the heater surface temperature may be sufficiently high to ignite the tub wall. Liquid level cutoff switches are recommended in FM Data Sheet 7-7, but they are not always installed or used. More sophisticated control systems have been designed for newer heater designs. For example, Lotti (1986) describes a highly reliable special control system for immersion heaters in which the heater power supply is dependent on two series wired, normally open solid state relays attached to a controller that monitors the signals from five independent sensors: a liquid temperature sensor, a liquid level sensor, a heating element temperature sensor, an automatic timer, and a smoke or flame detector. Although this much complexity and expense may not be warranted in many facilities, fault tree analyses similar to those described in Henley and Kumamoto (1981) can be conducted to determine the incremental reliability with each additional sensor and interlock.

The ignition source in this scenario is obviously the energized heater. Quantification of this source involves specifying the heater power level and its physical size, shape, and location in the

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To exhaust stack

I. K W immersion heater

Vapor flow Plating tank

Gold cyanide salt solution Normal liquid level 17 cm 20 cm 13 cm 30 cm 15 cm 66 cm Polypropylene booth

Immersion heater in polypropylene plating tank at semiconductor manufacturing facility

4 cm

Figure 1.3. Immersion heater near wall of wet bench

tub. In one representative incident, a 1 kW (0.95 Btu/sec) heater was immersed in a polypropylene plating tub shown in Figure 1.3. Vapors from the tub, which is one of several in a polypropylene booth used to process silicon wafers, are collected and exhausted through a wall duct and overhead exhaust duct. The actual heater size and location were not specified in the loss report, but we will assume the quartz heating element is 4 cm (1.6 in) in diameter, 20 cm (7.9 in) long, and situated near the end wall of the 30 cm (11.8 in) deep section of the tub.

The ignited material in this scenario is the polypropylene tub wall (or a polypropylene heater housing in some cases). According to the data in Table 5.11F of the NFPA Fire Protection Handbook (1986), the critical radiant heat flux for ignition of polypropylene is about 20 kW/m2

(1.76 Btu/sec-ft2_{). Since the lateral surface area of the quartz heating element is π(4)(20)}₌

251 cm2(39 in2), the 1 kW heater can generate a radiant surface heat flux of 40 kW/m2(3.5

Btu/sec-ft2_{). We assume that most of the heat transfer occurs via radiation to the tub walls when the liquid}

level falls below the bottom of the heater. The radiant heat flux on the tub wall is φ(40) kW/m2_,

where φ is the radiation view factor between an element on the tub wall and heater. The value of φ

corresponding to the critical heat flux for ignition is 20/40= 0.50. We can use the configuration

factor tables in Appendix A to find the wall-to-heater separation distance D such that a wall

element at the mid-elevation of the heater will receive a radiant heat flux of 20 kW/m2_{. Using}

Figure A.2, the result is D= 2 cm (0.79 in). Therefore, we would expect the heater to ignite the

tub wall when it is within 2 cm of the wall and remains energized for an indefinitely long time without being immersed in liquid.

The polypropylene tub fire in this scenario is most likely to produce flames with a high soot

content. According to Table 5.11F of the NFPA Handbook (1986), the soot yield, Ysmoke, for a

well ventilated polypropylene fire is about 0.08 g-soot/g-fuel. The heat release rate for a small polypropylene wall fire can be estimated from extrapolation of the data in Table A.3. The result is about 76 kWper m width (22 Btu/sec) per ft width of wall for a 30 cm (1ft) high wall burning

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in the open with unrestricted air access. The smoke release rate, which can be considered to be the source term for smoke damage analyses, can be estimated by multiplying the mass burning rate (heat release rate divided by the product of heat of combustion and combustion efficiency) by the soot yield, i.e.

˙msmoke = ˙ Q Hcχ Ysmoke

Using the values for Hc and χ for polypropylene in Appendix A (43.4 kJ/g [18,700 Btu/lb] and

0.89, respectively) and the previous values for heat release rate and soot yield. The estimated

smoke release rate is about 0.16 g/sec per m (1.07× 10−4lb/sec-ft) of tub wall burning. However,

since this is based on laboratory tests with well ventilated samples burning, whereas the tub fire is probably not well ventilated, the estimate should only be considered accurate only to within an order-of-magnitude. Large-scale wet bench test data would be far preferable. Some tests of this nature are described in Chapter 4, but smoke generation rate data were apparently not measured. As for the second material ignited, in this example it might well have been the plastic exhaust duct at the top of the tub, since the duct was probably directly exposed to substantial convective heating from the fire plume. If there is a strong downward ventilation flow over the wet bench, and exhaust ducting in the bench interior, the second material ignited can be the bench interior. Tests conducted with this wet bench configuration are described in Chapter 4.

Explosion scenarios – Combustion explosions (i.e. gas and dust explosions) are amenable to a scenario identification analysis directly analogous to that for fires. The pre-explosion situation should include a description of the various factors that influence the likelihood of ignition and the subsequent course of the explosion. Besides identifying the gas or dust to be ignited, some rough estimates of possible gas or dust concentration relative to the lower explosive limit (as given in Chapter 3-16 of the SFPE Handbook, for example) and relative to the stoichiometric or worst-case concentration (concentration producing the maximum rate of pressure rise) should be determined. As for the rate of flame spread and the heat release rate, these parameters are every bit as important for explosions as they are for fires. One complicating factor unique to combustion explosions is the effect of turbulence on flame speeds and associated energy release rates. Unfortunately, it is difficult to quantify the turbulence effect without access to large-scale test data for a relevant explosion configuration. A thorough discussion of these effects is beyond the scope of this text. The reader is referred to Chapter 3-16 of the SFPE Handbook (1995), and to references therein for a quantitative introduction to explosion protection evaluations.

1.1.2 CONSEQUENCE ANALYSIS

The consequences of a particular fire scenario can in principle be determined from knowledge of fire heat and smoke production rates and estimates of the extent of flame spread. Manual and auto-matic suppression system effectiveness in the given scenario should be assessed to estimate the extent of flame spread. When this assessment is conducted assuming installed suppression systems are functioning as designed, the resulting damage estimate (measured in dollars) at an industrial facility is called the Loss Expectancy. When the equivalent consequence analysis is conducted assuming installed suppression systems are not operational, the resulting financial damage esti-mate is called the Maximum Foreseeable Loss. Estiesti-mates of the loss expectancy and the maximum foreseeable loss are critical parameters needed by corporate risk managers and insurers.

Damages for industrial fires and explosions generally include property damage, injuries and fatalities, business interruption losses, and possible environmental damages. Traditionally, expected damages have been determined from loss history, i.e. from compilations of previous incidents in similar occupancies. However, loss expectancies will vary with the development

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of new products, processes, and fire protection technology. Furthermore, maximum foreseeable losses are rare occurrences.

Two alternatives to historical loss data are full-scale testing and theoretical analyses. Since full-scale testing is often expensive and logistically prohibitive (especially for personnel injury and environmental damage evaluations), there is considerable incentive to proceed with theoret-ical analyses, particularly for ‘what-if’ variations in the basic fire scenario. Theorettheoret-ical analyses sometimes involve deterministic evaluations, and other times utilize risk analysis (probabilistic) methodology. A brief explanation of how these methods can be used for consequence analyses is provided here with application to the example fire scenario of the semiconductor plant wet bench fire.

Property damage – Property damage caused by thermal loads imposed during a fire can be estimated through an assortment of analytical methods. Thermal loads generally consist of flame radiation heat fluxes (Appendix A) and convective heat fluxes associated with the fire plume and the hot ceiling jet (Chapters 3 and 5). Structural member fire resistance under these thermal loads (prior to or without sprinkler activation) can be estimated via methods described in Chapter 3. Thermal damage to equipment and products can easily be calculated with similar analyses if the equipment/product is a simple configuration incorporating materials with known thermal prop-erties and damage threshold temperatures. For example, plastic equipment/products may satisfy this criterion where the damage threshold temperature is associated with softening (thermoplas-tics), decomposition (thermosets) or ignition. Since these damage temperatures depend upon specific polymer composition, small-scale test data are needed for pertinent polymers and blends. Fortunately, standardized testing is being conducted for several of the more commonly used industrial equipment components, such as grouped electrical cables and plastic exhaust ducting.

Nonthermal damage due to smoke, water, and corrosive chemicals released during a fire cannot currently be calculated with any deterministic analytical methodology. As with thermal damage, laboratory scale tests of nonthermal damage to various industrial equipment and components are beginning and data may be available in a few years to incorporate into damage estimates. In the meantime, historical loss data is the primary source of information for nonthermal damage.

Example – In the previous example of the polypropylene tub fire in a semiconductor plant, there was substantial thermal and nonthermal damage. Thermal damage occurred to electrical equipment, the exhaust ducting, and the plating booth in which the tub was situated. Approxi-mately 200 silicon wafers in and around the booth were damaged and had to be discarded. Nearby electronic equipment was subjected to water damage from the two sprinkler heads that opened and controlled the fire. Widespread smoke damage occurred throughout the clean room. The total property damage was on the order of $1 million in this incident. Another incident, described in FM Data Sheet 7-6 (1986), involved an immersion heater igniting an empty hydrochloric acid tank and producing thermal to a structural steel roof to the extent of $800,000. A 1995 wet bench fire summarized in FM Data Sheet 7-7 (1997) contaminated 2300 in-process silicon wafers, caused approximately $12 million in damages, and required 74 delays to achieve pre-fire production levels. However, most incidents result in much less damage, with negligible thermal or nonthermal damage beyond the room since the exhaust system is usually equipped with mul-tiple filters. According to FM Data Sheet 7-6 (1986), the average property damage in this type of plastic tank fire is about $63,000.

Injuries and fatalities – Fire injuries and fatalities are due to toxic combustion products as well as burns. Deterministic methods are available for calculating the extent of the danger zone asso-ciated with toxicity and thermal effects. These methods are discussed in Section 2.1.1. However, casualty estimates are not usually amenable to an entirely deterministic methodology because of uncertainties associated with transient exposure toxicity effects and human response to a

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developing fire. Engineering risk analyses incorporating relevant statistical and probabilistic data can be utilized as shown for example by Boykin et al. (1986) for transformer fires in occupied buildings. A similar approach, but with the addition of more complete fire and toxicity models, has been used in a National Fire Protection Research Foundation study to analyze casualties due to hypothesized fires in homes, offices, hotels, and restaurants (Gann et al., 1991).

Example – Since the immersion heater fire scenario usually occurs in an unattended facility and does not involve a very rapid flame spread or extremely toxic combustion products, there are very rarely any serious injuries or fatalities. However, there have been several incidents in which fear of exposure to combustion or decomposition products from unknown chemicals in the tanks/tubs did significantly delay manual suppression of the fire. These fears can be alleviated (or accommodated when warranted) through emergency response planning, drills, etc., with the local fire department.

Business interruption – Business interruption losses refer to lost income incurred due to fire damage. Estimates of business interruption losses are based on the anticipated down time of the plant or process. It is inevitably a plant-specific determination best made by or in consultation with a professional adjuster. In the case of modern semiconductor fabrication facilities with a large backlog of orders to fill, business interruption losses can exceed property damage.

Environmental damages – Fire damage to the environment can occur either through airborne smoke and toxic combustion product deposition on vulnerable plants and animals, or through contaminated water runoff into a nearby river or lake. Although it is very difficult to quantify this type of loss, it warrants serious qualitative consideration. Its importance in pesticide and other toxic chemical fire scenarios should be obvious, but it can also be a major factor in other scenarios such as the August 1984 fire in a London warehouse complex (Kort, 1985) containing 318,000 kg (350 tons) of cocoa butter, among various other commodities. The cocoa butter melted and burned during the fire and flowed out of the warehouse and into the city storm sewers which empty into the London canal network. According to Kort (1985), the cocoa butter quickly killed most of the fish in the canals. Another unanticipated environmental effect from this fire was the widespread asbestos contamination originating from a layer of asbestos cement in the warehouse roof.

Perhaps the most environmentally notorious fire was the November 1986 Basel, Switzerland chemical warehouse fire in which toxic chemicals were washed into the Rhine River and destroyed most downstream aquatic life in France, Germany, and the Netherlands. In the aftermath of the fire, a huge holding tank for firefighting water runoff has been constructed in Basel to avoid future environmental catastrophes of this nature.

Explosion damage – Explosion damage mechanisms include pressure (and pressure-time impulse) damage and projectile/shrapnel damage. Explosion pressures within the enclosure con-taining the combustible gas or dust can be calculated using the methods described in Chapter 3-16 of the SFPE Handbook (1995). Blast wave pressures associated with commercial explosives and pressure vessel failures can be estimated from the methods described in Appendix C. These meth-ods are also commonly used to estimate vapor cloud explosion pressures outside the vapor cloud itself, providing there is a credible basis for estimating the quantity of flammable vapor in the cloud and the effective blast yield (fraction of combustion energy released in the form of blast waves). Projectile-induced damage estimates are more questionable, but techniques described in Baker et al. (1983) and Army Technical Manual TM5-1300 (1991) are available.

1.1.3 ALTERNATIVE PROTECTION EVALUATION

When the consequence analysis suggests the fire or explosion can cause an unacceptably large loss, it is necessary to evaluate alternative protection. The potentially more cost-effective alternatives

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fall into the two broad categories of preventive measures and damage control measures. Preven-tive measure alternaPreven-tives consist of less flammable materials and modifications to eliminate or reduce the frequency of ignition sources. Alternative damage control measures include improved detection, suppression, and smoke control systems, more fire resistant materials and structures, and improved drainage of water runoff.

A systematic comparison of these alternative protection measures sometimes entails estimating failure/success probabilities and using fault tree and event tree analyses such as those described in Henley and Kumamoto (1981) and the AIChE Guidelines for Chemical Process Quantitative Risk Analysis (1989). In other cases, such as the following example, it may be more appropriate to conduct deterministic analyses and/or fire testing.

Example – Returning to the wet bench electric heater fire scenario, several alternative preven-tive measures are possible. One modification could be the use of a less easily ignitable plastic in place of polypropylene. Data in Table 5.11F of the NFPA Handbook (1986) indicate that polyte-trafluoroethylene (Teflon) and some rigid phenolics (probably with fire retardant additives) have critical radiant heat fluxes for ignition that are approximately twice as large as that for polypropy-lene. Several new halogen free polymers that are beginning to be produced commercially are also very resistant to ignition. Factory Mutual Research Corporation has recently developed a Flamma-bility Test Protocol for clean room materials (1997) that includes time-to-ignition measurements at surface heat fluxes greater than the critical heat flux.

Alternatively, a less powerful heater or more reliable heater controls could be used as described previously. Another preventive measure suggested in the FM Data Sheet and from Lotti (1986) is the replacement of the electric heater with steam immersion coils. Factory Mutual Data Sheet 7-7 recommends that electric immersion heaters be replaced with other heating methods employing aqueous, or other noncombustible, heat transfer fluids.

Several polymers have significantly lower heat release rates and smoke release rates than polypropylene. For example, the data in Appendix A indicate that the heat release rate for poly-methyl methacrylate (PMMA) is at least 30% lower than that of polypropylene for similar configu-rations. Using Equation [1.1] and Appendix A values for PMMA, the estimated smoke release rate

for a PMMA tub wall fire would only be about 0.026 g-soot/sec per m (1.74× 10−5Btu/sec-ft)

wall width, i.e. about one sixth of the corresponding value for polypropylene.

The FMRC Clean Room Materials Flammability Test Protocol includes heat release rate tests with 10 cm (4 inch) wide test samples exposed to an oxygen enriched atmosphere and an imposed heat flux at the sample bottom. A Fire Propagation Index is calculated from the heat release rate data and time-to-ignition test data. A Smoke Damage Index is calculated from the soot yield and Fire Propagation Index, and a Corrosion Damage Index is calculated from the yield of corrosive combustion products. Materials with sufficiently low values of these indices are listed as FMRC Clean Room Materials that do not, of themselves, require fixed fire detection or suppression equipment. Two materials, a fire retardant polypropylene and a fire retardant polyvinyl chloride, were listed in the 1998 FMRC Approval Guide as having satisfied the Clean Room Materials Flammability Test Protocol.

If low flammability bench materials are not utilized, a damage control alternative is the use of a smoke detector and suppression system for the bench itself. The detector signal could de-energize the heater and actuate an alarm as well as initiate the discharge of suppression agent. Sophisticated fiber optic laser beam smoke detectors, and air sampling systems combined with light scattering detectors are also being utilized in some clean rooms. Detector and gaseous suppression system design considerations for this type of application are discussed in Chapter 4 as well as in FM Data Sheet 7-7. Portable carbon dioxide or other gaseous agent extinguishers placed near the tanks would also be useful for constantly attended operations.

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1.2 Statistical overview of industrial fires and explosions

The National Fire Protection Association (NFPA) compiles statistics on fires reported to public fire departments in the United States, and provides a statistical overview each year in the NFPA Journal. Occupancy categories correspond to the categories and groupings in the NFPA 901 reporting form. The groupings that might be considered ‘industrial’ are basic industry, utilities, manufacturing, and many of the storage properties. NFPA statistics for 1990 (Karter, 1991) indicate that there were 22,000 fires in the combined categories of basic industry, utilities and manufacturing, and an additional 39,500 fires in storage properties. These figures neglect the numerous fires that are not reported to the public fire department because they are extinguished by plant personnel or fixed suppression systems.

The US Occupational Safety and Health Administration (OSHA) maintains a database of workplace injuries. Their data for 1998 (Bureau of Labor Statistics, 2000) indicate that there were 4152 non-fatal workplace injuries due to fires, and another 1670 occupational injuries due to explosions. In addition, there were 206 fatalities in 1998 due to fires and explosions in US workplaces. These represent slightly less than 4% of all the workplace fatalities, most of which are due to vehicle accidents.

1.2.1 INDUSTRIAL OCCUPANCIES IN LARGE LOSS FIRES

Table 1.1 is a listing of US industrial fires and explosions with property damage of at least $30 million in 1990 dollars. The exact dollar amounts are not necessarily accurate because they are based on published data often from preliminary, unofficial estimates. Nevertheless, the tabulation of 64 incidents provides an overview of the types of facilities and events that have been responsible for the most costly US industrial fires and explosions.

Seventeen of these largest losses (27%) occurred in warehouses, with about half of these being used primarily for paper, plastic, or general commodity storage. There are also several flammable liquid warehouses, and several other cold storage warehouses. One common aspect of these warehouse fires was the failure of the installed sprinkler system to adequately control the fire. Warehouse storage sprinkler protection is discussed in Chapter 5.

Twelve of the largest losses (19%) occurred in petroleum refineries. The large quantities and concentrations of flammable liquids and vapors at these refineries provide both the potential and the realization of some very large fires and explosions. Property damage is often exacerbated by the high replacement costs of the sophisticated process equipment.

Other industrial occupancies with multiple occurrences in Table 1.1 are power plants (5 inci-dents), chemical plants (5), grain elevators (3), textile plants (2), telephone exchanges (2), ink manufacturing facility (2), and aluminum plants (2).

The British Fire Protection Association publishes annual compilations of losses in the United Kingdom causing at least £1 million. Data for the period 1985 – 86 indicate that the types of indus-trial facilities with the largest numbers of large-loss fires are general warehouses (13 incidents), textile mills (12), and the combined category of wood, furniture, paper, and printing plants (12). The relatively large number of textile mill fires is probably a manifestation of the large number of textile mills still in operation in the UK. The three largest industrial fire losses in this period were a £10 million ($15 million) fire at a general warehouse, a £9 million fire at a carpet warehouse, and a £8 million fire at a small tool manufacturing plant.

Perhaps the most costly industrial loss in recent history was the 1988 gas explosion and fire on the Piper Alpha oil production platform in the North Sea. According to a recent compilation of disasters by Swiss Re (1998), the insured loss due to the Piper Alpha catastrophe is estimated to be $2759 million. It also was responsible for the death of 167 workers. Extensive research into improved fire and explosion protection for offshore platforms was initiated soon after the Piper Alpha catastrophe.

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Ta b le 1 .1 . Lar g est U S indust ri al fire and expl osi o n losses sort ed b y p ropert y d amage Y ea r Lo ca tio n F ac ility T y p e o f fire or expl osi on Propert y damage a ($ millio n ) (1990 $ m illio n ) a 1989 Pasadena, T X C hemi cal Pl ant V apor Cl oud Expl osi on 750 758 1947 T exas C it y, T X S hi p & Chem Pl ant A mmoni um Ni tr at e E xpl osi on 67 558 1999 Dearborn, MI Powerhouse G as and D ust Expl osi ons 650 540 1975 Browns Ferry, A L N ucl ear Power Pl ant El ect ri cal Cabl e Fi re 227 507 1995 Lawrence, MA T extile Plant Flock Dust Explosion and Fire 500 427 1988 Norco, LA Pet rol eum R efinery V apor Cl oud Expl osi on 330 347 1953 Li voni a, MI Aut o T ransmi ssi on Pl ant F la mmabl e L iqui d F ir e 50 319 1999 The G rammercy Wo rk s, L A Al umi num Pl ant Pressure V essel B urst s due to St eam Over pr essur izat ion 300 249 1996 LA General S torage W arehouse Incendi ary F ir e 280 233 1999 Ri chmond, CA Oi l R efinery Gas/ V apor Expl osi on 247 205 1970 Li nden, NJ Oi l R efinery Pressure V essel B LEVEs 50 175 1987 Pampa, TX Chemi cal Pl ant V apor Cl oud Expl osi on 160 173 1995 GA Carpet Manufact urer Oi l Pool Fi re 200 171 1969 Rocky F la ts , C O N ucl ear W eapons Pl ant H ydrogen F ir e & Expl osi on 45 171 1999 Mi ssouri P ower Pl ant G as Expl osi on 196 163 1984 T inker A FB, O K Jet Engi ne Repai r Roofing Fi re 138 160 1985 El izabet h, NJ W arehouse A erosol St orage F ir e 123 139 1975 New Y ork, NY T el ephone Exchange El ect ri cal Cabl e F ir e 60 134 1982 Fal ls T ownshi p, P A G eneral W arehouse A erosol St orage F ir e 100 126 1984 Romeoville, IL O il Refinery V apor Cloud Explosion 100 116 1988 Henderson, NV Rocket Propel la nt Pl ant A mmoni um Perchl orat e Expl osi on 103 108 1973 Chi cago, IL Ink M anufact urer W arehouse St o rage Fi re 37 104 1994 TX Met hanol Product ion P la nt Expl osi on? 116 103 1991 Madi son, WI Col d W arehouse Food St orage Fi re 100 100 1992 Mi ssouri C ol d St o rage W arehouse Pol yst y rene Foam Insul at io n Fire 100 96 .6 (cont inued overl eaf )

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Ta b le 1 .1 . (cont inued ) Y ea r Lo ca tio n F ac ility T y p e o f fire or expl osi on Propert y damage a ($ millio n ) (1990 $ m illio n ) a 1976 Gal ena Park, T X G rai n El evat or Grai n D ust E xpl osi on 42 89 1995 TX Indust ri al C hemi cal St orage U nder Invest igat ion 100 85 1988 Los A ngel es, CA General W arehouse W arehouse St o rage Fi re 80 84 1977 Fairbanks, AK Oil/Gas Pumping Station Gas Explosion 4 0 7 9 1980 Bor ger, TX O il Refinery V apor Cl oud Expl osi on 50 75 1996 NJ General St orage W arehouse U nder Invest igat ion 84.5 70 1989 Bat on R ouge, LA P et rol eum Refinery V apor Cl oud Expl osi on 68.9 70 1998 IN Pl ast ic W arehouse W arehouse St o rage Fi re 85 68 1980 New C ast le , D E C hemi cal Pl ant V apor Cl oud expl osi on 45 67 1994 WV St eel Mi ll St ruct ure Fi re D ue T o Hydraul ic Oil S pray 75 66 1993 LA Pet rol eum R efinery Refinery C oker U ni t Fi re 65.2 6 2 1998 KS Grain E levator F acility Grain Dust E xplosion 7 5 6 0 1992 W ashi ngt on Col d St orage W arehouse R oof Insul at ion F ir e 62 60 1978 T exas C it y , TX R efinery Pressure V essel B LEVEs 32 60 1977 W est wego, LA Grai n E le vat or G rai n Dust Expl osi on 30 59 1999 Mart in ez, CA Oi l R efinery Napht ha Expl osi o n and Fi re 71 63 1983 A von, CA Oi l R efinery Fl ammabl e Sl u rry Fi re 49 58 1986 Bi smark, ND Power Pl ant ? 5 0 5 5 1981 Louisville, K Y Soybean Processing Flammable V apor Explosion 4 0 5 5 Pl ant and Muni ci pal S ewer 1978 Bensonville, IL G eneral W arehouse W arehouse Storage Fire 30 55 1995 NY Paper Products Manufacturer Paper storage Fire Resulting Fr om El ect ri cal Mal funct ion 62 53

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1988 Hi nsdal e, IL T el ephone Exchange El ect ri c C abl e Fi re 50 53 1987 Dayt on, OH Pai n t W arehouse W arehouse St o rage Fi re 49 53 1979 Edi son, NJ General W arehouse A erosol St orage Fi re 30 52 1993 LA Pet rol eum R efinery Refinery C oker U ni t Fi re 50 45 1996 W A Pl ywood Manufact uri n g Pl ant ? 5 0 4 2 1996 IL Paper R ecords St o rage W arehouse St o rage Fi re 50 42 1993 TX Paper/ pl ast ic W arehouse W arehouse St o rage Fi re 45 41 1989 Louisiana Oil and Gas Drilling P la tform N atural Gas F ire 4 0 4 0.7 1995 V A Steam Power Plant Fuel Line Fire Resulting Fro m Fa u lty T u rb in e 45 38 1996 NE Sugar R efinery Sugar D ust Expl osi on 44 37 1995 Rouseville, P A Refinery HC Fire 40 36.2 1994 IN Al umi num Fabri cat io n Pl ant ? 4 0 3 5 1990 Loui si ana W harf W arehouse B al ed Rubber St orage Fi re 34 34 1992 V ir gi ni a Nyl on F iber Manufact uri ng P la nt Nyl on fl uf f and fini shi ng oi l fire 34 33 1992 T exas P et rochemi cal Fl ammabl e L iqui d F ir e 32 .3 31 1989 Maryl and Col d St orage W arehouse Food St orage Fi re 3 0 3 0 .5 1990 Col o rado Combust ib le Li qui d T ank Farm A ir craft Fuel Fi re 3 0 3 0 1990 Ohi o Ink and Dye M anufact uri ng Pl ant Combust ibl e V apor Expl osi on and F ir e 30 30 aProperty d am age b as ed on data in NF P A F ir e Journal annual compilations of lar ge loss fi res and on data in the J&H Ma rsh & McL ennan thirty-year review (1998), w ith conversion o f reported property damage to 1990 $ using FM Data Sheet 9-3. Supplemental data w as also obtained from H oyle et al . (2000)

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Data on industrial fire losses in most other countries are more difficult to obtain, at least in English. One good source is the Marsh & McLennan 1998 thirty-year review of chemical and petroleum plant losses. It lists many refinery and gas processing plant explosions around the world with losses in excess of $100 million. Two other noteworthy losses in this category are the 1997 fire at a semiconductor fabrication facility in Taiwan (loss estimated to be $420 million), and the 1994 fire at a particularly large Russian vehicle assembly plant (loss estimated to be approximately $1000 million).

1.2.2 TYPES OF FIRES/EXPLOSIONS IN THE LARGEST LOSSES

The types of fires and explosions listed in Table 1.1 provide an overview of the types of challenges faced by fire protection engineers at industrial facilities. Eleven of the incidents (17%) involved flammable liquid fires. Flammable liquid ignitability, heat release rates in typical fire scenarios, and extinguishability are discussed in Chapter 7. Two of the historic fires described in Appendix B (the GM Livonia fire and the Sandoz Basel fire) were inherently flammable liquid fires.

Eight of the fires (12.5%) listed in Table 1.1 were plastic storage fires, which are described in Chapter 5. Appendix B includes a specific account of the Ford Cologne, Germany warehouse fire. Six incidents (9%) in Table 1.1 involved dust explosions. Dust explosions are often followed by extensive fires, such as the Lawrence, Massachusetts textile plant fire shown in Plate 1. Five incidents (8%) were vapor cloud explosions. The only aspects of explosion protection discussed in this book are explosion prevention and blast wave calculations. An overview of explosion pro-tection is provided in one chapter of the SFPE Handbook (Zalosh, 2001). A more comprehensive discussion of dust explosions can be found in Eckhoff (1997), and a more complete discussion of vapor cloud explosions is provided in the 1994 Guidelines published by the Center for Chemical Process Safety.

Other multiple incidents listed in Table 1.1 are gas explosions (3 incidents), electrical cable fires (3), aerosol product storage fires (3), gas fires (3), flammable vapor explosions (3), liquid container fires (2), Boiling Liquid Expanding Vapor Explosions (2 BLEVEs), and thermal insulation fires in cold warehouses (2). Some of these special types of fire scenarios are described in this text, whereas the explosion scenarios are covered in the previously cited explosion references.

1.2.3 FACILITIES INVOLVED IN MULTIPLE FATALITY FIRES AND EXPLOSIONS Table 1.2 is a tabulation of 36 reported worldwide industrial fires and explosions with at least 20 fatalities during the period 1981 – 2000. In culling through the references cited at the end of the table, transportation accidents, mining disasters, and military ammunition incidents were omitted. Other omissions involved incomplete reports in which the site of the incident may or may not have been an industrial facility. When different references reported differing fatality numbers, both numbers are listed in the table.

Ten of the 32 catastrophes listed in Table 1.2 occurred in petrochemical plants such as refineries. These were explosions, flash fires, BLEVEs, or flowing liquid fires. The 726 – 967 total fatalities in these incidents were due to inadequate warning and no time for employees and other victims to escape. In at least one of these catastrophes (the 1984 disaster in a suburb of Mexico City), the majority of the victims were residents in a densely populated poor community immediately adjacent to a large petrochemical facility.

Nine of the catastrophes listed in Table 1.2 occurred in various types of factories. The majority of the 549 – 606 fatalities in these cases were primarily due to inaccessible or inadequate exits and egress paths. In the Bangladesh fire and the Chinese rainwear factory fire, workers were trapped on the upper floor and roof, while in the North Carolina chicken plant fire many workers were

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Ta b le 1 .2 . Industrial fi res and explosions with more than twenty fatalities (1981 – 2000) Da te Lo ca tio n P la n t T y p e o f fire /e x p lo sio n F at alitie s (re fe re nc e) December 18 – 21, 1982 Car acas, V enezuel a F uel T ank F ar m F uel O il T ank Boi lover F ir e 128 a153 d February 25, 1984 Sao P aul o, B razi l G asol ine P ipel ine G asol ine F ir e 89 d508 b August 16, 1984 Ri o d e Janei ro, B razi l G as Product io n Pl at form G as Fi re 36 d November 19, 1984 Mexi co Ci ty, M exi co P EMEX LP-Gas Pl ant B LEVEs 334 a550 b May 19, 1985 Pri ol a, It al y Pet rochemi cal Pl ant E thyl ene E xpl osi on 23 b June 25, 1985 Jenni ngs, O kl ahoma F ir ewor ks Fact ory F ir eworks Expl osi on 21 a Apr il 26, 1986 Cher nobyl , U kr ai ne Nucl ear Power P la nt React or Expl osi on/ Fi re 31 c 1987 Grangemout h, UK Pet rochemi cal Pl ant H ydrocarbon Expl osi o n /Fi re 67 b July 6, 1988 North S ea Platform Piper A lpha Oil/Gas Gas E xplosions & Fires 167 a, b Oct ober 22, 1988 Shanghai , Chi na O il Refinery P et rochemi cal Expl osi on 25 d November 9, 1988 Maharasht ra, Indi a P et rochemi cal Pl ant N apht ha Fi re 25 b Oct ober 23, 1989 Pasadema, T exas, U SA Pet rochemi cal Pl ant E thyl ene V apor Cl oud Expl o 23 a, b 1989 Ant w erp, Bel gi um C hemi cal Pl ant A ldehyde Expl osi on 32 b November 5, 1990 Maharasht ra, Indi a P et rochemi cal Pl ant E thane/ Propane Fi re/ E xpl o 35 b December 27, 1990 Dhaka, Bangl adesh G ar ment Fact or y G ar ment Fi re 23 a January 5, 1991 Guat emal a G eot hermal P ower Pl ant ? 21 a May 30, 1991 Dongguang, China R ainwear Factory T extile Fire 66 a71 d June 6, 1991 Brazi l F ir eworks Fact ory Fi reworks Expl osi o n 2 4 a July 12, 1991 Meenampatti, India F irewor ks Factory F ireworks Explosion 3 8 a Sept ember 3 , 1991 Haml et , N Carol in a, USA Food Processi ng Pl ant H ydraul ic Oi l Spray Fi re 25 d December 10, 1991 Al bani a F ood W ar ehouse W ar ehouse F ir e ≥ 60 a (cont inued overl eaf )

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Ta b le 1 .2 . (cont inued ) Da te Lo ca tio n P la n t T y p e o f fire /e x p lo sio n F at alitie s (re fe re nc e) December 15, 1991 India Cotton M ill T extile Fire? ≥ 22 e Apri l 22, 1992 Guadal aj ara, Mexi co Unspeci fied F act ory H exane V apor Expl osi on in S ewers 170 a Apri l 29, 1992 New D el hi , Indi a W arehouse U nspeci fied C hemi cal Expl osi on 43 d May 10, 1993 Bangkok, Thai la nd T oy F act ory P la st ic s F ir e 88 a240 d November 19, 1993 Kui yong, Chi na D ol l F act ory U nspeci fied F ir e 81 d June 17, 1994 Zhuhai, China T extile Mill Unspecified F ire 7 6 d June 29, 1996 Pi ya, C hi na Unspeci fied F act ory U nspeci fied E xpl osi on 36 d Sept ember 14, 1997 V isag, Indi a Pet rol eum Refinery LPG T ank Fi re & Expl osi on 34 d 60 b Sept ember 20, 1997 Ji n Ji ang, Chi na S hoe Fact ory U nspeci fied F ir e 32 d December 11, 1998 Br azi l F ir ewor ks Fact or y F ir ewor ks Expl osi on 41 a May 13, 2000 Enschede, N et herl ands Fi reworks Fact ory Fi reworks Expl osi on 21 a aFrom individual reports on these fi res bFrom T able 9 of Khan and A bbasi, J. Los s P revention , 1999 cT h ere w ere 2 8 fatalities due to acute radiation sickness, and three others from non-radiation causes w ithin the three m onths following the Chernobyl accident (IAE A , 1996) dFrom UN E nvironmental P rogram Selected Accidents Involving H azardous Substances http://www.unepie.or g/apell/acci den t.ht m l eFrom L oss Prevention A ssociation of India compilation, 1992

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trapped because of an exit door locked from the outside. There were inevitably many other fire protection deficiencies in these nine factory fires, but details were not available for most of these incidents.

Two of the Table 1.2 catastrophes occurred on oil/gas production platforms, including Piper Alpha. The 203 reported fatalities in these cases were due to a combination of the factors described above, i.e. inadequate warning and time to escape, plus being isolated on the burning platform. Defects in installed fire and explosion protection were also important factors.

Five of the catastrophes were explosions in fireworks factories. In addition to a failure of preventive measures, these explosions involved failures to adequately isolate the inherently haz-ardous fireworks manufacturing operations and limit the quantity of explosive material. At least two of these five fireworks factories were situated in or immediately adjacent to densely populated towns.

Perhaps the best-known and most widely reported catastrophe cited in Table 1.2 is the Cher-nobyl nuclear reactor explosion and subsequent fire. Of the 31 reported near-term fatalities at Chernobyl, 28 were due to acute radiation sickness, mostly incurred during attempts to control the fire and install a cocoon around the reactor. Among other things, the Chernobyl disaster illustrates the need for adequate protection for plant fire brigades and other emergency response personnel dealing with special hazards.

There were two incidents in which the majority of the fatalities occurred far from the industrial plant site. In one case, a flammable liquid spill from a factory into the sewer system caused a subsequent series of explosions in a large section of the sewer system. Another case involved a gasoline pipeline in an industrial area in Brazil. Both these incidents are representative of many others that may not have originated in industrial facilities, but illustrate the need for awareness of the various fire and explosion scenarios associated with flammable liquid pipelines and discharges from industrial facilities.

1.2.4 IGNITION SOURCES

Figure 1.4 shows the most prevalent ignition source categories for large loss fires in man-ufacturing facilities and storage facilities as reported in the NFPA Journal annual compila-tions of large-loss fires. Electrical ignition sources are responsible for the greatest number (25%) of large loss manufacturing facility fires, whereas deliberately set open flame ignition sources are responsible for the greatest number (24%) of large loss storage facility fires. This is consistent with the preponderance of energized electrical equipment in manufacturing facili-ties, and with the large quantities of combustibles in storage facilities being targets for arson-ists. Similar statistics compiled for insured industrial properties indicate that electrical ignition sources are responsible overall for about twice as many fires and explosions as incendiary/arson fires. Arcing and shorting of fixed wiring are the major ignition mechanisms in fires started by faulty electrical equipment/wiring. Chapter 9 discusses the consequences of these electri-cal ignition sources that initiate fires in electrielectri-cal cables, transformers, and other electrielectri-cal equipment.

Other ignition sources playing significant roles in industrial fires as represented by the percent-ages shown in Figure 1.4 include cutting/welding operations, hot objects, fuel fired equipment, and spontaneous ignition. Cigarettes, which have responsible for a large percentage of residential fires, are a relatively infrequent ignition source (3 – 4%) in industrial fires.

These ignition source statistics indicate that an engineering approach to seek better preventive measures for industrial fires might best focus on reducing electrically induced ignitions. This could entail implementing more reliable electrical controls and interlocks, installing electrical cables with higher ignition temperatures (or critical heat fluxes), and/or providing greater physical separation between electrical equipment and combustible materials.

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Manufacturing facilities Electrical eq. 33% Open flame 15% Hot object 16% Cutting/welding 11% Fuled fired eq.

13% Spontaneous ign 8% Cigarette 4% Storage facilities Electrical eq. 29% Open flame Hot object 6% Cutting/welding 9% Fuled fired eq.

9%

Spontaneous ign 7%

Cigarette 6%

Figure 1.4. Ignition sources in industrial fires (based on NFPA large loss data excluding fires with unknown

ignition sources)

1.2.5 NEED FOR AUTOMATIC DETECTION AND SUPPRESSION

Many of the loss statistics make a strong case for installing automatic detection and suppression systems to reduce losses. One indication of this is the distribution of facility operating status categories for large loss fires. As shown in the pie chart in Figure 1.5, more than half of the NFPA 1985 large loss fires were initiated with nobody on the premises. Only about 36% of these losses occurred while the plant was in full operation with a full staff available for manual detection and suppression. According to the time distribution of large loss fires given in Figure 1.6, many more fires are initiated in the interval 12:00 A.M. to 6:00 A.M. than in any other six hour period. UK large loss fires follow similar patterns with about 64% of the fires occurring at night, i.e. between 6:00 P.M. and 6:00 A.M. (Ward, 1988). During these peak periods for ignition there is a large probability that plant personnel will not be available for a prompt response to the fire. Hence, there is a clear need for automatic detection and suppression.

A more direct measure of the benefits of automatic suppression systems is the comparison of losses with and without automatic sprinkler systems available. In the NFPA loss statistics for the period 1980 – 1983 (Cote and Linville, 1986), the overall average losses with and with-out sprinklers are $8500 and $20,700, respectively. Thus, the absence of automatic sprinklers

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Nobody in facility Other Partial operation Full operation 6 % 36 % 53 % 5 %

Figure 1.5. Facility operational status at time of fire (based on NFPA data for 238 fires in 1985)

12 AM to 6 AM 35 % 27 % 20 % 17 % 6 AM to Noon Noon to 6 PM _{6 PM to 12 AM}

Figure 1.6. Time distribution of fires in industrial facilities (from NFPA data on 338 fires in 1985)

increased the average loss by 140%. In some occupancy categories, such as machinery manu-facturing, the unsprinklered-to-sprinklered fire loss ratio is as high as 5.4. This type of data is important for risk managers to utilize to justify the cost of sprinkler installation.

The status of automatic suppression systems and detection systems in NFPA 1987 large loss industrial fires is summarized in Table 1.3. Suppression systems were not installed in half the

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Table 1.3. Status of automatic suppression systems and detection

systems in 1987 large loss fires (data from NFPA Journal, November/ December 1988)

Automatic sprinkler system status Number of fires

Not Installed 14

Overpowered by Fire 7

System Shut Off Before Fire 2

Not in Area of Fire Origin 3

Damaged by Explosion 1

Unknown 1

Total 28

Automatic detection system status Number of fires

Not Installed 19

Functioned as Designed 4

Not in Area of Fire Origin 1

Installation Incomplete 1

Unknown 3

Total 28

large losses, and were either shut off, not in the area of fire origin, or damaged by an explosion in another 25% of the losses. The suppression systems were overpowered by the fires in the other 25% of the losses. Thus, 75% of the large losses occurred without any active automatic suppression, while the other 25% involved inadequate automatic suppression. Design criteria and testing needed for effective sprinkler protection are discussed in the context of warehouse fires in Chapters 5 and 8, and for electric cable trays in Chapter 9.

In the case of automatic detection systems, data in Table 1.3 indicate 75% of the losses occurred where there were no installed detectors at all or in the area of fire origin. On the other hand, automatic detection did function as designed in at least 14% of the large loss fires. Therefore, the provision of automatic detection and suppression systems is a favorable, but not necessarily a sufficient factor in avoiding large losses.

1.3 Historic industrial fires and explosions

It is unfortunate but inevitable that most advances in fire protection occur in response to catas-trophic losses. Statistics are often not nearly as convincing as personalized accounts and pictures of large destructive fires and explosions. Appendix B contains descriptions of eight historic indus-trial losses that have had a large and lasting influence on contemporary fire protection engineering. These eight fires are:

• The 1911 Triangle Shirtwaist Garment Factory Fire in New York City • The 1953 GM Auto Transmission Plant Fire in Livonia, Michigan • The 1967 McCormick Place Convention Hall Fire in Chicago • The 1975 Bell Telephone Exchange Fire in New York City

• The 1977 Ford Automobile Parts Warehouse Fire in Cologne, Germany • The 1982 K Mart Warehouse Fire in Falls Township, Pennsylvania • The 1989 Ameritech Telephone Exchange Fire in Hinsdale, Illinois

Industrial Fire Protection Engineering - Robert G. Zalosh (Wiley, 2003)

INDUSTRIAL FIRE

PROTECTION

INDUSTRIAL FIRE

PROTECTION

ENGINEERING

Robert G. Zalosh

Center for Firesafety Studies, Worcester Polytechnic Institute,

Worcester, MA, USA

CONTENTS

PREFACE

1 INTRODUCTION

AND PERSPECTIVE

1.1 Engineering approach to industrial fire protection

1.2 Statistical overview of industrial fires and explosions

1.3 Historic industrial fires and explosions