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August 2011: Protecting Your COPE and Identifying your Commodity Will Help Reduce Fire Loss in Large Buildings

What is COPE? It is the Construction Occupancy Protection and Exposure risk for each building. Significant fire damage in large buildings occurs approximately 300 times per year in the United States. Such fires cause property damage, business interruption, injuries and possibly death. They also account for a disproportionate amount of property loss in dollars.

There are many factors that contribute to these losses. Some of the more critical are the construction of the building, presence of an adequate automatic sprinkler system, adequate fire protection water supply, commodity classification of the inventory, the time it takes before the fire is detected and the response time of the fire department.

Construction: The most significant way to mitigate possible loss due to fire for any building is to ensure that building walls and roofs are designed and built with non-combustible materials. Foam insulation used on the interior side of perimeter walls and also used within sandwich panel walls can cause a significant fire exposure. Also, ornamental dioramas occurring in retail occupancies may in fact be composed of exposed foam. If it is not practical to have these fire exposures removed, it is important to have a fire retardant coating applied or to provide a fire barrier. The ultimate goal should be to have a flame spread rating of less than 25.

Occupancy: The contents themselves also play a primary part in the rate of fire spread. Industrial facilities such as warehouses usually contain more combustible materials than an office or manufacturing building. In many cases the commodity classification in a warehouse is considered a plastic. It is critical that the occupancy be classified properly. Here are some guidelines.

Both NFPA and FM Global provide detailed information in determining the storage classification.

Common examples used in the fire protection industry include:

In Chapter 5 of NFPA 13, Standard for the Installation of Sprinkler Systems a Class III commodity shall be permitted to contain a limited amount of plastic. A limited amount is defined as less than 5% by weight or volume. A Class IV commodity may contain between 5% to 15% by weight of plastic or 5% to 25% by volume. Anything over this threshold is defined as a plastic. Plastics are broken down into three Groups (A, B and C). NFPA and FM have variations in their classification of the Groups. However Group A is the most common and hazardous.

FM Global has a detailed Data Sheet (DS) 8-1, Commodity Classification, which outlines each classification and provides several examples. FM lists polypropylene and polyethylene as Group B plastics while NFPA lists them as Group A plastics. The FM standards are based on detailed and comprehensive testing at their test lab in Rhode Island and, in our opinion, should be used for a commodity classification when the option is available. Polystyrene is given as an example of a Group A plastic by FM as it has a burn rate of 440 lb/min and Polypropylene is classified as a Group B plastic as it has a burn rate of 233 lb/min.

Plastics are also classified as being unexpanded or expanded. Unexpanded plastics are a solid dense product such as a plastic tote. Expanded plastics are low density plastic such as foam packaging or polystyrene coffee cups. The heat release rate of expanded plastics is greater than that of unexpanded plastics.

FM DS 8-1 also provides a similar definition to NFPA with regard to plastics. If more than 25% by volume of Group A or B is expanded plastic, then the commodity is defined as a plastic, if less than 25% by volume the commodity is a Class IV. If more than 15% by weight of Group A or B is unexpanded plastic, then the commodity is defined as a plastic if less than 5% by weight the commodity is a Class IV or less. If between 5% and 15% is unexpanded plastic, then the commodity may be a plastic or Class IV. More clarification is needed from FM DS 8-1.

It is critical that the commodity classification be selected properly especially in mixed occupancies. It is always best to be more conservative per NFPA and FM, and the requirements for the highest classified commodity classification should be used.

It is important to remember that most plastics have similar heat content as gasoline.

Response time: Despite traffic and pedestrian concerns, urban locations will usually have a shorter response time than more rural facilities. Rural locations also have a greater chance of having a part-time / volunteer fire department rather than a full-time, paid fire department that are quite common in cities. It may take several minutes for a fire to activate a sprinkler water flow alarm or detector, then several additional minutes for the fire department to respond, and even more time to prepare hose lines and enter the building to extinguish the fire. It is important to remember that automatic sprinkler systems (with the exception of {ESFR} Early Suppression Fast Response) are only designed to control the fire, reduce the heat and fire damage and pre-wet the surrounding fire area. They are not designed to extinguish the fire.

Automatic Sprinkler Protection and Water Supply: It is important to take a conservative approach when determining the commodity classification, in order to select the proper design criteria for an automatic sprinkler system. Both NFPA 13 and FM Data Sheet 8-9, Storage of Class 1, 2, 3, 4 and Plastic Commodities, provide charts and tables to help determine the proper design. Other FM Data Sheets might be needed to determine the proper design. An adequate water supply is just as critical as determining the correct commodity classification and designing the proper automatic sprinkler system. Providing a current hydrant flow test or pump test is an important factor in designing the protection.

Exposure: A recent $50M fire loss occurred in a multi tenanted warehouse in which the building burned to the ground. One tenant (A) was adequately protected with an automatic sprinkler system that was designed properly for plastic storage. The booster pump and public water provided an adequate water supply. The neighboring tenant (B) did not have a sprinkler system that was designed properly. A fire occurred late at night in the B section. The fire quickly overtaxed the B section of the facility and spread into tenant A's space. There were several other detrimental factors, but the end result was a total loss of the building.

The fire protection industry has a focus on the above mentioned categories, with a primary goal to provide a safe building for people, as well as an adequate protection system in case of a fire. Recent statistics have shown the need to emphasize fire protection engineering.

In a recent study by the National Fire Incident Reporting System (NFIRS) 5.0, the following results were obtained.

Large Loss Building Fires by Property Type*

Property Type

Percent of Large Building Fire Loss

Residential

48.4

Offices/Stores

16.2

Manufacturing

10.2

Storage

7.1

Assembly

5.4

Eating/Drinking

4.6

Basic Industrial

2.7

Educational

2.3

Other

1.8

Institutional

1.3


Loss Measures for Large Loss, Non-Large Loss and All Building Fires

Average Loss

Large Building

Non-Large Building

All Building Fires

Fatalities per 1,000 fires

29.1

4.5

4.5

Injuries per 1,000 fires

93.3

24.5

24.7

$ Loss per fire

$2,591,930

$14,280

$19,250


In 41% of all large loss fires, the cause is undetermined. However, the following major causes account for 32% of large loss fires:

Fire Spread

Percent of Large Loss

Percent of Non-Large Loss

Beyond floor or origin

87.8

20.3

Contained to floor of origin / small area

12.2

79.7

Electrical arcing, heat from power equipment and sparks from operating equipment all account for 33% of large loss fires. It is also important to take into consideration any combustible materials that might be stored in proximity to electrical equipment as a fire hazard.

Fire suppression (such as automatic sprinkler and alarm systems) is crucial to detecting fires and mitigating potential loss. Automatic extinguishing systems were present in only 16% of non-residential, large loss fires. However, it is just as important to make sure these systems are tested properly and are in optimal working condition. Failure of alarms and/or sprinklers to work in active large building fire events accounts for 33% of property loss.

Risk Logic can help identify fire risks in your facility. We have highly qualified fire protection engineers that can correctly identify commodities and provide the detailed analysis as to whether your fire protection system is adequate or if changes are necessary.

Source: U.S. Fire Administration/FEMA