Fires: minimizing the risks and damage.

Fires: Minimizing the risks and damage

Fires can be devastating to a business. While insurance helps, damage to a company usually goes way beyond the loss of materials, machines or buildings. It means lost production time. It means lost sales. It means employees lose work. It means a lot of things that casualty insurance and business interruption insurance just don't cover.

Because of the potential catastrophic nature of fire, as well as other "disasters," many companies have adopted aggressive loss prevention programs. Along with this, numerous insurance companies have established programs to deal with loss prevention. These programs benefit both the insurer and the insured.

One of the companies that works with both insurance providers as well as manufacturers is Factory Mutual Engineering and Research, also known as Factory Mutual Engineering Organization (FMEO). This company provides three services to both insurance companies and manufacturers: Adjustments, training and fire research.

Fire prevention technology has been one of the major focuses of FMEO for some time. They currently operate one of the largest fire research centers in the world. Having been involved in this type of business for over 150 years, they have a long history and wealth of knowledge that they apply to the casualty loss area.

In recent years, efforts have particularly been devoted to sprinkler technology. As most businesses know, sprinklers have been required fire suppression items since the early 1950s. As originally developed, they had a tremendous benefit in controlling the spread of fires. However, they did little to actually put out fires that were under way.

Toward the end of the 1970s, an attempt was made to improve fire control. This brought large drop sprinklers into the market. While this was an improvement, the large drop sprinklers still addressed control of an existing fire - not suppression.

About two years ago, the problem of suppression was addressed by FMEO with the advent of the Early Suppression-Fast Response system. Rather than just controlling the spread of a fire, this system was developed to actually put the fire out.

Why were new techniques needed?

As stated before, sprinkler systems that have been in use for the last four decades are designed to control fires - that is, prevent their spreading to adjacent materials and areas. They do this by wetting down combustible materials near the fire. While effective at fire control and preventing the fire from engulfing the entire building, damage to materials and items stored near the fire is often just as extensive as if it had been burned. While losses are limited, total loss dollars can still be quite high. This is particularly true when the adjacent area contains sophisticated electronics equipment and other high value items.

The first attempt at sprinkler systems that would suppress a fire rather than just control was the large drop sprinkler. These became available in 1979. The objective of these systems was to have larger drops of water coming from the sprinkler head. These larger drops have greater power to penetrate the flame plume and actually get to the burning material. While an improvement over the standard systems, their effectiveness has still been limited. In particular, fires classified as "high challenge" fires were generally only controlled by thoroughly soaking materials adjacent to the fire. Some of the reasons for the failure of these systems in high challenge fires were:

* Sprinklers did not activate until the fire was well established and had a high intensity;

* In the high intensity fires, the flame plume would often vaporize a number of the drops. In addition, with the flame plume traveling at speeds of 30 mph or more, more drops were diverted from the flame and the burning surface.

High challenge fires are those that result from materials that provide lots of fuel in a confined area. They are most common in storage situations where products or materials are stacked in racks 20 or more feet high. Plastics, particularly plastic foams, are one of the more common fuels for this type of fire. Rubber products are also a good fuel for this type of fire. In general, they can produce heats of combustion two and one-half times greater than "normal" materials. Even with in-the-rack sprinklers, fires in these situations escalate very rapidly.

How does ESFR work?

The object of the ESFR system is to extinguish a fire with just a few sprinkler heads activating. By extinguishing a fire before it develops a severe fire plume, the need to wet adjacent material can be avoided. The system was developed with the following objectives:

* Put out fires, not just control them.

* Require only four sprinkler heads to activate.

* Extinguish the fire before more than 10% of the fuel material in the stack exposed to the flame burns.

ESFR sprinklers must activate much sooner than standard sprinklers for the system to work. Because they activate sooner, fewer need to be activated to control and suppress a fire. This, in turn, reduces the water damage to adjacent materials.

In developing the system, researchers developed three criteria to measure performance:

* Sprinkler response time.

* Required delivery density.

* Actual delivery density.

Sprinkler response time depends on the responsiveness of the temperature sensor on the sprinkler, the temperature rating of the sensor and how far the sprinkler is from the fire.

Required delivery density defines how much water is required to extinguish the fire.

Actual delivery density is the amount of water that the sprinkler actually delivered to the fire. This factor takes into consideration the distribution pattern of the sprinkler as well as how much water actually penetrates the flame plume. Penetration is likewise dependent on the size of the water drop, its momentum, the velocity of the flame plume and the distance that it must travel.

In the ESFR system, actual delivery density must exceed the required delivery density.

In order to achieve the needed response time, the temperature rating on the sprinkler heads was reduced from 286 [degrees] F to 165 [degrees] F. Sensitivity was improved by reducing the mass of the sensor. As a result, they detect temperature changes much faster than standard sprinklers. Reports on actual tests show that response time for the ESFR sprinkler was 54 seconds versus 86 seconds for the standard sprinkler - 32 valuable seconds sooner.

In addition, ESFR sprinklers deliver a significantly greater amount of water to the fire - 100 gallons per minute versus approximately 60 gallons per minute for standard sprinklers. Sprinkler heads are also arranged so as to be pointed downward. This differs from standard sprinklers which are generally mounted above the delivery pipe to provide an umbrella effect with water delivery.

The result of all of this is that a lot more water is delivered to a fire sooner with a lot more force. Hence, it has a much greater chance of putting out a fire before it has a chance to become firmly established.

What are the benefits?

As mentioned earlier, the primary benefit is reduced property loss if a fire does occur. In addition, use of the system allows for higher density storage. According to FMEO, in-the-rack sprinklers can be eliminated, reducing maintenance costs and replacement costs when racking is replaced. In most areas, use of ESFR sprinklers will allow the user to use aisle space for storage of material. This can result in lower operational costs.

Compared to situations where in-the-rack sprinklers are required, cost of installation of an ESFR system will vary from 75-100% of the cost of standard sprinklers.

Retro-fitting an existing system with an ESFR system is just about impossible. First, ESFR systems typically require two-inch water delivery lines in the system, significantly larger than the standard system. Next, in order for sensors to function properly, they must be located within 13 inches of the ceiling. Standard sprinkler systems typically mount the sprinkler heads above the delivery pipe, creating an umbrella effect with the water. ESFR systems mount the heads below the pipe, pointed downwards to increase the velocity of the water. Since the 13 inch rule still applies, delivery pipes must necessarily be re-hung.

Standard sprinkler systems are required only to deliver 60 gallons of water per minute out of the sprinkler. Since there is no velocity requirement for the water coming out, there is a wide range of possible configurations related to water pressure in the system, pipe size, etc. The ESFR system, on the other hand, is designed for 50 psi of water pressure at the head during use. This reduces the possibilities for system configuration significantly. If the incoming water pressure is insufficient, a booster pump may be necessary.

Spacing of sprinkler heads is the same in both systems - each head is located to cover an area of 80-100 sq. ft.

Is ESFR the ultimate answer?

Unfortunately, no. While it is a dramatic improvement over existing systems, there are still situations that the ESFR system will not handle.

Problems arise when the materials in the storage racks have a high surface area that is largely protected from the water deluge. For example, in one test on tires stacked open in a rack, the system did not put out the fire. The problem here was the fact that the inside surface of the tires could not be reached by the water. In another case, plastic foam egg cartons stacked open in a rack were not extinguished in a test fire. Again, there was too much open area that was protected that the water could not reach.

When stored in closed cartons in a rack, however, test fires with both these items were extinguished.

The ESFR system depends on delivery of high volumes of water to the burning surface. By enclosing the items in closed cartons, water was able to cascade down over burning surfaces and extinguish the fire.

Storing materials in cartons does no good if the cartons are left open. When this is done, water from the sprinkler is caught by the open boxes and will not cascade down over other materials/boxes in the rack.

One final potential problem lies with the sensor. One of the key elements of the system is the fact that the 165 [degrees] sensor reacts much quicker and at a lower temperature than the standard sensor. While there are no reports of premature initiation to date, use of this sensor is not recommended in areas where the ambient temperature exceeds 100 [degrees] F. In temperature controlled warehouses and areas, this limitation presents no problem. However, in uncontrolled areas in the south or the west, this could present a problem that should be thoroughly investigated prior to installation. If a problem exists, it would be possible to use the 286 [degrees] sensor and still use the high volume sprinkler heads.

The last consideration, but certainly not the least, is local building codes. While most major metropolitan areas have adopted standards allowing use of the ESFR sprinklers, some areas still have not. If this is the case, some education of local officials may be necessary. One of the key elements in this education would be the fact that the latest NFP guidelines, specifically NFP Standard 13, have included the ESFR type systems.

Summary

As mentioned earlier, losses from fires and other disasters extend well beyond most insurance coverage. In all cases, we must take steps to mitigate against all the potential losses such a disaster causes. It seems that this type of sprinkler system may be one positive step. Its use will probably not reduce your insurance rates, but it could make a major difference in your ability to stay in business and serve your customers if a fire occurs.