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Sprinkler Safety

Don't neglect your sprinkler system in the maintenance of your school facility.

Today's technology has allowed sprinkler systems to become more and more hidden in the cosmetic treatments of buildings to the point that it sometimes takes an experienced eye to identify if a school or university building has a sprinkler system. As a result, sprinklers may be neglected in overall maintenance.

Automatic sprinklers were invented in the late 19th century. Their use originally was confined to industrial applications, and has spread to include commercial and public buildings.

Sprinklers have an impressive history of property protection. They have saved many buildings from devastation and owners from huge financial losses. Statistically, two or less sprinklers stop about 61 percent of all sprinkler-controlled fires. While sprinklers do not always extinguish a fire, they can control it until firefighters arrive.

Sprinkler know-how

Some facts regarding sprinklers:

  • Properly installed sprinklers are very reliable

    The odds of a sprinkler opening because of a manufacturing defect are about one in 16 million.

  • When sprinklers activate, they do not all go off at the same time

    Only the sprinklers exposed to the heat of a fire will open. This number usually is less than four.

  • The water damage from a sprinkler release is not the major cost of the fire

    The size of the fire and the amount of related water damage from fire department hose lines will be much larger than the damage from the fire and water damage from a sprinkler head. The average sprinkler head discharges approximately 25 to 35 gallons per minute. A fire department hose stream discharges from 100 to 250 gallons per minute.

  • A sprinkler head will activate to control a fire within minutes of its start

    Fires in unsprinklered facilities may develop over a number of hours and involve damage to much of a facility, and will require much higher water flows to bring the fire under control.

To enhance the effectiveness of sprinklers as a fire-protection device, most educational facilities also are equipped with fire-detection systems that sense the presence of fires in their incipient stages and to alert occupants to evacuate. Many of these systems also are connected directly to local fire-protection services and will initiate an automatic response.

Accidental discharges

Sprinklers are rugged assemblies, usually constructed of cast brass and an arrangement of metal or glass parts that are locked into position under pressure to maintain a seal at the orifice of the sprinkler. The odds of a sprinkler accidentally discharging due to a manufacturing defect are extremely low. In most cases, a sprinkler will discharge only if it has been exposed to extreme heat or if it is mechanically damaged by some outside force.

One of the best ways to avoid accidental sprinkler discharges is to inspect your facilities to determine if there may be sprinkler heads in locations that would be prone to damage from activities such as moving equipment; construction activities; sports activities where balls or other sporting equipment might contact a sprinkler head; or changes in use that may cause indoor temperatures to change due to heat-producing equipment.

This inspection may indicate that a sprinkler head needs a higher temperature rating. You may need to provide a protective cage to protect the head from mechanical damage. In addition, the age of sprinkler heads should be inspected periodically. Heads manufactured more than 50 years ago should be replaced with new heads of the same rating and type.

The sprinkler system also needs periodic attention. System components, such as alarm valves, need to be tested. The entire system needs to be flow tested, and critical valves and switches should be inspected for wear and proper operation. Proper maintenance of the system and attention to the location and protection of sprinkler heads will go a long way toward avoiding accidental discharges.

Accidents happen

The majority of automatic sprinkler systems installed today are classified as “wet systems.” This means that the piping system that attaches the sprinkler head to the water source is already full of water. This water essentially is trapped in the system by control valves and status sensors at the water source. Since water is trapped in the pipe, it will tend to develop a life of its own — the water in the pipe will react with the pipe and any impurities to develop microbiological growths. The same type of buildup also is possible in so-called “dry systems” if the piping is not allowed to properly dry and drain after system testing or any other periodic discharges.

The microbial growths are of little concern to building occupants during normal conditions because the sprinkler pipe is a closed system and the organisms are trapped. However, once released from the piping system, the water may produce a strong odor because of the contaminants in the pipe, and the color of the initial flow may be black. The odor and color are dispersed quickly, and the eventual flow from the head is the same quality and content as that obtained from the local water mains or other water source.

The sprinkler head will continue to flow for a number of minutes. Most fire departments do not allow sprinklers to be turned off until they arrive on scene and authorize the property owner to close the valve and stop the flow. This means that hundreds of gallons of water will flow from a single head in as little as 15 minutes (a typical response time). This amount of water will be sufficient to purge the system of contaminants and provide a “clean” flow from the head.

Initially, most fire departments will assist the property owner in much of cleaning the area by removing the sprinkler water using typical salvage techniques. The remaining water will need to be removed by facility personnel. The cleaning staff should initiate drying, delineate the extent of water damage, discard unsalvageable material, and apply disinfectant. The staff should be aware of the types of cleaning and disinfecting materials available to them, and instructed in the proper use of each prior to cleanup.

In addition, local facility managers may want to considerprofessional cleaning services that specialize in fire- restoration services. Wet vacuum equipment and mops can be used to collect water, which can then be discharged to local sanitary lines or storm drains. Salvageable soaked materials can be washed with appropriate detergents, dried and returned to service. Damaged material that cannot be salvaged can be disposed of through normal solid-waste-disposal means. Final cleaning should be accomplished with disinfectant cleaners. A scent-masking or scented cleaner often is used to combat offensive odors.

Particular attention should be paid to damaged surfaces that can absorb water and become a source of potential mold growth — material such as wallboard, carpeting or wood flooring. Pay special attention to areas not readily visible, such as subfloor areas, behind walls, carpets under equipment, and areas behind cove bases. You may need to remove sections of walls and insulation, and apply large volumes of air to dry the surfaces. Effectively drying these hidden cavities is critical to remove any potential conditions for mold to develop and thrive.

SIDEBAR: When a good sprinkler system failed

Although it occurs rarely, sprinkler system components can sometimes go bad, resulting in extensive water damage. Such was the case for a newly constructed Massachusetts middle school in 2001. At about 4 a.m. on a day in late August, a sprinkler head situated above the administrative office area failed for reasons that remain unknown.

The failure resulted in water pouring from the sprinkler head for about an hour before maintenance personnel arrived and discovered the problem. The system was alarmed only in-house and was not connected to a central monitoring system that would have alerted local fire and police departments.

A significant potential problem from this sprinkler head failure was microbial growth of fungi and bacteria on the building materials affected by the water damage. An estimated 2,000 gallons of water had sprayed from the failed sprinkler head and water had pooled to a few inches in several areas. However, prompt response by maintenance personnel prevented or minimized microbial growth in the affected areas.

Workers using wet vacuums immediately removed accumulated water from several administrative offices, adjacent hallways and an auxiliary gymnasium. A professional remediation company was contacted and used a combination of hot-air drying machines and large fans to dry the affected building materials. They removed the wet carpeting from the affected areas rather than trying to dry it. They also cut away damaged wallboard to approximately one-foot height above the floor level and removed wallboard entirely from windowed areas below. They selected this approach because wallboard is a porous, cellulose-containing material that can quickly wick up accumulated water and can be an excellent growth medium for various types of fungi. The fiberglass insulation behind these cut-away wallboard areas, which is also a good growth medium for microbes, also was removed. Finally, they removed the coving around the gymnasium floor so that the hot air from the drying machines could reach areas below the wood floor.

The prompt, appropriate and thorough responses by school personnel were critical in limiting further possible damage in the school. The primary focus of such efforts is to dry or remove water-damaged materials within 24 to 48 hours of the initial incident so that microbial growth does not begin.

Tremblay is senior associate and McCarthy, Sc.D., CIH, is president of Environmental Health & Engineering Inc., Newton, Mass. A booklet, “Mold Remediation in Schools and Commercial Buildings,” is available from the EPA publication number is EPA 402-K-01-00.

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