PLANNING THE USE OF PRIVATE FIRE EXTINGUISHING SYSTEMS AT TARGET HAZARDS
VOLUNTEERS CORNER
A target hazard occupancy generally has a potential for a large life or substantial property loss if a fire occurs. Hospital, schools, and geriatric facilities are considered target hazards as are large manufacturing or warehouse installations. A target hazard is not judged on size alone; a small high-technology site could sustain a large dollar loss.
A private fire protection system is one installed and maintained by the building owner. It may provide fire suppression/control. as do sprinklers, or provide assistance to the fire department, as does a private hydrant or standpipe system. The purpose of systems with extinguishing capabilities is to suppress the fire in the incipient stage or at least to hold the fire to a small area until the fire brigade or fire department arrives to complete extinguishment.
The automatic sprinkler system is a commonly used private fire protection system. Other kinds of private systems include dry chemical, gaseous agent (halon. C02), foam, and standpipe. The fire department must have direct knowledge of how the system functions to be able to use it efficiently during a fire.
PREFIRE PUNNING
Prefire planning for a facility with a private protection system begins with a prearranged visit and appointment with the facility personnel in charge of the system. These individuals can provide the following information: how the system functions, the size and location of the area it covers, and the locations of its operational controls. They also can relate any cautions that must be observed when the system is operating. During this meeting, the fire department also should obtain emergency numbers at which facility personnel can be reached should an incident occur after hours or on weekends. All information gathered during the visit should be recorded as part of the preincident plan. Specific fire department operations and procedures should become part of the standard operating procedure for the location, and any precautions vital to the safety of personnel or the efficient operation of the system must be highlighted.
The review of a sprinklered building should cover a number of items that will enable the fire department or brigade to use the system most effectively during an incident. Most importantly, first determine the sufficiency of the water supply available: Will it require augmenting? If so, what auxiliary water supply, if any, is available? Will connecting to the on-site private or public hydrants rob water from the automatic sprinkler system that is applying water directly on the fire? Determine if private fire hydrants are intended to supply pumpers (they have a steamer connection) or just to supply handlines directly off the hydrant. Often, the harm caused by well-intentioned master streams or handlines that take water from the well-placed sprinkler heads is greater than the assistance they give in controlling the fire. Where is the fire department sprinkler connection that must be used to increase the pressure to the sprinklers or possibly bypass a closed valve? Is there a single fire department connection or one for each system? Which hydrant is best for this and what hoselay will be used—multiple lines or single large diameter? Which engine company will be assigned this task? Determine the required pump pressure to provide 150 psi at the inlet. This can be difficult, since the actual flow is unknown. For short lays, a rule of thumb is 150 psi at the pump. On longer hoselays, additional pressure is added for friction loss to the connection. How can the system be supplied if there is damage to the fire department connection?
Of major importance is the extent of the sprinkler system. Is it complete or partial protection, and are concealed spaces such as attics covered? Some buildings have only the halls and public areas sprinklered. Plans will have to be made to stretch handlines to complete extinguishment in unprotected areas. Learn and record the locations of all system controls and valves. Are they accessible during a fire? What are the design pressure and flow of each sprinkler system?
The locations of gate valves in the main sprinkler supply, riser, and surrounding the fire pump (if there is one) are all important. A firefighter should be assigned on arrival to check that all system valves are open and functioning properly. If valves are closed, a firefighter who is in radio communication with the incident commander must be assigned to stand by in case they require reopening.
Other fire department tasks that need to be evaluated include the necessity of vertical ventilation to reduce mushrooming heat that would open extensive heads and possibly overtax the system. Horizontal ventilation also may be needed. Some buildings are equipped with automatic venting systems to assist in ventilation. Evaluate the need for salvage operations. This could include covering expensive equipment, removing water from floors, or building dams or bags to control water flow. In target hazards, salvage operations become a vital part of minimizing losses and need to be planned extensively before an incident. This can range from a resident’s personal mementos to a firm’s accounts receivable. Care must be taken during overhaul to assure complete extinguishment. Either the system must be restored to operation or the building owner must be well-prepared to handle the situation before the last fire company returns to quarters. A good training program for review by departments with sprinklered buildings is “Fighting Fires in Sprinklered Buildings” from Factory Mutual. It discusses the reasons sprinklered buildings burn, describes the components and operation of sprinkler systems, and details prefire planning of these structures.
The operations at buildings equipped with standpipes are similar to those with sprinkler systems. However, the variations in pump pressure will differ extensively due to the heights of standpipe-equipped buildings. The location of the fire department connection, the hydrant to use, and the engine company assigned to supply the system must all be determined. The pump pressure can be calculated for the different hoselines possibly employed on varying floors of the structure. The location of the standpipe outlets in the building and how they will be used by the department must be considered. Will a single light attack line be used or a single heavy attack line (2’/2-inch) be required? Will a combination of 2K-inch to a gated wye with two light attack lines attached be used? How many standpipe packs will be necessary, and what equipment should be included?
Are the standpipe outlets fitted with pressure-reducing valves? They must be carefully researched since there arc different models that do not function in the same manner. It may be necessary to use solidstream nozzles and larger (2!Ainch) handlines to get adequate flows at the lower pressures. Remember that the apparatus pump must discharge at the pressure required for operations on the highest floor (even for fires on lower floors) to supply the nozzle with the proper pressure. Which floor will be used for connecting to the standpipe (usually the one below the fire)? How much hose will be necessary to make the fire area? How and where will the hose be laid out? What will need to be done if the connection is damaged and unusable at either the fire department connection or the floor outlet? In a building with a dry standpipe system, an apparatus flowmeter will display how much water is being used.
Remember that buildings equipped with automatic sprinkler systems or standpipes also may have a fire pump. The first-due engine company should assign a firefighter to check that the pump is operating and all valves are open. The preplan should include all necessary information on how to start and operate the fire pump. The discharge pressure of the pump should be learned so the fire department pumper can work in unison.
Dry chemical systems are generally limited in scope and cover special operations such as cooking vents and ducts or dip tanks. They are limited by the amount of extinguishing agent available and the nozzle locations. These systems will cover a local area or totally flood a small, confined area. Fire department support is limited to prefire planning to determine coverage, how to manually operate the system, and see that the system is in working condition.
Gaseous agent systems may use carbon dioxide or halogenated hydrocarbons (halons). They often are used in computer rooms and electrical equipment rooms. These systems may cover a specific hazard or totally flood a room. Firefighters entering areas that have been totally flooded will require self-contained breathing apparatus. Personnel should be familiar with these systems and regularly inspect to see they are in working order.
Foam systems may be installed in industrial areas, which sometimes are served by a fire brigade. It is best to coordinate with the industrial fire chief to determine what the system protects, design pressures and flows, and how the municipal fire department will be used to support the system. In most cases, it will be in a water supply operation or to provide additional foam resources if available.
There are several benefits of performing a good prefire planning walk-through of a private protection system. There will be an adequate response of personnel and equipment. Tentative apparatus placement can be deter mined. How the system will be supported for maximum effectiveness will become a part of the operating procedures. Most importantly, the fire department will have a thorough knowledge of the system and be able to work with it to achieve early extinguishment with a minimal loss of lives and property damage.
