Responding to an activated fire alarm is a daily occurrence for most fire departments. Many times the fire alarm is a false alarm, but what happens to our responses when then alarm is based on a sprinkler system activation? Many departments will request a full alarm assignment or even add additional units. The alarm condition may be indicated by a water flow alarm, multiple water flow alarms, or reports from the occupant.
When an automatic sprinkler system has activated there are a couple of outcomes. The system may have been activated due to a fire, broken pipe, or accidental sprinkler activation. Based on these different situations, our responses will vary. Regardless of the situation the public expects the men and women who arrive to solve their problem. This may include recommendations on how to restore the system.
The response should be based on department policy, although it is important for crews to determine the size and extent of the fire. The responding engine companies may need to supplement the system through the fire department connection. The NFPA 13E Standard provides specific guidance on proper techniques and response routes. This may include which engine supplies the fire department connection and at what pressures.
Recommended Operating Procedures For Fires
Depending on the system age, design pressures, or capacity the recommended pressures are based around 150 pounds per square inch (psi) at the connection. It is important to note that certain buildings will require additional pressures due to system design and may be indicated on the ring around the fire department connection. These specific conditions are a great supporting reason for a documented pre-plan.
As the units begin to arrive and size up the situation, interior crews should take note of the fire conditions. These may include a fire under control or a fire which is spreading to additional areas. When system engineers design sprinkler systems, they are based on the use of the space or contents stored. If tenants change the commodity storage or type of product without proper evaluation of the sprinkler system, it is possible for the new configuration to affect the performance of the system. This could be a possible cause for the fire to not be controlled by the sprinkler system. Keep in mind that each sprinkler system is not the same. As the fire load increases, the sprinkler flow and pressure will rise. A sprinkler in an office may be designed for 15 gallons per minute (gpm), while a sprinkler in a warehouse could be designed at 75 gpm or higher.
During the design process of the sprinkler system, it is the intent to control the fire and prevent flashover from occurring. Malicious activity, including shutting down the sprinkler system or a suspicious fire with fires in two locations could be the cause of the spread of fire. Additional crews should investigate the riser assembly and ensure the valves are in the open position or the status of the buildings fire pump (if provided).
Interior crews should use proper protective equipment, including self-contained breathing apparatus, thermal imaging cameras, and proper techniques in these environments. Once the fire is extinguished, crews should work with the incident commander to shut down the affected portion of the sprinkler system. The investigator should determine the number of sprinklers which operated and if the system performed as expected and order the repair of the system by an approved contractor.
Accidental Sprinkler Discharge
Does our response change when the system is an accidental discharge? Accidental discharge could include a broken pipe, broken sprinkler due to an operational process, or even a frozen pipe that was not properly drained.
Crews must ensure that the system activation was an accidental discharge and not due to fire. Once this is determined, the company officer may order the system to be shut down. The crews should work to only shut down the affected area and open the appropriate drain. This may be a floor, one system riser, or it may be the entire system because there is only one system valve.