P. 41-44 Fire Pump Signals
17/10/06
3:13 pm
in the pump room while the engine is running. The visible signals must be separate and unique so that a person looking at the controller can tell what the specific problem is. The three signals that are required to be sent to a constantly attended location for a diesel engine driven fire pump are (see section 12.4.2.2): 1. Engine running 2. Controller turned to “off” or “manual” position 3. Any of the eleven signals at the controller that indicate a problem.
The signals sent to a constantly attended location are allowed to be audible or visible. Two of the signals are required to be separate and distinct, the engine running and the controller turned off. The other signal is allowed to be a single signal that lets the person monitoring the system know that there is something wrong. A person would need to be dispatched to the pump room to read the controller to find out exactly which of the situations is the current problem. There are a number of situations that are not required to be monitored by NFPA 20, but would provide better performance and reliability if they were looked after. Since there is no requirement for these situations to be monitored, there is no requirement for whether they need to be provided with signals at the controller, or at a constantly attended location, or both. The situations that NFPA 20 recommends, but does not require signals are (see section A.5.23): Low pump room temperature Relief valve discharge Flowmeter left on, bypassing pump Water level in suction supply below normal ● Water level in suction supply near depletion ● Diesel fuel supply below normal ● Steam pressure below normal (steam driven pumps) ● ● ● ●
NFPA 72 REQUIREMENTS Even though NFPA 72 is not referenced by NFPA 20, there are many times where NFPA 72 will become the governing document for fire pump signals. This will happen where a code or ordinance required that the fire protection system be supervised in accordance with NFPA 72 or where an engineer has specified the supervision of the entire fire protection system in accordance with NFPA 72. Note that this is different
44
INTERNATIONAL FIRE PROTECTION www.ifpmag.com
Page 44
It should be noted that it is not the intent of NFPA 72 to require an entire alarm and detection system in a building just because the fire pump is being supervised in accordance with NFPA 72. from a requirement for the valves to be supervised in accordance with NFPA 72. In order to bring in the requirements for fire pump equipment signals to be installed and monitored per NFPA 72, the code or ordinance needs to apply to the entire fire protection system, which includes the fire pump. It should be noted that it is not the intent of NFPA 72 to require an entire alarm and detection system in a building just because the fire pump is being supervised in accordance with NFPA 72. The requirement for the building to have a complete fire alarm system is completely separate from the pump requirements and is generally handled by the building code. NFPA 72 specifically comes out and states that the pump running signal is a supervisory signal, not an alarm signal (see section 3.3.88.2 and A.6.8.5.7.3 of NFPA 72). However, there is an appendix note in NFPA 72 (A.5.11) that allows the fire alarm to be activated when the pump starts running if the designer of the fire alarm system so desires. This may not be a good idea from the reasons stated at the beginning of the article, but if the designer has taken these testing issues into account, the system is allowed to be set up to sound the alarm upon starting of the fire pump. NFPA 72 allows other fire protection system supervisory signals to be transmitted over the same path as the fire pump supervisory signals. If this is the case, there needs to be some method of making sure that the fire pump supervisory signals get priority if some other supervisory signal is trying to be sent at the same time. (See section 6.8.5.8 of NFPA 72.) Another requirement from NFPA 72 that is often overlooked has to do with firefighter communication. Many buildings are required to have two-way telephone communication service for fire fighter use in the building. When this is the case, a telephone jack or telephone station is required to be placed in the pump room so that the incident com-
mander can be in communication with the person monitoring the pump in that room. (See section 6.9.9.10 of NFPA 72.) The following is a list of the supervisory conditions that can be required to be monitored (in addition to the requirements of NFPA 20) if the equipment exists on the installation. NFPA 72 does not directly require all of these items to be supervised, but lays out performance requirements in case they are specified by the designer to be supervised. This article only includes equipment common to fire pump installations. If a fire pump system has unusual equipment, it may require supervision even though not contained on the following list. ● ● ● ● ● ● ● ● ● ●
Suction control valve supervised open (5.13.1) Discharge control valve supervised open (5.13.1) Bypass control valves supervised open (5.13.1) Test header valves supervised closed (5.13.1) Flow test meter bypass lines supervised closed (5.13.1) Water level in suction tank (5.13.3) Water level in break tank (5.13.3) Water temperature in suction tank (5.14.4) Water temperature in break tank (5.14.4) Temperature in pump room (5.13.5)
CONCLUSION Hopefully this article has clarified some of the confusion surrounding the types of signals required for a fire pump installation and the appropriate actions to take when those signals arrive at the constantly attended location. This article has not attempted to define what a “constantly attended location” is and will leave that discussion to a future article.