I did some checking on the water spray system. These systems use regular firefighting nozzles, directed on a specific potential hazard, with the intention of extinguishing a fire that originates at that specific location.

Water spray protection for firefighting is mostly used for following categories of fire hazards:
- Flammable gaseous and liquid materials
- Electrical hazards such as transformers, motors, cable trays
- Ordinary combustible materials such as paper, wood and textile
- Some hazardous solids such as propellants.

If you look at a tank farm you will see the fixed piping with nozzles point at a fixed location.

If you look at the Scope of NFPA 13 this section of the document states, “This standard shall provide the minimum requirements for the design and installation of automatic fire sprinkler systems and exposure protection sprinkler systems covered within this standard.” When it comes to the Purpose, the documents states, “The purpose of this standard shall be to provide a reasonable degree of protection for life and property from fire through standardization of design, installation, and testing requirements for sprinkler systems, including private fire service mains, based on sound engineering principles, test data, and field experience.”
There only place where I found an explanation was in Annex C of NFPA 13. In this section they are addressing the test data and procedures for rack storage. Here it states, “Control is defined as holding the fire in check through the extinguishing system until the commodities initially involved are consumed or until the fire is extinguished by the extinguishing system or manual aid.” This is an indicator that the sprinkler system is only being designed as a control device and not an extinguishment device.

When investigating this subject I began to wonder if the connection of sprinkler systems and extinguishment may have been due to a misunderstand of the actual intent for the sprinkler system. An example of this is the document shared by John. The book states that the basic economy that the designer provides is that concise and accurate design which minimizes the overall risk of property damage. The inherent goal is always present then, to insure the rapid extinguishment of a potential fire for all areas of the building. Note the author uses the term “extinguishment” and does not mention control. This person cites numerous cases where sprinkler systems in homes extinguished fires. This is the support used for his statement about extinguishment. Let’s compare his statement about the intended goal of the residential sprinkler system to the purpose found in NFPA 13R. The purpose section from NFPA 13R states, “The purpose of this standard is to supply a sprinkler system that aids in the detection and control of residential fires and thus supply improved protection injury, life loss, and property damage.
These are the inconsistencies that caused me to ask the original question. I am not saying sprinkler systems have not and do not extinguish fires. What I am concerned about is information that would suggest that the intent of the design was for the system to extinguish a fire when that may have never been the intent. In reading the upcoming 921 I can see where there may be this type of misunderstand about sprinkler systems.

Jim Mazerat
Forensic Investigations Group