OMG - My placard is missing!
- Chris Beckman CFPS SFPE ARM
- Dec 19, 2024
- 3 min read
The concern
If your sprinkler system was installed since the mid 1980's a placard something like this should have been attached to your sprinkler riser when it was installed. If the placard is missing or the data is illegible, the fun begins. Until the 2025 edition of NFPA 13 was released, this was no big deal. That changed with the requirement in Chapter 30 of NFPA 13 2025 that all systems have placards present.
What does Basis of Design mean?
Your sprinkler system was designed to protect a specific hazard. This can be the overall occupancy or special hazards, typically high piled storage. The design is based on two different methods. The first is an area density design. The density is the amount of water in gallons per minute (GPM) that is to be applied to each square foot in the design area. This is generally a number between 0.10 and 0.80. The second part of this is the design area. This is the square foot area of application for the density. This is generally between 900 square feet and 3,000 square feet. A typical area density design would be shown as .20/2000. The design density is .20 GPM per sq. ft over 2000 square feet. The second method of design involves using a specific sprinkler head and flowing a number of sprinkler heads as the design area. The second part of this design is the starting pressure that is required for the sprinkler head in use. You need to know the details on the sprinkler head involved and the hazard intended to be protected. This type of design is commonly used for high piled storage protection.
What is System Demand?
The above numbers will drive the hydraulic calculation process to develop two numbers. The Residual Pressure at Base of Riser is the water pressure in Pounds per Square Inch (PSI) that is needed to deliver the Total Required Flow that is the quantity of water in GPM for the design. These two numbers are often expressed as 400 GPM @ 45 PSI. Hose Allowance is an addition quantity of water in GPM that is added to the sprinkler demand to allow for fire department hose streams to complete extinguishment or the overhaul the fire scene. This amount of water is between 100 and 750 GPM.
Hazard Identification
This placard also has data elements for hazard identification. Occupancy classification is used when the system is designed to protect an occupancy. NFPA 13 has several occupancy classifications. Light, Ordinary 1, Ordinary 2, Extra Hazard 1 and Extra Hazard 2. The density and design areas for each class cation are found in NFPA 13. The most common basis for design other than occupancy is a design based on a high piled storage exposure. The commodity classification defines the fuel anticipated. The maximum storage height is the upper limit that the fuel can be piled and be protected. Changes in commodity or storage height can impact sprinkler system adequacy. Absent a placard, there is no way to know this visually.
Why should you care?
Without the placard there is no way to accurately determine the basis of the design for your sprinkler system or the required water supply to make that design work.
Who else cares?
There are two groups that may weigh in on this topic. The first is the fire department and building department. If you cannot prove that your system is properly designed and the water supply is adequate, you may get an order to re-engineer the system to get the placard data. Or you may not get a building permit since you cannot document the adequacy of sprinkler system in place. There is code language supporting this requirement.
Group two is the insurance industry. Insurers have been the biggest users of placard data. Missing placards are an almost insurmountable roadblock to getting a sprinkler credit assigned to your property. No placard, no credit. This costs you money every year when you pay for property insurance. Now that the code requires a placard, look for insurance carriers to make this recommendation as part of thier inspection practice.
Where can I find this information?
This information was on the original plans for the sprinkler system and also within the hydraulic calculation that accompanied those sprinkler plans. If the plans have not been retained, you may ask the original installing contractor to provide copies. There may be a cost to research and duplicate these materials. Some contractors may not retain these records and will not be able to provide this upon request.
In the absence of available drawings and calculations, you need to engage the services of a sprinkler designer or fire protection engineer to conduct a site survey to recreate the piping layout and other details to produce the calculations. This can cost several thousand dollars.