Almost all automatic sprinkler systems designed today are hydraulically calculated — an engineered approach that matches the potential fire hazard to the pressure and volume of the available water supply. The sprinkler plans examiner verifies the hydraulic calculations to ensure that all of the design considerations are met.
To help keep track of the design criteria, NFPA 13 requires that the installing contractor identify hydraulically designed sprinkler systems with a permanently marked weatherproof metal or rigid plastic sign secured with corrosion-resistant wire, chain, or other approved means. The sign must be placed at every system riser, floor control assembly, alarm valve, dry pipe valve, pre-action valve or deluge valve supplying the corresponding hydraulically designed area unless the authority having jurisdiction (AHJ) approves an alternate location.
According to NFPA 13, the sign must have the following minimum information:
- The location of the design area(s). These are also known as the “hydraulic remote areas” and make up the portion of the building and contents that are most challenging for the sprinkler system to protect. It is important to remember that the hydraulic remote area may not be the area physically most remote from the sprinkler risers.
- The discharge densities over the design area or areas. This is the amount of water that the design criteria specify is needed to control a fire in the hydraulic remote area. This value may come from NFPA 13 or the authority having jurisdiction.
- Size (area) of, or number of sprinklers in, the design area.
- The required flow and residual pressure demand at the base of the riser or the fire pump, where applicable.
- Occupancy classification or commodity classification and maximum permitted storage height and configuration.
- Hose stream allowance included in addition to the sprinkler demand.
- The name of the installing contractor.
Hydraulic Nameplate
Maryland Office of State Fire Marshal
Action step for learning more about the installation of fire sprinkler systems
Review NFPA 13 to stay up-to-code with the industry standard for installation of automatic sprinkler systems.
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