In NFPA 13R, when is valve use required due to water pressure?

In NFPA 13R, when is valve use required due to water pressure?

• A. Pressure exceeding 300 psi requires valve use.
• B. Pressure exceeding 175 psi requires valve use.
• C. Pressure above 100 psi requires valve use.
• D. Valve use is not required at any pressure.

Answer: (B)

The main point is protecting sprinkler components by controlling incoming water pressure. NFPA 13R designs for low‑rise homes assume a certain maximum pressure in the sprinkler system, and if the water supply is higher than that, a valve is needed to bring the pressure down to a safe, workable level. The standard uses 175 psi as the cutoff: when water pressure exceeds 175 psi, a pressure‑reducing valve must be installed so the system isn’t exposed to pressures it isn’t designed to handle. This helps prevent damage to heads, piping, and fittings, reduces the risk of water hammer, and ensures the system delivers predictable performance. If the supply pressure is at or below 175 psi, a valve isn’t required. Pressures as high as 300 psi aren’t the defined threshold, and saying no valve is needed at any pressure isn’t correct because high-pressure supplies do require protection.

The main point is protecting sprinkler components by controlling incoming water pressure. NFPA 13R designs for low‑rise homes assume a certain maximum pressure in the sprinkler system, and if the water supply is higher than that, a valve is needed to bring the pressure down to a safe, workable level. The standard uses 175 psi as the cutoff: when water pressure exceeds 175 psi, a pressure‑reducing valve must be installed so the system isn’t exposed to pressures it isn’t designed to handle. This helps prevent damage to heads, piping, and fittings, reduces the risk of water hammer, and ensures the system delivers predictable performance. If the supply pressure is at or below 175 psi, a valve isn’t required. Pressures as high as 300 psi aren’t the defined threshold, and saying no valve is needed at any pressure isn’t correct because high-pressure supplies do require protection.