What is the discharge pressure rating of the fire pumps?

• A. 100 PSIG
• B. 150 PSIG
• C. 200 PSIG
• D. 120 PSIG

Answer: (B)

The discharge pressure rating is the pressure the fire pump is designed to deliver into the fire protection system when it runs under design conditions. It must be high enough to supply the required pressure at the most hydraulically remote point, after accounting for friction losses in pipes, fittings, and any elevation differences, as well as the demand from sprinklers and hose streams. A value around 150 PSIG is used because it strikes a practical balance: it provides sufficient pressure for most systems and longest runs, without pushing the system to unnecessarily high pressures that could cause excessive wear or water hammer. Lower ratings risk inadequate pressure; higher ratings aren’t typically needed and add unnecessary complexity. So the commonly used discharge pressure rating is 150 PSIG.