NFPA 25 requires not less than _______ sprinklers or 1 % shall be sent for testing at different intervals depending on the sprinkler type.

NFPA 25 requires not less than _______ sprinklers or 1 % shall be sent for testing at different intervals depending on the sprinkler type.

• A. 2
• B. 6
• C. 4
• D. 8

Answer: (C)

NFPA 25 uses a sampling approach to verify that installed sprinklers maintain their listed performance. Not less than four sprinklers—or 1% of the total installed sprinklers, whichever is greater—must be sent to a testing facility, with the exact timing depending on sprinkler type. The four-sprinkler minimum ensures small systems still have an meaningful sample, while the 1% rule scales for larger systems. Different sprinkler types have different failure tendencies and testing needs, so the intervals are tailored by type. That’s why four is the standard minimum in this context.

NFPA 25 uses a sampling approach to verify that installed sprinklers maintain their listed performance. Not less than four sprinklers—or 1% of the total installed sprinklers, whichever is greater—must be sent to a testing facility, with the exact timing depending on sprinkler type. The four-sprinkler minimum ensures small systems still have an meaningful sample, while the 1% rule scales for larger systems. Different sprinkler types have different failure tendencies and testing needs, so the intervals are tailored by type. That’s why four is the standard minimum in this context.