Total area of uncclosable openings shall not exceed what percent for dry chemical systems?

• A. 15%
• B. 10%
• C. 20%
• D. 5%

Answer: (A)

In a dry chemical extinguishing system, you limit openings in the protected space that cannot be closed during discharge. The idea is to keep enough agent inside the space to suppress the fire while preventing too much powder from escaping to adjacent areas. Therefore, the total area of those uncclosable openings must stay within a modest portion of the space being protected, so the system can deliver and maintain the agent where it’s needed without excessive leakage. The standard limit for this scenario is 15% of the protected space’s area. This balance helps ensure effective fire control while recognizing that some openings (like uncloseable vents or large fixed gaps) can’t be sealed completely.