If no fire-resistant dividing wall is present, how far must support equipment be kept from explosives?

• A. 10 feet
• B. 40 feet
• C. 60 feet
• D. 25 feet

Answer: (D)

When there is no fire‑resistant dividing wall, the distance between support equipment and explosives must be enough to prevent ignition sources from reaching the explosives. Without a barrier to contain heat, sparks, or a small flame, a larger buffer is required. Twenty-five feet provides a practical safety margin so that heat, sparks, or minor fires from equipment (generators, electrical gear, tools) are unlikely to ignite explosives. With a fire-resistant wall, spacing could potentially be closer, but without that protection, the minimum of twenty-five feet is the safe standard. The smaller distances would not reliably prevent ignition, while the larger distances are more than necessary for this scenario.