Identify the minimum separation required between buried mortars and the wall of troughs or drums.

Identify the minimum separation required between buried mortars and the wall of troughs or drums.

• A. 1 inch
• B. 3 inches
• C. 2 inches
• D. 4 inches

Answer: (C)

Two inches is the minimum separation. This clearance helps prevent heat, blast energy, or flying fragments from reaching the wall of troughs or drums, which could damage the wall, cause spalling, or ignite adjacent devices. The space also allows for slight movement, debris deflection, and thermal expansion of the mortar casing during firing, reducing the chance of contact with the wall. Distances smaller than two inches are unsafe because they increase energy transfer and contact risk; larger gaps exceed the minimum but are not required by the rule.

Two inches is the minimum separation. This clearance helps prevent heat, blast energy, or flying fragments from reaching the wall of troughs or drums, which could damage the wall, cause spalling, or ignite adjacent devices. The space also allows for slight movement, debris deflection, and thermal expansion of the mortar casing during firing, reducing the chance of contact with the wall. Distances smaller than two inches are unsafe because they increase energy transfer and contact risk; larger gaps exceed the minimum but are not required by the rule.