Sand traps shall be provided with a ____ inch trap.

• A. 3 inch
• B. 4 inch
• C. 2 inch
• D. 5 inch

Answer: (B)

Sand traps are used to capture sand and other heavy solids before they can enter downstream piping or equipment, so the trap must have enough internal space and flow capacity to allow solids to settle and to be cleaned without frequent blockages. A 4-inch trap provides that balance: it offers sufficient volume and a workable flow path for typical installations, making maintenance practical and reducing the chance of clogs. Smaller traps would fill and clog too quickly, while a much larger trap would be unnecessary and take more space and cost. So the standard requirement is a four-inch trap.