When fire pumps are used for other than firefighting service, each pipe connecting the other service (except for branch lines used for deck washing) must have a __________.

Correct Answer: Option D — shut off valve at a manifold near the pump

Title 46 CFR mandates that when fire mains are cross-connected for auxiliary services like washdown, a shut-off valve must be installed at a manifold near the pump to isolate non-firefighting lines and maintain full firemain pressure and integrity during an emergency.