46 CFR 181.310: Fire main and hydrant requirements
Last reviewed: October 14, 2026
This section covers fire hydrants and the fire main on a vessel. A vessel that has a power driven fire pump must have enough hydrants to reach any part of the vessel using a single length of firehose. It also sets rules for fire main piping, hydrant valves, and spanner wrenches.
What it says
A vessel that has a power driven fire pump must have enough fire hydrants to reach any part of the vessel using a single length of firehose.
46 CFR 181.310(a)“A vessel that has a power driven fire pump must have a sufficient number of fire hydrants to reach any part of the vessel using a single length of firehose.”
Piping, valves, and fittings in a fire main system must comply with subpart G, part 182, of this chapter.
46 CFR 181.310(b)“Piping, valves, and fittings in a fire main system must comply with subpart G, part 182, of this chapter.”
Each fire hydrant must have a valve that lets the firehose be removed while the fire main is under pressure.
46 CFR 181.310(c)“Each fire hydrant must have a valve installed to allow the firehose to be removed while the fire main is under pressure.”
Spanner wrenches must be provided where a 40 millimeter (1.5 inch) diameter firehose is required by § 181.320(b).
46 CFR 181.310(d)“Spanner wrenches must be provided where a 40 millimeter (1.5 inch) diameter firehose is required by § 181.320(b).”
Existing vessels as of July 22, 2016 have 180 days to comply with the spanner wrench requirement.
46 CFR 181.310(d)“Existing vessels as of July 22, 2016 have 180 days to comply with this requirement.”
Common questions
How many fire hydrants must a vessel have?
A vessel that has a power driven fire pump must have enough fire hydrants to reach any part of the vessel using a single length of firehose.
“A vessel that has a power driven fire pump must have a sufficient number of fire hydrants to reach any part of the vessel using a single length of firehose.”
Must fire hydrants have valves?
Yes. Each fire hydrant must have a valve so the firehose can be removed while the fire main is under pressure.
“Each fire hydrant must have a valve installed to allow the firehose to be removed while the fire main is under pressure.”
When are spanner wrenches required on a vessel?
Spanner wrenches must be provided where a 40 millimeter (1.5 inch) diameter firehose is required by § 181.320(b).
“Spanner wrenches must be provided where a 40 millimeter (1.5 inch) diameter firehose is required by § 181.320(b).”
What rules apply to fire main piping and fittings?
Piping, valves, and fittings in a fire main system must comply with subpart G, part 182, of this chapter.
“Piping, valves, and fittings in a fire main system must comply with subpart G, part 182, of this chapter.”
The text of 46 CFR 181.310
Electronic Code of Federal Regulations (eCFR), current as of April 16, 2026 · Read it on eCFR
Fire main and hydrants
(a) A vessel that has a power driven fire pump must have a sufficient number of fire hydrants to reach any part of the vessel using a single length of firehose.
(b) Piping, valves, and fittings in a fire main system must comply with subpart G, part 182, of this chapter.
(c) Each fire hydrant must have a valve installed to allow the firehose to be removed while the fire main is under pressure.
(d) Spanner wrenches must be provided where a 40 millimeter (1.5 inch) diameter firehose is required by § 181.320(b). Existing vessels as of July 22, 2016 have 180 days to comply with this requirement.
Sections it refers to
The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of April 16, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.