The ABYC Standards & Compliance department frequently receives questions regarding hose clamp requirements and installation, which is addressed in several of our standards. This week’s Tech Tuesday post covers some common hose clamp questions and requirements, with a second part regarding installation next week, May 5.
Common Fuel and Exhaust Hose Clamp Requirements
Clamps depending solely on the spring tension of the metal shall not be used.
All components of hose clamps shall have a resistance to corrosion equal to or greater than 300 series stainless steel.
Hose clamps shall be reusable.
- EXCEPTIONS:
- Clamps used with outboard engine primer bulb assembly(s).
- Clamps used in connections of fuel hose from the primer bulb to the outboard engine(s).
- Clamps used with quick connect couplings.
Hose Clamp Band Width
ABYC standards specify minimum band widths based on hose diameter to ensure a reliable seal. Exhaust hose connection clamp bands shall be a minimum of 0.5 in (12 mm) in width, and minimum fuel system hose connection clamp band widths depend on the hose diameter.
Hose Clamp Widths Minimum Nominal Clamp Band Width
|
OUTSIDE HOSE DIAMETER |
MINIMUM CLAMP BAND WIDTH in (mm) |
|
< 7/16 (11.11) |
1/4 (6) |
|
7/16 – 13/16 (11.11 – 20.64) |
5/16 (8) |
|
> 13/16 (20.64) |
3/8 (9.5) |
| Any hose used in fuel tank fill system as per H-24.7.7 |
1/2 (12) |
Thru-hull Fittings and Seacock Hose Connections
ABYC H-27 Seacocks, Thru-Hull Fittings, and Drain Plugs addresses fittings intended for the passage of water in or out of a boat that penetrate the hull at or below the maximum heeled waterline.
Contrary to popular belief, ABYC H-27 does not require two clamps on thru-hull fittings and seacock hose connections. H-27 requires a single 0.5 in (12.7 mm) wide clamp positioned beyond the bead or over the serrations of the spud with a minimum of one clamp width from the clamp to the hose end.
From H-27 July 2021:
27.9.2 If a thru-hull fitting or the fitting attached to the seacock is intended for use with a hose, the hose connection shall:
27.9.2.1 have a bead or a series of annular grooves or serrations not less than 0.015 in (0.38 mm) deep, and
27.9.2.2 be of such length that a 0.5 in (12.7 mm) wide clamp can be positioned beyond the bead or over the serrations of the spud with a minimum of one clamp width from the clamp to the hose end.
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Questions about hose clamps or other standards and compliance issues? Contact [email protected].