Boat U.S. - May 2008 - (Page 46) From the Files of DIY Boat Owner Magazine Is Your Boat Ignition Protected? All electrical components exposed to a potentially explosive environment must be ignition protected. At risk of an explosion and/or fire are older boats with electrical devices added by previous owners and newer boats with replacement and add-on parts. Here’s how to and minimize that risk. which equal and/or exceed the federal requirement but are not enforceable as law, are intended to apply to builders, repairers and boaters servicing or maintaining a boat. (Boats with diesel engines are not exempt if an ignition source, a battery inverter, for example, is located in the engine compartment.) Start by identifying the potential sources of a gasoline fuel leak. These include piping connections at fuel fill fittings, tanks, tank vent fittings and engines, as well as any other connections that may be found in between. Next, evaluate the degree to which electrical components are isolated from the potential sources of a fuel leak you have identified. Fuel vapors are heavier than air and will tend to settle in low areas. If not isolated from potential fuel sources by bulkheads, decks or special enclosures, electrical components must be ignition protected. The only permitted exception to this requirement is for components installed at least two feet (61cm) away from a gasoline fuel source in compartments that are open to the atmosphere. A compartment is considered “open to the atmosphere” if it has an unobstructed opening of at least 15 sq. in. (97 sq. cm), to the environment outside the boat, for every square foot (square .09m) of compartment volume. line onboard a boat, there’s an inherent risk of explosion and/ or flash fire occurring if gasoline Sealed vapors are present and there is a source of ignition such as a Fuel Source This Side Of Bulkhead spark. That’s why U.S. federal law requires builders of gasolinepowered boats to install ignition protected electrical components in these potentially explosive Plugged environments. Drain Ignition-protected compoElectrical Components Water Resistant Height nents are designed and conThis Side of Bulkhead Use 1/3 Maximum Height As It Is Less Than 12" structed so they won’t ignite a flammable hydrocarbon mixture Isolation bulkheads must be water resistant (and vapor tight) for — gasoline, propane (LPG) or at least one-third of their height, or 12” (30cm), whichever is less. compresed natural gas and Openings above the water-resistant height of an isolation bulkoxygen — under normal operat- head must not have more than a 1/4” (6mm) wide space around whatever passes through the bulkhead, e.g., wiring, piping, etc. ing conditions. Ignition protection of electrical components knowledge of what’s required to minimize is achieved using seals, flame arrestors that risk are essential to the continued safe and/or potting (encapsulation) to prevent operation of your boat. sparks from escaping when the equipment is operating. To be able to label their Onboard Inspection electrical products as “ignition protected,” If your boat has a gasoline-fueled manufacturers must obtain independent inboard engine (propulsion or generator) or third-party certification in accordance with a permanently installed fuel tank, include specified Society of Automotive Engineers (SAE J1171), Underwriters Laboratories (UL ignition protection on your annual fuel system checklist. While the federal law is 1500) or United States Coast Guard test intended to apply solely to boatbuilders procedures. (new boats), compliance has been a key While it’s generally safe to presume factor in preventing explosions and fires trigthat a new boat from a reputable builder gered by the deadly combination of explohas been constructed in compliance with sive vapors and an ignition source. federal law and that installed electrical Even though the law does not apply components exposed to a potentially exploto the individual boat owner, you would be, sive environment are ignition protected as quite literally, playing with fire to comprorequired, that status can easily be compromise the built-in safety features by cheaping mised by aftermarket modifications to the out with non-complying equipment when boat’s structure or equipment. Your awaredoing your own repairs. ABYC standards, ness of the risk of explosion or fire and the Bulkhead Extends Full Height Water Resistant Height 1/3 Maximum Height Maximum Height Of Bulkhead 12" Anytime you have gaso- Bulkhead Extends Full Width Not More Than 1/4" Annular Space Isolating Fuel Sources Isolation bulkheads must effectively close off one space from another. They must be closely fitted to the top, sides and bottom of the space being closed off. By law, isolation bulkheads must be water resistant (and vapor tight) for at least one-third of their height, or 12” (30cm), whichever is less. For example, if the total height of a bulkhead is 30” (76cm), then its water-resistant height must be at least 10” (25cm). If a bulkhead is 60” (1.5m) high, its water-resistant height must be at least 12” (30cm). Any openings below the water-resistant height of an isolation bulkhead for wiring, piping, controls, doors, hatches, access panels or drains must be sealed or have a fitting to minimize seepage. There should be no limber holes. By law, the maximum seepage permitted for all bulkhead openings and edges may not exceed 1/4-ounce or about 2 46 BoatU.S. Magazine May 2008
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