Boat U.S. - May 2008 - (Page 47) From the Files of DIY Boat Owner Magazine Figure 2 Fuel Connection Is A Fuel Source Instrument Panel May Be An Ignition Source Unless It Is Ignition-Protected Ignition Protected Blower 2' Fuel Tank 2' Gasoline Tank Ignition-Protected Engine 15 Sq Inches Open Area For Each Cubic Foot Of Open Space In Which The Ignition Source Is Located Ignition-Protected Pump Below Fuel Source The switches in the dashboard are within 2’ (61cm) of both the fuel fill fitting in the foredeck and fuel hose connection at the fuel tank. Since both of these connections are potential sources of a fuel leak, all dashboard switches must be ignition protected. Figure 3 Ignition - Protected Components - No Separation From Fuel Sources Trim Motor Openings - Annular Space Not More Than 1/4 In. Pump - Ignition Protection Not Required Fuel Tank Water-Tight Bulkhead to 1/3 Height Or 12 Inches Whichever Is Less Ignition-Protected Engine and Components Spaces Requiring Ignition-Protected Equipment An enclosure is provided to isolate electrical components at the helm; they need not be ignition protected. However, the bilge pump, blower and engine electrical components must be ignition protected. Figure 4 Electrical components in the engine compartment require ignition protection; however, given the isolation bulkhead forward of the engine, the bilge pump need not be. tsp (7ml) of water per hour. Per Coast Guard policy, “Any hole installed for drainage in an isolation bulkhead must be fitted with a plug or sealing device that is intended to be in place when the boat is being used. The plug or sealing device must be attached to the drain fitting or bulkhead near the drain hole so that it will not be lost. It must be understood that when this drain hole is open, the isolation integrity of the bulkhead has been breached causing a potentially hazardous condition. It is the responsibility of the boat manufacturer to make this intent known to the consumer via means such as labeling, information in a boat owner’s manual, etc.” Openings above the water-resistant height of an isolation bulkhead should not have more than a 1/4” (6mm) wide space around whatever passes through the bulkhead, e.g., wiring, piping, etc. Openings in bulkheads around engines and their exhaust systems require special attention since they must also be sealed to prevent the passage of carbon monoxide gas. Figure 1 depicts many of the attributes of an isolation bulkhead. An electrical component can also be isolated from a potential gasoline fuel source by a deck located between the two, or by means of an enclosure. If the electrical component is installed below the fuel source, the isolation deck or enclosure must be water (and vapor) tight. If the component is located above the fuel source, then there must be a deck or enclosure to provide isolation, but it need not be water or vapor tight. As you evaluate your boat’s isolation bulkheads, floors and enclosures, pay particular attention to any aftermarket modifications to these structures that may have compromised their ability to isolate electrical components from potential fuel sources. Figures 2, 3 and 4 illustrate the use of isolation bulkheads, decks and enclosures. ers, alternators, fuel pumps, distributors, water pumps and water heaters, to name a few. Since many of these products are also marketed to boaters, it’s truly a case of buyer beware. Gas Hazards When combined with oxygen, both propane and CNG can also explode if ignited. Boats with LPG or CNG piping connections belowdecks (allowed only at the appliance) are very likely operating at increased risk. Should vapor leak from one of these connections, a non-ignition-protected electrical component or internal combustion engine located in the same compartment could potentially trigger an explosion. Boat owners should refer to the appropriate ABYC standard for further guidance in correcting such a situation. Gasoline containers and reserve LPG or CNG cylinders also pose a significant hazard belowdecks if not stowed in an appropriately vented enclosure or locker that meets or exceeds ABYC standards. Cost Factors An automotive alternator, distributor or starter sells for half the price or less of an equivalent marine ignition-protected unit. The cost of a rebuilt starter that is ignition protected but not certified to that protection can shave $100 off the bill. You’ll save a bundle purchasing a household water heater versus a marine one. Valid considerations for sure but what could happen if that non-ignition-protected starter attached to a gasoline engine should spark? Or a non-ignition-protected air conditioner was placed with the lead-acid (hydrogen gas) battery that powers the bow thruster or windlass in the same locker? How about the budget RV water heater to replace the rusted one in your gasoline engine space? Don’t be tempted to take the risk. The extra cost of the protection provided by certified marine ignition-protected equipment is a best buy in boating. There are many reasons for the higher price of marine ignition-protected electrical components. Production runs are small compared to automotive. Manufacturers must shell out additional fees for extensive UL and SAE testing and certification. Additionally, ignition-protected units are periodically pulled off production lines and tested to insure they meet standards. — By Susan Canfield Susan Canfield is a marine surveyor in Annapolis, MD. BoatU.S. Magazine May 2008 Checks and Tests Once you have determined which electrical components on your boat are not isolated from potential fuel sources, verify that those components are ignition protected. If you can’t find a label on an electrical component, or verify its ignition protected status by reading the owner’s manual or by calling the manufacturer, the only safe assumption is that it is not. To minimize the risk of explosion, any component not in compliance with the law should be replaced. Electrical components produced for the automotive and recreational vehicle (RV) markets are typically not ignition protected, e.g., start- 47
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