Many times ignition protection is taken for granted or misunderstood by boat owners and marine professionals. I don't know how many times I've heard people say when buying replacement parts " I called the marina and they wanted $350.00 for a starter so I went down to the auto parts store and got the same one for $19.95." But the question really is did they get the same part? Another common comment is "I got sick and tired of changing points year after year so I went down to the Junk Yard and bought an electronic ignition distributor from a GM car. I knew it would work because my engine is manufactured by GM." While it will work, is it acceptable in a marine application? The results of placing these parts and others in engine and fuel spaces can be disasters. Most people don't worry about ignition protected or UL Marine rated until after they have seen or lived through a boat explosion or flash fire.

There are three things necessary for a flash fire or explosion to occur they are 1. a fuel source, 2. oxygen, 3. an ignition source. The most common occurrence of an explosion happens after fueling. While fueling the fuel tank is pressurized, which can allow a large amount of fuel to leak from a hole or loose clamp in a supply, vent or file hose. Thus the fuel source has been entered into the fuel or engine compartment. As the gasoline evaporates the vapors mix with the oxygen which is present in the bilge areas. Once the gasoline air mixture has reached the lower explosion limit (1.4 percent by volume) there is a danger of an explosion or flash fire. If a large volume of gasoline has been spilled into the bilge, which depending on the size of the bilge space could be less than a gallon, even running the bilge blowers will not remove the vapor level below the explosive range, and may actually induce more oxygen into the bilge compartment allowing the vapor level to remain in the explosive range. Even with the fuel level in the explosive range the ignition of the fuel air mixture cannot take place without an ignition source. In 99.9% of all explosions caused by gasoline leaks, the ignition point was a non-ignition protected, or altered ignition protected component. If all of the components are ignition protected, as they are required to be, the ignition of the vapors should not take place.

Under 33 CFR183.410 Ignition Protection is defined as follows:

(a) Each electrical component must not ignite a propane gas and air mixture that is 4.25 to 5.25 percent propane gas by volume surrounding the electrical component when it is operated at each manufactures rated voltages and current loadings, unless it is isolated from gasoline fuel sources, such as engines, and valves, connections, or other fittings in vent lines, fill lines, distribution lines or on fuel tanks in accordance with paragraph (b) of this section.

(b) An electrical component is isolated from a gasoline fuel source if:

(1) a bulkhead that meets the requirements of paragraph (c) of this section is between the electrical component and the gasoline fuel source;

(2) The electrical component is:

(i) Lower than the gasoline fuel source and a means is provided to prevent fuel vapors that may leak from the gasoline fuel source from becoming exposed to the electrical component; or

(ii) Higher than the gasoline fuel source and a deck or other enclosure is between it and the gasoline fuel source; or

(3) The space between the electrical component and the gasoline fuel source is at least two feet and the space is open to the atmosphere.

(c) Each bulkhead required by paragraph (b)(1) of this section must:

(1) Separate the electrical component from the gasoline fuel source and extend both vertically and horizontally the distance of the open space between the fuel source and the ignition source;

(2) Resist a water level that is 12 inches high or one third of the maximum height of the bulkhead, which ever is less, without seepage of more than one quarter fluid once of fresh water per hour; and

(3) Have no opening located higher than 12 inches or one third the maximum height of the bulkhead, whichever is less, unless the opening is used for the passage of conductors, piping, ventilation ducts, mechanical equipment, and similar items, or doors, hatches, and access panels, and the maximum annular space around each item or door, hatch or accessory panel must not be more than one quarter inch.

NFPA 302 Pleasure and Commercial Motor Craft states the same regulations under section 7-9, with the exception of section 7-9.2 which deals with LPG or CNG devices which cycle automatically. As this article is not covering all concerns of LPG or CNG we will not examine it.

Electrical components are tested in a propane gas and air mixture because of its ability to defuse and fill any space in a short time. This means that when a test tank is filled with the propane air mixture to the 4.25 to 5.25 percent propane gas by volume level the mixture will easily enter the electrical component inside of the tank. When the component, such as a starter, is then operated the electrical arcing between the brushes and armature inside the starter will ignite the mixture that has entered the starter. If the ignited mixture inside the component is then able to ignite the mixture in the tank it is not considered ignition protected. The component is considered ignition protected if it does not ignite the mixture in the tank, thus containing the explosion inside of the component.

Speaking with UL Laboratories, Marine Products Division, we found that in order for an electrical component to be considered UL Marine Ignition Protected the component must pass the above test with a few alterations. The same test is run but the mixture is also induced directly into the component, thus insuring that the propane air mixture is present. If operation of the component will not ignite the mixture then a spark ignition source is then added to the component. The results are required to be the same for consideration, with the exception that the same component must pass the same test between 150 and 200 times without igniting the propane air mixture once. So as you can see if a product is rated UL Marine Ignition Protected it has been thoroughly tested.

The placement and design of the bulkhead, or bulkheads if the fuel/ engine compartment is midships, described is necessary to consider when determining what parts are necessary to be ignition protected as the engine compartment usually houses bilge pumps, solenoid switches, trim tab pumps, fresh water pumps, possibly air conditioning pumps or compressors and a possible array of equipment to long to list. As all of these items are electric components, they are required to meet the above regulations. The amount of equipment needed to be checked for ignition protection will vary greatly depending on the hull layout and bulkhead placement (Figures 1-6).

INSPECTION OF ENGINE AND FUEL SPACES FOR IGNITION PROTECTION:

Proper inspection of the engine and fuel spaces is essential. Unfortunately, many surveyors and marine professionals overlook the importance if ignition protection while inspecting these areas. The first step that needs to be taken while inspecting these spaces is to determine where the bulkhead or bulkheads are located that meet 33CFR183.410(c). This will determine the area where all electrical components are required to be ignition protected. If these bulkheads are not present or have been altered i.e. openings cut in them higher than 12 inches or one third the maximum height, then all of the bilge spaces are considered fuel spaces and are required to be equipped with ignition protected equipment.

After the spaces to be examined have been determined the next step is to attempt to determine if all of the electrical components are ignition protected. Unfortunately, while 33CFR outlines the requirements of ignition protection it does not require labeling of "Ignition protected" on electrical components which have met the criteria. NFPA 7-7.2 "Marking of Equipment" does require labeling of ignition protection, if applicable, but as we are aware NFPA regulations are voluntary guidelines and not Federal Law. Hopefully you will find these items marked and your job will be easy. However, you most likely will find that this is not the case and you will have to carefully examine each item to attempt to determine if it is ignition protected.

Generally speaking items which are original equipment on Marine Engines (Mercruiser, OMC, Pleasure craft, Crusader, ect.) are ignition protected. This is not to say that these items should not be scrutinized. Most starters and alternators which are approved for marine use are labeled ignition protected and are UL Marine rated. Distributors are also generally labeled as ignition protected if approved. If you are unsure on any of these items the following may help:

Starters are generally the most difficult to determine. They generally look like there automotive counterpart, but may be gasketed at the cover plate end, which is a good indication that the starter is ignition protected (figure 7). The starter solenoid, if attached to the starter, is generally a sealed unit. While examining the starter it is important to ensure that the battery cables are in good condition (conductors must be ignition protected or sheathed). Any arcing from a conductor is also a potential ignition source.

Ignition protected alternators (or generator if prior to 1965) are usually identifiable by viewing the rear of the alternator. If the alternator is ignition protected the brushes and slip ring assembly are external of the alternator and completely covered and gasketed (Figure 8).

Generally, any distributor which has a vacuum advance (figure 9) is designed for automotive use and is not ignition protected.

Ignition protected distributors are completely enclosed with the possible exception of a ventilation hole which is screen covered. If the screen has been removed the distributor will no longer be ignition protected. There also is normally a gasket between the distributor cap and the distributor. The spark plug wires should also be thoroughly checked for condition as they carry high voltage. Any deterioration of the leads or spark plug boots could result in arcing even if the nearest grounded metal surface is a 1/2" away.

Outdrive trim pumps (if the boat is equipped with an outdrive) and there control solenoids are also normally ignition protected as they are manufactured by the individual manufacture of the marine engine. They should be checked for any alterations or modifications to determine that the gaskets and other original equipment is still in place.

Ignition protection of other electrical components in the bilge area, including bilge pumps, air conditioning pumps, fresh water pumps, trim tab pumps, ect. may be much more difficult to determine if they are not labeled as so. UL Marine Division engineers stated that generally speaking, any opening in an electrical component over 1/4 inch not screen covered is suspect. In other words, if there is an opening in a component case that you suspect copy the manufacture name model and serial number and call the manufacture to determine for sure that the component is ignition protected.

The process of determining if all of the components in the fuel and engine spaces are ignition protected may take an extended period of time, especially if calling any manufactures is required. But, think of the possibilities if a fuel leak occurs and a non-ignition protected item ignites an explosion which kills someone.... Suddenly all of the time it would have taken to inspect these items for ignition protection is meaningless.