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Why marine-related filters?

Apr 27, 2018

Contrary to popular belief, the marine label isn’t just an excuse by the manufacturer to charge a premium — there are genuine and critical differences.

The primary difference between the MA and FG/FH models involves their resistance to flame. Filters designed to be used in marine applications must be capable of withstanding two and a half minutes of exposure to flame. The guideline, set forth in the American Boat and Yacht Council’s Standards, which, with some exceptions, applies to all fuel-carrying components, reads:

ABYC H-33.5.6
All individual components of the fuel system, as installed in the boat, shall be capable of withstanding a two-and-a-half-minute exposure to free burning fuel (N-Heptane), or No. 2 diesel fuel without leakage, when tested in accordance with Title 33 CFR, Section 183.590, “Fire test.”

Exceptions:
1. Portions of fuel distribution systems located outside the engine compartment if a break at any point in this system will result in the discharge of no more than 5 ounces of fuel in two and a half minutes, including fuel that may drain from the engine.

2. Self-draining fill and vent pipes located in a separate compartment from the engine compartment.

3. Fill and vent external fittings.

4. Clips and straps not essential for anti-siphon protection required by this standard.


In the case of Racor Turbine series filters, making the determination as to whether they meet this standard or not is exceptionally easy. Those that meet it will carry an MA suffix (or MAM in the case of non-Turbine series filters), such as 500MA or 900MA, while those that don’t will carry an FG or FH suffix. Additionally, the label lettering on the MA units is blue, while that of the FG/FH units may be black, brown or orange.

Internally, the MA and FG/FH units are identical; the difference is purely external. In addition to carrying different color labels, MA units also include the distinctive matte-finish stainless steel bowl. The label alone isn’t a sufficient indicator, as it’s possible for the bowl to have been removed at some point in the filter’s life.

In order to remain compliant with the above-mentioned ABYC standard, any fuel filter with a clear plastic bowl must either be equipped with a heat shield or the plastic bowl must be replaced with one that is metallic. On their own, few (if any) plastic fuel components meet the flame-resistance test.

Many believe the stainless steel bowl is present to catch drips and minor leaks, but that’s not the case. Close examination would reveal a small drain hole that would make them unsuited for that purpose. In fact, the bowl is a heat shield that protects the filter’s clear plastic bowl from flames for the prescribed two and a half minutes.

When I visited the Racor facility that makes all MA turbine series filters in Modesto, Calif., a few years ago, I chatted with some of the folks responsible for designing and manufacturing this and other Racor products. They made it clear that without the heat shield, all bets are off where fire is concerned. The filter must have it in order to meet the ABYC and Underwriters Laboratories marine rating.

Yet another important difference between the MA and industrial units is the drain. The latter come equipped with a plastic spout-type drain that’s used to remove water from the bowl, making that process quick and easy without the need for any tools.

The MA filters, on the other hand, do away with the plastic drain. Because it’s outside the heat shield, in the presence of a fire it would melt. MA filters rely on a metallic drain boss and hex head plug, making the assembly both flame resistant and especially inconvenient to service — two combination wrenches are needed for plug removal.

It’s worth noting that depending on where the filter is located in relation to the fuel tanks, a melted or even broken or leaking drain could potentially empty the entire contents of a tank into the vessel’s bilge. The inconvenience of the drain plug can be replaced with the convenience of a drain valve, provided it’s metallic and UL approved — meaning it must turn through no more than 90 degrees, and it avoids the use of a spring, which is found in tapered cone-style valves. It must be stamped “Marine Use.”

If your recreational vessel is equipped with FG or FH filters, the news isn’t all bad. You can retrofit the heat shield and metallic drain assembly to these models at a modest cost. Because these filters carry distinctive serial numbers, performing a retrofit is not permitted aboard inspected vessels; in the event of a fire, investigators would use that serial number to determine with which type of filter the vessel was equipped.

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