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Primary Fuel Filters

Primary Fuel Filters

Nov 12, 2019

In the field of Marine fuel filtration, there is no shortage of opinions on the correct, most reliable and effective Settings. However, opinions should not be divided in one area concerning the fire resistance of the various fuel bearing components in the system, including the main fuel filter.

To MA or not MA

Several manufacturers offer major fuel filters in various sizes and styles. Though there are others, Parker Hannifin's Racor line is arguably the leader in packaging. They are versatile and come in all sizes, from gossamer 15gp units for small generators and heating systems to giant three-cylinder 540gph models for very large propulsion units on large yachts and commercial ships. .

Regardless of brand or model, the most common installation defects I encountered when inspecting ships involved the fire resistance of the filters. For many shipowners, certain shipyards and shipyards, while the look is similar, there is a clear distinction between industrial and automotive filters and those designed specifically for Marine use and therefore fire resistant.

Contrary to popular belief, the ocean label is not just an excuse for manufacturers to charge a premium; There are real and critical differences.

The main difference between the two models is their flame retardancy. Filters designed for Marine applications must be able to withstand 2-1/2 minutes of flame exposure. The guidelines set out in the United States boat and yacht board standards applicable to all oil-carrying components are as follows:

Highly 33.5.6

All individual components of the fuel system installed on the ship shall be able to withstand 2 to 1/2 minutes of free burning fuel (n-heptane) or no. 2 diesel without leakage when tested as follows. Compliance with title 33 CFR, section 183.590, fire test.


1. If a portion of the fuel distribution system is located outside the engine compartment, any rupture in the system will result in the discharge of no more than 5 ounces of fuel within 2-1/2 minutes, including any possible discharge from the engine.

2. Self-draining water injection and exhaust pipe in another compartment separate from the engine compartment.

3. Fill and exhaust external accessories.

4. Clamps and belts not required for anti-siphonage protection as required by this standard.

For Racor filters, it is very easy to determine whether they meet this standard. Suffixes with MA (or MAM for non-turbine series filters), such as 500MA or 900MA, without FG or FH suffixes. In addition, the label letters on the MA unit are blue, while the label letters on the FG and FH units may be black, brown or orange.

Internally, MA and FG units are the same, the difference is only external. In addition to the different color labels, the MA device includes a unique matte finish stainless steel filter cup (the label alone is not enough as the filter cup may be removed at some point in the filter's life).

Many people think this is done to prevent drips and small leaks, but this is not the case. Close inspection will reveal a small drain hole which will make them unsuitable for the purpose. In fact, the filter cup is a heat shield that protects the clear plastic filter cup from fire for the specified 2-1/2 minutes.

A few years ago, when I visited the Racor plant in modesto, California, which manufactures all MA turbine series filters, I spoke with the people responsible for designing and manufacturing this and other Racor products. They made it clear that without a heat shield, which must be installed in the filters to meet ABYC and Underwriter Laboratories' Marine rating, all bets would disappear on fire.

Incidentally, any fuel filter with a clear plastic bowl must be equipped with a heat shield, or a metal plastic bowl must be used instead of a plastic bowl, to maintain ABYC compliance. By itself, almost no plastic fuel composition can meet the test for flame retardancy.

Another important difference between MA and the industrial sector is drainage. The latter is equipped with a plastic spout-type drain that is used to drain water out of the bowl, making the process fast, simple and without any tools.

On the other hand, MA filter can eliminate plastic leakage. Because it is outside the heat shield, it will melt in case of fire. The MA filter relies on metal blowout boss and hexagonal plug, which makes the assembly both flame-retardant and particularly unmaintainable - removing the plug requires two combination wrenches

It is important to note that depending on the position of the filter relative to the fuel tank, melting or even cracking or leaking of the drain may dump the entire contents of the fuel tank into the bottom of the boat.

If your leisure boat is equipped with FG or FH filters, the news is not a bad thing, because you can retrofit your heat shield and metal drain into these models at a modest cost. Because these filters have unique serial Numbers, modifications on inspected vessels are not allowed in the event of a fire; The researchers will use the serial number to determine the type of filter the container is equipped with.

Many insurance companies require fuel filters to meet ABYC fire resistance standards as a condition of coverage. Some people are known to have sent disposable cameras to the insured to take filters and then returned to the insurance company to verify compliance.