In the world of marine fuel filtration there’s no shortage of opinions on the right, most reliable, and most effective set-up. There is one area, however, where opinions should not diverge, and that involves the fire resistance of the individual fuel-carrying components within the system including primary fuel filters.
TO MA OR NOT TO MA
Primary fuel filters are available in a range of sizes and styles from several manufacturers. While there are others, Parker Hannifin’s Racor series undeniably leads the pack in popularity. They offer a variety of features and are available in a range of sizes, from a gossamer 15gp unit, suitable for small generators and heating systems, to the gargantuan triplex 540gph model that is designed for very large propulsion plants found on mega yachts and commercial vessels.
Regardless of the brand or model, among the most common installation flaws that I encounter when inspecting a vessel involves the filter’s fire resistance. Unbeknownst to many boat owners, and some boatbuilders and yards, while they may look similar in appearance, there is a decided difference between filters destined for industrial and automotive applications versus those specifically designed for marine, and therefore fire resistant, use.
Contrary to popular belief, the ‘marine’ label isn’t just an excuse by the manufacturer to charger a premium; there are genuine and critical differences.
The primary difference between the two models involves their resistance to flame. Filters designed to be used in marine applications must be capable of withstanding 2-1/2 minutes of exposure to flame. The guideline, set forth in the American Boat and Yacht Council’s Standards, which applies to all fuel carrying components, reads…
All individual components of the fuel system, as installed in the boat, shall be capable of withstanding a 2-1/2 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.
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 five ounces of fuel in 2-1/2 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 filters, making the determination as to whether they meet this standard or not is exceptionally easy. Those that do carry an MA (or MAM in the case of non-turbine series filters) suffix, such as 500MA or 900MA, and those that don’t carry an FG or FH suffix. Additionally, the label lettering on the MA units is blue, while that of the FG and FH units may be black, brown or orange.
Internally, the MA and FG 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).
Many believe this 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 2-1/2 minutes.
When I visited the Racor facility that makes all MA turbine series filters, in Modesto, California 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 Underwriter Laboratories marine rating.
As an aside, 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.
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.
If your recreational vessel is equipped with FG or FH filters the news isn’t all bad, as 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.
Many insurers require that fuel filters meet ABYC fire resistance standards as a condition of coverage. Some have been known to send their insured a disposable camera to photograph filters and then return to the insurer, to verify compliance.
ACCESSORIZING YOUR MA FILTER
After making certain that your filter meets fire resistance guidelines, you may wish to add accessories that will further improve its functionality and ease of service. A vacuum gauge can be used to both determine the condition of the filter element as well as troubleshoot the fuel supply system. Ideally, vacuum gauges should be permanently plumbed to the filter’s outlet plumbing rather than installed in place of the T-handle.
Permanent installations are more protected, and less prone to damage during filter replacement or from an errant tool bag or if inadvertently used as a handle (I’ve seen gauges broken off when grabbed by a person losing his balance while in a seaway).
The aforementioned metallic drain plug arrangement will benefit from an upgrade to a valve, which will make water drainage much more convenient, however, not just any valve will do.
In order to remain ABYC compliant and thus fire resistant, the valve must be metallic, the handle must turn through no more and no less than 90 degrees, it must not rely on spring tension to maintain liquid tight, and it must be capable of accepting a plug in its outlet (which also must be installed as a n additional measure against leaks). Valves that meet these standards are typically so marked to show their compliance with Underwriters Laboratories.
The final accessory is a water sensor probe and attendant helm-mounted audio-visual alarm console. Racor turbine fuel filters are capable of performing near-miracles when it comes to water removal, however, there’s one thing they can’t do, drain themselves of water.
If the filter is accumulating water and the operator isn’t aware of it, it will eventually become overwhelmed, which will lead to unexpected engine shutdown and/or severe fuel injection system damage. The alarm will alert the user to the presence of water long before it becomes critical. Water sensors can be added to every Racor turbine series and many other styles of filter.
Review your primary fuel filter installation to ensure it meets the all-important fire resistance standards established by ABYC. If it doesn’t, it should be retrofitted to bring it into compliance as soon as possible.
While you’re at it, consider adding a vacuum gauge and water probe kit. They are valuable insurance against engine trouble and damage.