Posted by Darrell Nicholson at 11:55AM - Comments: (5)
Three days after I blogged about the risks of having liquid petroleum gas (LPG) onboard boats, and shared frequent PS contributor and marine surveyor Capt. Frank Lanier’s tips on checking for leaks, an LPG explosion killed a Swedish sailor who was docked in Livingston, Guatemala. In the upcoming March 2013 issue of Practical Sailor, Lanier goes over LPG safety from top to bottom, and I hope everyone will read the article carefully. It is an introduction to a series of tests comparing products found in the LPG system—ranging from tanks to valves, and from aftermarket lockers to solenoid valves.
While the dangers associated with storing and using liquid petroleum gas on board are real, the risks of accident can be minimized by maintaining your system to current standards and following basic safety practices. According to initial reports, had the victim's boat been equipped with some of the items that we’ll be testing, or had the owner followed basic safety practices in handling and using LPG, a tragedy could have been prevented.
At 6:30 a.m. Jan. 2, 2014, an explosion aboard a sailboat rocked the docks at the Vista Rio Hotel and Marina in Rio Dulce, Livingston, Izabal, Guatemala. Marine surveyor Capt. John Brandes (http://www.riodulcesurveyors.com), who was on the scene, supplied PS with the accompanying photo and details of the propane-related explosion.
According to Brandes, the destroyed boat was an older 37-foot Hunter Cherubini named Panacea. The owner had been complaining of a rat problem, and it seems that overnight, a rat chewed a hole in a flexible hose in the propane supply line. When the owner lit a cigarette in the morning, it ignited an explosion that decimated the boat, fatally injured the owner, and damaged two neighboring boats.
The LPG-fueled stove, LPG tank, and supply hoses were later recovered from the wreckage. It was obvious that the system was an aftermarket, DIY setup that ignored basic safety standards, such as those established by the American Boat and Yacht Council. Brandes reported that the tank had no remote shutoff valve and that it was found almost empty with the valve open, but it still had a little gas remaining that was flowing from the hose.
Tape, Thread Sealant, or Nothing
One common question we get about LPG systems, is how to handle connections. In short, the fewer the connections, the better, but some are unavoidable. A tight seal is critical at each of these unions. The number of unions belowdecks should be kept at an absolute minimum.
In addition to the specialty fitting used at the tank, typical marine LPG system connectors include quarter-inch or 3/8-inch national pipe thread (NPT) and/or 45-degree SAE flare connections (male and female). Only NPT fittings require the use of Teflon (PTFE) tape or thread sealant (aka pipe dope) on the threads; SAE flare connections are self-sealing.
Either Teflon tape or thread sealant will work fine, so choosing which one to use boils down to personal choice. But use just one, not both—using both is counterproductive and not recommended—and be sure to follow the manufacturer’s instructions.
The yellow variety of Teflon tape is specifically designed for LPG systems; it’s thicker and more durable than the white PTFE tape, which is normally used for water pipe joints.
When applying Teflon tape, wrap three or four layers around the connector threads, avoiding any tape overlap at the end of the hose, which could come loose and cause clogging issues in the system. Next, insert the fitting and twist until hand tight, then snug it up with a wrench, but don’t over-tighten (which can damage both fitting and threads). Finally, test the fitting for leaks using leak detection fluid or the DIY water-soap solution. If leaks are found, try gently tightening the fitting a bit and retesting. If it still leaks, replace the fittings and try again until all leaks are fixed.
Tips for Safe Grilling
Because grills are located above decks, boaters tend to treat them with a more cavalier safety attitude than galley ranges. Bad idea. According to the Insurance Information Institute, each year, grills cause more than 2,000 fires, over 300 related injuries, and at least three deaths. Here are a few tips on how to avoid becoming a barbecue statistic.
1. Make sure your grill is mounted securely and in accordance with the manufacturer’s instructions. Avoid using camp-type grills on a boat; they typically have no means to be properly mounted.
2. As with your galley stove, grill burner controls should have two-stage operation when going from ”off” to “on” to prevent accidentally opening the valve during handling or storage, and the controls should be located at the front of the grill so you can operate them without reaching over the burner.
3. If your grill is fueled by an LPG system, inspect the system frequently. If it uses portable gas cylinders, they must be DOT-approved 2P/2Q 8-ounce units with rim vent releases.