WestlawnMasthead27_Sept2013H.pub - page 27

The Masthead
Sept. 2013 Page 27
heesy puns aside, the last few weeks have shown that
standards based questions are contagious making
Thermal Appliance and more specifically liquid petroleum
gas (LPG) Systems, one
Hot Topic.
I have on more than one
occasion answered the same question multiple times in one
day. That made choosing a “back to school” topic for this
issue easy.
With LPG being the dominant cooking and heating fuel for
boats in the US, it’s easy to see wild fluctuations in how the
fuel systems and appliances are installed from boat to boat.
Many installations are thoroughly thought out, with every
safety precaution being made and every detail of the
standards being observed. Unfortunately there is no short-
age of improperly installed systems as well. The results of
improper installations can be catastrophic.
Since LPG is heavier than air, when released into a boat it
settles in the lowest spot it can find and will invisibly over-
flow from one compartment into another through shared
airspaces. The slightest spark in that pool of invisible gas
will ignite the fuel and the resulting flame travels at 2,800
feet per second and can burn at nearly 3,500°F. So there is
good reason to be cautious with this fuel. Much like natural
gas in our homes, an odor is added to help notify the user
when a leak may be present. For that to be valuable how-
ever, there must be a user on-board the vessel that can rec-
ognize something is wrong and shut off the fuel.
The most common cooking appliance installation is the port-
able rail mounted grill with a 16.4-oz. bottle screwed into
the side. With the simplicity of this installation, any leakage
that may occur merely leaks overboard. But did you know
that the canisters are subject to the same requirements as
the larger permanent cylinders? The capacity of the portable
tank exceeds the maximum allowable for interior storage as
required in A-30
Cooking Appliances with Integral LPG Cylin-
Looking towards the larger permanent installations, storage
cylinders need a dedicated locker that does not share air
space with the hull interior and vented at the bottom of the
locker draining only outboard (above the waterline). We
often see LPG lockers used to store additional items like
cleaning supplies, fenders, and mooring lines because of the
locker’s convenience to the cockpit. A-1,
Marine Liquefied
Petroleum Gas Systems
strictly prohibits this in order to limit
the possibility of the drains being plugged. A-1 goes on to
require that all appliance fuel lines must originate inside the
locker and be dedicated for each appliance with no connec-
tions along the path. A manifold is acceptable to distribute
the fuel to multiple appliances, but it must remain in the
locker along with the fuel pressure regulator. Finally, when
the fuel line arrives at the appliance, a flexible connector is
allowed to accommodate gimbaled stoves, but only perma-
Thermal Appliances — One Hot Topic
By Matthew Weinold, ABYC Standards Specialist
Portable 16.4-oz. fuel bottles such as this are treated just
like the large cylinders and require ventilation.
Photo: Undisclosed
A poor attempt at a LPG locker.
Photo: ABYC Member, Captain Wallace Gouk
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