Where did you mount your gas detector?

[viking69]

Hi all.
well i am tired of my old alchol stove and am installing a gas stove instead. Anyway I am curious to know where people have mounted their gas detectors. I was thinking that seeing as the gas is heavier then air then below the stove where the gas is likely to sink to should it get a leak or should a fitting leak would be the go. What do you all reckon would this work or am i way of the money?
Thanks
Andy

[GordMay]

Propane Detector Locations:

You want to select a sensor mounting location, where propane is likely to accumulate.
Since propane is heavier than air, this is generally within 6" - 12" of the floor, and often near the propane supply, near fittings, or the propane appliance(s).

Consider the effects of barriers (bulkheads, cabinetry, etc), that might prevent the leaking gas from reaching the sensor. Avoid “dead air” spaces, such as corners.

Also remember, gas detectors must be protected from water, high humidity, and other “contaminants” (which will disable or destroy them).

I recommend units that will automatically shut off your electrically operated gas solenoid valve*.

*ie: Trident 12 VDC MARINE GAS CONTROL & DETECTION SYSTEM:
Trident Marine: LPG Control & Detection

Some rules of thumb for mounting gas detection sensors:
* Heavier than air (Propane, LPG, Refrigerants): about one foot above the floor
* Carbon Monoxide (CO*): at breathing level (about 4-5 feet high).
* Lighter than air (Methane, Natural Gas, Hydrogen): one foot below the ceiling.
* Combustible Gases: Mounting height depends on the specific gravity (weight) of the gas: about 1 foot above floor for Gasoline & Diesel*

* Once a diesel engine warms up, there is not enough CO in the exhaust to be detected, so a NO2 detector (Nitrogen Dioxide) should be installed.

[seaclusion]

Gord,

Excellent answer and right on the money.

Richard

[Boracay]

So one would not put a propane detector in the bilge?

[GordMay]

Some would, I would NOT mount a sensor in the bilge.

[viking69]

Thanks for that gord. now i just have to find out if i can get something similar here if if i adapt those fittings to suit Aussie gas bottles. i reckon every one with gas should have something like that fitted.

[Alan Wheeler]

Viking, the fittings do fit right into the bottles. It goes in directly after the valve where the normal connection would have gone. The the regulator screws directly into the electric valve and the hose onto the regulator.
There are detectors that have a further connection to run a bilge blower as well.
I have a set of two tanks. A solinoid valve on each, a regulator after each, then tee'd together into the single main gas line. The electric valves can be switched off from the Galley switch board as two seperate tanks. so we run one tank and when it is empty, switch over to the other tank. When we leave the boat, the tanks are switched off from the galley. If a fire starts in the galley, the tank swtiches can be easily reached to shut off the gas. If gas is detected, then the tanks switch off and the bilge blower starts up till the detector stops the alarm. The tanks do not switch back on however.
I have a twin sensor detector. One detector is down in the engine room bilge and one is directly under the gas oven bilge area. The bilge under the gas oven can not ever get wet. If it does, we are in rather seriouse trouble and gas will be my last problem. the engine room sensor is a difficult one. As Gord said, bilges are NOT the best location and this sensor has already been wet from a pipe failure from the saltwater intake and washing water from a hose and now does not work. It needs to be replaced. The problem is, the bilge in this area is something like 6ft down and is the lowest point in the boat and all other bilge areas drain to this point. Of course, the gas line runs through the entire boat, so if there is a leak, then gas will also go to this point. What I intend to do in the future is to mount the new sensor in a plastic water proof box with large holes cut in the bottom of it. This should allow water to rise but as air pressure in the box will stop water from entering, I hope it will stop the sensor from getting wet and will certainly stop water splashing around from getting over it.

[senormechanico]

Alan,
Asking a sensor to stay dry in the bilge is hopeful thinking imho.
With salt water, cool damp salty air and motion of the boat, it's just not going to make a difference. Why not just drill a big hole in the bottom of the boat so the fumes can drain out?

Steve B.

[cat man do]

Thank's for that Gord, that would be similar to the LPG solenoid in a cars system Trident Marine: LPG Control & Detection .

Maybe a wrecking yard could be a place to get a solenoid at the right price.

Dave

[Alan Wheeler]

Why not just drill a big hole in the bottom of the boat so the fumes can drain out?

Now that's just plain stupid. Don't you know that only works for water. You know, you drill a hole just below where the water is coming in so it can drain straight back out again.;-)
Seriousely though, the sensors have a small heater element in them by the way they work. So moisture in the bilge is not a problem. It is total emmersion they don't like. Besides, if water gets up to the sensor level, the sensor is not my worry. the reason it got wet initially was when I had a saltwater hose seperate and sprayed the engine room. so I washed it all down with the fresh water hose. But I forgot all about a sensor and I sprayed water into it before I realised.

Dave, mmmmm, I am not sure if that would be of benifit to you. You still have to fit it to the higth pressure side of the bottle. That is going to take some fittings and I would suggest you are not going to save much in the end. I suggest you go buy the proper valve and know it is working right the the get go and that it will continue to work right, plus they come with all the fittings ready to go.

[GordMay]

From the BoatUS “BoatTECH Guides” ~ by Don Casey BoatUS.com: BoatTECH Guides
specifically
Propane Systems: Propane Systems by Don Casey
and
CO and Fume Detectors: BoatUS BoatTECH Guides: CO and Fume Detectors

Personally, I think we get more useful free information from the CF membership, than Don Casey’s articles generally offer (but he’s a published best-selling author, hence “expert”).

[viking69]

Well i found this one from a supplier very close by. It comes in at around a grand but i guess if it saves your boat just once it was worth it.

ITIM Systems

[GordMay]

See also ABYC Sections:

A-24 ~ Carbon Monoxide Detection Systems
http://www.abycinc.org/committees/A-24.pdf

A-14 ~ Gasoline and Propane Gas Detection Systems
http://www.abycinc.org/committees/A-14.pdf