LPG ON BOARD...

[Chenega]

I have LPG for use with galley stove / oven, and a force 10 LPG bulkhead heater. I always do an AM sniff check in the bilge, have a sniffer at the cabin sole level and regularly do a soap water check on fittings. If I do discover gas in the bilge, would an explosion-proof engine room blower be safe to use to evacuate the fumes? Should I have it blow air into the bilge and another vent hose discharge overboard? I would of course get all crew off the boat before trying anything... In the interest of having a plan - how would you deal with this?

[jgbrown]

A propane solenoid with sensor, that I keep off at all times unless actively in use.
I've thought about adding powered ventilation, but for now I have passive vents that move air into and out of the bilge. I'd open the hatch, turn off all power and get off the boat. I should check if my breakers are ignition proof now that I think about it...

[nwdiver]

A sniffer properly sited raises the alarm far before the gas reaches concentrations that are explosive, so you hear an alarm, close off the gas at the tank and unless the sniffer is eye level in the cabin it will dissipate slowly and the alarm will go off. So a sniffer in the bilge near the gas source gives lots of warning of a problem. Returning to the boat with the alarm sounding is your problem, you should turn off the gas every time you leave the boat for any amount of time, well short of walking along the dock to attach a hose for water.

[Nicholson58]

If you have an explosin proof blower then you can use it to evacuate. There are enough air leaks in boats to admit any air you exhaust. The place for the exhaust pick up is the lowest point in the bilge since propane is ralatively heavier than air.

[Bash]

Originally Posted by Chenega

I have LPG for use with galley stove / oven, and a force 10 LPG bulkhead heater. I always do an AM sniff check in the bilge, have a sniffer at the cabin sole level and regularly do a soap water check on fittings. If I do discover gas in the bilge, would an explosion-proof engine room blower be safe to use to evacuate the fumes? Should I have it blow air into the bilge and another vent hose discharge overboard? I would of course get all crew off the boat before trying anything... In the interest of having a plan - how would you deal with this?

A vent hose discharge in the bilge? Think about that for a minute.

[delmarrey]

W/O knowing what your set up is at present, it's hard to make recommendations.

But first of all you don't want LPG getting in the bilges at all. Your LPG tank should be out side the boat away from hatches, or in a sealed LPG box with dump line and a cut out valve, which should always be off unless your using gas.

All fittings should be inspected on a regular basis, which you do. If you do get LPG in the bilges the best thing is to slowly open all the hatches and get off the boat for awhile. The gas will dissipate quickly with air movement and heat. If cold it will settle in the lowest spots.

If you had to pump it out, it would be better to use a hand diaphragm pump up on deck with a hose running into the low areas. No sparks!

[Nemo55]

Using an ducted fan to blow air in would be safer than sucking it out,,,it will dissipate with the introduction of fresh air. as for all other considerations,,Follow Dellmarrey's suggestions and you should be as sound as a pound.

[Chenega]

Originally Posted by Bash

A vent hose discharge in the bilge? Think about that for a minute.

As in Chapmans

[delmarrey]

Originally Posted by Chenega

As in Chapmans

Attachment 53027

This is for gasoline fumes! Not LPG.

[Cheechako]

Originally Posted by Chenega

As in Chapmans

Attachment 53027

Yes that appears to be a proper installation. Arent normal bilge blowers spark proof? They are commonly used on gas powered craft.....

[Chenega]

Originally Posted by delmarrey

This is for gasoline fumes! Not LPG.

Right for clearing out explosive fumes - that's the question... Would this type of system be safe for getting rid of LPG fumes? Suck the fumes out or blow fresh air in? Looking for info and discussion.

[shorebird]

A blower approved for use in the presence of highly volatile gasoline fumes should certainly be ok for propane.

[delmarrey]

Originally Posted by Chenega

Right for clearing out explosive fumes - that's the question... Would this type of system be safe for getting rid of LPG fumes? Suck the fumes out or blow fresh air in? Looking for info and discussion.

Two things I see wrong in the picture;
One, is the suction intake needs to at the lowest point in the bilge, just above the bilge pump float switch.
And Second the discharge outlet needs to go directly overboard, not aft and possibly back into the cockpit.

Bilge blowers are just fine as long as they are not saturated in the gas. They need to be in a space away from the source of the gas. The gas can run thru the pump vanes, but not thru the motor. Unless that motor is spark resistant. And that's what one wants to check before buying. Some good, some not!

[denverd0n]

Originally Posted by Chenega

Suck the fumes out or blow fresh air in? Looking for info and discussion.

I would suck the fumes out.

If you blow fresh air in, the LPG fumes mix around with them, but still sink to the lowest level. Hence, the LPG fumes would stay down in the boat longer, though I'm sure the concentration would quickly be reduced to a safe level. To really get all of the LPG fumes out you would need to suck them out from the lowest level possible to reach.

Make sense? It does to me.

[Cheechako]

Originally Posted by delmarrey

Two things I see wrong in the picture;
One, is the suction intake needs to at the lowest point in the bilge, just above the bilge pump float switch.
And Second the discharge outlet needs to go directly overboard, not aft and possibly back into the cockpit.

Bilge blowers are just fine as long as they are not saturated in the gas. They need to be in a space away from the source of the gas. The gas can run thru the pump vanes, but not thru the motor. Unless that motor is spark resistant. And that's what one wants to check before buying. Some good, some not!

if I'm seeing it right, it goes directly over from a cowl vent at the motor....? Probably better than the stern as the stern is a "vacuum" pulling air forward when moving.....