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30-08-2010, 05:26
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#31
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Senior Cruiser
Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 49,130
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How long will it take for diffusion (under Graham's Law) to disperse concentrations of stratified (settled under Law of Gravity) LPG to a safe concentration?
Propane gas vapours are about 1½ times heavier than air. Without moving air currents, Propane gas settles down toward the lowest floor level until normal diffusion* eventually mixes it with air. Propane is not toxic; however, as the gas takes the place of air, it becomes a simple asphyxiate and can cause suffocation from lack of oxygen.
* Both the rate of diffusion of a gas, and its rate of effusion depend on its molar mass. Lighter gases diffuse faster than heavier gases such as LPG.
From the Propane Gas Association of Canada:
“At one and a half times the weight of air, propane will settle in low areas.”*
➥ Propane Gas Association of Canada - All About Propane: Propane Information Properties
From the Ontario Propane Association:
“ Because propane is heavier than air, it tends to settle in the lowest available space. Very small amounts of propane are required to create a flammable mixture of gas and air. In the limited space of a recreation vehicle, for example, a propane leak can create a hazardous situation.”
➥ Ontario Propane Association - The Clean Truth
* Specific Gravity of Propane Vapour at 60̊F = 1.52 (Air =1)
National Fire Protection Association (NFPA) Bulletins No. 54 and No. 58 are recommended sources of safety information and practices for the proper handling and storage of Propane.
LPG Gas Code (NFPA 58)
➥ http://www.minhbao.vn/userfiles/file/A_NFPA58.pdf
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"
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30-08-2010, 05:38
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#32
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Registered User
Join Date: Jan 2010
Location: Netherlands, Holland
Boat: Sold Sigma 33 OOD some time ago, will be chartering in Turkey really soon
Posts: 361
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Gord: I fully agree with your analyses. Instead of flammable mixture I would name it explosive.
If I were moderator of this board I might consider deleting posts that suggest propane is harmless and will dissipate. It is untrue and incorrect.
Eric
__________________
Sailors do it with the wind...
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30-08-2010, 07:21
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#33
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Registered User
Join Date: Feb 2010
Location: Florida
Boat: Oyster Mariner 35
Posts: 166
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30-08-2010, 08:28
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#34
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Nearly an old salt
Join Date: Jun 2009
Location: Lefkas Marina ,Greece
Boat: Bavaria 36
Posts: 22,801
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MarkJ
The vast majority of the advice here is nuts,
I suspect you have an ENO stove thats the standard on a 393 ( some did have a plastimo one).
Its an all metric stoveENO make a dedicated connction hose, that connects from the rigid supply hose ( low pressure -post regulator). to the stove. Buy that. It doesnt get supplied as standard. It also maintains the CE integritry of the Boat
As to making flared ends FORGET IT. or practice loads on water or oil first.!
DAve
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30-08-2010, 08:50
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#35
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Marine Service Provider
Join Date: Jul 2010
Location: Sydney
Boat: Allied Mistress 39'
Posts: 89
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Quote:
Originally Posted by GordMay
How long will it take for diffusion (under Graham's Law) to disperse concentrations of stratified (settled under Law of Gravity) LPG to a safe concentration?
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From "seconds" to a "very long time"
In real life settings it depends on the amount, the volume of space, the restrictions to the environment, air displacement in the environment itself...how soon your co-worker wants a cigarette; how lucky you feel....
You can do the math for your theoretical scenario and set up the variables however you want. Tell us what you find out.
The rest of the stuff in your post is good boiler plate information. You can't have your customers not having a good experience with your product. You managed to do it without hysteria...unlike some.
I think it might be because they confuse "settle" with "stay", and think gas behaves like liquid.
They can incorrectly draw what ever fear induced conclusion they want. I don't recall saying anything contrary to what the Canadian gas association, or whatever they're called, has stated....except that a monkey can do a compression fitting....let me know.
But you can't argue with crazy and can't reason with scared.
So, sorry, but the most dangerous thing on a boat is between our ears. propane comes a distant third behind a pissed off 1st mate.
...it's better to be careful than fearful. Now, go do those boat projects.
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30-08-2010, 10:35
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#36
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Long Range Cruiser
Join Date: Dec 2007
Location: Australian living on "Sea Life" currently in England.
Boat: Beneteau 393 "Sea Life"
Posts: 12,822
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Thanks for everyones help!
OK well, this is how my day went....
Ya just gotta love cruising... You go to the shop to buy a 'simple' gadget.... they don't have one so the send you half way accross the city.....
I hit Nice at 8am and was still walking at 12 noon when I gave up and came back to the boat, before I pumped up little dink (she is sinking) I thought I should go speak to the Nautor Swan Service centre a few hundred yards away (You're thinking why didnt Mark do that FIRST!) Anyway, the guy there goes through EVERY box of bits and pieces till he finally finds one. Voila! he says with my fav French word! Voila indeed!!!!!!
I went straight on so was fine...
Then it took me an hour to reposition the gimbles on a stave thats meant to be the same size as the old!!!!!
LOL
Thats Crusin'!
heres a photo on the new stove! INSTSALLED!!!!
(Don't dare notice the scratch on the varnish!)
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30-08-2010, 10:36
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#37
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Registered User
Join Date: Aug 2009
Location: Naxos Greece
Boat: Lidgard 50ft performance cat/ Canados50s
Posts: 766
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I have read some trollop here , but as a gas engineer who does gas instillation for a living in the winter months here in the uk I do gas safety inspections on leisure/charter vessels of which i am governed by uk health and safety regulations and licensed to do so all you need is 3/8 straight male compression fitting and just remove the olive and nut and fit to your cooker and fit your gas hose to that fitting then you should carry out a gas tightness test by fitting a manometer at the gas regulator for all materials used on gas should meet the following BS or ISO standards malleable iron fittings bs143 bs1256, copper tube bs en1057, polyethylene tube bs en1555-1&-2, thread sealing material bs en751 or bs 6956-5 , ball valves bs en 331 compression fittings and capillary fittings bs en1254 or bs 864-2
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30-08-2010, 10:46
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#38
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Registered User
Join Date: Jan 2010
Location: Netherlands, Holland
Boat: Sold Sigma 33 OOD some time ago, will be chartering in Turkey really soon
Posts: 361
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Quote:
Originally Posted by MarkJ
Thanks for everyones help!
heres a photo on the new stove! INSTSALLED!!!!
(Don't dare notice the scratch on the varnish!)
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Good for you, my compliments. Did you mean the scratches on the left or on the right?
Hope you followed the advice in the above post (pressure and leakage test; I do not think you have the proper equipment for that) or at least have carried out a leak test with soapy water or better special leak detection spray can.
Did you try the deux pression?
Be carefull when you light it up tomorrow morning; I'm sure it was fine when you just connected it. This click does happen more often than you would think.
__________________
Sailors do it with the wind...
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30-08-2010, 10:49
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#39
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Nearly an old salt
Join Date: Jun 2009
Location: Lefkas Marina ,Greece
Boat: Bavaria 36
Posts: 22,801
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Quote:
you need is 3/8 straight male compression fitting a
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egh its a metric stove...
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30-08-2010, 12:26
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#40
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Long Range Cruiser
Join Date: Dec 2007
Location: Australian living on "Sea Life" currently in England.
Boat: Beneteau 393 "Sea Life"
Posts: 12,822
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Quote:
Originally Posted by beneteau-500
fitting a manometer
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I think some of the girls on this forum have a Manometer!
Quote:
I do gas safety inspections on leisure/charter vessels
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Well, stop hanging around that dreary old place and come have a cruise with me. I'll supply booze and the cigarette lighter and you can test the gas
And if it all works out I'll cook you dinner. Whats your fav dish? (And don't say: Bomb Alaska!)
Mark
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30-08-2010, 12:32
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#41
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Registered User
Join Date: Oct 2008
Location: Northern British Columbia, part of the time in Prince Rupert and part of the time on Moresby Island.
Boat: 50-ft steel Ketch
Posts: 1,884
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Quote:
I think some of the girls on this forum have a Manometer!
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naturally!
__________________
'Tis evening on the moorland free,The starlit wave is still: Home is the sailor from the sea, The hunter from the hill.
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30-08-2010, 13:25
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#42
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Registered User
Join Date: Mar 2006
Location: Winnipeg
Boat: None at this time
Posts: 8,462
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Quote:
heres a photo on the new stove! INSTSALLED!!!!
(Don't dare notice the scratch on the varnish!)
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Sure is a pretty stove...
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30-08-2010, 13:46
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#43
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֍֎֍֎֍֎֍֎֍֎
Join Date: Apr 2006
Posts: 15,136
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So, Mark, perhaps you saw the episode of M*A*S*H where Radar is trying to mail home an entire Jeep, one piece at a time?
Congratulations on your new Swan! Only 49,617 more pieces to go! <VBG>
The deceptive thing about ferrules is that they look fairly durable. But they are in fact just like copper crush washers--designed to distort on installation, and be thrown away after the one use. (Or at best, the one location.)
If you ever do have to use flair fittings, even the $10 flairing tools will work. The big trick is to buy an extra two feet of copper tubing, and make a couple of practice flairs first, to get the knack of it. And to use a pipe cutter, for a clean level cut.
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30-08-2010, 14:03
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#44
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Nearly an old salt
Join Date: Jun 2009
Location: Lefkas Marina ,Greece
Boat: Bavaria 36
Posts: 22,801
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where I come from there known as "olives"
Dave
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30-08-2010, 14:27
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#45
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Senior Cruiser
Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 49,130
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From whence do you come, dave?
Ferrules/olive nuts/compression sleeves are synonymous terms for the same part.
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"
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