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-   -   Propane box (https://www.moyermarineforum.com/forums/showthread.php?t=10033)

bobtookmm 03-03-2017 01:15 AM

Propane box
 
Is this good practice or are there real regulations? I wonder why a box is needed for a bomb proof steel pressure container anyway. The real risk is the hosing and other downstream attachments.

ndutton 03-03-2017 02:32 AM

1 Attachment(s)
Real regulations.

ABYC A-1 is attached, section A 1.12 addresses your question directly. The USCG adopts ABYC A-1 in 46 CFR §184.240(a) making the provisions federal law.

joe_db 03-03-2017 06:22 AM

The box is as much for controlling gas leaks as protecting the tank ;)

ndutton 03-03-2017 08:24 AM

What Joe said.
Propane is very similar to gasoline in that vapors are heavier than air meaning in the event of leakage they'll settle into an explosive pool in the bilge and the energy is only slightly less but comparable to gasoline. Propane storage tank pressures can range between roughly 30 to 200 PSI. Typical on board regulators are single stage that reduce the tank pressure to less than 1/2 PSI.

joe_db 03-03-2017 09:45 AM

Another thing - you cannot use a propane box INSIDE a boat. We got a propane job where the owner wanted a box inside the boat. We warned him, but did as requested. I did say we needed a surveyor to sign off to keep us from getting sued if he blew himself up.
The surveyor said no way no how and we then built a teak and stainless mount to keep the tanks on the stern rail overhanging the water. We got nice aluminum 10 pound bottles and it ended up looking OK.

Marty Levenson 03-03-2017 12:38 PM

minimal propane storage
 
A la one of Don Casey's books, I built a pvc tube with a sealed capped bottom end and a removable pvc top lid. It perfectly holds three one lb canisters stacked. It attaches to the stern rail, and has a 1/4" hole in the bottom of the outboard edge to vent fumes.

romantic comedy 03-03-2017 08:42 PM

I have a propane locker that holds 2 11 pounder inside the boat, in the cockpit locker. It is vented thru the hull.

Is this not legal?

ndutton 03-03-2017 08:54 PM

Quote:

Originally Posted by romantic comedy (Post 104655)
I have a propane locker that holds 2 11 pounder inside the boat, in the cockpit locker. It is vented thru the hull.

Is this not legal?

Read section A-1.8 (page 4) in the referenced ABYC A-1 standard to see if your LPG locker is compliant.

romantic comedy 03-04-2017 12:17 AM

Thanks Neil. Looks like I am compliant. Although I am not 100 percent sure. The locker is mounted on a hinge. It has to lay down in order to remove the cylinders. so maybe/maybe not.The locker was installed by the PO and was part of the pre purchase survey. As I recall, there was no issue with the locker on the survey. But that was a survey, lol.

I have been happy with it. Mostly what I have seen is propane bottles attached on the deck somewhere. Often they are at the rail or overhanging the water. i have also seen a few that were inboard and not vented.

joe_db 03-04-2017 10:31 AM

According to our surveyor, NO no way no how not even close :eek:
Those lockers were never intended to be gas-tight inside a boat. They need to open to the outside. Also even if they were 100% gas tight, if there ever is a propane leak all the propane dumps right in the bilge when you open it to change tanks. I didn't think it looked right when our customer wanted it mounted that way and it turned out I was right.
EDIT:
Installation:
Pressure Regulators
LPG LOCKERS

A-1.8.2.1
LPG lockers shall be installed so that the
locker opens only directly to the outside atmosphere, and
A-1.8.2.2
If a LPG locker is installed inside a boat
locker, the LPG locker shall be located as high and as close
to the boat locker’s opening as possible in order to comply
with A-1.8.2.1.
A-1.8.3

Our surveyor assumed that 18.2.2 meant the locker itself was not connected to the interior of the boat. I think you could make a case this rule does not exactly say that, but I have never ever seen any production boat with propane inside the boat ever. 100% of all propane lockers I have ever seen that were from the factory only opened to the exterior of the boat with a few exceptions where there was a larger locker that was sealed from the interior itself, in essence a big propane locker, and the smaller propane locker inside it was mainly to keep things from hitting the tanks. This is actually a nice kind of locker to have to store other flammables like gas cans* for the dinghy or acetone.

* total thread creep, but I was aboard a Cabo Rico 38, got a lecture about the extreme danger of gasoline engines, and then the skipper climbed down in the engine room to fish out a Clorox bottle of gasoline for his dinghy and we also had water on for coffee on the propane stove :rolleyes:

Quote:

Originally Posted by romantic comedy (Post 104655)
I have a propane locker that holds 2 11 pounder inside the boat, in the cockpit locker. It is vented thru the hull.

Is this not legal?


romantic comedy 03-04-2017 06:43 PM

Interesting. Is it not possible to have a legal propane locker in the boat?

ndutton 03-04-2017 07:02 PM

Can you please post some pictures of your propane locker?

captainmurph 03-05-2017 09:31 AM

Quote:

Originally Posted by romantic comedy (Post 104663)
Interesting. Is it not possible to have a legal propane locker in the boat?

It is possible to have a legal propane locker inside the boat. If a surveyor says it is not, he is erring on the side of safety. That is certainly not bad but it is not an accurate interpretation of ABYC standards.

The standards are very clear about the need for the locker to be vapor proof and have venting outside the boat in a specific way. The lockers that may be purchased to install directly (as expensive as they are!) will meet the requirements as long as the venting is done according to ABYC standards.

If one wants to mount LPG on the stern pulpit or elsewhere on the exterior, they should still be cautious on any possibility of vapors settling into any opening into the boat.

bobtookmm 03-26-2017 07:36 PM

re:
File Type: pdf ABYC A-1 Propane.pdf (75.8 KB, 69 views)

Good Grief

looks like the big can goes on the rail.

Are the camp stove pound size subject to this to this tome?

ndutton 03-26-2017 08:56 PM

Quote:

Originally Posted by bobtookmm (Post 104960)
Are the camp stove pound size subject to this to this tome?

Yuuuuuuppp!

romantic comedy 03-27-2017 01:06 AM

1 Attachment(s)
Looks like I missed a request.
Here is a picture of the locker looking in the cockpit locker. It hold 2 11 pounders. It is mounted on a platform that hinges to allow the locker to lay down so I can remove the top and access the cylinders. The deck plate gives me access to the valve for the inboard cylinder. There is the usual solenoid for the hoses and vapor sniffer and alarm. There is a vent at the bottom, that was molded in. It goes to a thru hull above the water line. The PO installed this locker. I added the deck plate.

joe_db 03-27-2017 09:29 AM

That is pretty much identical to what our surveyor said would never be able to be insured. If there is a propane leak, as soon as you open that container you have a boat full of propane :eek:

romantic comedy 03-27-2017 09:39 AM

That is good to know. I wonder if any propane installation meets specs.
I would guess the propane would drain out the thru hull. But also a top vent would help to let air in and propane out.

I was never sure of the locker, that is why I put the deck plate in. I turn it on when I needed it and off when I am done. Of course the tank can vent or leak.

joe_db 03-27-2017 09:53 AM

A tiny slow leak will go out the drain. Anything but the tiniest leak will produce some pressure, which might get past the seals on the top. Propane is heavier than air, but not by much and gasses diffuse. It is not like a water tank that can only leak out of the top if the drain is clogged.
If the tank has any kind of major leak at all, large quantities of propane will be coming out of there the second the top is opened. Speaking of which, that access port was never designed to hold back explosive gasses.

ndutton 03-27-2017 10:05 AM

1 Attachment(s)
I think if the top opening were at deck level rather than inside the boat combined with the overboard bottom vent you'd be good, at least arguable. Here is a poor picture of a compliant locker showing the top opening open above deck level. My friend's Ericson is configured the same.

As for the small 1 lb. containers, storage in a foredeck anchor locker meets the requirements at least in spirit.

joe_db 03-27-2017 03:00 PM

That is how all factory propane locker are set up that I have ever seen, they open to the exterior of the boat, not inside of it.

romantic comedy 03-27-2017 11:45 PM

Opening to deck or cockpit level would be a better way to go.

I dont see how any pressure could build when the locker is vented to atmosphere. If there was a catastrophic failure I could see some pressure momentarily.

I am not trying to defend my locker. The locker is sealed with an oring that is not really air tight and the locker is flexible, so it is not air tight. The thru hull would be underwater when heeled.

are the new installations vented at the bottom? I assume that they are cockpit lockers, and any spillover would go into the cockpit?

ndutton 03-28-2017 12:41 AM

Quote:

Originally Posted by romantic comedy (Post 105014)
are the new installations vented at the bottom? I assume that they are cockpit lockers, and any spillover would go into the cockpit?

Vented at the bottom, yes. The vent goes through the hull, not into the cockpit if that's what you meant. Section A-1.8 on page 4 of the ABYC reference in post #2 of this thread addresses the locker installation in detail.

joe_db 03-28-2017 09:32 AM

What does it do then :confused:
I *tiny* leak *might* drain out the bottom, but as mentioned earlier, gasses are not water and you will have propane leaking out of that thing if you have a leak of any significance.. I would be buying a gas detector ASAP and/or moving that tank outside.

Quote:

Originally Posted by romantic comedy (Post 105014)
Opening to deck or cockpit level would be a better way to go.

I dont see how any pressure could build when the locker is vented to atmosphere. If there was a catastrophic failure I could see some pressure momentarily.

I am not trying to defend my locker. The locker is sealed with an oring that is not really air tight and the locker is flexible, so it is not air tight. The thru hull would be underwater when heeled.

are the new installations vented at the bottom? I assume that they are cockpit lockers, and any spillover would go into the cockpit?


romantic comedy 03-28-2017 11:00 PM

All good info.
I have a leak sensor in the locker and one in the bilge.

Right now I have the locker out of the boat as I am doing all sorts of repairs and maintenance. I think I can live with my installation, but it certainly is not perfect.


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