Vent for gas locker

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richardh10

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This came up recently but I can't find it now, so could somebody point me in the right direction for vents for a gas locker. I've got a hole in the hull blanked off, but obviously I need to stop the water getting in.

Thanks once again. Launch date now set for 2nd April so be prepared for a last minute deluge of questions/ramblings etc!
 
richardh10 said:
This came up recently but I can't find it now, so could somebody point me in the right direction for vents for a gas locker. I've got a hole in the hull blanked off, but obviously I need to stop the water getting in.

Thanks once again. Launch date now set for 2nd April so be prepared for a last minute deluge of questions/ramblings etc!
Click to expand...

Not sure that there is a requirement for a vent as such, only for the locker to be gas tight, apart from the drain, up to a point above the HP components.

However you should find all you need to know about lockers and drains in the BSS (chapter 7 refers to LPG systems) http://www.boatsafetyscheme.org/media/180428/bss guide 2005 complete web.pdf

Must point out that that link is to the second edition, but there are more recent guidelines for inspection elsewhere on the BSS website
 
PCUK said:
The gas locker must drain overboard from the bottom of the locker.
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The gas locker must be made from a material which will contain liquid gas and have a drain through the hull
above the waterline. ( I had to fit one after insurance survey- the boat initially had a double burner with the
camping gaz bottle hanging underneath) The lid may also be a requirement.
 
philwebb said:
The gas locker must be made from a material which will contain liquid gas and have a drain through the hull
above the waterline. ( I had to fit one after insurance survey- the boat initially had a double burner with the
camping gaz bottle hanging underneath) The lid may also be a requirement.
Click to expand...

"must be made from a material which will contain liquid gas" I must have missed that. Where does it say that?
 
VicS said:
"must be made from a material which will contain liquid gas" I must have missed that. Where does it say that?
Click to expand...

The biggest problem with many older boats is finding a location to have the locker above the waterline and deep enough to contain a cylinder and regulator. The requirement is just for the locker to be sealed from the accommodation and a drain overboard above the waterline. You can buy ready made containers, but often they are not the shape/size to fit your space, so you have to build a sealed locker in yourself and ply with the joints sealed with glass tape and epoxy is one way of doing it.
 
richardh10 said:
So presumably if I make a locker out of ply and line it with fibreglass, then fibreglass the locker to the hull, then that would be ok?
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I'm sure I've read somewhere that it needs to have a 5 minute fire resistance. Elsewhere, I've read that this means either that it needs to be made of "metal" or it can be fire-retardant fibreglass at least 5mm thick.
 
Avocet said:
I'm sure I've read somewhere that it needs to have a 5 minute fire resistance. Elsewhere, I've read that this means either that it needs to be made of "metal" or it can be fire-retardant fibreglass at least 5mm thick.
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The BSS:

7.4.5/R REQUIREMENT

Is the cylinder locker constructed of material of the
required thickness?
Determine the construction material of the cylinder lockers and estimate
the thickness of the cylinder lockers.
Cylinder lockers must be constructed of materials that are either
the same material and thickness of the surrounding hull structure; or,
metal of minimum thickness of approximately 1mm; or,
FRP of minimum thickness of approximately 5mm (1⁄4 in) thickness.
Note – a combination of wooden cylinder-lockers lined with FRP of
a lesser thickness than 5mm (1⁄4 in) may be estimated as equivalent.​
 
VicS said:
The BSS:

7.4.5/R REQUIREMENT

Is the cylinder locker constructed of material of the
required thickness?
Determine the construction material of the cylinder lockers and estimate
the thickness of the cylinder lockers.
Cylinder lockers must be constructed of materials that are either
the same material and thickness of the surrounding hull structure; or,
metal of minimum thickness of approximately 1mm; or,
FRP of minimum thickness of approximately 5mm (1⁄4 in) thickness.
Note – a combination of wooden cylinder-lockers lined with FRP of
a lesser thickness than 5mm (1⁄4 in) may be estimated as equivalent.​
Click to expand...

Apologies for dimwitedness but what is FRP?
 
PIPEWORK.

7.8.3/R REQUIREMENT

All LPG pipe joints must be accessible for inspection.
All LPG pipe joints must be compression fittings on copper pipework
or compression or screwed fittings on copper alloy or stainless
steel pipework.

The above is an extract from the BSS Essential Guide.
Personally I would not be using compression fittings for straight or elbow connections, it would be a yorkshire fitting every time. Less chance of leaks!
 
BERT T said:
7.8.3/R REQUIREMENT

All LPG pipe joints must be accessible for inspection.
All LPG pipe joints must be compression fittings on copper pipework
or compression or screwed fittings on copper alloy or stainless
steel pipework.

The above is an extract from the BSS Essential Guide.
Personally I would not be using compression fittings for straight or elbow connections, it would be a yorkshire fitting every time. Less chance of leaks!
Click to expand...

If they are following the BSS then soldered joints are not allowed.
 
VicS said:
Not dim-witted at all. I wondered what it meant. Fire resistant, or retarded, plastic....... I think

Or maybe just fibre reinforced plastic
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Nothing to do with fire resistance, it's a reasonably common alternative to "GRP" and just means ordinary fibreglass.

Pete
 
Although there are discussions in the BSS scheme about alternatives, their inspectors sometimes seem to wish to impose only their personal preferred interpretation - judging by posts here, even if those ionterpretations don't seem to us to match the BSS recommendations! There are a number of areas of the scheme which are obviously framed with only an inland boat in mind and may prove impossible to embody in an offshore cruiser which wasn't designed with these requirements in mind. Likewise the ISO standards contain details which may not be possible to implement retrospectively.

I was surprised that my gas locker actually seems to meet all the requirements of the BSS scheme as it is sealed from the bilges, has a lid and two drains of around 3/4 in overboard. Unfortunately, as the drains are holes through the stern overhang, a good choppy sea promotes geysers within the locker as the stern slams down onto a wave! I don't believe there is any requirement for a vent above the gas level, indeed the lid, while not entirely gas proof, might be expected to minimise the egress of gas into the cockpit should a major escape occur - forcing the gas to exit through the drains. Incidentally, a sister ship to my own has home made diffusers in the drains to stop the slamming problem. As the lockers have twice the recommended drainage, I shall be experimenting with a ball of net curtain in each this season to see if it keeps the content dry!

To design in a locker as a retrofit, the shape of the space available is paramount. If tall and thin, then bottles with regulators screwed on are OK, but if short and squat, a bulkhead mounted regulator and pigtails will better suit the height available. If starting from scratch, I would take a drain out through the transom and fill the lower part of the locker to make it effectively from the base.

Rob.
 
prv said:
Nothing to do with fire resistance, it's a reasonably common alternative to "GRP" and just means ordinary fibreglass.

Pete
Click to expand...
It's more general than GRP, it can mean any fibre in any resin, so could be carbon or Kevlar.
 
PCUK said:
If they are following the BSS then soldered joints are not allowed.
Click to expand...

On my own boat I will still be using welded joints regardless of the regulations until someone somewhere, inspector or otherwise can prove to me beyond all reasonable doubt that compression fittings are more suitable and less prone to leaking.
 
Yes, Bert, I don't blame you. But as the BSS has nothing to do with sea going boats (or common sense in many areas!) I don't know why people keep on about it unless they moor on BW or EA waters. And as for BSS "Inspectors", Easy money for no experience and little sense - or is that just the ones I've dealt with.
 
Gas locker

For line and verse on the gas locker situation look at "Tolley's Domestic Gas Installation" John Hazlehurst on Google Books pg147.
Regarding gas tightness the exact phrase is "be vapour tight to the boats interior" I consulted Calor Gas about the box, they told me the
standard and supplied the fibreglass box.
 
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