Drysuit Valve Placement

[scubadoo]

Hi,

Just wanted to find out if anyone had any recommendations on where one would have fitted the:

1. Inflator Valve - centre or centre right or left on chest.
2. Dump Valve - left arm cuff or right arm cuff or left arm shoulder.

Any preference in makes? Apeks or SI Tech? Recommendations!

[Gareth]

Assuming this is not a wind up.

Inflators

Generally Inflators have been placed in the center of the chest. This is an area easily accessable to the majority of individuals. Relatively free from equipment. Obvious to the buddy.
Some 'busty' individuals have difficulty with this becasue when pressing on the button (if stiff) the button doesn't operate easily.
The solution is to move the button slightly to left or right of the center line, again some find this uncomfortable, & the risk of the button being obscured by 'stab jackets/equipment' increases.

The other alternative is to fit the inflator on the leg. Often seen on older drysuits where the ABLJ would have obscured access to the inflator.
The other traditional alternative is on the hip or side - accress obscured by modern stab' jackets.

So Generally the center of the chest is preferred for the inflate.

Dump
There are two traditional types of dump
1. Cuff Dump
2. ADV (Automatic Dump Valve)

1. Cuff Dumps (the small round valve with a small piece of rubber acting as the valve).
These are fitted on the inside of the left or right cuff. They are fitted here because by raising the arm, it can become the highest point - allow air to migrate to the arm & dump through the valve. Or the arm can be lowered, stopping air from dumping.
The downside with cuff dumps is that if you wave your arms around or raise it accidentally you can start to dump air. You also need to positively raise your arm for the valve to be effective.

The position is fixed to either left or right cuff.

2. ADV
ADV ( A sprung loaded valve, the pressure can be adjusted by rotating the valve, the valve can be locked shut (fully rotated clockwise), or fully opened (fully rotated anti clockwise).
These are fitted to the highest natural point either the outside of the left or right shoulder (infact the arm just below the shoulder). This should be a position to which air will naturally migrate if slightly head up or vertically upright in the water.
The advantage of an ADV, is that, assuming it is correctly set, it will keep the ambient pressure constant inside the suit as a diver ascends, thus dumping air automatically as you ascend.
Most users of ADV roll slightly right shoulder up on ascents (assuming the valve is fitted on the right shoulder - convention), this is subconcious, this ensures air does migrate to the dump valve during the ascent.

Poorly fitted ADV's can be a pain, air migrates past the valve into an area above the valve . This is normally because they are fitted either to far down the arm or towards the inside of the arm. This makes dumping air difficult.

I hope this answers your question!

Gareth

[Roz]

When it comes to inflators and suit dumps the market is pretty much dominated by two manufacturers – SI-Tech and Apeks. The start of the Millenium saw both manufactures strive to design more streamline products, with the launch of the latest generation of low profile inflators and shoulder dumps.

I’ve not dived a suit fitted with a SI-Tech dump or inflator, so feel that I cannot crit their products fully. I am aware that the dive industry feels that SI-Tech does have an excellent reputation for manufacturing quality inflators and dumps.

One thing that you should note. As with your regulator having a matched First Stage, Second Stage and Octopus by the same manufacturer, your dumps and inflators should also match. So if you have a Si-Tech Inflator, you have a Si-Tech Dump. These two products have been designed and tested to work together.

The suits I dive are fitted with Apeks products, as supplied by the dry suit manufacturer. I do love the suit inflator. Thought went into the design of the low profile 350º swivel suit inflator, as the back is dish shaped to ensure it does not get so clogged with dry suit material. Another plus with this shape is that divers shouldn’t suffer from the occasional scratched nose when taking a back donning suit off. If you have never dived anything but a swiveling 350º suit inflator, you will not realize just what a boon this is. This unit gives you effortless, elegant hose routings.

Buoyancy redundancy has been considered as the inflator is fitted with a standard Shraeder valve which is compatible with most BC inflators. This means that if one LPI hose malfunctions, you still have the other hose that can be swapped between the suit and the BC. Redundancy is everything. Finally with the unit now sitting lower on the chest, the potential for snagging has been reduced. All in all a delight to use.

When it comes to the site of the dry suit inflator, you don’t always have a choice, so please do not give your manufacturer a hard time over this. Your suit arrives with the inflator fitted in the middle of the chest. The thinking being that it is easy to access for inflating. You should also be able to simply and quickly disconnect the LPI (in the unlikely event that it does stick open and continue inflating), and the button shouldn’t get snagged by the BC straps to stop accidental actuation of the inflator. However some manufacturers have thought about where hands need to go during chest compressions (heart massage), and this is normally where the dry suit inflator traditionally sits. If you have the option with your manufacturer, it’s worth donning your suit, then getting kitted up in your BC or Harness. Do up all the straps, cumberband and crotch strap and see where the best place is for you to locate your dry suit inflator.

When it comes to dumps, there are two main types – shoulder dumps and cuff dumps. A cuff dump is automatic and idiot proof, and approximately the size of a small Marmite lid. A cuff dump is normally located on the left hand arm, above the wrist seal. To vent air, the diver just raises their left hand. This can be a problem when teaching, deploying a DSMB (delayed surface marker buoy) or hanging onto a shot line, as you are involuntarily dumping air, and so your buoyancy changes. It also means that you can lose a “working” wrist. I like the freedom to have computers on both wrists. A cuff dump means that you can’t have a computer on that wrist as it will impair air flow. That said, this is a good option for new divers, because it is so simple to use.

I prefer a shoulder dump. It’s adjustable. By turning the dump valve you can control the degree by which the air is vented off. This means that I can screw it down to stop gas escaping, if I have a very long decompression stop. It can be set to automatic, so as you rise, the air inside the suit expands and thus escapes through the dump. Alternatively you can hold the dump down to allow more air to escape.

[Keith Lawrence]

Hi,

Just wanted to find out if anyone had any recommendations on where one would have fitted the:

1. Inflator Valve - centre or centre right or left on chest.
2. Dump Valve - left arm cuff or right arm cuff or left arm shoulder.

Any preference in makes? Apeks or SI Tech? Recommendations!Personally I like the inflator centre - I can easily find it and it's not going to be behind any stages/gubbings I might want to carry. I use an Apeks, what I do recommend is the swivel ones, it means that I can use different sets and just about any hose routing will work with it.

Dump valves - cuff or shoulder... every diver will have their own personal opinion :) I have always dived with a shoulder mounted auto-dump. Love it, dead easy to use, just flick your elbow out to get it to dump a bit more. Brilliant things when your left hand is otherwise occupied with a reel or some such. Some people loath them and prefer cuff dumps!

Final little tip - I used to suffer from leaky valves, I found that it was coming down the threads and getting past the sealing ring! To cure that one I have a reel of PFTE (Plumbers Tape) in my dive kit, a few winds of that around the thread has cured many a leaking dry suit value.

HTH

Keith L

[Ben Panter]

One thing that you should note. As with your regulator having a matched First Stage, Second Stage and Octopus by the same manufacturer, your dumps and inflators should also match. So if you have a Si-Tech Inflator, you have a Si-Tech Dump. These two products have been designed and tested to work together.

Roz,

The rest of your post is excellent but this bit is just plain wrong. The inflator acts only to increase the amount of air in the suit. It's a simple on/off, controlled by the diver. Nothing automatic about it. The autodump regulates the difference in pressure over itself between the contents of the suit and the water around it. There is absolutely no physical reason why you should not mix and match inflator and dump, be it auto or cuff.

Regulator matching is another question - personally I mix and match, but accept that there are physical/engineering issues why this might not always be a good idea - IP, flow rate etc. The issues are not the same for a drysuit.

Ben

[Roz]

Ben, perhaps you are not aware but dry suit inflators and dumps do have to match in order to comply with CE marking. They will have been through a series of stringent tests to achieve their CE mark. One of the key criteria tests is that the shoulder dump must be able to dump more air than the inflator is able to inject into the suit. So therefore mix and matching inflators and dumps from different manufactuers is not recommeded by the industry.

[Mark]

[QUOTE=Roz]dry suit inflators and dumps do have to match in order to comply with CE marking. One of the key criteria tests is that the shoulder dump must be able to dump more air than the inflator is able to inject into the suit.=QUOTE]

I'll have to remember that. Makes sense, but i'd not have thought of it. :cool:

[Nigel Hewitt]

Ben, perhaps you are not aware but dry suit inflators and dumps do have to match in order to comply with CE marking. They will have been through a series of stringent tests to achieve their CE mark. One of the key criteria tests is that the shoulder dump must be able to dump more air than the inflator is able to inject into the suit. So therefore mix and matching inflators and dumps from different manufactuers is not recommeded by the industry.I'm impressed.
That's even more stupid than normal.
I'll treat that like the usual daft stuff that comes out of the dive industry.
Vested interest wrapped up in long words to make it sound plausable.

[Ben Panter]

Ben, perhaps you are not aware but dry suit inflators and dumps do have to match in order to comply with CE marking. They will have been through a series of stringent tests to achieve their CE mark. One of the key criteria tests is that the shoulder dump must be able to dump more air than the inflator is able to inject into the suit. So therefore mix and matching inflators and dumps from different manufactuers is not recommeded by the industry.

You're quite right, I wasn't aware of that. Fair enough.

I'm usually sympathetic to such marking, but in this case I'm also a bit suspicious.

How does the criterea work? I can't image that the inflation rate is too close to the dumping rate for this kit. In fact if there has to be a difference, to make it reliably present I'd expect it to be big. So big in fact that an apeks dump with an SI-Tech inflate, or vice-versa, will still satisfy the criterea. Do they publish dumping and inflating rates?

How does this work for a suit sold without valves? Or a suit sold with valves that you fit yourself?

Ben

[Vic]

That's even more stupid than normal.
I'll treat that like the usual daft stuff that comes out of the dive industry.
Vested interest wrapped up in long words to make it sound plausable.

Indeed.

I tend to let others handle the CE-marking stuff,so I'm no expert on the topic, but I was certainly under the impression that you CE-mark "products", not "components"; as such it would be impossible to have the CE-marking of one valve reliant on the operation of another.

There is an argument that the whole drysuit is a CE-marked item, and therefore its qualification relies on the sum of its parts, but we're starting to get just a touch specious here...

Vic.

[Chris Cherrington]

I'm impressed.
That's even more stupid than normal.
I'll treat that like the usual daft stuff that comes out of the dive industry.
Vested interest wrapped up in long words to make it sound plausable.

Pahh... next you will tell me those nitrox fins in green are not O2 compatible.

Chris

[Roz]

Last year I wrote a three chapter article for Fins Magazine about the basics of buying a dry suit. (This is a glossy diving magazine from Ireland).

I'd written a couple of articles on buying dry suits about five years ago, but as part of my research I went back to the suit manufacturers and spent a lot of time with them doing background research, clarifying facts and looking at how suit manufacturing had moved on in half a decade.

Many aspects of suit manufacturing were covered, including dumps and inflators. These were discussed in depth, and this was where I was told by not one but several manufacturers that dumps and inflators should match, and why.

Vic observed he is no expert on CE Marking, and neither am I, so I cannot comment on whether you CE test/mark components or products. What I have observed is some of the preparation that a piece of diving equipment has to go through to achieve CE marking. These guys really have to jump through umpteen hoops as everything this scrutinised and documented to the enth degree.

I understand that the dumps and inflators are tested together and that the shoulder dump has to be able to dump more air than the inflator can put into the suit, however I can't quote you flow rates as I don't have them to hand. I would recommend therefore that if you really want to get full data on this you contact Apeks and Si-Tech direct, they should have the flow rates at their finger tips.

I would hope that if you are buying valves for a suit, that the retailer sells you a matching pair, ie both from the same manufacturer. Or if you are only buying one item, they will ask you who made the other component, to match accordingly.

I hope that this helps.

As for Oxygen compatible green fins, you have got yellow straps on them, haven't you? ;)

[Martyn Ward]

I have a reel of PFTE (Plumbers Tape) in my dive kit,

For the saddo's out there, (Nigel?), that's "Poly-tetra-flouro-ethylene".

Owzabout that then Guys an' Gals :D :D :D

[Nigel Hewitt]

For the saddo's out there, (Nigel?), that's "Poly-tetra-flouro-ethylene".You can't catch me out on plumbing.
I built two centeral heating systems over the years.
PolyTetraFluoroEthylene tape is stock in trade and cheap. Try B&Q.
It replaced soft plumber's string years ago.

The nicest gas seals I ever used were flat faced and you had a ring of soft gold wire that was compressed as you bolted them up. You could tell the tax payer was paying.