scuba tanks and firefighter tanks

[Kim]

Hi-
This is a curiosity question really. Does anyone know why divers wear tanks the opposite way round to firefighters? I have a Japanese friend who is a scuba instructor and a firefighter - when I asked him the question he said that the probable reason that firefighters wear theirs valve down is that it is then easier to access the valve. When I said - OK, so why don't scuba divers do the same? He didn't really know. I suspect that some people are going to talk about entanglement issues but in a world where for instance DIR divers use long hoses routed aroung their bodies I would have thought that this wouldn't have to be a problem. Does anyone know a concrete explanation? My mate and I are both curious!

 

[Diver0001]

Hi-
This is a curiosity question really. Does anyone know why divers wear tanks the opposite way round to firefighters? I have a Japanese friend who is a scuba instructor and a firefighter - when I asked him the question he said that the probable reason that firefighters wear theirs valve down is that it is then easier to access the valve. When I said - OK, so why don't scuba divers do the same? He didn't really know. I suspect that some people are going to talk about entanglement issues but in a world where for instance DIR divers use long hoses routed aroung their bodies I would have thought that this wouldn't have to be a problem. Does anyone know a concrete explanation? My mate and I are both curious!

Part of the answer is certainly in convention. Early regulators were designed such that the tanks needed to be mounted valve up. There was no other way. So the reason has a starting point.

Part of the answer also certainly lies in gravity. Fire fighters can't easily tilt a bit forward and have their tank slip a little further up their back for easy access to the valves. Under water this isn't such a problem.

And part of the answer is in available materials. Hoses are made in standard lengths (going back to convention) on the assumption that tanks will be mounted valve up. Mounting tanks valve down would require longer (special) hoses which are harder to route and aren't available at your dive shop around the corner.

Mounting tanks valve down also creates little problems associated with how to make it stand up and so forth but those problems would have been solved if there were any real benefit to doing so.

R..

 

[christopher1260]

I would say that part of the reason is that with a tank mounted valve down, it would be nearly impossible to doff your equipment when you get out of the water without hitting the valve and your first stage on something. Also, you would almost have to completely dissasemble your rig everytime you needed an air fill, which would be incredibly time consuming (this is more important for liveaboards, where you dive for a week without doing any more disassebly than removing your first stage for filling.) Most firefighters now use carbon fiber tanks, which are MUCH lighter than steel or aluminum tanks, and therefore easier to take off without slamming the valve into something.

 

[fdog]

I put on my Scott 4.5 about 3 times a day at work. I also had the pleasure of chatting with a member of the design team several years ago.

He indicated that they have no allegiance to any tank configuration. The overwhelming reason for the inverted tank is ease of use.

Every diver that I've seen try on a firefighting SCBA, and felt the valve, has expressed approval at the valve position. It appears there is just too much inertia for the "traditional" upright valve position.

Long hoses and valve protectors exist that enable the inverted tank. I can change out my SCBA cylinder way faster than on my SCUBA equipment. It's just inertia.

All the best, James

 

[pipedope]

If you look at commercial divers you will find the bailout bottles (often an AL80) worn valve down or valve up.

Dressing in and out with the help of a tender makes both ways work just fine without damage to the valve or regulator.

Personally I like my commercial rig valve down and my sport scuba rig valve up.