Is it safe to use a homemade breathing apparatus at like 5 ft?

[jboneng]

Sure you might be able to create a "safe" scuba/snuba/rebreather apperarus in your garage, if you know what you are doing (be very aware of the dunning-kruger effect), have a engeenering degree with speciality on regulator construction and design, expert knowledge on materials and tools used in manufacturing regulators for delivering breathing gas under water and also is knowledgeable in the field of hyperbaric physiology and the effects and dangers of breathing compressed breathing gas and so on.

It also depends on the degree of DIYism... create everything from scratch or buy the parts and assemble it.

I recommend you to take a scuba class to learn what equipment is needed to safely execute a dive.

this reminds me of this picture

 

[Lincoln Schick]

Reminds me of this video. It made me nervous reading the comments left by young kids. I worry about some kid trying this and getting killed due to pulmonary barotrauma because to someone who is not certified "Why would you exhale before/as you ascend if you are out of air?"

 

[2airishuman]

I know, did scubas are the lung popping devil, but I was wondering if it would be safe to use one in like a 5 ft pool.

No, but it's worth going over the "why," which is touched upon upthread.

Accidents and fatalities occur with some regularity involving shallow dives with improvised breathing equipment. There are three problems:

1) Most people doing this are untrained. They are unaware of the inherent hazards in diving, and do not know how to dive safely. (For trained, certified divers, it's such a simple matter to use standard SCUBA gear that any sort of surface-supplied system is only contemplated in very unusual situations, like dives in remote areas where air fills are unavailable, or very long dives in shallow water, or dives where SCUBA gear is not permitted or would attract undue attention)

2) There are a number of difficulties designing a system that delivers breathing-grade air, even at the lower pressures needed for shallow dives. The two most common problems are contamination of the air by internal components of the pump, particularly oil, and the presence of contaminants at the intake point for the pump, particularly carbon monoxide.

3) Even the best surface-supplied systems are not as reliable as SCUBA (i.e. self contained systems where you bring a high-pressure tank with you underwater). Homemade systems are typically less reliable. Even at four feet, an interruption of air supply can lead to an accident, especially for untrained divers.

Take a look at the Brownie's Third Lung surface supplied system to see what they do for safety. They are expensive systems, and training is included with their purchase. There are also some similar Chinese systems on eBay, and while I wouldn't recommend them, at least they have more attention to design than an improvised homemade system. Even the Chinese systems are more costly than a very basic SCUBA tank and regulator.

Good luck, and dive safe.

 

[TMHeimer]

We still haven't heard back from the OP as to what contraption he's got and why he's doing this. Maybe he got what he wanted and logged off....

 

[Subcooled]

As repeatedly stated above, the need for proper dive training cannot be over emphasized as lung injury (e.g. due to ascent while holding ones breath) is a real danger even at very shallow depth. In the following text though, I will describe equipment related dangers only.

Even if the home made breathing apparatus served canned breathing quality air (e.g. from a dive shop), you would still need to be able to build a pressure regulator that serves air exactly at ambient pressure. If your home made pressure regulator fails, someone dies.

If the breathing apparatus serves surface supplied air from a "low" pressure compressor through a hose, then the same precautions apply, and you must also make sure that the air is of breathing quality and does not contain carbon monoxide, carbon dioxide, oil, or other stuff. If the pump fails and the air starts to go back up along the hose (while the diver is at depth), then various unpleasant things could happen to the diver.

If you use an open bottom helmet, then overpressure is less of a problem as extra air can escape, but failure to pump adequately soon causes panic and carbon dioxide poisoning and hypoxia (and I am not saying that a sudden blast of 200 bar on top of ones head would be healthy, so manual pumps only). Also, stumbling and falling (or a failure of the pump) floods the helmet. In this case an inexperienced diver facing issues would panic, inhale water and drown. Finally, if the helmet is not well made but fails (e.g. the window shatters) then the diver is up for an unpleasant surprise.

I do not know what lubricants manual pumps use and what kind of oil or dust or other residue they leave in the air, so the air pumped might not be of the healthiest sort. The ancient manual pumps used with the Siebe-Gorman dress were made out of brass (I believe copper is antibacterial to some extent) and used vegetable oil as lubricant. I don't know how pure the air delivered was, but a $10 pump from China might not be as good...

Closed helmets come with even more hidden dangers (some of which are quite nasty).

I cannot guarantee that the above list would be exhaustive. There are probably many more dangers that I am unaware of. Hence, diving with home made diving equipment can be risky.

Attached you will find an image of historical diving using an open bottomed helmet and a manual air pump intended for car decks. The dive was a short demonstration dive only.

 

[EastEndDiver]

Simple answer to OP......NO

 

[CT-Rich]

The greatest pressure Change in diving in first five feet of water. If you did make a pool toy that was capable of providing clean, reliable breathable air you might feel that it was a mistake when you are held liable for some untrained user ending up in the hospital because of it. Either buy proper gear and training or don't do it. Diving is a very safe recreation, but only with training. Quality used gear is available at reasonable prices.

If you are talking about knocking around in 5' of water a mask and snorkel from target will work. If you want comfort the prices go up from there. Snorkeling is safe and cheap way to get started.

 

[TMHeimer]

The greatest pressure Change in diving in first five feet of water. If you did make a pool toy that was capable of providing clean, reliable breathable air you might feel that it was a mistake when you are held liable for some untrained user ending up in the hospital because of it. Either buy proper gear and training or don't do it. Diving is a very safe recreation, but only with training. Quality used gear is available at reasonable prices.

If you are talking about knocking around in 5' of water a mask and snorkel from target will work. If you want comfort the prices go up from there. Snorkeling is safe and cheap way to get started.

CT, yeah you are agreeing with my snorkel advice. But let's assume the OP actually has dive knowledge--such as don't hold breath and ascend from 5 feet. Guess I'd still ask why you would not snorkel....