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SCBA tank

Posted: Wed Oct 14, 2009 7:02 pm
by deathbyDWV
I found this tank on ebay for what i think is a great price. I have a couple of questions though. I did search for answers but couldn't find much.

http://cgi.ebay.com/SCBA-Sigma-Survivai ... 35a432e262

Answers don't have to be specifically for this model, just for this type of tank.

Does anyone know the size or pressure rating of these tanks?

How hard would it be to attach an npt fitting? Would i need to weld it?

Would this be good for a refrigerator compressor tank?

Any answers are appreciated. :)

:D Thanks in advance!!! :D

Posted: Wed Oct 14, 2009 7:22 pm
by twizi
great tank when was it hydrod doesint matter really becuse your frige will go to 1000psi but those tanks are rated to 4500psi it should be perfect
no u dont need to weld i would et a paintball adapter then it would attach to 1/8

Posted: Wed Oct 14, 2009 7:24 pm
by Technician1002
SCBA stands for Self Contained Breathing Apparatus. The tanks come in 2 styles, a standard version and a higher capacity version. OSHA requires a recertification every 3 years. The standard tank is filled to 1800 PSI and holds enough air for 15-30 minutes of breathing air. I don't remember the pressure on the higher pressure version, but they are built like a SCUBA tank. Due to the operating pressure, they are no problems for anything a refrigerator compressor can dish out.

Most standard tanks are aluminum, so no welding. Some extended tanks are heavier aluminum or steel.

If the tank is a newer one the valve contains a pressure gauge so the tank pressure can be checked before grabbing the equipment to use it. At work, we are not permitted to use any that has fallen in pressure below 1500 PSI.

I am a member of the Emergency Response Team at work, so I am certified to use this equipment.

These tanks are basically SCUBA tanks and a regular dive shop can refill them. Finding the regulator fittings for a SCUBA regulator will fit these tanks. It is not recommended to remove the valve. They are very tight and require proper tools to get them loose. For this reason, I have no idea what the tank threads are. A dive shop may be able to answer that question.

@ twizi, Don't overfill the standard tank. They have a max on the gauge of 2500 PSI. 4500 PSI is not safe. Only the extended tanks have a top pressure of 4500 PSI, but I believe they are only filled to 3800, but don't quote me on that. I'm not sure what they fill those to.

Posted: Wed Oct 14, 2009 7:30 pm
by deathbyDWV
That is great!!! Thanks so much. Do you know the approx. volume of these tanks? Also what kind of paintball adapter were you suggesting?

Edit: I'm a super slow typer. I didn't see tech's post.

How big is the valve connection on the top?

Could it be cut off and rethreaded?

Posted: Wed Oct 14, 2009 7:56 pm
by rp181
Any kind of modification is not wise for high pressure vessels. buy a normal adapter.

Posted: Wed Oct 14, 2009 7:58 pm
by Technician1002
deathbyDWV wrote:That is great!!! Thanks so much. Do you know the approx. volume of these tanks? Also what kind of paintball adapter were you suggesting?
There are five main markings on a scuba tank:

1. Last Test Date
2. Testing Station Stamp
3. Working Pressure
4. Test Pressure
5. Water Capacity

Ask the seller for all the tank markings. Water capacity is the amount of water the tank can hold if it is filled with water. The volume of water is given by it's weight in Pounds. So volume will be about 1 gallon for each 8.35 pounds.

There are several brands of tanks so there are a couple valve variations. The yoke mount used in SCUBA is most often not used on SCBA. SCBA tanks most often have a valve with a threaded port in the side of the valve that a hand wheel fitting with an o ring screws onto. The hand wheel is for rapid tank changes without using any tools.

The paintball adaptor most often fits the yoke style valve on a SCUBA tank. You will need to write the seller to get details on the tank valve to find if it is yoke or DIN. I can't tell from the crappy photo.

Edit This page has info on the tank threads.
http://www.divegearexpress.com/library/valves.shtml

DIN and yoke fittings are in this page.

http://www.ukrecscuba.org.uk/ukdiver/din/index.html

Info on the low pressure tanks is here.
http://www.labsafety.com/SCOTT-Low-Pres ... irect=true

Image

All suited up ready to shut off the leaking Chlorine.

EDIT
The cylinders I use have the DIN fitting that looks like this;
Image

Posted: Wed Oct 14, 2009 8:05 pm
by deathbyDWV
Thanks tech. You seem to have great info on everything. I am very greatfull. :D

Re: SCBA tank

Posted: Wed Oct 14, 2009 10:34 pm
by velocity3x
deathbyDWV wrote:How hard would it be to attach an npt fitting? Would i need to weld it?
Not hard. It a simple job for a machine shop.

Posted: Wed Oct 14, 2009 11:11 pm
by deathbyDWV
That is really how i think i'll do it velocity3x. My uncle has a machine shop, my grandpa has a lathe, and me and my dad have things like a drill press and other normal tools.