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HenryG
December 3rd, 2007, 07:29 PM
Does anyone know of any problem with using a Fire Service SCBA cascade system for filling SCUBA tanks. Our SCBA tanks fill to 4500 psi and the scuba is to 3000 psi. Seems to me like it should work with an adabtor that I have purchased, but some question if it can be done. I say if I can use the air in there to go into a fire I can use it to go underwater ... but, just in case, I figured I'd ask the forum.

waylander48
December 3rd, 2007, 08:07 PM
I used to get mine filled at the fire department all the time the only problem you should have is the the valves are different you will have to buy an adapter or a fill whip for SCUBA

Gary D.
December 3rd, 2007, 08:34 PM
We've been doing it for over 20 years. Just make sure the system is installed , filtered and maintained properly. We get less than 5% of our air through dive shops.

Gary D.

bridgediver
December 3rd, 2007, 09:37 PM
We do too.

One thing you need to double check is the air purity standards. Make sure that the values meet scuba. Some of the partial pressures which may be OK for ambient (or fire) may not be good for depth (or scuba). Especially mositure content and CO2

CBulla
December 3rd, 2007, 09:58 PM
I used to get mine filled off an SCBA setup for a while and I'm still alive to talk about it. I've since learned that more filtration might have been needed, but its to late to look back then and see.

Boater Dan
December 4th, 2007, 07:52 AM
As someone else stated, the filtration for diving air is greater than fire service air. I am going from memory (whichi is dangerous for me), but I believe diving air is Grade E and fire service is Grade D. Our compressor system had been check for air quality and was inspected to dive quality air.

Dan

bleeb
December 4th, 2007, 10:45 AM
As someone else stated, the filtration for diving air is greater than fire service air. I am going from memory (whichi is dangerous for me), but I believe diving air is Grade E and fire service is Grade D.

I don't know about the uses of Grade D, but dive grade air appears most often (but not universally) to be somewhere between E and 'E+'. The standards for diving air (or other gasses) aren't all that definitive and how a particuar compressor is operated is subject to individual decisions on the part of the operating organisation.

Here's a link with some background that I copied down from another SB discussion, although it's oriented a bit towards the LDS providing the gas: Fill Express -- Quality of Breathing Gases (http://www.fillexpress.com/library/gasquality.shtml)

mavdog
December 4th, 2007, 07:34 PM
We use our system to fill both scba and scuba tanks. We just updated (thanks to homeland security grant) to 4500 psi scba bottles but the compressor fills to 6000psi for the air bank. The tech that installed the system said that because of the hepa fillters we will have no problem with scuba.

Semper Fi

dittrimd
December 5th, 2007, 01:27 PM
Grade D for SCBA/fire fighting is right out of OSHA 29 1910 134 as is testing to certify air purity every 6 months. What I cannot find in OSHA is Grade E for SCUBA. Maybe that is just a NFPA requirement. I know that your compressor must have a certificate visible on the compressor from a qualified company that shows your breathing air quality test and grade as well as the date of your last inspection. This is a requirment for either SCBA or SCUBA.

Mark D.

mdjh51
December 5th, 2007, 03:08 PM
As long as your SCBA compressor meets the air purity standards for SCUBA you should be okay. Remember that firefighting takes place at ambient pressures while diving involves increased partial pressures. Hence the different standards in air quality. A benign contaminate at ambient pressure may be catastrophic at depth.

jumbo
December 5th, 2007, 04:39 PM
Ive done it a few times

jumbo

BladesRobinson
December 5th, 2007, 10:21 PM
There is extensive information that has been condensed to a four page PDF for your convenience. Please visit:

http://www.airsystems.com/Reference/CGA%20Air%20Grade%20Specifications.pdf (http://www.airsystems.com/Reference/CGA%20Air%20Grade%20Specifications.pdf)

In a nut shell, the dive industry recommends Grade E and the fire industry recommends Grade D.

A quick scan shows Grade D allows for O2 variation between 19.5 to 23.5 %

Grade E has allows for a small fluctuation, between 20 to 22 %

If the air is used for blending then the tolerance levels are more restricted. Many filling cylinders at the local fire department may find that the air is tested for Grade D compliance but would also pass the Grade E standard.

FYI only...

Blades Robinson

Desert Pirate
December 6th, 2007, 10:28 PM
Im a lil ignorant on this, I fill at our SCBA station 90% of the time, I dont know what the firestation compressor grade is, but if it is required to be grade D, will they only test it only to be certified to be grade D... or is it the same filtration test, were if it is greater, they would give it an E grade? If anyone knows, I dont want to open a door were ppl argue over how they do or should do these tests...

Boater Dan
December 7th, 2007, 08:02 AM
Desert Pirate: They should be testing the air on a regular basis anyhow even for Fire Service. I "believe" a testing company will only certify to what you ask for. So, they should ask to qualify the air to grade E if it is being used in a scuba environment.

Dan

bridgediver
December 7th, 2007, 10:06 AM
We need to do air purity tests twice a year on all breathing gases up here too.

When the test comes back it should give you all the levels of the test so it should be easy to determine what realm it falls into be it "E" or "D".

Firediver32
December 7th, 2007, 11:09 AM
I use ours all the time. We have our air tested quarterly and maintain it for grade E. As for the fill whip, I asked the service guy for a yoke adapter and he made me one for about 100 bucks. From what I can gather though (and depending on who you ask) Grade E is not ok for O2 blending so none of my tanks are o2 cleaned for nitrox.

Dan
Barnard Fire District, Rochester NY

Desert Pirate
December 7th, 2007, 04:18 PM
Boater Dan > They should be testing the air on a regular basis anyhow even for Fire Service. I "believe" a testing company will only certify to what you ask for. So, they should ask to qualify the air to grade E if it is being used in a scuba environment.

Bridge Diver> When the test comes back it should give you all the levels of the test so it should be easy to determine what realm it falls into be it "E" or "D".

ok... conflicting, but this is exactly my question, is the difference because your in seperate countries? I will ask our fire chief too, and post what I find out as well.
thanks,
Clay
__________________

bridgediver
December 8th, 2007, 09:41 AM
, is the difference because your in seperate countries?

Could be but I just asked the testing company for the data/print out when they send the cert. It's this data that they used to determine if its safe so they should have it somewhere

fireplug
December 15th, 2007, 11:51 PM
We have an Eagle Air for SCBA fills in our FD. One thing we have found when filling SCUBA tanks is having to remove the plastic boot on the bottom of 80 CF tanks. This allows the cylinder to fit into the blast chamber that must be closed and latched to allow air movement from the compressor or bank to the cylinder to be filled. I get real twitchy when I see someone filling a cylinder with a whip or a home made deal and the unrestrained & unprotected cylinder sitting in the middle of the floor. If a cylinder won't fit in our blast drawer it goes somewhere else to be filled.

Been dealing with "Won't happen to me, people" my whole career.

Desert Pirate
December 17th, 2007, 03:41 PM
Thats a good point Fireplug.. I have never done this, but have had ppl tell me that by puting the cylinder in a bucket of water will prove as a blast chamber as well. The tanks that are filled by our portable cascade system in our trailer dont have blast chambers, they fill from 5000 lb tanks through fill whips, and I have seen this done for saftey measures. I know the air out of this system is grade E... but I am more willing to chance the air from the FD than an absence of blast chamber in our trailer. reason why 90% of my fills come from the FD and not our cascade...
my question now is ... does a bucket of water form a blast shield? i dont see how, but Im not a scientist either.

this thread is making me think...
Clay

mavdog
December 18th, 2007, 10:49 PM
I thought the water was just to keep the tanks cool. less stress on the metal my LDS fills the tanks in water. We just use a whip for Scuba tanks. For SCBA they spin inside the machine. The old system the tank slid inside a container we had one tank pop the valve out taking the fill hose with it. It hit the ceiling scared the hell out of the firefighter that was filling it. We did have a new guy blow a preasure disc once filling another depts tanks 3000 lbs disc will not make it to 4500lbs.

bridgediver
December 19th, 2007, 11:45 AM
As water is realitively incompressable, an exploding tank inside of water will actually amplify the damage. In a sense it transmits the shockwave through the water to the vessel holding it and releases the energy there.

If you talk to u/w DMT the clearence they need to be from an explosion u/w is thousands of meters compared to a couple of hundered if on land

vshearer
December 19th, 2007, 04:54 PM
We have an Eagle Air for SCBA fills in our FD. One thing we have found when filling SCUBA tanks is having to remove the plastic boot on the bottom of 80 CF tanks. This allows the cylinder to fit into the blast chamber that must be closed and latched to allow air movement from the compressor or bank to the cylinder to be filled. I get real twitchy when I see someone filling a cylinder with a whip or a home made deal and the unrestrained & unprotected cylinder sitting in the middle of the floor. If a cylinder won't fit in our blast drawer it goes somewhere else to be filled.

Been dealing with "Won't happen to me, people" my whole career.

Same experience here, I have an AL80 that is 28.8" with the valve and no boot. That is about .25" too long to close the blast door on the mobile and stand-alone unit that our FD has. So the tank length may be a major issue. The more common AL compact 80's are 28.1".

Desert Pirate
December 20th, 2007, 11:07 AM
Bridge, that is what I was thinking as well, which is why you wont find me standing inside the trailer while they are filling tanks. I can remember as a kid putin firecrackers in a hole poked on the top of soup cans, watchin them jump... then you fill an ice cream can about half full of water, place the soup can in, and when it jumped, it went 4-5xs as high. It just dosnt add up as a saftey procedure to me. Now keeping tanks cool... it may help, but hopefully nobody is "flash filling" tanks anyways. It seems to me there is supposed to be a rule of thumb about 100 psi/min or something like that.
Clay

mavdog
December 20th, 2007, 12:48 PM
You guys are making me do some research now.
Scott Air System – Operational Guideline
The slower you fill the SCBA cylinder, the cooler you keep the
pressurized air. It is recommended that you fill the cylinder as slowly
as you can. The slower you fill the more air you will fill the cylinder
with. Increased temperature of compressed air displaces more
volume than does air at ambient temperature, hence once a hot filled
cylinder cools to ambient temperature, you will loose 10 to 25% of
your total volumetric capacity. In terms of minutes, on a 30 minute
bottle, this is almost 10 minutes of breathing air.

bridgediver
December 21st, 2007, 12:12 PM
Bridge, that is what I was thinking as well, which is why you wont find me standing inside the trailer while they are filling tanks. I can remember as a kid putin firecrackers in a hole poked on the top of soup cans, watchin them jump... then you fill an ice cream can about half full of water, place the soup can in, and when it jumped, it went 4-5xs as high. It just dosnt add up as a saftey procedure to me. Now keeping tanks cool... it may help, but hopefully nobody is "flash filling" tanks anyways. It seems to me there is supposed to be a rule of thumb about 100 psi/min or something like that.
Clay

IMO shops that fill tanks in a tub of water are old school. For the amount of time that the tank is in the water during a fill (even a slow one) the heat that the water will absorb is negligable - it makes no difference.
Also add to the fact that your obviously risking getting water in the tank from this process which is highly likely after multiple fills of a tank in this way

Yotsie
December 29th, 2007, 04:20 PM
We've been filling our tanks at our local FD for years. They keep their compressor in excellent working order and the certs on air grade kept up. This saves us a huge amount of time and money. We do fill slow, so as to keep heat to a minimum and the fill to a max. We have two adapters to fill both DIN and Yoke off their SCBA whip.

We will also fill and run our surface supplied rig off their "Light/Air" engine. They are very good about responding on our more lengthy recoveries. It's nice to be able to fill on scene, again at a slow rate.

This is one area were it pays off to be nice to our local hose draggers.... ;-)

Gil57usa
January 2nd, 2008, 12:36 PM
Our Fire Dept. has been filling our SCUBA bottles from the SCBA cascade for years with no problems. You just have to make sure the air is Grade E or better. Your air quality has to be certified and there should be a certificate posted at the compressor or cascade system.

iguana dan
February 23rd, 2008, 01:43 PM
1) refer to the US Navy diving manual chapter for scuba and air.
2) refer to nstm Ch074 vol 3 for grade d air standard.
3) refer to navy safety center. Opav 1500.19d
4) refer to US Navy diving manual.

Grade D air is safe for Scuba and it will not change partial pressures of the gasses. The only difference between Grade D air and Grade E is water and oil vapor measurments.

erich k
February 27th, 2008, 04:14 PM
Make sure you set up another line with regulator capped at 3000psi so no one screws up using your 4500# reg.
E

SCBASCUBA
February 13th, 2009, 12:09 AM
There is no mechanical difference between SCBA and SCUBA compressors. The difference lies in the grade of air desired for the diving you are doing.

Grade D - Historically used in FD operations. Less than 1000 PPM CO2. Current NFPA1500 requlations now recommend Grade E for FD SCBA operations.
Grade E - Typically used in diving to depths below 50 feet Less than 500 PPM CO2(Depth might be more Im rough on the details right now) .

However, most FD SCBA compressor systems will purifiy air to Grade E standards provided Grade E is available ambiently. Typical compressor purifiers do not filter out CO2, they will add CO2 when they convert CO (carbon monoxide to carbon dioxide) Normal purfiers that are designed to maintain a constant pressure of near 1800 psi even when not in use, will allow CO2 to impinge within the purifier chambers (hold like a sponge) If air pressure were to drop in the purifier chamber, the CO will release and travel down stream to storage in one sudden burst.

Keep in mind.
Air compressors must be operating to specification. Too much oil passing rings and burning off at valves will generate high concentrations of Carbon Monoxide. Performing purifiers will convert the CO to CO2, some CO will hold within the chamber if kept pressurized.

A CO monitor is now required on SCBA compressors. As Purifiers can become saturated, fail and allow CO to pass into your storage cylinders at anytime. Air good today can fail tomorrow and you wont know it unless you have a calibrated CO monitor sampling the air as it passes the purifier.

Another question I hope I can answer for this string. Immersing cylinders in water while filling is designed to dilute the blood that will fill the room if the the cylinder explodes, while any one is near by. Filling in water was thought to cool the cylinder during the refilling cycle. The heat generated during recommpression can distort your tanks cutting down on their life (early failure during hydrostatic testing) Tests found that filling in water did not cool the air within the tank enough to have a positive effect on cylinder life or the need to top off tanks when they cool. SCBA and SCUBA cylinders should be filled using metered air flow that limits pressure rise to 1500 PSI per minute. This will avoid hot fills, distorted and stretched cylinders and the need to top off cylinders when the internal air cools.

Always fill in an approved explosion proof fill enclosure. Its your life on the line. If a cylinder were to fail during refilling chances are good someone will be seriously hurt or killed. Even a blown hose at 5000 PSI can cause major bodily damage if it were to pass too close to your skin, ear, eyes or head. Dont take a chance on your life. fill safetly.

Finally, Is there anyone in florida that can give me information on companies servicing High Pressure Breathing air? We are considering opening a sales and service center in Naples or Punta Gorda area to service FD breathing air systems. dive too. Is there a need for a professional service center in the area? Do the companies providing this service meet the needs of the customers? We are in the beginning stages of information gathering and would welcome any information you can offer.
Thank you,
Fred

Steve in Seattle
February 18th, 2009, 04:18 AM
1) refer to the US Navy diving manual chapter for scuba and air.
2) refer to nstm Ch074 vol 3 for grade d air standard.
3) refer to navy safety center. Opav 1500.19d
4) refer to US Navy diving manual.

Grade D air is safe for Scuba and it will not change partial pressures of the gasses. The only difference between Grade D air and Grade E is water and oil vapor measurments.

Agreed. Compressed air is only good to depths of 6 or 7 atmospheres anyway... D is probably fine.

If SCBA was limited to 1000 ppm CO2 in the past, that's 0.1%... or 3 times the normal atmospheric level. At depth, it's only 0.006atm CO2 partial pressure at depth... about 1/3rd the threshold for symptoms to form. Considering we breath out 4% to 5% CO2, I doubt the 0.1% extra is worth worrying over. I wouldn't use it to feed a Nitrox mixer, but I doubt you'd even notice when diving on air alone... especially if SCBA's limit is now 500ppm.

That said, I'm curious what the CO limit for SCBA is... that may be a different story.


5.7.3 Cylinder Inspection and Maintenance
Cylinders should not be placed in a water bath for filling. The risk of water entering a cylinder while immersed in water and the resulting corrosion is potentially more hazardous than the risk of over-heating during filling... Water in a cylinder can create a particularly dangerous condition in cold water diving, since ice can form in the first stage or in the hose prior to the second stage valve, causing the flow of air to the diver to be interrupted.

Compressor purity is really more of an issue with Nitrox or other oxygen-rich mixing. NOAA requires less than 2 ppm hydrocarbons for their oxygen cylinders to avoid spontaneous combustion in ultra pure, high pressure oxidizer. Nitrox can be mixed without pure oxygen supplies using several methods, but higher than 40% O2 makes things more of an issue.

Some SCUBA fillers may accept 1500psi/min, but I believe the NOAA regs are for no more than 1000 psi/min to limit heating. Nitrox fills are limited to 400 psi/min while doing the air portion, but only 60 psi/min with pure O2. They also call for a top-off 30 minutes later once the gas has mixed and cooled.

Chapters 15 (nitrox) and 16 (mixed gas) in the NOAA Dive Manual cover this pretty extensively. Deep mixed-gas dives have serious concerns of gas purity (CO/CO2 being the main ones). Oxygen enriched gases have hydrocarbon concerns due to mixing... not really for dive problems.

RescueDiver2407
March 24th, 2009, 03:12 PM
We have two cascades here at my FD. One is a newer model that has the tall blast cabinet to fill SCUBA bottles and is rated "E". The other is our older one and you have to use a fill whip for SCUBA bottles, and I personally REFUSE to use that one. Remember, 80% of bottle failures are at the fill station (according to PSI).

I had to check, but PSI recommends a 300-600 psi/min fill rate for all bottles.


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