Air Fills from a Volunteer Firehouse

[Firefyter]

Many grades of air are available.

http://www.stallionair.com/airtest.htm

That's a pretty good resource, but outdated as far as the NFPA numbers are concerned. NFPA now uses NFPA 1989, because they recognized the confusion caused by differing standards. NFPA 1989 is the same standard as the NFPA Grade E, with the exception of the O² content. 1989 still has the content ranging from 19.5% to 23.5%. All the other levels remained the same.

As I said earlier, if they're adhering to NFPA 1989 as they should, it's every bit as good as LDS air. My question is, how many of you that are so worried about this regularly check the compressors and test results at the LDS? I know I've seen several shop compressors that were in terrible shape, yet divers buy from them with no hesitation. Just something to ponder......

 

[Nudgeroni]

Again this has to do with depth that divers get vs. fireman... the deeper you go, the more gas you will consume... so at 33 ft roughly you'll be getting 50ppm of methane if the gas has 25ppm at the surface... 75ppm at 66 ft. and 100ppm at 99ft...

I don't think that concentration under depth has anything to do with it. From what I found on exposure levels of methane, 25ppm is a very low threshold. OSHA has no methane exposure limit, it is simple asphyxiant.--

edit: With Firefyter's post, this seems to be moot anyway.

 

[Hemlon]

I don't think that concentration under depth has anything to do with it. From what I found on exposure levels of methane, 25ppm is a very low threshold. OSHA has no methane exposure limit, it is simple asphyxiant.--

edit: With Firefyter's post, this seems to be moot anyway.

 

[AndyA]

I don't think that concentration under depth has anything to do with it. From what I found on exposure levels of methane, 25ppm is a very low threshold. OSHA has no methane exposure limit, it is simple asphyxiant.--

edit: With Firefyter's post, this seems to be moot anyway.

FYI Make sure you have a real good dive buddy, you will need one if you continue. Please talk to someone local that is experienced, also there are some good dive theory books "Get One"!!!!!

 

[Nudgeroni]

FYI Make sure you have a real good dive buddy, you will need one if you continue. Please talk to someone local that is experienced, also there are some good dive theory books "Get One"!!!!!

er, I don't follow. Please clarify.

 

[Hemlon]

FYI Make sure you have a real good dive buddy, you will need one if you continue. Please talk to someone local that is experienced, also there are some good dive theory books "Get One"!!!!!

.

 

[bmcsteve]

It has a lot to do with partial pressure of gases and how they increase exponentially at depth. I agree that you should do some reading on gas laws.... but I also agree that if the FD is adhering to NFPA 1989, you should be ok. I am a firefighter and have been considering this myself, when and if I ever buy my own tanks.

 

[bane51031]

I am on the Sherriff's dive team here in town, and we are fortunate to have the backing of the Fire dept., they are tasked with our shore support on scene if needed and we can fill directly from the cascade off the main truck if needed, we are able to fill our teams tanks and I am lucky enough to have my personal tanks filled as well at the fire station. As far as a filling tanks for someone off the street in our town that would be a no go due to the liability issue, it does save me money by not having to pay for fills but, if you consider the time I volunteer to our team the cost of air fills is a drop in the bucket to the compensation I recieve but, I don't do it for the $$$.
You might want to see if there is a Sherriff's or Fire dept. SAR dive team and help out with shore support, lugging gear and such, they may need the help and it would be good experiance for you too.

 

[Nudgeroni]

It has a lot to do with partial pressure of gases and how they increase exponentially at depth. I agree that you should do some reading on gas laws.... but I also agree that if the FD is adhering to NFPA 1989, you should be ok. I am a firefighter and have been considering this myself, when and if I ever buy my own tanks.

Ah, thank you for the straight forward response. Here was my reasoning: 25ppm=.0025% or a partial pressure of .0025atm. Even at 130ft, the partial pressure goes upto .0125atm. True, I was off base by changing the ppm rather than referring to partial pressure, but my point was that an asphyxiant at that concentration is not a problem.

 

[Nudgeroni]

You might want to see if there is a Sherriff's or Fire dept. SAR dive team and help out with shore support, lugging gear and such, they may need the help and it would be good experiance for you too.

Thanks for the idea. I would love to volunteer some time our with the local SAR folk.