Air fed respirator & compressor CFM

[m5dkw82]

I have recently discovered that my 3m half mask does not protect me from isocyanates which I believe I have been spraying (2k) for quite some time, I have looked into respirators which do protect against isocyanates and non offer protection for the level I require.

(Gerson offer a half mask but they say it is not suitable for use in a contained area such as a booth)

Only thing for it, is to go with an air fed mask, may as well be the full face helmet.

One thing I can't get my head around is regarding the CFM, I know compressors are advertised with "x" amount CFM and 9 times out of 10 this number is not the free air delivery (FAD), so with FAD in mind I have been looking at various respirators, one of which says it requires 7 CFM and that the waist belt regulator drops the air pressure to 1 bar.

now, here is my question, If I get a compressor which is 9 CFM free air delivery and I run the mask which states 7 CFM, how quickly is the compressor going to empty itself, 50 litre V twin warrior 14 CFM displacement. (spray gun will run from 2nd compressor so eliminate that from the equation)


Thanks for any help

Dave

 

[eil]

That size compressor shouldn't have any problems keeping up for just the mask, wouldn't expect it to empty at all.

 

[m5dkw82]

Cheers, was hoping that be the case.

Is it a simple calculation, if you don't mind sharing the math, my next task is to consider changing over my guns, from HVLP to LVLP

looking to replace my Sata RP digital which is rated 10.3 cfm @ 29 PSI but my other compressor is an old clarke raider rated 14 cfm air displacement. (assume this would be about 9 cfm FAD)

 

[Daz1968]

I have a sperian full face mask, similar to the devilbiss one, I use a 3hp clarke se16c100 compressor and when just using the mask it runs about 90 seconds, then the compressor cuts in and runs a similar amount of time to replenish the tank. I did drop my cutout pressure on receiver to help with cooler running and it has not been a problem, I also use my devilbiss sri pro spraygun at same time but this is small air requirement so I can still work without worry of the belt whistle cutting in.