Supplied-Air Respirator On the Cheap?

Mac · February 18, 2005, 07:56:55 PM

I found this today in a catalog I get at work. Check out

www.conney.com
Then: respirators
Then: supplied air
Then: Allegro disposable and low press. adapter

Suppose a feller was to rig one of these hoods and low pressure adapters (total cost under 60 bucks) to a small compressor - regulator - filter, set up outside the spray booth / shop?

Sure it's a "disposable hood" but might just be the ticket for us hobbyist - one project use.

What am I missing here?

Well, looks like the link doesn't last due to the secure nature of that section of the site. Here's a pic:

EMSjunkie · February 18, 2005, 09:09:02 PM

Looks like a good deal for a DIY'er. just be sure your air supply has enough volumn and flow to "wash out" the exhaled CO2. if not, you are gonna re-breathe your exhaled air, and that isn't good. makes you go to sleep and not wake up. make sure there is no way for cross-contamination, especially if using a gasoline powered air compressor. don't want to draw in unwanted fumes, then force feed them to yourself

just my 2 cents worth.

Vance

Mac · February 18, 2005, 10:38:22 PM

So does anybody know what CFM a human runs at?

1FATGMC · February 19, 2005, 12:09:01 AM

Quote from: "Mac"I found this today in a catalog I get at work. Check out

www.conney.com
Then: respirators
Then: supplied air
Then: Allegro disposable and low press. adapter

Suppose a feller was to rig one of these hoods and low pressure adapters (total cost under 60 bucks) to a small compressor - regulator - filter, set up outside the spray booth / shop?

Sure it's a "disposable hood" but might just be the ticket for us hobbyist - one project use.

What am I missing here? Well, looks like the link doesn't last due to the secure nature of that section of the site. Here's a pic:

I would post the question on the autobody site as I think this has come up over and over on that board.

But I believe you can't use a regular compressor that has oil in the crankcase as it can get into the air you are breathing and that is not good. Now I think they make filters to take care of that, but I don't believe they are cheap. You also need to buy the air hoses and and a regulator that is out at the end of the hose where you are to drop the pressure. The Hobby Air uses a large hose from the compressor to you. I tape an air line for the gun to the supplied air hose to keep it all straight when I'm painting.

Also if your compressor is barely able to keep up with your gun on an "over-all" paint job. like my 5 hp, then you can't afford to lose the air going to you and not the gun. So now if you have to buy another compressor, regulator, hose and a special filter to use that hood you are probably about the same cost as a Hobby Air.

I'm not saying it won't work and I like to make things myself instead of buying them, but this is one case where I thought I would be better off to bite the bullet and buy a proven product.

I spent about $30-$50 more on mine to get the one that is suppose to support two people. I also got two 25 foot air lines and it was all just a little more than $450, but that was a couple years ago and I don't know the current prices.

c ya, Sum

purplepickup · February 19, 2005, 01:51:07 AM

Quote from: "Mac"So does anybody know what CFM a human runs at?

You aren't pumping the air right into your lungs....you're just creating a positive air pressure in you hood so that the fumes can't get in and you are breathing fresh air. The fresh air system I've got sounds almost like a vacuum sweeper. I always wondered if a clean, new shop vac would be able to supply the air. They have a particle filter and there isn't any oil vapor.

Crosley.In.AZ · February 19, 2005, 10:56:26 AM

One item you have to watch for is dehydration.

Most cases you are not using the system for very long, but the dryer air will cause a person to dehydrate if you are not careful

EMSjunkie · February 19, 2005, 07:41:49 PM

Quote from: "Mac"So does anybody know what CFM a human runs at?

If I remember my book lernin' it should be around 600 to 700 cc's per breath for the average adult human male. more during hard acceleration

operating pressures are around 40-45 torr.

Vance

Mac · February 19, 2005, 09:25:09 PM

Thanks for all the responses folks.

Sum's probbly right that trying to cobble something up would end up being an exercise in "tail chasing". I certainly don't want to *-fixiate myself.

Unlike the Hobby-Air unit that uses a turbine, this system from Allegro uses what looks to be a conventional compressor (although oil-less no doubt) rated at 3/4 hp for the 1 man model. The hose adapter for the disposo-hood talks about use for a 2-40 psi supply. Besides the stationary 7hp compressor I'd use for my paint gun I have a smaller portable one that I figured could be parked outside the shop for the supplied-air hood. That's what gave me the idea that maybe with just a regulator to dial down to the 2-40 psi range and a filter on the output side could work.

bowtietillidie · February 20, 2005, 09:38:58 PM

I have followed this post with great interest . I feel I must put in my two
cents . I am a retired boilermaker so I have had a lot of experience around fresh air breathing equipment. I can not stress what I am about to say strong enough !!!!!!!!!!!!!!!! DO NOT CUT CORNERS WITH BREATHING AIR!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! The dangers of this are in the area of clean air . I was placed in a fresh suit while working in a refinery the compressor was putting oil into the system ( This system had been checked by our boilermaker safety man and the refinery) About a mount after the job was complete I started to have trouble breathing after doctoring for several weeks it was found that I had a fungus growing in my lungs . I took one helluva long time to clear this up . I still am short of breath when I work hard for any length of time. Now for the good news. You want clean air to breath for cheap , go to your oxygen
supplier ask for a bottle of Hospital grade oxygen while there ask about a regulator for Breathing AIR hook this up to your hood turn on the air
set it to what you feel is right for you . Now put some Sweet and Low in plastic bottle squirt this around where the hood meets your shoulders chest and back also around the valve that controls the air you breath out.
If you start to cough or you can taste the sweet and Low Stop and find the leak also turn up the air pressure test again till there are no leaks.
I have also read that some people think charcoal filters will filter out the harmful particles while painting NOT TRUE Charcoal removes smells not particulate(spelling) matter Go to 3M site and do some serious reading

parklane · February 21, 2005, 12:05:26 AM

My son & I were talking about this fresh air thing, and he suggested using a "scott air pac" which is what firemen use, or scuba tank & reg. You could leave the tank in one spot, and run a hose to the reg in your mouth. A refill is only $6. and will last a lot longer than 1 paintjob. We already have the scuba gear, but you should be able to buy it on the cheap for an old set. Just a thought.

John

bowtietillidie · February 21, 2005, 01:12:08 PM

The Scott air unit is a very good unit. But you may find that strapping it on your back and painting to be a chore. I need freedom of movement
to paint . This is why I like using the hood and a long hose to supply air
Your mileage may differ

parklane · February 21, 2005, 09:04:11 PM

Yes, I agree with the fact that hanging it on your back wouldn't be the most comfortable thing to do. I was thinking more along the line of having it in one spot and having a high pressure line running to the reg/mask. that way you are not restricted, but one fillup of air would still go a long way.

John

Beck · February 22, 2005, 12:18:17 AM

The SCOTT won't work for painting. I suck one of the 2.2 bottles empty in about 15 min. when working. They are available in higher pressure also. This is the fire gear stuff like you said. Some of the older 2.2 aluminum bottles could probably be picked up from departments upgrading to the fiber high pressure bottles. This gear doesn't come cheap though. I have a hard enough time painting with a respirator. There is no way I could do it in an air pack. The face masks like to fog up at the worst times. They only have one great use -- putting the wet stuff on the red stuff. (That's fireman talk).
Beck

bowtietillidie · February 22, 2005, 01:30:47 AM

The Scott pac's that I have used have a bell warning system and they don't last very long. This gave you time to get out before you ran completely out of air. We didn't use these very often ( good for inspecting damage then get out when or before the bell rang. We ( boilermakers)
used a self contained suit and hood with air supplied from out side of the work area via a battery of oxygen bottles full of hospital grade air. This system still had the bell system plus a small two way radio to let us know what was going on outside also if we got in trouble we could holler for assintance. All thought you would not need all the bells and whistles
in your garage/paint booth. btw The last time I checked on hospital grade oxygen (220 cu ft 2200lbs ) was seventy dollars for thirty days
than you pay demerage on the bottle till it comes back to the dealer. Prices may be different in your area. This seems cheap to me in just the piece of mind knowing I am breathing clean air . Another thought , buy the bottle it's there when you need it . It takes up very little space. Buy some tyvex paper suits and gloves along with your hood regulator and hose. You now have a very good and safe paint system .