Gas monitors/detectors and respirators

glassblaze · #1 2007-04-02, 8:33am

I have been having trouble with ventilation and although I have done everything I am supposed to do I still get lightheaded and sick when I work so I have decided to invest in a detector. I found one that detects O2, calculates CO2, CO sensor (0 to 4000ppm), NO/NOX sensor ( 0 to 4000ppm) and was wondering if there is anything else I would have to consider that the torch gives off? Also, does anyone know of a reasonably priced monitor I can get online? This one I described above is about $4000 (ouch).

Also, are there respirator masks that can protect from NOx?

Thanks for your time!

MikeAurelius · #2 2007-04-02, 8:54am

No -- a respirator is not designed to handle contaminated air issues, only particulates such as dust. The only thing you can use to deal with NOX is a SCBA (selfcontained breathing apparatus) similar to what firemen wear. I don't recommend it. NOX is better dealt with by proper ventilation.

You really don't need to invest in an expensive detector.

Can you describe your existing ventilation system and I can try to diagnose what is going on.

glassblaze · #3 2007-04-02, 9:02am

Here is a pic of my current system. The propane tank is kept outside and under the bench I keep my oxygen concentrator. Behind me about 6 ft is is a door to the outside always kept wide open and a little fan blowing fresh air in. The fan in the box blows outside at a rate of about 1300CFM. The "hood" opening is 3 feet long by 2 feet high. The torch is a few inches in the hood. This seems like it should work from everything I've read but it isn't doing the job

glassblaze · #4 2007-04-02, 9:04am

Oh and before you mention that the box is wood and flammable I should mention I have some sheet metal on order from my hardware store to line the walls with

Dale M. · #5 2007-04-02, 9:47am

Quote:

Originally Posted by glassblaze

Here is a pic of my current system. The propane tank is kept outside and under the bench I keep my oxygen concentrator. Behind me about 6 ft is is a door to the outside always kept wide open and a little fan blowing fresh air in. The fan in the box blows outside at a rate of about 1300CFM. The "hood" opening is 3 feet long by 2 feet high. The torch is a few inches in the hood. This seems like it should work from everything I've read but it isn't doing the job

IF things are as you describe, vent system should suck everything out including all the heat from your torch and even you (just kidding but its a lot of air movement).. Are you sure vent fan is 1300CFM and not 130 cfm?

I can see through fan that exhaust is direct to outside so there does not seem to be any exhaust obstruction unless fan is up against some glass....

Dale

glassblaze · #6 2007-04-02, 10:08am

Ya I feel this should be adequate too which is why I'm so confused why it is not working. The specs of my fan are here: http://www.seabreeze.ca/fans/TurboAire/turboaire.html

Basically it says that on high it should be 1350CFM at 2 inches and over 800 at 10ft from the fan. My torch is only a few inches away.

I was torching in the winter months and had a few scares because it was cold so I wasn't allowing enough input are and so didn't start again until a couple weeks ago. I was feeling dizzy and my fingers and lips were tingly but I figured I was psyching myself out because of my scare in the winter. Anyways I ignored the warning signs then yesterday came seconds from passing out before running outside for fresh air. Now yesterday I DID do a lot of high detail so my head was in the box further than usual so I could see what I was doing. I also removed the bead to get a better look at outside of the box a few times- does a red hot bead give off fumes or just when it is actually in the torch?

I've also been coughing since I started a couple weeks ago, maybe it is just bead release that is bothering me? Would bead release make you feel this way though? Could the O2 concentrator be thinning out the air? This is why I want the detector, to see what fumes are causing the problem...

glassblaze · #7 2007-04-02, 10:11am

Oh yeah there is a piece of tarp tacked to the outside wall to keep rain from destroying my fan, but when the fan is on it blows it up no problem it is a very small and light piece.

MikeAurelius · #8 2007-04-02, 10:28am

Are you absolutely sure you are setting the fan on high? This is a 3 speed fan, and if it is running on low speed, that will definately not be enough air, but the medium or high settings should be more than sufficient..

What kind of building/room is this? Are there any other furnaces or hot water heaters nearby?

I'm thinking perhaps you may be backdrafting a furnace or hotwater heater and drawing combustion fumes into your workroom.

glassblaze · #9 2007-04-02, 11:17am

It's definitely set on high, and is very fast. If I had my head near the torch in the box would this be bad? Even though the fan should still be sucking everything out from in front of it? Does a glowing hot bead give off fumes? How do people go about getting into detail and getting close to the bead?

Oh the building is an 8x10ft tool shed in my yard, nothing else in it but tools, my kiln, torch, and O2 concentrator...

MikeAurelius · #10 2007-04-02, 11:58am

No -- beads don't give off fumes...

But I think I see the problem....

I think your "fresh air door" is too close to the exhaust duct and you are pulling fumes back into the shed.

The exhaust duct *absolutely* has to be at least 10 feet away from the fresh air source. If your bench is on a side wall, you are about 3-4 feet away from the door.

What you are going to have to do is add some duct work to the exhaust fan and duct the exhaust fumes away from the door.

Get some ducting the same size as the fan. You will need at least 3 90 degree bends and some straight lengths.

There are a couple of options here, but the best one would be to run the ducting to the side of the building furthest away from the door, then go straight up above the peak of the building, then back down, using only the 90 degree bends (two of them will accomplish this). You are building a "goose neck" which will prevent rain/snow from running down the exhaust duct. Be sure the final part of the goose neck is above the peak of the building so that any wind can mix and carry the fumes away. Also put some 1" screen mesh in the goose neck opening so that birds won't try to nest in it.

glassblaze · #11 2007-04-02, 12:14pm

The fan and door are on opposite sides of the shed, so isn't this the furthest they can be from eachother? Here's another pic to give you a better idea. I think you're right about needing ducting though. I just phoned a ventilation guy who said it could have to do with not enough static pressure with just the box, that to get static pressure you need ducting. I'm not entirely sure what this means though. He doesn't know about lampworking but is researching it for me. Other than NOx and sulphur compounds what are the main fumes that it gives off?

Dale M. · #12 2007-04-02, 12:24pm

Umm... You don't want static pressure, static pressure is resistance to air flow....

Ventilation guy doesn't seem to understand situation....

Dale

MikeAurelius · #13 2007-04-02, 12:32pm

No -- some fans do need some slight resistance to work, but the fan being used isn't one of those.

In looking at the above picture, it looks the fan is blowing outwards towards that berm and heavy tree band in the background, which might be part of the problem.....

What direction does the wind normally come from as it relates to the shed? What I'm thinking is that the berm and heavy tree band behind the shed is acting as a barrier to wind flow, so the exhausted air is sitting behind the shed, and getting drawn back into the shed through the open door or any other cracks in the walls.

The 10 foot rule is the minimum distance, but when there are other issues like blocked wind flow, natural ground contours, etc, you have to adjust to fit the conditions.

In your case, I really think you are going to have to go up above the peak of the shed to solve this problem.

glassblaze · #14 2007-04-03, 10:03am

The big tree you see is about 20ft away. I'm wondering if the piece of tarp I have attached is making a difference? The wind blows from the right to the left usually (when looking at building from that second picture). One thing I was just thinking of is I keep an insulator blanket in the kiln, could this be giving off fumes? I can't remember what the blanket is called, it's for beads though for putting them in between to slow down the cooling.

I have found a place that will rent me a detector for $100 for a day. I think I might just do this before I make anymore holes in the building, because after all the research I did this really should work, so maybe it's something completely unrelated to gases, like maybe the flare from the beads is making me dizzy? Or maybe just standing on my feet for so long looking down is cutting off circulation or making me dizzy or something (I rarely sit on my stool, I usually stand). Also maybe there is a propane leak in the hose which I haven't found and isn't being sucked out because it is too far from the fan. I don't know, it could be anything I am going to rent out the detector to see if I can rule out fumes or not...

Thanks for all your input, I will let you know what the little machine tells me!

Oh btw other than NO, NO2, LEL, and CO do you know if there are any other gases I should check for?

BlueBetween · #15 2007-04-03, 11:36am

If I remember right, you should be able to spray your propane hose with soapy water (out of a spraybottle) and if it fuzzes/foams up then you can see the leak. I was taught to do this when I connect the hoses to the new tank each time, to spray around the connections to make sure it's on tight (but I haven't done it in a long time, no studio for a year).