safety and fumes

[chickenhawk]

I just finished making my first hood. I used an 80 cfm bathroom exaust fan in about a 4 cubic foot space. I have schedule 40pvc running out my shop window and up 18inches higher than the roof peak. That way it draws air like a chimney. The air is drawn in from the bottom. The walls are plexy glass so my light is mounted outside the hood, and ALL seams are caulked. I also have a 5 gal. bucket & lid handy in case I need to move the solution outside for any reason. Now have i done enough? Is there a way to detect fumes from AR? I know miners used small birds to detect harmfull gases, but is there a "digital bird" or something that changes color in the presence fumes associated with AR? If not I bet with all the knowledge on this forum it wont be long before one of you guys invents a system. Anyhow I just want to be sure I've done everything right before i start using my hood. Hmmm I think I'll light a smoke bomb off inside to test it. Any input will be appriciated.

 

[jeneje]

Hmmm I think I'll light a smoke bomb off inside to test it. Any input will be appriciated.

:lol: Thats one way ...go for it ...let us know how it turns out.
Ken :mrgreen:

edited: chickenhawk, use a paper towel to test it. i really can't believe you wrote that. DO NOT USE A SMOKE BOMB.

 

[Westerngs]

You can use Draeger detector tubes to determine if you are being exposed to acids. See link below.

http://www.afcintl.com/product/tabid/93/productid/377/sename/draeger-short-term-detector-tubes-h/default.aspx

Look around the website for the tube that's right for you.

By the way, the OSHA permissible exposure limit for nitric acid is 2 ppm and for hydrochloric acid it is 5 ppm.

 

[butcher]

A fume hood will usually draw fumes from the bottom as well as the top, many of these gaseous fumes are heavier than air and will sink towards the floor, try pouring the red NO2 fumes out of a jar in still air, you can pour it out and watch it fall as it is heavier than air, chlorine, sulfur dioxide and many of the gases we generate are heavier than air.

Your fume hood design should take this into consideration.

 

[chickenhawk]

Sorry a bad joke. No smoke bombs, but i did the paper towel and it worked great. It only draws from the bottom because I know most of the fumes are hevier than air, so I didnt think about letting any air in from the top, and I didnt know the exposure limits. I thought it best to shoot for 0 ppm

 

[chickenhawk]

Thank you westerngs. That is exactly what i was looking for. I love this forum

 

[jeneje]

Sorry a bad joke. No smoke bombs, but i did the paper towel and it worked great. It only draws from the bottom because I know most of the fumes are hevier than air, so I didnt think about letting any air in from the top, and I didnt know the exposure limits. I thought it best to shoot for 0 ppm

Chickenhawk i am glad you tested anotherway. Did not mean to insult you here if i did please except my apology. Sometimes we have members join that write stuff that they are serious about doing , glad thats not you. I don't know if you have a scrubber system yet but you might want to look into that as well. There are some great threads about it up here, 4metals has wrote some good information on the subject.
Ken
Edited: Chickenhawk here is a pic for you, If you have a copy of C.M. Hoke the direction on how to make it is on page 41 I believe. What i did was use a 250ml beaker for the reaction vessil set it in a baking dish added 3/4" of water and then took an old coffee pot removed the handle and then set it on top. This allows me to use the hood as needed to remove the nox gas. Hope this helps you.

 

[chickenhawk]

Ok Im hitting the hoke again. I dont know how I missed that. I read someplace about using a 5 gal. bucket, but I dont think it worked very well. The bubbles comming out were very big and still had a lot of color. Im new to this hobby, but I wont take chances with these chemicals. I had a big box fan handy so i hooked it up and put it close enough to the bucket to make the fumes that ( I believe) were escaping disapate The set up in the pic looked like a much better way for me as I am still small scale. Thanks again

 

[jeneje]

Ok Im hitting the hoke again. I dont know how I missed that. I read someplace about using a 5 gal. bucket, but I dont think it worked very well. The bubbles comming out were very big and still had a lot of color. Im new to this hobby, but I wont take chances with these chemicals. I had a big box fan handy so i hooked it up and put it close enough to the bucket to make the fumes that ( I believe) were escaping disapate The set up in the pic looked like a much better way for me as I am still small scale. Thanks again

Also you need to know ,when the red fumes seem to leave or clearup,THAT DOES NOT MEAN THEY ARE GONE, lift the top container slowly let a little air in and you will see the red NOX form again if they are still there, let it settle and continue till you have no more fumes form in the container. And always wear a resparator if you have one, if not put a wet cloth over your mouth and nose. Better safe then sorry later.
Ken

 

[publius]

Ken, wet cloth over the nose and mouth is ineffective at the least and foolish at best. There is no air filtering resporator cartridge that will remove or neutralized nitrous oxide fumes. NONE! An ineffective ventilation system is just as bad. I speak from experience as I was a respiratory protection Petty Officer in the US Navy. Please avoid giving such misleading advice.

 

[jeneje]

Ken, wet cloth over the nose and mouth is ineffective at the least and foolish at best. There is no air filtering resporator cartridge that will remove or neutralized nitrous oxide fumes. NONE! An ineffective ventilation system is just as bad. I speak from experience as I was a respiratory protection Petty Officer in the US Navy. Please avoid giving such misleading advice.

You are right, the ONLY way to rid the fumes is through a scrubbing system with the proper addition a NaOH, as the fumes travel through a packing bed. With that said, most people up here do not nor can not afford such a system. Therefore all i was doing was trying to give some protection from the fumes as he releses them into the air a little at a time. I did not mean to mis-inform him at all. If he is going to use nitric acid he should have a scrubbing system for his setup.
Thanks for the corection
Ken

 

[chickenhawk]

Thank you to all for the input. Jeneje I made the set up in the pic but Im kinda proud of my 1st hood it changes the air about every other second. So Im putting the scrubber in the hood. It fits great and people can laugh all they want. A little Redundance never hurt. So maybe next weekend I'll do some testing with very small amounts. This weekend I have some reading to do. I want to learn all I can about scrubbers before I go trying to use one.
Thanx again

 

[jeneje]

Thank you to all for the input. Jeneje I made the set up in the pic but Im kinda proud of my 1st hood it changes the air about every other second. So Im putting the scrubber in the hood. It fits great and people can laugh all they want. A little Redundance never hurt. So maybe next weekend I'll do some testing with very small amounts. This weekend I have some reading to do. I want to learn all I can about scrubbers before I go trying to use one.
Thanx again

Your welcome, take care and be safe.
Ken