HVAC in a welding/machine shop

[bill nye scienceguy!]

Hiya

I need to spec up a ventilation system for a small welding and machine shop. The area will have ten welders, one large vertical machining centre, a bunch of small machine tools and things like air compressors, heat treatment, small(ish) cranes and air compressors etc.

My question is: if I know the heat output in a volume, is there a standard relation I can use to approximate the amount of air flow (or whatever other variable is appropriate) I need to maintain a relatively constant and comfortable air temperature in that volume?

HVAC is not my forte so any help is much appreciated.

 

[russ_watters]

Btu/dT/1.08=CFM

 

[AECenter]

Also, practically speaking... the amount of air that you are going to be exhausting with all that stuff is going to really challenge your ability to fine tune the temperature of the space. A shop like that is bound to have huge bay doors that will be opening and closing through the day as materials and products go in and out of the space, high ceilings, and lots of sweaty workers wearing protective clothing.

In kitchens they will have hoods over the cooking devices and Make Up Air units that minimally treat the incoming air, because it is just going to get sucked right back out with the greasy smoke. Do you see anything like that going on over the welding stations?


-chris
aec.us.com

 

[pantaz]

There are many companies manufacturing ventilation and filtration units specifically for welding and cutting operations.
Also, you will need to read up on government regulations -- such as OSHA for the U.S. -- They (OSHA) updated many of the rules in the pasty few years due to studies (and lawsuits) over cadmium exposure, among other things.

Here's a quickie overview of a few things:
http://www.aws.org/wj/amwelder/04-02/keep_safe.html

OSHA's "overview":
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_id=9853&p_table=standards

Couple of paragraphs from the ANSI Safety Standard Z49.1:

Fumes and gases from welding and cutting cannot be classified simply. The composition and quantity of fumes and gases are dependent upon the metal being worked, the process and consumables being used, coatings on the work such as paint, galvanizing, or plating, contaminants in the atmosphere such as halogenated hydrocarbon vapors from cleaning and degreasing activities, as well as the factors itemized in this section for adequate ventilation.

Ventilation should not produce more than approximately 100 feet per minute (0.5 meters per second) air velocity at the work (welding or cutting) zone. This is to prevent disturbance of the arc or flame. It should be recognized that approximately 100 feet per minute (0.5 meters per second) air velocity is a recommended maximum value for quality control purposes in welding and cutting. It is not intended to imply adequacy in contaminant control for worker health protection.