Work Shop Ventilation

[enerGwizz]

I'm designing the HVAC for a building that has woodworking and metal shops in it. The wood shop has mills, lathes, various saws/ sanders, etc and the metal shop has welding/cutting/grinding. What is the main strategy for keeping the air clean? Do I put an exhaust above or below each piece of equipment or is it already built in? Do they get a mini-hood or a snorkel-type exhaust? How many cfm? Thanks!

[big johnson]

If the wood shop has that much equipment, the only way to contain and keep most of the dust out of the air and off the equipment is to have a vacuum system at each "point of use." The systems I'm familiar with have overhead ducting with flexible snorkels attatched to the chip and dust outlets of the shop tools. It's a specialzed piece of equipment that you may want to research. If the shop is big enough, you may have to consider a source of make-up air while the vacuum runs. Some dust collectors will filter the air and then return it to the space. Local fire codes may also require sprinkler protection at the collection site of the system.

There are many companies that make portable vacuum hoods for welding or gas and smoke type contaminants. Again, it depends on the size and application of the shop. A company called Smog Hog has a wall mounted welding system that uses EAC's and sends the air back into the room.

As for cfm, just like any other ventilation job, you need to know the load and exact application and desired outcome.

Good luck.

[enerGwizz]

Great advice.. Thanks Big

[Coolmaniac]

Whichever way you run it, I would also figure to use heavy guage or spiral duct and accesses if you put together a collection system. I was in a polishing shop years ago, where an overhead system with drops at each station, had recently been installed using KD( not by me). And the main system duct was almost pressed flat from the weight of the rouge dust laying in the bottom, and no way to access it for clean out except to take it apart. Sawdust isn't likely to be as heavy or sticky but you wanna take a chance?

[big johnson]

Spiral duct is a must for a wood shop. Besides sawdust, chips and chunks get sucked up and rattle down the runs. It's got to be heavy duty. The runs also need to be designed with clean outs, at least on the main trunks.