Ventilation fan for shop question.

[sharkhunter]

So there are three types of fan ventilation systems.

1)Supply (positive pressure)
2)Exhaust (negative pressure)
3)Balanced system

Has anyone used a balanced system in their shop and what if any benefit is it ? So this would be two supply fans on one end of the shop and two exhaust fans at the other. Both wall mounted. This is a welding shop and fresh air is a concern.

[bboswell]

I have not but unless all doors are closed I would think incoming air is unlimited so exhaust is all you need. That’s all we use and it makes a huge difference

[Blank]

We use a semi-balanced system, with 2 60% exhaust (one for the general shop where painting occurs and one for a specific welding hood over the welding table), and 1 larger 100% supply fan. Runs slightly negative when welding.

For my 40 foot home shop, I just run a single wall mounted exhaust fan and do everything in that general area.