ventillation system for paint shop

[abbasi]

hi
we have shifted a portion of our factory to some other site. in basement we have sheet metal and paint shop. its all covered up. i need to design a ventillation system. can u ppl help me in this regard i.e how to calculate fresh and exhaust air +static

rgds

[frank]

Hi Abbasi

What areas do you want to ventilate?

Can you give me the size of the rooms and the air changes you want?

[US Iceman]

abassi,

One thing you may want to consider is the air dilution required to minimize airborne vapors or chemicals since the paint booth and sheet metal shop are below grade.

You may have to bring in some additional outside air to dilute the ppm (parts per million) of any chemical or VOC (volatile organic compound) in the indoor air. You may also want to pressurize the sheet metal shop to keep any additional flammable vapors out of the "hot areas".

Smoke exhaust from cutting or welding and the paint booth are an interesting combination of requirements to have together.

[abbasi]

actually honestly speaking its a blunder that our building designer made but we are stranded its a large basement area we have to accomodate sheetmetal coil shop and paint shop.
yes it makes no sense at all but when every thing is done i m assigned a task to ventalise it. i m all at sea.
my questions are
1.how can i pressurize sheet metal?
2.should i isolate the paint shop completely by building walls around it and separate exit?

its a large basement of 100 ft x 50 ft x 25 ft or more we have to divide it into 3 parts as above.
as for air changes may be maximum is wat i presume coz in our part of world health concerns are not taken properly into consideration and masks in paint shop are not often used.

rgds

[frank]

The first thing to consider is to make the paint shop a seperate but not isolated area and then to make it negative pressure. This will ensure that paint overspray will stay in the area.

next, provide most of the make up air into the other areas. This will cause the air to move from clean area into paint area.

Now you need to decide the level of ventilation, i.e. how many air changes do you want per hour? in both the paint shop and the sheet metal shop.

Decide this and I can do some calcs for you.

[abbasi]

Please see attachment as layout and advise accordingly.

note that coil shop is also in the set up and cleanin/pressure stand of coils and chemical treatment also happens here.

rgds

Ali Abbasi

[arkay]

Hi Ali,

I have done a vehicle paint booth about two years ago and with the experience I would like to give my suggestions.
You will need two levels of ventilation in the paint booth: one for preparation work before painting, the second for the painting exercise.
For preparation work normal 6-8 air changes should be okay unless you have a lot of dust (if you have polishing works).
For painting, I propose to extract air thru vertical ducts fixed on the wall at 2-3 metre intervals all round the room. Extract grilles on the duct to be placed at three different heights to take all the paint particles. Theoretically air should flow at capture velocity to take all articles away but it's very hard to achieve.
Air-intake shall be around 75% of extract volume to create a negative pressure in the room.
Now, the exhaust is also important: what we have done here is to blow the air filled with paint particles vertically down on a water basin, the exhaust being at 4-6 inches from the water surface. The water traps the paint and avoids messing the whole area outside.
Keep me posted if this helps.

[abbasi]

hmmm rite well what i can deduce is that paint(powder spray) area is the one where ducts that suck air out will be installed and furnace to bake the paint on other side.
Also -ve pressure will be created in paint shop and porous grills will be installed in paint shop to extract air from sheet metal/coil shop. air changes in coil/sheet metal will be at least 3.

rgds