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Originally Posted by lzenglish

OK, time for some details! What size is your room? Do you have a house cooling return air space, between the ceiling,and the roof? Now this is just shooting from the hip. without knowing those details, but here is what i have done in the past: Mount your dedicated HVAC unit in the center of the room, with a 4 way diffuser. Then mount long slot return air diffusers around the perimeter of the room. Then, you will need to adjust the supply, and return air volume so it creates a negative return air pressure, such as a minimum of .05in-1.in.of water collum, to produce your negative pressure in the smoking room! In other words, when someone opens or closes the entry door, it will draw air into the room, as opposes to discharge air and smoke. It would be best to mount the main entry door as to pull to open, and door closure to close. This is just another safeguard, to prevent smoke from entering the open office space. This is just the general idea of what i did on my smoking rooms, and i hope you can get something out of it. Best of Luck.

Wayne

PS: You can also incorporate an exaust fan, but like i say, this is all i can give you from what i know. at this time.

^^^^ That is impossible....and the RTU would not work right..


you need an exhaust fan or power exhaust on the RTU with OSA.......I bet this room has no AC at all and only has exhaust and OSA coming in...the transfer grill in my guess is to bring in the conditioned air from another room to help maintain some kind of comfort...but they really don't care about that. Because its just a smoking room...

But back to the main question about the transfer grill if your really set on that.....Install a fire damper/smoke damper that is tied into the exhaust fan..when the fan comes on the damper opens up.... something like this http://www.grainger.com/Grainger/DAY...130509141812:s

and if you want to keep the room in a negative vacuum you will need few more control than you have...and the cost will rise...You may want to get someone to engineer this before you sink a lot of money for something very simple.

OK, time for some details! What size is your room? Do you have a house cooling return air space, between the ceiling,and the roof? Now this is just shooting from the hip. without knowing those details, but here is what i have done in the past: Mount your dedicated HVAC unit in the center of the room, with a 4 way diffuser. Then mount long slot return air diffusers around the perimeter of the room. Then, you will need to adjust the supply, and return air volume so it creates a negative return air pressure, such as a minimum of .05in-1.in.of water collum, to produce your negative pressure in the smoking room! In other words, when someone opens or closes the entry door, it will draw air into the room, as opposes to discharge air and smoke. It would be best to mount the main entry door as to pull to open, and door closure to close. This is just another safeguard, to prevent smoke from entering the open office space. This is just the general idea of what i did on my smoking rooms, and i hope you can get something out of it. Best of Luck.

Wayne

PS: You can also incorporate an exaust fan, but like i say, this is all i can give you from what i know. at this time.

Why the need for a transfer grille? Does this not defeat the purpose of maintaining the appropiate room pressurizations? Seems like it will act as more of a neutralizing piece of equipment.

Originally Posted by dlove

I did something like this many years ago.. Not sure why they are asking for transfers grills. Even though you have 100% OSA you need to know how much can be made up and what size fan you need or have to exhaust, otherwise you will have one hell of a vacuum in the room and doors will be hard to open or you will have noise.

Unless they think they need to pull air from those rooms as well i see no reason to have a transfer grill. Is the OSA coming into this room only?


Just wondering how do you make "negative pressure" I would really like to see that?

its like "neg zero" cant figure that one out either

I did something like this many years ago.. Not sure why they are asking for transfers grills. Even though you have 100% OSA you need to know how much can be made up and what size fan you need or have to exhaust, otherwise you will have one hell of a vacuum in the room and doors will be hard to open or you will have noise.

Unless they think they need to pull air from those rooms as well i see no reason to have a transfer grill. Is the OSA coming into this room only?


Just wondering how do you make "negative pressure" I would really like to see that?

Assuming your walls go up to the deck, you will also need a smoke damper. buy yourself a smoke damper with wall sleeve, then add a backdraft on the end with an adjustable weight. setup the backdraft to close as the other positive pressure side fan winds down.

There is only supply (100% OSA) and Extract. No return. So we don't have to worry about smell from the HVAC system.

I am required to do two things according to our client:

1. Provide a negative pressure in the smoking room, relative to adjacent space
2. Provide a transfer grille of some sort between these spaces

The transfer grille is my concern, in that even though there is negative pressure there could be smell transferred out on rare ocassions. Therefore, I was wondering if putting a backdraft damper would be sufficient, or if theres something else you might recommend.

Hope that clarifies a bit!

Originally Posted by deten

Hi folks,

We have a smoking room thats supplied and extracted by one system along with all the other spaces (no return). We are providing more extract than supply in the smoking room, and in the adjacent area we are providing more supply than extract. The total supply and extract between the other space and the smoking room is the same, and my question is how to handle the transfer air?

I expect we need a transfer grille with some sort of pressure dependent backdraft damper. So if the pressure in the room drops below, say 50Pa, the backdraft damper closes, but once the pressure in the room returns to 50Pa it would begin to open to allow air from the non-smoking-area, into the smoking area.

Anyone have experience with this?

You have a What, in Who?
Lol Just kidding! But you do know this went bye bye long ago! BUT, as Building Engineers, we aim to please, right?
The only thing you can do is install a dedicated, well filtered (charcoal filtered if possible), supply and return air Exaust System, that will not in any way come in contact with your Building House Cooling and or Air Conditioning system. I have done it a couple of times, for head honcho's who had the required horsepower to make it happen, but they were Very High Up on the food Chain. Just make sure you have your request papers signed, in case the lawsuits start flowing in.

Wayne

I'm not an engineer but a dedicated system that designed to provide a calculated air changes per minute may help this situation.......

Smoking Room - How to handle transfer air

Hi folks,

We have a smoking room thats supplied and extracted by one system along with all the other spaces (no return). We are providing more extract than supply in the smoking room, and in the adjacent area we are providing more supply than extract. The total supply and extract between the other space and the smoking room is the same, and my question is how to handle the transfer air?

I expect we need a transfer grille with some sort of pressure dependent backdraft damper. So if the pressure in the room drops below, say 50Pa, the backdraft damper closes, but once the pressure in the room returns to 50Pa it would begin to open to allow air from the non-smoking-area, into the smoking area.

Anyone have experience with this?