Clean Room Design Help

[woldfield]

We are working on a clean room design for a room that is Class 1000, 4500 sqft., 10' ceiling. I've figured the cooling load to be about 15 tons - using 40 btu/sqf just to cool the room itself. I've guessed about 10 tons for additional heat load from equipment, etc. for a total of 25 tons.

We think it will require 90,000 CFM total to satisfy 180 air changes per hour. That might be overkill?

My question is this... what's the best type of system to design? My thinking tells me a 25 ton dedicated cooling unit and a recirculation setup...

Any thoughts or suggestions?

 

[cdxx139]

Look at ISPE guidelines, it will answer all your questions.

You seem a little over your head. You need to do actual loads (not Rule Of Thumbs). Dont assume 10 tons, put togather an equipment list with heat loads. Do psychrometric charts etc. Good Luck

knowledge is power

 

[woldfield]

Thanks. We will take a look at ISPE. Not over "our" head - We don't do things by rule of thumb, we do real loads. Our staff ME is pretty green and I am trying to do a rule of thumb/guestimate just to make sure he isn't too far off.

I should have been more specific when I said "we are working on a clean room"... We don't have the project, it's a pipe dream for an owner at this point and just trying to throw out some ballpark figures and design ideas without getting too deep into design, etc.

Thanks again.

 

[jmk0407]

woldfield
are you sure you're ready to be able to design a clean room? they aren't your normal ball of wax. i would suggest maybe getting someone else who knows what he or she is doing.

 

[yehezkel]

hi
I'm working in AD cleanrooms / planning and building cleanrooms HVAC + structure.
you have to take some considerations:
1.for class 1000 we are taking 130ach
2.cooling load - normal calculation for HVAC
3. cleanroom usually need to be pressurized . for +25.0 pascal (normal) you need 4000cfm freshair - add this for cooling load !
4. usually cleanroom needs relative humidity of max60% , dewpoint 53 F this mean 4000/120= 33.3 TR (this is in israel , you must calculate in your region).
good luck

 

[dbill74]

Clean rooms also have very specific air flow patterns usually from roof to floor. Two examples:
1) Operating room: Will have laminar flow diffuser with HEPA filter directly over patient with return grilles on walls in corners.
2) Microchip manufacturing floor: All over head, diffusers directing all air straight down. Metal grate flooring allows air to pass through to returns below floor.

 

[RossABQ]

Class 1000 is kind of an inflection point between the "really clean" classes and Class 10k semi-clean. Frequently sidewall return (not thru the floor) is adequate, as it is not a laminar flow situation. 20 - 50 fpm room velocity, 20 - 40% ceiling filter coverage. Client requirements drive where in these ranges your design needs to be. Ditto the comments on make-up air and pressure. Be sure to include exhaust losses.

 

[willard3]

I encourage you not to teach the green ME to use rules of thumb, it sets a bad example for him.

If you don't know how to do this, find an Engineer who does and have him help the green ME.

 

[317069]

"My thinking tells me a 25 ton dedicated cooling unit and a recirculation setup..."
Can you explain your idea with more details especially about recirculation set up

 

[woldfield]

KILL THE THREAD...