Exhaust Fan

Do you have a clue of what your doing?

You, good man, are an A$$HOLE.

Exhaust fan calculations may be based on:
Room volume (ft³)
Room area (ft²)
Room occupancy (number of people)
Various heat loads in the room
Local code eccentricities
Contract specifications, whether rational or not
and maybe some other stuff.

More info needed.

You need a BFEF.

Acronym alert!

These are the questions you need to answer first,

1) What is the typical application of that exhaust fan. Is it for clean room, (ICU)hospital or other industrial application?

2) What is the concentration of dust in the room, is it ventilated (if so what is the concentration of dust from the source air (ambient,perhaps), by how much is ambient air is being brought inside(cross section of diffuser x air velocity). Know the sources of dust. (OSHA has methods for knowing the concentration, TND or TD) you can use the data

3) Typically for just dust removal, you have to consider only a recirculating system.

This will be your working equation:

Rate of removal => Rate of dust infiltration

then you can design a Filter system using HEPA Filter, its not an air exhaust system, take note. It is because the exhausted air from these filters are already cleaned from dust particles. (See Hepa Filter specification, google it)

or you can just buy something like these (HEPA FILTER)

How long is a piece of string.

How many times do you need the room volume in air removed , say, per hour.

Are you restricted in the placement of fans.

Is there any forced inwards airflow.

Is the room sealed.

Do you have a piece of string.

Do you have noise restrictions, internal and external.

Get a piece of string measure it, and give us some "Criteria". All of it...!

Thick string or thin string.

Then someone maybe someone will help you.

Me personally...I don't think you have a clue, do you.

Tyre kickers, sort of interested, but not really.

Sorry to be blunt, but.........!

Cheers Mark N.

Try this.!

http://www.engineeringtoolbox.com/fan-types-d_142.html

Mark N.

Minimum data required is Number of air changes and sources of heat . Multiple the volume of the room by number of air changes per hour will give you the quantity of air to be exhausted. From the standards fan literature you can select the exhaust fan.

This answer should suffice.I would say that we are all professionals and should not discourage/ confuse the professional.

As he said, it is for sucking dust particles, the right approach will be to tell us everything you know about these particles. are they heavy or if you can quantify them.

This will help you in finding optimum number of air changes required to remove them. And if possible any process which produces these particulates.

Even if you know the process taking place there. rules of thumbs can then be told to calculate CFM to be exhausted.

Call me/ E-mail with more details to help you further.--Esskay11@live.com

The typical resident genius (in their minds only) heckling should be ignored. It would help if you gave a bit more info on what type "dust" you're talking about. I'd hold back on any Hepa system. That was a really stupid reply unless the dust you're exhausting has to be treated to meet some code or emission requirement. You need to know that. Hepa filters are quite costly for "dust". The suggestions you got for "air changes per hour" are valid. So how many time an hour or day do you expect to completely change the volume of air in the room? You have to have an idea before you can size a fan. Theres an old rule in HVAC that gets forgotten all the time. It goes like this, "you can't take it out if you don't put it in first". Which means you have to make sure you have a source of "new air" to replace the air you're removing. So it's really important to know if this hall is a conditioned space? It's wasteful to condition air and then exhaust it. If the hall isn't critical you might want to take in outside air or a combination of outside and conditioned. You're probably able to set up a fan but you really might want to consult with an HVAC person to not only get the airflow you want but to do it without setting up a system thats pumping dollars through the roof. Good luck.

Still with the condescending remarks. Does that actually work for you? Seriously do you expect bloggers to be subordinate to you? You're a slow learner if you think I'll listen to anything you say. And it IS a stupid remark. I'm a long time HVAC contractor is So Calif. I know exactly what I'm talking about on this topic. If the guy is located in certain air districts he might be required to treat his exhaust, but again it depends on what type of "dust" he plans to exhaust. If it's inert it would be extremely costly to install a Hepa system that doesn't even require filtration in the first place. Which is more than stupid, but if you need to install an exhaust system please feel free to install a few powered Hepa's to vent your bathroom or kitchen.

It is amazing..............!

Our mate "Guest" who has asked the question, as not entered further into the debate.

I doubt he is really interested in the correct answer, as he really hasn't defined his question, after 2 days, hasn't bothered to help himself, with more information.

We are left guessing whether his string is of Natural Fibre or Synthetic. If someone presumes to give an answer, to the ill defined question, chances are it will be in Error.

No answer in this situation is "Dumb".

If we are to converse amongst ourselves, with no more input from "Guest", then we are all dumb, for trying to second guess this bloke.

I reckon, by now, he has swapped his battered bucket, for some kids bright new bucket, picked up his spade, and is now playing in the rich kids sandpit at the end of the street.

I mean, should we have bothered in the first place.??????

Those who help themselves, WILL get help from others.

Cheers and Good Health.

Mark N

"It is amazing..............!

Our mate "Guest" who has asked the question, as not entered further into the debate."

This is actually rather common; and annoying.

You should first ask your Instructor to be more specific about your →Home Work Assignments←

Yes. Possibly Right.

Couldn't see the student for the teachers.

Mark N.