Need to bring fresh air. - Gearslutz.com

 Gearslutz.com Need to bring fresh air.

 8th October 2012 #1 Gear maniac   Joined: Apr 2005 Location: London Posts: 299 Thread Starter 1 Review written Need to bring fresh air. Hi. I need to bring in fresh air, any ideas on a fan. I have air conditioning with dehumidier. Antony
 8th October 2012 #2 Lives for gear   Joined: May 2012 Posts: 1,208 What is the volume of the area?
 8th October 2012 #3 Gear maniac   Joined: Apr 2005 Location: London Posts: 299 Thread Starter 1 Review written Live room about 650 sq foot monitor room is 25ft by 10...
8th October 2012   #4
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Quote:
 Originally Posted by antony Live room about 650 sq foot monitor room is 25ft by 10...
This is not the rooms' volume. The volume is required to calculate the fan CFM.

8th October 2012   #5
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Quote:
 Originally Posted by OpusOfTrolls This is not the rooms' volume. The volume is required to calculate the fan CFM.
Yes, room height is also needed to calculate volume.

 8th October 2012 #6 Gear maniac   Joined: Apr 2005 Location: London Posts: 299 Thread Starter 1 Review written The live room ceiling is eved at its highest aprox 21 ft. Monitor 10 ft. How do I work out the volume.
9th October 2012   #7
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Quote:
 Originally Posted by OpusOfTrolls What is the volume of the area?
11

9th October 2012   #8
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Quote:
 Originally Posted by antony The live room ceiling is eved at its highest aprox 21 ft. Monitor 10 ft. How do I work out the volume.
volume is:
Length times Width times Height
LxWxH

 9th October 2012 #9 Gear maniac   Joined: Apr 2005 Location: London Posts: 299 Thread Starter 1 Review written Ok, are there any standard makes of fans that is used.
 9th October 2012 #10 Gear maniac   Joined: Apr 2005 Location: London Posts: 299 Thread Starter 1 Review written I amorous mint that because I have inverter aircon in the live room I need my fan to suck the air out to Chang the air in the room. And In the monitor took I don't have aircon so would I have the air gently blowing in
 9th October 2012 #11 Lives for gear     Joined: Sep 2007 Location: Old Tappan, NJ USA Posts: 1,313 figure you need at least 5 liters of fresh area per person per hour, or 8-10 complete changes of air per hour. so take your room volume and divide by 60 to obtain the air volume you need per minute. then you need to define the area of the ducting and openings etc to get the air velocity down to say 300fpm or less. then there are a lot of other considerations like losses of the system, pressure balance, energy conservation, moisture control, etc as well as cost of installation and maintenance. here's a nice reference: Practical Ventilation and Air Conditioning Design for Recording Studios, Control Rooms and Auditoria - Articles - Ambthair UPDATE: note that the "fresh air" component of the air exchange is (based on US standards) around 4% or 7.5cfm/100ft2 of the total air flow (the 8-10 air changes i recommend). I suspect Rod will be along shortly to further correct or improve on my comments here. __________________ Glenn www.runnel.com
 10th October 2012 #12 Gear maniac   Joined: Apr 2005 Location: London Posts: 299 Thread Starter 1 Review written Great info thanks, just to mention I am in London and also are there any manufacturers you could recommend. Cheers Antony
 10th October 2012 #13 Lives for gear     Joined: Sep 2007 Location: Old Tappan, NJ USA Posts: 1,313 you can probably locate the information in UK building codes but i believe the EPA air quality info was based on the ASHRAE and IRC 2006 codes so it is probably close. as far as products - bet bet is to reach out to a licensed HVAC contractor to assist with your space - they can help with the proper calculations based on your actual environment, their experience, and should be fully versed in the building codes and kit needed. on the other hand going with a contractor will add cost since they usually require compensation...
 10th October 2012 #14 Lives for gear     Joined: Jul 2003 Location: Central Village CT Posts: 3,154 OK - let's take a breath here for a moment and make sure this is all clear to the OP. The specific question he asked related to fresh air requirements. Fresh air requirements generally have nothing to do with the volume of a room. I say generally because there are exceptions to the rule. However - in this type of occupancy use group - what is typical (at least here in the states) is to determine fresh air requirements by taking into consideration the total occupancy load that is capable of using the space simultaneously (which is proscribed by code) and then applying a factor (also proscribed by code) multiplied by the area of the space - not the volume. Now - you need to know this information as a part of a full system design (because untreated fresh air will (generally) add to both the latent and sensible loads inside of the building space) - it is the final system that is then the focus on total air exchanges within that space. Now - more often then not - the application of 15 cfm of fresh air supply per person (which is not uncommon as a minimum standard in a lot of jurisdictions here in the states) will actually exceed the ASHRAE minimums for a space: This example for a classroom: Classroom area = 400 sf. Maximum Occupancy load per Table 1004.1.2 of the IBC = 20 persons Requirements per the IMC: Mechanical ventilation - Flow rate requirements follow ASHRAE Standard 62.1 ventilation rate procedure, based on cfm per person plus cfm per ft2 most spaces. An IAQ procedure is also allowed for (IAQ is an Indoor Air Quality Procedure.) ASHRAE classroom requirements for a classroom (age 5+) is 10 cfm/p +0.12 cfm/ft2 Thus 200 cfm (per person) + 48 cfm (for room area) for a total of 248 cfm. Note this is the same regardless of ceiling height, 8' - 10' or 40' makes no difference. However - now that we understand that information - and are moving on to the system design for the HVAC in that space - the amount of air we need to circulate within the space is absolutely dependent on that ceiling height. You could not possibly circulate enough air in a room that size with 40' ceiling heights (16,000 c.f.) using a system designed to satisfy the room if the ceiling heights were only 8' (3,200 c.f.) - you simply would not move enough air. Now - if you were to take that same area and use 15cfm per person as the design criteria for fresh air - you would have 300 cfm - which would exceed the minimum standards of 248 cfm. I hope this helped........ Rod I hope this helped
11th October 2012   #15
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Quote:
 Originally Posted by Rod Gervais However - now that we understand that information
lol

 11th October 2012 #16 Gear maniac   Joined: Apr 2005 Location: London Posts: 299 Thread Starter 1 Review written Wow......Cheers Rod as always a wealth of info, i have just finished my studio and thank you lots for all your help, I will post some pics in due course. Ok let's get one thing clear to start of with, I'm a drummer, and a producer so I'm struggling with all that info, I need laymans terms, my monitor room is 10ft by 22 by 10, I want to extract the air from that room. I own to the roof for ducting, I suppose I don't need a big extractor for that space. I am old school all be it young but don't mind people smoking in there within reason I own the building so no legal problems, I have aircon so just looking for the most cost affective way to extract from a room that size, any manufacturers come mind.... Cheers Antony

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