Remind them that ASHRAE 62 references this Manual as an alternative to their standard which should be used for what is defined as Class 4 air (air that could contain enough contaminants to be a health or safety hazard).  There is a general drawing for the spray booth in the manual with all the calculations for it. ACGIH, I believe, still recommends a higher face velocity because their primary aim is protecting the operator and not energy savings.  ASHRAE waves in the "wind."  It always finds cockamamie ways to lower fresh air requirements when there is another energy crisis and you may remember the sick building issues in the 80s.  And ambient CO2 levels are 100 - 200 ppm higher than they were in the 1970s.  My reports all recommend staying with ASHRAE 62-2001 fresh air requirements combined with the better placement of supply/exhaust.

 

For gosh sakes tell them that the ACGIH Manual specifically recommends avoiding Heat Wheel energy recovery systems for this class 4 exhaust.  These wheels pass the two air streams past each other.  To believe they work you would also have to believe you can assign a section of a Jacuzzi for peeing.  

 

Be suspicious of LEED's recommendations regarding anything industrial.  They are usually wrong.  I know a building where a heat wheel was used for this kind of exhaust, so don't tell me it can't happen.  And that building has LEED certification.

 

The manual also has, in the chapter on hood design, good drawings of the turbulence issues created in systems by the presence of operators or objects.

 

-----Original Message-----
From: Lawrence M Gibbs <lgibbs**At_Symbol_Here**STANFORD.EDU>
To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Sent: Thu, Oct 10, 2013 7:26 pm
Subject: Re: [DCHAS-L] Fume Hood & Lab ventilation presentation for Engineering students - what would you include?