DCHAS-L Archives Jun 22 2011 - Fwd: Fwd: [DCHAS-L] Heat Recovery Wheel help needed

Kim, For your answer, I defer to a more subject relevant expert below. Hope this is helpful. Regards, -- Craig M Conway *Technical Risk Analyst* ---------- Forwarded message ---------- From: MICHAEL CONWAY Date: Wed, Jun 22, 2011 at 11:50 AM Subject: Re: Fwd: [DCHAS-L] Heat Recovery Wheel help needed To: Craig Conway Heat wheels are made from aluminum allow which reacts with cl and a host of acids and other compounds so the durability is questionable in a lab exhaust. The term is used loosely because there are several different types including what is commonly referred to as an enthalpy wheel. They collect the latent heat, moisture, and put it back in the incomming air stream which in this app I would advise against. The crossover rate, leak , referred to is real but if they are on fume hoods they are looking at brand X anyway, it should be designed with a heatpipe, stainless steel, no crossover and no corrosion factor. Leeds cert on a lab does not make economic sense unless "return on investment" is not a consideration. A properly designed building would put the common areas and offices etc at +.03" wc, the labs at atomosphere and the hazardous storage a a clear negative relative to the lab. The makeup air for the fume hoodsshould be 80% of the exhaust volume and the fume hoods by nature are in a negative. The outside air supplied to the lab should be 50 cfm per rated occupant with a minimum 12 air changes per hour possible but modulating based on iaq. I have worked on a few of these 'LEEDS' projects and I have found that the owners don't want to pay the architect or engineers for proper supervision so the projects never come out as intended. On a lab project my design criteria would be worker safety, building occupant safety, general public and environment safety and finally energy efficiency. I would design the building first and the lab design would basically be it's own design with only my control bus be common to both. "Not everything that can be counted counts, and not everything that counts can be counted." Albert Einstein (1879-1955) "Change is the law of life. And those who look only to the past or present are certain to miss the future." -- John F. Kennedy MICHAEL A. CONWAY CONWAYMECHANICAL,LLC. 182 MANTOLOKING ROAD BRICK, NEW JERSEY 08723 PH 866-374-6661 FAX 732-475-2784 CELL 848-992-1048 --- On *Wed, 6/22/11, Craig Conway * wrote: From: Craig Conway Subject: Fwd: [DCHAS-L] Heat Recovery Wheel help needed To: "MICHAEL CONWAY" Date: Wednesday, June 22, 2011, 11:14 AM Dad, Do you know of a design that would work for these folks? Or would you agree that its generally not recommended?j ~Craig ---------- Forwarded message ---------- From: *Margaret Rakas* > Date: Wed, Jun 22, 2011 at 9:57 AM Subject: Re: [DCHAS-L] Heat Recovery Wheel help needed To: DCHAS-L**At_Symbol_Here**list.uvm.edu I am so glad ACGIH took a stand on this in the face of this large push for sustainability, some of which makes a lot of sense, and some which makes no sense whatsoever if you have a building with hazardous chemicals, biologicals hazards and/or radiochemicals. I had to fight tooth and nail to have these removed from the design of our new building; I won, due to some articles that (I think) members of this listserv brought to my attention. But this recommendation is much stronger than the articles. Now I have an invitation to attend a "Low Energy Lab Design" seminar, which will discuss, among other things, "The goal of reducing laboratory air flow rates to two air changes per hour and how to safely achieve this." If you have a building where everyone is highly experienced and trained, the materials you are working with are fairly low-hazard--I can see this. But for those of you who keep tabs on this sort of thing--are they serious about trying to implement this in a building where you have a fair number of inexperienced researchers? Margaret the above is my personal opinion only, not business or legal advice, and may not represent the opinion of my employer or any group to which I belong... >>> > 6/21/2011 10:49 PM >>> Kim, Re: heat wheels: The ACGIH Manual of recommended practice specifically says these should not be used. The following is a quote from page 10-11 of the 27th edition of the book: "The use of a heat wheel should be avoided where there are hazardous substances in the exhaust air stream since there is leakage between the exhaust and supply air zones. To isolate these air streams, wipers are employed to seal the spaces on the upstream and downstream sides of the wheel. During the operating life of the wheel, seals must be inspected for adjustment and replacement. The casings in the energy wheel lose their effectiveness and need to be replaced after several years. The drive motor and v-belt and chain also require inspection and maintenance. Care also must be exercised when the exhaust air stream has a high moisture content and the incoming air stream could be lower than 32 F. When it is below freezing outside, the cold incoming air could drop the wheel temperature below the dew point of the exhaust air causing water drops to form. These water drops could then freeze on the wheel causing deterioration of the wheel materials." But it's the first line of the quote from the manual that is most important: "...there is leakage between the exhaust and supply air zones." Look hard at the mechanical drawings of the heat wheel system. To believe that thing only returns 4% of the contaminated air to the building as the manufacturers claim you'd have to believe that you can assign a section of a Jacuzzi for peeing. Monona In a message dated 6/21/2011 4:21:44 PM Eastern Daylight Time, kauletta**At_Symbol_Here**NOTES.CC.SUNYSB.EDUwrites: Do any of your buildings have a heat recovery wheel in the HVAC/Fume hood system? Our newest building has a heat recovery wheel installed for LEED certification but new researchers are questioning the safety of this system (energy research). I do not understand how these systems work. The architect has forwarded some white papers, but these are vague, at best, on chemical safety data &testing. If you have a heat recovery wheel in a chemistry building - How did you determine it was safe to use? Do you have chemical restrictions? What criteria do you use for restricting chemicals because of this system? Any help or insight you could provide is greatly appreciated! Kim Auletta Lab Safety Specialist EH&S Z=6200 Stony Brook University kauletta**At_Symbol_Here**notes.cc.sunysb.edu 631-632-3032 FAX: 631-632-9683 EH&S Web site: http://www.stonybrook.edu/ehs/lab/ Remember to wash your hands!

---------- Forwarded message ----------
From: MICHAEL CONWAY &l t;conwaymech**At_Symbol_Here**yahoo.com>
Date: Wed, Jun 22, 2011 at 11:50 AM
Subject: Re: Fwd: [DCHAS-L] Heat Rec overy Wheel help needed
To: Craig Conway <conway.csa**At_Symbol_Here**gmail.com>

Heat wheels are m ade from aluminum allow
which reacts with cl and a host of acids and oth er compounds so the durability is questionable in a lab exhaust. The term i s used loosely because there are several different types including what is commonly referred to as an enthalpy wheel. They collect the latent heat, mo isture, and put it back in the incomming air stream which in this app I wou ld advise against. The crossover rate, leak , referred to is real but if th ey are on fume hoods they are looking at brand X anyway, it should be desig ned with a heatpipe, stainless steel, no crossover and no corrosion factor. Leeds cert on a lab does not make economic sense unless=A0 "return on investment" is not a consideration.

A properly designed building would put the common areas and offices etc at +.03" wc, the labs at atomosphere and the hazardou s storage a a clear negative relative to the lab. The makeup air for the fu me hoodsshould be 80% of the exhaust volume and the fume hoods by nature ar e in a negative. The outside air supplied to the lab should be 50 cfm per r ated occupant with a minimum 12 air changes per hour possible but modulatin g based on iaq.

=A0

I have worked on a few=A0 of these 'LEEDS' projects and I have found that the owners don't want to pay the architect or engineers for proper supervision so the projects never come out as intended. On a lab pr oject my design criteria would be worker safety, building occupant safety, general public and environment safety and finally energy efficiency. I woul d design the building first and the lab design=A0would basically be it' s own design with only my control bus be common to both.=A0=A0

"Not everything that can be counted counts, and not everything that counts can be counted."

=A0

=A0Albert Einstein (1879-1955)

=A0

"Change is the law of life. And those who look only to the past o r present are certain to miss the future." -- John F. Kennedy

MICHAEL A. CONWAY
CONWAYMECHANICAL,LLC.
182 MANTOLOKING ROAD
BRICK, NEW JERSEY 08723
PH 866-374-6661 FAX 732-475-2784
CELL 848-992-1048

--- On Wed, 6/22/11, Craig Conway <conway.csa**At_Symbol_Here**gmail.com> wro te:

From: Craig Conway <conway.csa**At_Symbol_Here**gmail.com>
Subject: Fwd: [D CHAS-L] Heat Recovery Wheel help needed
To: "MICHAEL CONWAY" <conwaymech**At_Symbol_Here**yahoo.com>
Date: Wednesday, June 22, 2011, 11:14 AM

Dad,=A0

Do you know of a design that would work for these folks? Or would you agree that its generally not recommended?j

~Craig

---------- Forwarded message ----------
From: Margaret Rakas <mrakas**At_Symbol_Here**smith.ed u>
Date: Wed, Jun 22, 2011 at 9:57 AM
Subject: Re: [DCHAS-L] Heat Recovery Wheel help needed
To: DCHAS-L**At_Symbol_Here**l ist.uvm.edu

I am so glad ACGIH took a stand on this in the face of this larg e push for sustainability, some of which makes a lot of sense, and some whi ch makes no sense whatsoever if you have a building with hazardous chemical s, biologicals hazards and/or radiochemicals.

I had to fight tooth and nail to have these removed from the des ign of our new building; I won, due to some articles that (I think) members of this listserv brought to my attention. =A0=A0But this recommendation is much stronger than the articles. =A0

Now I have an invitation to attend a "Low Energy Lab Design " seminar, which will discuss, among other things, "The goal of r educing laboratory air flow rates to two air changes per hour and how to sa fely achieve this." =A0If you have a building where everyone is highly experienced and trained, the materials you are working with are fairly low -hazard--I can see this. =A0But for those of you who keep tabs on this sort of thing--are they serious about trying to implement this in a building wh ere you have a fair number of inexperienced researchers?

Margaret
the above is my personal opinion only, not business or legal advice, and may not represent the opinion of my employer or any group to w hich I belong...

>>> < ACTSNYC**At_Symbol_Here**CS.COM> 6/21/2011 10:49 P M >>>

Kim,

Re: heat wheels:=A0 The ACGIH Manual of re commended practice specifically says these should not be used.=A0=A0 The fo llowing is a quote from page 10-11 of the 27th edition of the book:

"The use of a heat wheel should be avoided where there are hazardous substances in the exhaust air stream since there is leakage between the exhaust and supply air zones.=A0 To isolate these air streams, wipers are employed to seal the spaces on the upstream and downstream sides of the wheel.=A0 During the operating life o f the wheel, seals must be inspected for adjustment and replacement.=A0 The casings in the energy wheel lose their effectiveness and need to be replaced after several years.=A0 The drive motor and v-belt and chain also require inspection and maintenance.

Care also must be exer cised when the exhaust air stream has a high moisture content and the incom ing air stream could be lower than 32 F.=A0 When it is below freezing outsi de, the cold incoming air could drop the wheel temperature below the dew po int of the exhaust air causing water drops to form.=A0 These water drops co uld then freeze on the wheel causing deterioration of the wheel materials.& quot;

But it's the first line o f the quote from the manual that is most important:=A0=A0 "...there is leakage between the exhaust and supply air zones."=A0 Look hard at th e mechanical drawings of the heat wheel system.=A0 To believe that thing on ly returns 4% of the contaminated air to the building as the manufacturers claim you& #39;d have to believe that you can assign a section of a Jacuzzi for peeing .

Monona

In a message dated 6/21/2011 4:21:44 PM Eastern Daylight Time, kauletta**At_Symbol_Here**NOTES.CC.SUNYSB.EDU write s:

Do any of your buildi ngs have a heat recovery wheel in the HVAC/Fume hood system? Our newest bui lding has a heat recovery wheel installed for LEED certification but new re searchers are questioning the safety of this system (energy research).

I do not understand how these systems work. The architect has forwarded some white papers, but these are vague, at best, on chemical safety data &testing.

If you have a heat recovery wheel in a chemistry building -

How did you determine it was safe to use?
Do you have chemical restrictions?
What criteria do you use for restricting chemicals because of this system?

Any help or insight you could provide is greatly appreciated!

Kim Auletta
Lab Safety Specialist
EH&S=A0=A0=A0 Z=6200
Stony Br ook University
kauletta**At_Symbol_Here**notes.cc.sunysb.e du
631-632-3032
FAX: 631- 632-9683
EH&S Web site: http://www.stonybrook.edu/ehs/lab/

Remember to wash your hands!

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