Marc:
Since we are (virtual) friends, I will come out right up front and
tell you that I wrote the design documentation requirements for Std 62-89R.
I believe that creating the documentation listed there will tremendously
benefit everyone in the process, save money, and avoid disputes and law
suits. It will result in more satisfied clients (building owners), better
indoor air quality, and better system performance. It will allow future
designers (of tenant improvements or other modifications) to understand what
the system is designed to do and what it is.
There is lots of attention to the law suits and workers comp claims
following SBS problems, but there is very little attention to the far more
common problem of claims between and among design professionals, owners,
contractors, and tenants. There will be an enormous reduction in the law
suits and claims by using the required documentation to confirm with the
client, the contractor, and the TAB and commissioning agents that all that
is assumed is understood and agreed and that all that is required has been
accomplished.
I believe the standard is far from being ready to adopt. It will
require a substantial amount of work. The committee knew that when it put it
out to public review. We got over 7900 comments to prove it. However, I
believe that the bulk of the standard does what it is supposed to do and
should be adopted. I believe it reflects the knowledge in the fields of HVAC
engineering and indoor air quality in a reasonably balanced way. With the
exception of Section 6, I believe it is nearly ready to be adopted and that
all in those in relevant professional fields, trades, and disciplines would
do well to follow it now. What is in it will become the standard of care
eventually, and it is only a question of time and to many law suits until
that becomes more clearly and widely understood.
Section 6 on ventilation rates is complicated. I think it should be
clarified and refined. The committee is committed to publishing a manual
concurrently with the adoption of the standard. A spread sheet program
together with that manual will make what appears complicated in the current
language far simpler, I am certain.
On the other hand, I do not believe the general approach to
ventilation rates is any more complicated than the approach used in
structural engineering for buildings of similarl complexity. If you have a
simple structure, you look up each members' size in a table in the code. Std
62 lets you do that for single zone systems too. If you have a complicated
structural, you have to do some calculation that involves numerous
considerations. Designing big buildings (over 10,000 to 20,000 sq ft) for
good indoor air quality and efficient, economical ventilation is not simple.
Designing very large buildings (over 100,000 sq ft) is very important and
very difficult. The emphasis is on designing, not just selecting distinct
items from a catalogue - conceiving of HVAC within a system that includes
the whole building, its users and the environment. The HVAC system must be
pretty sophisticated to respond optimally to the almost constant changes in
demands on it coming from those major system components.
I believe 62-89R looks more complicated than it is. Try downloading
the spreadsheet from ASHRAE's web site. It will let you see a simple way to
do deal with systems. The multiple zone problem has never really been dealt
with adequately from an outdoor air supply requirement perspective. I urge
you to study it carefully and tell me (and the rest of the committee) if you
can think of a better way to handle it. I look forward to hearing your thoughts.
I have sent a copy of this message to most of the members of the
committee, since I think your perspective is shared by many folks out there.
Best,
Hal
At 08:29 AM 3/28/97 EST, you wrote:
>I believe the Standard 62-89R that Tom refers to is only a DRAFT - I asked a
>committee member if he thought it would be adopted by ASHRAE this year and he
>thought it doubtful. So it doesn't seem to me to be the new "standard of care"
>just yet.
>
>The most useful parts in it for me were the ways to assess how far exhaust
>components need to be from intake components and windows.
>
>I thought the new standard to be overly complicated and unwieldy, and likely
>that very few engineers who make their living designing these systems day in
>and day out were on the committee writing them - too complicated. Just check
>out the requirements for design documentation!
>
>Marc
.-
Hal Levin <hlevin@cruzio.com>
__________________________________________________________________
This greenbuilding dialogue is sponsored by Oikos (www.oikos.com)
and Environmental Building News (www.ebuild.com). For instructions
send e-mail to greenbuilding-request@crest.org.
__________________________________________________________________