ASHRAE Journal - October 2022 - 10

LETTERS
* How is the finding valid when
the products' liability record of 25
million units over 42 years does not
reveal emission-related concerns?
* How is this finding valid when
the preponderance of evidence
indicates otherwise?
These questions are very consequential
as the assertions of this
article formed the basis for SSPC
62.2 to vote to publish Addendum j,
which is a ban on unvented gas
heating products. For such an
extreme action to occur, the evidence
should be overwhelming and
incontrovertible. Such evidence is
nonexistent, not even close.
Sue Walker, Bowling Green, Ky.
The Authors Respond
The letter writers bring up a variety
of points that are common issue
for the industry. In the writing and
reviewing of our paper, we considered
all of these points. The authors
do not have space to rebut all these
issues, but offer a short summary:
Ron Smith implies that the equipment
we used does not actually
meet the Z21 standard to which it
was certified. We did not measure
the performance of any equipment
to know; rather we assumed that
the equipment does minimally
meet that safety standard and that
the home otherwise minimally met
Standard 62.2.
Our purpose was to find out
under what conditions (e.g., burn
rate) both standards could be met
and acceptable IAQ could still be
achieved. While the article does
not advocate for a product ban, or
any other changes to the standard,
members of either committee can
use this information to improve
their standard. The article merely
10
enables solutions to safely achieve
acceptable IAQ.
Eric Adair opines that our moisture
calculations were incorrect
because the ventilation rate we
used is 14 times too small. Since
moisture (like carbon monoxide)
turned out not to be a limiting factor,
it would not matter even if true,
but we can assure him the psychrometrics
were properly done. His
confusion may be because the IECC
value he cites is for air tightness
and not ventilation.
We would also disagree with his
assertion that 70% indoor relative
humidity would be acceptable.
Anything near this could be a disaster
(for example, in a cold climate),
as many ASHRAE publications have
shown.
Frank Stanonik objects to our use
of carbon dioxide as a contaminant
of concern, citing ASHRAE's position
document on carbon dioxide.
A careful reading of that document
would show that that position is
looking " at commonly observed
indoor concentrations, " which
are typically around 1,000 ppm.
At some concentrations higher
than commonly observed, carbon
dioxide becomes a health hazard;
and thus, becomes a contaminant
of concern to be controlled rather
than just a metric. Mr. Stanonik
calculates that it is possible to get
2,500 ppm just from people's exhalations.
While that is certainly true,
it is not true in any space meeting
ASHRAE's ventilation standard and
thus his concerns do not apply to
our article.
Despite the clear and supported
assumptions of what the article is
doing, several of the letter writers
object to the article using
ASHRAE JOURNAL ashrae.o rg O CTO B E R 2022
steady-state and thus not considering
that some of the equipment
may cycle because of a thermostat.
It is certainly true that in some situations
steady-state might not be
achieved, but as neither of the two
standards have any requirements
about thermal load, temperature
settings or on-time length, it can
easily be true that the equipment
could be used for many hours in
a row. The rather extensive information
the letter writers refer to
that uses cycling, or does not use
minimally acceptable equipment
or does not meet Standard 62.2, is
thus not very useful for the article's
purpose.
Several of the letter writers take
the position that our article is
flawed because there has not been
enough successful litigation against
manufacturers. Admittedly, we
did not consider lawsuits to be relevant
to calculating contaminant
levels. Rather, we set out to enable
improvements to IAQ in homes by
advancing the arts and sciences of
HVAC&R.
Max Sherman, Ph.D., Fellow/Life Member ASHRAE,
Moraga, Calif; Philip Fairey, Life Member ASHRAE,
Cocoa, Fla; Roy Crawford, Ph.D., Life Member ASHRAE,
Norman, Okla.
ASHRAE Journal welcomes
letters to the editor. The letters
should be no more than
250 words and must relate
to an article published in
ASHRAE Journal.
Please send your letters to
rebecca@ashrae.org.
https://www.ashrae.org/
ASHRAE Journal - October 2022

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