ASHRAE Journal - November 2021 - 33

ROUNDTABLE
refrigerant, not the A2Ls. So the second edition of UL
60335-2-89 for example is going to allow for open cases,
up to 500 grams (1.1 lb) of an A3. For closed-door cases,
because you think if you have an evaporator leak that
refrigerant could accumulate in the closed door case,
or that drawer case and not come out all at once, we're
allowing only 300 grams (0.67 lb).
Commercial refrigeration, when we're using the A3s,
we have this test. It is Annex CC in UL 60335-2-89 where
we are looking at the concentration at 50% LFL around
the enclosure, because a commercial kitchen has many
ignition sources. An A3 is highly fl ammable, and can be
really explosive. So, if you fail the Annex CC test and get
above 50% of the LFL around the enclosure, we're saying
you cannot put an ignition source within 20 ft (6 m) of
that. That's a marking that is going to go on the equipment,
and that's carried over into ASHRAE Standard
15. So in the commercial kitchen, it's going to limit the
size of that commercial refrigerator. You're not going
to be able to have one of these cases that has 300 grams
(0.67 lb) of an A3 located in that space.
Kujak: I think a lot of readers can relate to commercial
refrigeration, because every time I go to the grocery
store, almost everything has a door on it now to meet the
U.S. Department of Energy effi ciency minimums.
Rodgers: Right.
Kujak: So it seems we're going to more and more to
enclosed spaces for everything in the refrigeration area.
Butsch: That was one of our concerns when we developed
the standard: retrofi tting doors onto equipment is
common practice today. But with a fl ammable refrigerant
that won't be allowed, unless you bring the whole
case into compliance with the lower charge limits and
mitigations outlined in UL 60335-2-89 and ASHRAE
Standard 15.
Kujak: Who regulates that? Let's say a grocery store
hires somebody and says, " I'm going to put doors on all
my open cases. " What jurisdiction has authority over
these installations to show compliance?
Grider: If you do that, and you had a listed refrigerator
display case, and you put a door on it, if that is not part
of the listing to have that door on it, it is now no longer
listed, because you modifi ed the construction. So you
would technically not have a listed product anymore.
Tharp: Proposed addendum l to ASHRAE Standard
15-2019 says it has to be approved for a door to be put on.
As to who actually enforces it, it's the same as all codes.
Right? There's a local authority having jurisdiction (AHJ)
who does the enforcement aspects. As people note concerns,
there will be people who do things and don't follow
the code and don't pull permits, that does happen.
But as a general rule, if people are following the rules, an
AHJ will come to validate the change.
Kujak: Is that a rigorous process?
Tharp: I'm going to say Brian Rogers and Craig Grider
probably have a lot more interaction with AHJs than I do.
But, based upon my knowledge, it's a challenge sometimes
for contractors to go get in line for an inspection
by the AHJ. And I've seen places where AHJs are very
picky.
Grider: These days, just given the way things are going,
it could be longer queue times for inspections and
approvals. I will say by the time a request for a site evaluation
gets to UL or any safety consultant, it's usually a
quick turnaround for us to complete the work. When we
come out, we're just assessing the installation with minimal
testing; we're looking at the construction and comparing
it to the safety standard, and once we complete
all our checks we are giving the AHJ the information they
need to feel comfortable with it. So, I think probably just
like what Rusty was saying, just the queue time getting
the AHJ involved because-like so many of us currently-
they are backed up too. What do you think, Brian?
Rodgers: Yeah, it's what we'd call fi eld evaluation.
That's called out in proposed Addendum i to Standard
15. So one of the options is, the AHJ can say, " I want an
NRTL [nationally recognized testing laboratory] to come
out and do a fi eld evaluation. " Craig says, " One of the
NRTLs can come out there, evaluate that product, make
sure now that it's got a door it doesn't exceed that 300
gram [0.67 lb] charge. " We may want to do some followup
testing. Did the manufacturer actually do some testing
prior where the door is an option already? That type
of thing. We'd come out there and do that evaluation. It's
done today when they modify equipment in the fi eld.
Kujak: Do the standards prevent people from converting
units from Class A1 refrigerants to Class A2L, A2 or
A3 refrigerants? Is that called out specifi cally?
Tharp: Yes, both Standard 15 and Standard 15.2P specifi
cally say you can't change refrigerant classes.
Rodgers: Actually, the EPA came out and made it a law
that you cannot retrofi t household refrigerators from
R-134a to an A3. Really, they're using isobutane in many
household refrigerators. There was a big rash of that,
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ASHRAE Journal - November 2021

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