ASHRAE Journal - November 2021 - 29

ROUNDTABLE
So now, we have had to look at products that span from
small room air conditioners all the way up to large
chillers that operate at thousands of volts. With that,
it becomes diffi cult to look at how we need to apply
requirements for the safe use of fl ammable refrigerants
across the entire board of HVAC and refrigeration
products.
The main focus currently for most of the industry is
A2L refrigerants. We have accepted A2s and A3s into the
safety standards, but for now at least, the charge limitations
are much lower than those of A2Ls. The industry
is going to need to work doing research and updating
these standards on a continuous basis as we try to keep
up with the new designs and innovative technology that
will come with the change to fl ammable refrigerants. So
again for me, this is a huge scope we're looking at, and
that's why it's taken over a decade with a lot of research
testing and discussions by the industry to get to this
point.
Kujak: I know there's discussion around charge limit
changes and detectors for use of fl ammables. Let's talk a
bit about that.
Brian Rodgers: We started on international standards
fi rst, which stemmed from IEC SC61D, the international
subcommittee responsible for IEC 60335-2-40 for airconditioning
equipment and the UL SDP (Standard
Development Process). We decided to join forces, and
work on the IEC 60335-2-40 standard fi rst. We brought
this back and drafted the UL-60335-2-40 with North
American deviations. Once research and consensus
was achieved, we proposed the same A2L requirements
to UL 60335-2-89. We decided to put UL 60335-2-89
[Household and Similar Electrical Appliances - Safety - Part 2-89:
Particular Requirements for Commercial Refrigerating Appliances
with an Incorporated or Remote Refrigerant Unit or Compressor]
for commercial refrigeration on hold and do all the work
in the air-conditioning industry fi rst and then bring that
into the UL 60335-2-89 group to harmonize safety practices.
As of the date of this roundtable recording, the second
edition of UL 60335-2-89 was to be published in the
U.S. on Oct. 27. We tried to harmonize the charge limits,
and the mitigation schemes, and detector requirements
as much as possible between the UL 60335-2-89 and the
UL-60335-2-40.
If you look at the third edition of UL-60335-2-40 that's
currently published, and the UL 60335-2-89 standard ,
a lot of the requirements and concepts for charge limits
and mitigation strategies are very similar. We are working
on the fourth edition of UL-60335-2-40. It's gone
out for preliminary review; we're currently reviewing
well over 700 comments that were received, and the
standards are diverging as the two working groups have
different opinions on what is safe for the two types of
equipment. The commercial refrigeration requirements
are going to be quite a bit different. You think of a multisplit
system-they really have the same thing in commercial
refrigeration where you've got a rack system back in
the back in the machinery room, and you're supplying
several cases, whether they're freezer cases or refrigeration
cases. Each standard has the same kind of concepts.
Keep it below the lower fl ammability limit (LFL) .
We have this M1 charge limit-M1 is the charge limit
when only room area is used to determine the charge
limit: M1 ≤ 6 × LFL. Above that we have to look at mitigation,
and that involves mitigation methods like turning
on safety shutoff valves, or turning on fans, shutting
down compressors, or maybe leaving them on if it
reduces the leak rate. So there's a lot of harmonization
between commercial refrigeration and the air-conditioning
world. But one thing we're looking at is-we've
done so much research-we've involved the fi re service
and the building code guys into developing these
requirements. There have been struggles. We've done
a lot of training out there, and the fi re service and the
code guys are starting to see that we really can have safe
equipment using fl ammables. As long as the installation
is done properly to the manufacturer's instructions, you
can have a safe application as well.
Grider: Following on what Brian was saying, one of the
major installation changes happening in the codes and
standards for charge limitations is that we are looking at
the releasable charge. So that it's not just about the total
About the Roundtable Contributors
Rusty Tharp, Member ASHRAE, senior director of regulatory affairs, Goodman
Manufacturing Company | Craig Grider, P.Eng., Associate Member ASHRAE, regional
chief engineer-HVAC, refrigeration, and gas appliances, Intertek | Brian Rodgers, senior
director of regulatory affairs, Goodman Manufacturing Company | Jennifer Butsch,
Associate Member ASHRAE, director of regulatory affairs, Emerson Commercial and
Residential Solutions | Jim VerShaw, Member ASHRAE, chief engineer, residential HVAC
& supply, Trane Technologies | Greg Relue, Principal, VRG Consulting LLC, representing
Emerson Climate Technologies | Moderator Steve Kujak, Member ASHRAE, director of
next generation refrigerant research, Trane Technologies
N O V E M B E R 2 0 2 1 ashrae.o rg ASHRAE JOURNAL
29
http://ashrae.org
ASHRAE Journal - November 2021

Table of Contents for the Digital Edition of ASHRAE Journal - November 2021
