ASHRAE Journal - September 2022 - 29

COLUMN IEQ APPLICATIONS
that seeks to clarify what an unusual source is and adds
an informative note directing users to the informative
appendix, which includes descriptions of potential
contaminant sources considered by the committee
for spaces listed under the ventilation rate procedure.
Another clarifi cation was changing the term " cooling
towers " to " evaporative heat-rejection equipment "
and providing a new defi nition of the same to indicate
that requirements related to cooling towers apply to all
devices that evaporate water from open loops to reject
heat.
A change to the defi nition of recirculated air was made
to clarify that the requirements also apply to devices that
recirculate air within a space, such as chilled beams and
fan coil units. Finally, a clarifi cation was made to indicate
the conditions under which leakage and carryover
at energy recovery devices is to be determined and that
any air transferred through energy recovery devices is
not considered to be ventilation air.
Several requirements of the standard were made
to harmonize the requirements with other ASHRAE
standards. New to ANSI/ASHRAE Standard 62.1-2022
is the requirement that the designers include all
documentation required for the owner to comply
with ANSI/ASHRAE Standard 188-2018, Legionellosis:
Risk Management for Building Water Systems. This requirement,
and the aforementioned clarifi cation related to
evaporative heat-rejection equipment, builds on the
existing requirements intended to reduce the risk of
Legionellosis associated with HVAC systems.
Another change seeks to harmonize Standard 62.1 with
ANSI/ASHRAE Standard 62.2 by removing dwelling units
as a space under the Ventilation Rate Procedure (VRP).
This harmonization also unifi ed the air class of kitchen
exhausts and applied the recirculation restriction on
dwelling units to all sleeping rooms, including hotel
rooms and dormitories. The last harmonization effort
relocated the outpatient health-care occupancy spaces
from the VRP to a normative appendix. This change may
seem inconsequential to many, but Standard 62.1-2019
includes language which invokes ANSI/ASHRAE/ASHE
Standard 170, Ventilation of Health Care Facilities, for spaces
within its scope, and as of the 2021 edition of Standard
170 the outpatient health-care spaces appeared in both
standards, creating the potential for confusion.
Due to the way model code authorities incorporate
these standards, committee members representing the
International Code Council requested that the rates be
included in Standard 62.1 for non-health-care occupancies
(e.g., medical offi ces, schools), which is why the
outpatient spaces were retained in a normative appendix
for use when Standard 170 does not apply. The rates
in the new normative appendix were also updated to be
consistent with those in Standard 170.
A New Way
The most signifi cant change that users of ANSI/
ASHRAE 62.1-2022 will notice is that there has been
a major revision to the Indoor Air Quality Procedure
(IAQP). This change was begun as an addendum to the
2016 edition of the standard and has undergone four
publication public reviews and response to over 200
comments from more than 60 unique commenters. The
basic principles of the previous IAQP are unchanged;
the designer must still use mass balance analyses to
determine the concentration of contaminants and
combinations of contaminants, and the indoor air quality
conditions in the building must still be evaluated
subjectively. These changes have been clarifi ed with
new language, a formula presentation of combinations
of contaminants, and a list and concentration limits
of design compounds and PM2.5 that must be not be
exceeded has been added, as have specifi c combinations
of design compounds.
Notably absent is the inclusion of carbon dioxide;
for more information on why this is so, the reader is
directed to the ASHRAE Position Document on Indoor
Carbon Dioxide (https://tinyurl.com/bdcvh4yk). It is
important to note that the design compounds are not
exhaustive and that the designer is obligated to include
additional contaminants based on the local air quality
assessment and those contaminants that the designer
deems relevant and for which a cognizant authority has
established a design limit, which may include carbon
dioxide in some countries.
This new IAQP has also cleared the way for the publication
of a companion addendum related specifi cally to
exhaust systems, which was approved previously but
not published until the new IAQP procedure was available.
The new addendum includes references to ANSI/
ASHRAE Standard 154 for kitchen exhaust, exclusions
for open parking garages based on model building codes
and additional requirements related to combustion
sources and laboratories.
S E P T E M B E R 2 0 2 2 ashrae.o rg ASHRAE JOURNAL
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ASHRAE Journal - September 2022

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