ASHRAE Journal - February 2020 - 51

standards have been referenced where appropriate,
such as ANSI/ASHRAE/ASHE Standard 170, Ventilation
of Health Care Facilities, and ANSI/ASSP/AIHA Z9.5,
Laboratory Ventilation.
"There has also been an emphasis in equipment and
building performance that recognizes improved humidity control and attention to ozone-producing devices,"
she said.
The 2019 update includes new material in sections
5.1, which details maximum indoor dew point to reflect
concerns of designers and practitioners, and 5.7, which
addresses ozone-producing equipment, according to
Isenbeck.
Hoy Bohanon, P.E., Life Member ASHRAE, who served
as the committee's chair from 2015 -2019, said designers
can develop more efficient air distribution systems by
taking credit on zone air distribution effectiveness (Ez)
with the standard.
Isenbeck also recognized other ASHRAE members for their contributions to this update, including
Bohanon and committee and subcommittee chairs
Wayne Thomann, Member ASHRAE; Tina Brueckner,
Member ASHRAE; Nathan Ho, P.E., Associate Member
ASHRAE; Dan Pettway, Life Member ASHRAE; and Brian
Hafendorfer, P.E., Member ASHRAE.

Standard 62.2:
Easier to Understand, Apply
The biggest barrier in residential indoor air quality is
most residences do not have ventilation systems, said
Iain Walker, Ph.D., Fellow ASHRAE. This is changing
as the adoption of ANSI/ASHRAE Standard 62.2-2019,
Ventilation and Acceptable Indoor Air Quality in Residential
Buildings, increases in new construction, but remains a
major challenge.
The standard's 2019 update allows for more design
flexibility through the use of the optional particle filtration credit. The standard's compartmentalization
requirements will mean designers and practitioners
need to pay more attention to this aspect of building
construction to be in compliance with the standard, said
Walker, chair of the standard's project committee.
Walker said the most important technical updates:
* Give the industry more flexibility (by allowing a
ventilation credit if advanced particle filtration systems
are used);
* Make field testing easier (by including calculations

for single-point envelope leakage testing);
* Improve system design and selection processes (by
more correctly accounting for the differences between
balanced and unbalanced ventilation systems); and
* Take the first steps to better approaches for multifamily dwellings (by having new compartmentalization
limits).
"Across the buildings community these changes will
allow for improved specifications of residential ventilation that result in more consistently having homes with
acceptable indoor air quality," he said. "The combination of increased flexibility for compliance together with
changes for clarity of intent and simpler field-testing
options make the standard easier and more consistent to
use. In turn, this makes it easier for the industry to build
homes that are 62.2 compliant or to upgrade existing
homes to meet the standard."
He said one of the biggest challenges the committee
faced during the revision process was making sure users
and adopters could understand the standard.
"Many of the changes from the 2016 version of the
standard were to clarify the language in several sections
in response to change proposals and interpretation
requests. Some of this is the result of increased adoption
of the standard and a corresponding increase in questions and issues from users," he said, adding that the
project committee plans to continue to work to clarify
the standard to make it applicable to high-rise and lowrise residential buildings.
Other changes in the 2019 update both simplify the
calculations and lead to better estimates of total ventilation that will not require significant changes to building practice. There may be small changes to minimum
mechanical system airflows for unbalanced systems,
but this will still allow ventilation systems to be installed
that designers and practitioners are already familiar
with, said Walker. The standard also allows for singlepoint envelope leakage test results to be used when calculating infiltration credit.
During the revision process, the committee discussed
various aspects of residential IAQ, said Walker, including
how difficult it is to test a multi-family dwelling unit for
air leakage and how to balance the IAQ improvements
from better particle filtration with other contaminants
to allow for ventilation credits.
Walker said developing requirements for unvented
combustion was a significant challenge, and the
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