ASHRAE Journal - May 2023 - 48

TECHNICAL FEATURE
FIGURE 1 The compliance path and flow for air leakage requirements in Standard 90.1-2022.
Or
5.4.3
Air Leakage
5.4.3.1.1
5.4.3.1
Whole Building Air
Leakage Testing
And
And
And
5.4.3.2
Continuous Air
Barrier Design and
Installation
5.4.3.3
Loading Dock
Weatherseals
5.4.3.4
Vestibules and
Revolving Doors
Less than 10,000 ft2 and Single
Zone: ASTM E779, ASTM E1827,
or ASTM E3158
been removed because plants are not considered durable
or guaranteed to last the life of the building.
Air Leakage
Continuous air barriers have been required in most
buildings for a number of Standard 90.1 editions. Air barrier
requirements for commercial buildings underwent
significant changes in the 2022 edition through addendum
t. They include clarifications to the Whole Building
Performance testing methods, stringency, design phase
requirements, material and assembly requirements and
on-site installation verification requirements. These
updates improved performance related to air tightness
requirements and were found to be cost-effective. Figure 1
outlines the compliance path and flow for air leakage
requirements in Standard 90.1-2022.
Whole-building air leakage threshold criteria have
been updated in the following ways:
* The air leakage rate for compliance without having
to conduct further diagnostics was lowered from
0.40 cfm/ft2 to 0.35 cfm/ft2 (2.0 L/s·m2 to 1.8 L/s·m2).
* The air leakage rate for compliance when further
diagnostics are performed was lowered from
0.60 cfm/ft2 to 0.45 cfm/ft2 (3.0 L/s·m2 to 2.2 L/s·m2).
* Whole-building air leakage testing and measure48
ASHRAE
JOURNAL ashrae.o rg M AY 2023
Greater than or Equal to
10,000 ft2: ASTM E3158
5.4.3.1.4
Measured Air Leakage
Less than 10,000 ft2
and Single Zone
Or
Or
FP&T per 5.9.1.2
5.4.3.1.2
Greater than or Equal to
10,000 ft2 and Multizone
5.4.3.1.3
Alteration or Addition
Or
ment was required to be performed on buildings with
less than 10,000 ft2 (929 m2) of gross conditioned floor
area, while for buildings larger than 10,000 ft2 (929 m2),
the option remains to test or perform a visual inspection.
* ASTM E3158, Standard Test Method for Measuring the Air
Leakage Rate of a Large or Multizone Building, was added to
the acceptable test list. Its inclusion allowed alternate
test methods based on building size and complexity to
better align with the scopes of the ASTM standards.
* A clarification was added to Section 11, Normative
Appendix C and Normative Appendix G that accommodated
performance differences when compliance is
achieved through whole-building testing as opposed to
the verification without testing option. In addition, the
language modifications in Appendix G better describe
the path for capturing air leakage improvements when
minimum performance requirements are exceeded.
Other improvements to air leakage requirements
across Standard 90.1-2022 are as follows:
* Definitions for " air leakage " and " infiltration " and
their use in the standard are updated to correspond to
the correct requirements of Section 5.
* The SI value of 75 Pascals is the underlying requirement
for whole-building air leakage testing and is now
reflected in the revised I-P value.
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