ASHRAE Journal Supplement - AMCA InMotion - November 2021 - 23

When designing for resilience, thermally effi cient
dampers offer a level of protection against the elements
that standard control dampers do not. Their design
typically includes low-pressure-drop airfoil blades and
ultra-tight closure for AMCA Class 1A leakage. Dampers
rated for AMCA Class 1A leakage are the optimal choice
for shutoff and help to reduce costs attributed to wasted
fan energy or the infi ltration of extreme-temperature
outside air. When balancing performance, cost, and overall
resilience, thermally effi cient dampers are the premium
choice for airfl ow-, pressure-, and temperature-control
ventilation strategies.
Damper Performance and Certifi cation
Subsequent to being tested in accordance with ANSI/
AMCA Standard 500-D, dampers can be certifi ed for air
performance in accordance with AMCA Publication 511
as part of the AMCA Certifi ed Ratings Program (CRP).
The purpose of the CRP is to assure buyers, specifi ers,
and users of air-control devices that published ratings are
accurate and reliable. At the same time, the CRP assures
manufacturers that competitors' ratings are based on
standard test methods and procedures and subject to
periodic checks by an impartial authority. (For more on
the AMCA CRP, see " Inside the AMCA Laboratory and
Certifi ed Ratings Program, " Page 38.)
Conclusion
Understanding differences in the construction and performance
of control dampers allows designers and owners
to specify features that are essential and benefi cial to
damper operation. Specifying the correct type of control
dampers for your data-center ventilation strategy will
ensure system design requirements are met and provide
an environment conducive to the effi cient operation of
I.T. equipment. Validating the performance of dampers
ensures systems will operate within parameters to achieve
the overall design intent.
About the Author
Michael J. Bulzomi is director of marketing, louvers
and dampers, for Nailor Industries Inc. and a member of
the AMCA North America Region Air Control Advocacy
Committee.
www.amca.org
Triple-V blade
Flat blades
Airfoil blade
General damper-blade types. Source: AMCA Publication
502-06 (R2009), Damper Application Manual for Heating, Ventilating,
and Air Conditioning
SI Maximum Allowable Leakage, L/s/m2
Class at 0.25 kPa1 at 1.0 kPa1,3 at x kPa2
1A
15.2
1
2
3
20
51
203
N/A
40
102
406
N/A
2√ˉx × 20
2√ˉx × 51
2√ˉx × 203
I-P Maximum Allowable Leakage, cfm/ft2
Class at 1 in. wg1 at 4 in. wg1,3 at x in. wg2
1A
3
1
2
3
4
10
40
N/A
8
20
80
N/A
√ˉx × 4
√ˉx × 10
√ˉx × 40
Notes:
1. These pressures are required and shall be cataloged.
2. Any other pressure may be cataloged using these formulas.
3. Economizer dampers do not require leakage testing or published
ratings at this pressure.
TABLE 1. Allowable air leakage to achieve
classifi cation. Source: AMCA Publication 511-21, Certifi ed
Ratings Program Product Rating Manual for Air Control Devices
2021 AMCA inmot ion
23
http://www.amca.org
ASHRAE Journal Supplement - AMCA InMotion - November 2021

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