ASHRAE Journal - April 2013 - 25

fans7 in 2010 and AMCA International published Standard
205 in the same year. The AMCA standard focuses on defining a fan efficiency metric, called a fan efficiency grade
(FEG) based on the aerodynamic quality of the fan separate
from its motor and drive. The ISO standard has a harmonized definition of FEG, but also defines a metric that includes the motor/drive assembly, i.e., fan motor efficiency
grade (FMEG).
In 2011, the European Commission published the fan efficiency regulation, (EU) No. (327)/2011 that internalized sections of ISO 12759 that apply only to motorized fans using
the FMEG metric, with modifications.8 EU 327 took effect
on Jan. 1, 2013 with initial efficiency requirements. In 2015,
a second, more stringent, tier of efficiency requirements will
take effect. For more information about (EU) 327/2011, visit
www.amca.org/feg/fmeg.aspx. The remainder of this article
covers AMCA Standard 205 and U.S. fan efficiency codes and
standards.
In the U.S., the 2012 International Green Construction Code
adopted AMCA 205-10 for expressing fan efficiency requirements for supply, return, and exhaust fans greater than 1 hp
(750 W) for buildings less than 25,000 ft2 (2323 m2). The requirement has a minimum FEG rating of 71, and a fan sizing/
selection window of 10 percentage points from peak total or
static efficiency.
Earlier versions of Standard 90.1 had some fan efficiency requirements through the section on “fan power limits.”
However, this section primarily limits fan energy consumption through static efficiency requirements on air distribution
systems. It did not encourage manufacturers to produce more
efficient fans.9 Explicit fan efficiency requirements were adopted in Standard 90.1-2013 through ASHRAE’s continuous
maintenance process as Standard 90.1-2010 Addendum u.
Addendum u underwent an advisory public peer review in
2011, and a conventional public peer review in 2012.10 The
final language is shown in the sidebar, Fan Efficiency Requirements.
Because the AMCA 205 standard and FEG metric are relatively new to the industry, they are summarized below.

AMCA Standard 205
The scope of AMCA 205 is limited to fans having an impeller diameter of 5 in. (125 mm) or greater, operating with
a shaft power 1 hp (750 W) and above, and having a total efficiency calculated in accordance with procedures specified in
established fan test standards including:
• ANSI/AMCA 210 (ANSI/ASHRAE 51), Laboratory
Methods of Testing Fans for Certified Aerodynamic Performance Rating;
• ANSI/AMCA 230, Laboratory Methods of Testing Air
Circulating Fans for Rating and Certification;
• AMCA 260, Laboratory Methods of Testing Induced Flow
Fans for Rating; and
• ISO 5801, Industrial Fans—Performance Testing Using
Standardized Airways.
April 2013

Fan Efficiency Requirements
When Standard 90.1-2013 is published later this year,
it will contain some new fan efficiency requirements.
6.5.3.1 Fan System Power and Efficiency.
6.5.3.1.3 Fan Efficiency. Fans shall have a Fan Efficiency Grade (FEG) of 67 or higher based on manufacturers’ certified data, as defined by AMCA 205. The total
efficiency of the fan at the design point of operation
shall be within 15 percentage points of the maximum
total efficiency of the fan.
Exceptions:
a. Single fans with a motor nameplate horsepower
of 5 hp (4 kW) or less.
b. Multiple fans in series or parallel (e.g., fan arrays) that have a combined motor nameplate horsepower of 5 hp (4 kW) or less and are operated as the
functional equivalent of a single fan.
c. Fans that are part of equipment listed under
6.4.1.1 Minimum Equipment Efficiencies – Listed Equipment – Standard Rating and Operating Conditions.
d. Fans included in equipment bearing a third-party-certified seal for air or energy performance of the
equipment package.
e. Powered wall/roof ventilators (PRV).
f. Fans outside the scope of AMCA 205.
g. Fans that are intended to only operate during
emergency conditions.
Fans that cannot be tested to one of these standards are excluded from AMCA 205 and any code or standard with fan
efficiency requirements based on AMCA 205.
AMCA 205 defines FEG as “the efficiency grade of a fan
without consideration of the drives” and as “an indicator of the
fan’s aerodynamic ability to convert shaft power, or impeller
power in the case of a direct driven fan, to air power.” The FEG
is calculated using the fan’s peak total efficiency, fan size, and
application defined by its test configuration.
The FEG is an indicator of the fan’s aerodynamic quality.
It accounts for all the energy delivered to the airstream. As
such, the fan total pressure is used in the determination of the
FEG. For more information on fan peak total efficiency, see
Reference 11.
FEG calculation procedures are provided in Annex A of
AMCA 205. Generally, AMCA or fan manufacturers, not
HVAC system designers, contractors, or code officials, use
these calculations to establish the FEG. Once the FEG is determined, it is simply reported as fan data in manufacturers’
brochures and electronic software to engineers, contractors,
equipment packagers, etc., so they can establish compliance
with the applicable code or standard. Manufacturers can elect
ASHRAE Journal

ASHRAE Journal - April 2013

Table of Contents for the Digital Edition of ASHRAE Journal - April 2013