Certified equipment ratings for HVAC

Keeping abreast of standards is a must for specifying equipment.

By J. Patrick Banse, PE, LEED AP, Smith Seckman Reid Inc., Houston August 4, 2010
At a Glance

Standards organizations regularly develop and update standards for HVAC products and equipment, identifying minimum safety levels as well capacity and performance criteria. Although keeping up with the standards can sometimes be difficult, talking to equipment manufacturers and reviewing information on standards organizations’ websites are two ways to stay in the loop.

HVAC engineers and designers spend much of their time during the design phase of a project selecting and specifying all types of air moving, heating, and cooling equipment. During the construction phase, when the contractor provides submittals and product data for the HVAC equipment, the submittal information must then be reviewed to determine general compliance with the contract documents. One of the ways engineers set minimum requirements is to specify products and equipment that meet established certifications, test requirements, and procedures.

Nationally recognized testing groups and standards writing organizations have long been in existence to create these minimum requirements. As products are updated or new ones created, new test procedures and standards are developed. Some standards that have been in use for a while are updated to account for higher equipment efficiencies or a change in material or design that performs the same function.

Standards organizations test products and write standards, many of which are referenced in model building codes and in manufacturer’s literature. The sidebar lists some of these code and standard writing organizations.

Each organization writes its own standards, but in some cases ANSI has jointly written and/or approved a standard with other organizations. ANSI/AHRI Standard 430, Central Station Air Handling Units, and ANSI/NEMA MG1, Motors and Generators, are just two examples.

Many standards are written to identify a minimum level of safety for a product in addition to capacity and/or performance. A standard will have the standard writer’s designation along with an identifier or designation such as AHRI 430. It is important to identify the year of the adopted standard or the latest version the equipment was built to or tested under. This method ensures that the specifier’s intentions and expectations are met and may avoid any confusion with differing editions of the same standard. 

The following products and equipment are some of the many that, when specified, are required to meet certain standards and test procedures by virtue of the referenced standard.

Central station air handling units

Central station air handling units as a whole, as well as their multiple components, are built and tested to many standards. Air coils are tested to certify capacities and pressure drops and are selected in accordance with AHRI (ARI) Standard 410-2001, Forced-Circulation Air-Cooling and Air-Heating Coils. Air handling units with fans are rated in accordance with AHRI 430-2009, Performance Rating of Central Station Air Handling Units, for airflow, static pressure, and fan speed performance. UL 1995-2005 (formerly UL 465) tests for heating and cooling equipment safety. AMCA Standards 300-08 and 301-06 identify the methods for sound testing of fans and calculating sound ratings from laboratory test data. AMCA Publication 611-10 is a certified ratings program-product rating manual for airflow measurement stations. ANSI/NEMA MG1-2009 covers the air handling unit motors. AMCA 210-07 covers fans and identifies Laboratory Methods of Testing Fans for Certified Aerodynamic Performance Rating. Air filters are tested and MERV rated to ASHRAE 52.2-2007. Dampers, if installed, are tested to AMCA Standard 500-D-07, Laboratory Methods of Testing Dampers for Rating. AMCA Standard 610-06, Laboratory Methods of Testing Airflow Measurement Stations for Performance Rating, provides test methods for airflow measurement. ASTM C1071, ASTM C338, and ASTM E477 are applicable for test methods of thermal and acoustic insulation.

Air handling units that are tested and whose components have certified ratings are allowed to bear the seal of that testing organization, such as NEMA, AMCA UL, and AHRI. Equipment should be specified to bear the label of the testing and certifying organization as quality assurance to the owner.


Like air handlers, air- and water-cooled chillers must meet multiple tests and manufacturing criteria to earn the right to bear the label of the standards organization. AHRI 550/590-2003, Performance Rating of Water Chilling Packages Using Vapor Compression Cycle, identifies the minimum performance and predicts the anticipated efficiency that equipment has to meet at standard AHRI conditions for the integrated part load value (IPLV) and for the nonstandard part load value (NPLV). Chiller motors must comply with NEMA MG1-2009. UL 1995 provides for the safety of the heating and cooling equipment. ANSI/ASHRAE Standard 15-2007, Safety Standard for Refrigeration Systems, and ANSI/ASHRAE Standard 34-2007, Designation and Safety Classification of Refrigerants, require specific methods to safely handle, detect, store, and ventilate refrigerants used in the equipment and machine rooms.

The evaporator and condenser shell and tube sections must be constructed to the 2007 edition of ASME Boiler and Pressure Vessel Code, Section VIII, and carry the ASME stamp. ANSI/ASHRAE Standard 575-2008, Method of Measuring Machinery Sound within an Equipment Space, for indoor rooms, and AHRI Standard 275-2009, Application of Sound Rating Levels of Outdoor Unitary Equipment, may also need to be identified depending upon the type of water chiller being specified.


Fan types such as centrifugal fans, inline tubular centrifugal fans, belted vent sets, and similar housed fans must meet AMCA Standard 210-07 for fan performance ratings; AMCA Standard 204-05, Balance Quality and Vibration Levels for Fans; and AMCA Standards 300-08 and 301-06 for measurement and calculating fan sound ratings. Additionally, special use fans such as power roof ventilators must meet UL Standard 705-04, Standard for Power Roof Ventilators. Fans connected to grease ducts must meet UL 762-10, Power Roof Ventilators for Restaurant Exhaust Appliances. All fans should be certified to bear the listing agency label.


Particulate air filtration must meet ASHRAE Standard 52.2-2007 for filter efficiency, effectiveness, and MERV ratings for airflow and pressure drops and UL900-04, Standard for Air Filter Units. In addition, filter construction must meet NFPA 90A for flame spread and smoke developed ratings and UL 181 for air duct connectors. The manufacturing facility should meet the requirements of ISO 9001 for a certified manufacturing facility.


There are many kinds of dampers used in HVAC systems. Dampers are used for control functions; for isolation; for safety as static and dynamic fire dampers, smoke dampers, and combination fire smoke dampers; and for economizer use in air handling units. Leakage performance dampers such as control dampers, back draft dampers, and economizer dampers are tested in accordance with AMCA 500-D-07, Laboratory Methods of Testing Dampers for Rating, to certify the airflow, leakage amount, and static pressure drop of damper sizes at all anticipated airflow rates.

Fire dampers are tested to UL 555, Standard for Fire Dampers, to certify the operation and fire-resistance rating at minimum airflow velocities and minimum static pressures. The latest UL555 edition is 2006. Smoke dampers are tested to UL555S (1999 edition), Standard for Smoke Dampers, to certify operation of the damper with a factory installed operator, the leakage class at minimum airflow velocities, and minimum static pressure drops. Both standards identify the safety requirements of the damper and were approved by ANSI in May 2010.

Fire and smoke dampers also must meet the requirements of NFPA 90A, 92A, and 92B for smoke management systems. Dampers complying with the test procedure are licensed to have the AMCA and UL seals affixed to the damper.


Not all co-standards—ANSI/UL, for example—are adopted or approved at the same time. For instance, although UL may have written and approved a standard in 2004, ANSI may put it in its next review cycle and the standard may not get approved until several years later.

Keeping up with adopted and latest editions of the standards can be a chore, especially when trying to keep a master specification up to date. It is best to talk with equipment manufacturers and review applicable standards regularly with the writing organization’s website. As a specifier and designer, it is good to be familiar with the testing and measuring criteria to which the standard applies, so you know what to expect and do not require items that may be irrelevant or difficult to achieve. Reading the standards once in a while is also a good practice to keep informed.

Banse has more than 30 years of experience in the consulting engineering field with the past 25 years in healthcare design and engineering. He is a member of Consulting-Specifying Engineer‘s Editorial Advisory Board.

Code and standard writing organizations

  • Underwriters Laboratories (UL), www.ul.org
  • Air Movement and Control Association (AMCA), www.amca.org
  • National Electrical Manufacturers Association (NEMA), www.nema.org
  • Air-Conditioning, Heating and Refrigeration Institute (AHRI), www.ahrinet.org
  • American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), www.ashrae.org
  • Institute of Electrical and Electronic Engineers (IEEE), www.ieee.org
  • American National Standards Institute (ANSI), www.ansi.org
  • American Society of Mechanical Engineers (ASME), www.asme.org
  • National Fire Protection Association (NFPA), www.nfpa.org
  • Air-Conditioning and Refrigeration Institute (ARI), www.ari.org