Applications
Air curtain applications primarily fall under one of three designations: environmental separation, insect control, and processing. The first two, typically, are of particular interest to owners and managers of commercial establishments, such as arenas and convention centers.
Environmental separation protects an exterior door from the unwanted infiltration of outdoor air and the escape of indoor air caused by the effects of wind and/or temperature differences. Research shows that in both warm and cold climates, an air curtain can reduce infiltration significantly (see references 1, 2, and 3).
Between interior rooms connected by a common opening, air curtains can be very effective in preventing unwanted infiltration of unconditioned air or the loss of conditioned air from one room to the other. Specialized applications that fall under this category include coolers, freezers, and ovens.
Flying insect control is a common requirement in facilities in which food products are produced or processed, such as kitchens, cafeterias, and counter services. For these facilities, air curtains provide the higher velocity airstream needed.
It’s important to note that air curtains perform best in a balanced or a positive-pressure building. Applications where a negative pressure exists because of, for instance, mechanical ventilation or stack effect require special considerations. Under negative pressure, an air curtain unit will not adequately protect an opening from unwanted infiltration caused by wind and/or temperature differences.
Codes and Certifications
Energy codes, such as ANSI/ASHRAE/IES 90.1-2019 and the IECC, allow air curtains to be used as an alternative to vestibules as a path to compliance. High-performance energy codes, such as ANSI/ASHRAE/ICC/USGBC/IES 189.1, “Standard for the Design of High-Performance Green Buildings Except Low-Rise Residential Buildings,” and the International Green Construction Code (IgCC), allow air curtains to be used in conjunction with vestibules to provide an even more efficient way to reduce building envelope infiltration.
For decades, air curtains have been included in state and local sanitation codes to help protect food service environments and, in some cases, are required to be in operation before an establishment can open.
Safety codes applicable to air curtains are based on a wide variety of standards and remain focused on life, electrical, and fire safety. Several organizations, including Underwriters Laboratories (UL), Intertek’s ETL SEMKO division, CSA Group, and International Organization for Standardization (ISO), define standards and, in some cases, test air curtains for compliance.
What these codes have in common is that they require validation through certification. While manufacturers are free to test products and publish their findings, certification requires a third party to test for compliance under its own programs.
Aerodynamic performance testing is among the most influential certification and is required by all energy codes. Air Movement and Control Association (AMCA) International was among the first internationally recognized organizations to perform aerodynamic performance testing.
ANSI/AMCA Standard 220, “Laboratory Methods of Testing Air Curtain Units for Aerodynamic Performance Rating,” and ISO 27327-1:2009, “Fans - Air Curtain Units - Part 1: Laboratory Methods of Testing for Aerodynamic Performance Rating," are used to determine aerodynamic performance in terms of airflow rate, outlet air velocity uniformity, power consumption, and air velocity projection for rating or guarantee purposes. The AMCA Certified Ratings Program (CRP) is used to certify that published performance data have been validated by a third party.
Air curtains for food service applications may be required to be tested in accordance with NSF/ANSI Standard 37, “Air Curtains for Entranceways in Food and Food Service Establishments.” This standard has an established testing procedure to address public health safety in food service environments and has both performance and construction requirements.
Lastly, there is sound performance testing. While there are many ways to measure sound, ANSI/AMCA Standard 300, “Reverberant Room Method for Sound Testing of Fans,” establishes procedures for determining the sound performance of air curtains. The data can be certified using the AMCA CRP.