Automatic door operators fall into three primary categories, each designed for different traffic patterns, accessibility requirements, and safety profiles. The correct category depends on the application, the expected volume of use, and whether the door must remain operable as a manual opening when the operator is de-energized.
Low-Energy Automatic Door Operators
Low-energy operators, governed by ANSI/BHMA A156.19, are the most commonly specified type for ADA accessibility retrofits and interior commercial applications. These operators open and close doors at reduced speeds and forces, which eliminates the need for presence sensors in many installations. The low kinetic energy output means the door will not cause injury if it contacts a person during its swing cycle.
Low-energy operators are appropriate for interior corridor doors, restroom entries, office suite entrances, and healthcare facility doors where pedestrian traffic is moderate. They typically operate on a push-and-go basis (the user initiates movement by pushing the door slightly) or through an activation device such as a push plate, wave sensor, or card reader.
ANSI A156.19 specifies maximum opening and closing speeds, maximum force thresholds, and hold-open timing parameters. The standard also requires that low-energy operators allow the door to function as a manual opening when power is removed, which is critical for egress during power outages.
Full-Power Automatic Door Operators
Full-power operators, governed by ANSI/BHMA A156.10, deliver higher opening and closing forces and are designed for high-traffic entrances where doors cycle frequently throughout the day. Supermarket entries, hospital main entrances, airport corridors, and retail storefronts are typical full-power applications.
Because full-power operators move doors with sufficient force to cause injury, ANSI A156.10 requires the installation of safety sensors to detect pedestrians in the door swing path. These presence sensors must comply with UL 325, which sets safety requirements for door, drapery, gate, louver, and window operators and systems. The sensor array typically includes overhead presence sensors, guide-side safety sensors, and in some cases, floor-mat activation zones.
Full-power operators can be configured for one-way or two-way traffic, and most models offer adjustable speed, hold-open duration, and backcheck settings. On fire-rated openings, full-power operators must release the door to the self-closing device upon fire alarm activation.
Power-Assist Operators
Power-assist operators reduce the effort required to open a door without fully automating the opening cycle. The user must initiate the opening motion, and the operator supplements the applied force to reduce the effective resistance below ADA thresholds. Once released, the door closes under its own closer power.
Power-assist operators are governed by ANSI/BHMA A156.19 (the same standard covering low-energy operators) and are commonly specified where full automation is not desired but where the door closer's resistance exceeds the ADA maximum of 5 pounds of force for interior doors. They are frequently used on heavy fire-rated doors where the closer spring tension required for reliable latching makes manual operation difficult for some users.
