Automatic Door Injuries Expert Article

Door strikes are one of the most common pedestrian hazards related to automatic doors. A door that closes prematurely or with excessive force while the doorway is still occupied has the potential to cause injuries. While there are many types of automatic doors, this article focuses on pedestrian sliding doors.

Automatic Door Injury Expert Witness Investigations

The most common type of automatic pedestrian door is the bi-parting horizontal sliding door, which has two door panels that slide open in opposite directions away from the center. Since the panels slide out of the way, they maximize door opening space and accommodate higher traffic in both directions.

These doors are commonly found at the entrance/exit of large commercial buildings such as hotels, grocery stores, big box stores, hospitals, shopping malls, airports, business offices, and healthcare buildings.

Automatic Door Sequencing & Components

Modern automatic sliding doors are designed to open automatically when a person is detected approaching the door. Upon opening, the doors remain open for a minimum period and then close only if the doorway is clear and no additional approaching pedestrians are detected.

The speed and force with which the doors open and close can be programmed to optimize safety, the throughput of traffic, and heating/air-conditioning efficiency.

This functionality requires a series of sensors and motors working in unison.

• Motion Sensors:  Detect movement approaching the door. Various sensor types are utilized, with the most common sensor type being doppler radar.
• Safety Presence Sensors:  Detect objects and people in the doorway. Active infrared sensors are the most commonly used primary presence sensors. Photoelectric sensors are occasionally used as a second line of defense.
• Pressure Sensors:  Rarely used on modern sliding doors, pressure-sensitive floor mats were commonly used in the 1960s-1990s to trigger the door to open and hold the door open when stepped upon. Today, pressure sensors most commonly exist in vertical applications and on revolving door systems.
• Access Control Systems (on non-automatic door systems):  Keycard, keyfob, push button, or touchpad can be used to manually activate door opening. These are referred to as “knowing act” door activation systems.
• Controller:  Processes signals from the sensors to command the motor to open and close the door. The controller manages the open/close timing, open/close speed, and the closing force of the motor/door.
• Motor/Drive System:  Typically drives a belt to move the doors along their track.
• Backup Power:  Some systems include an uninterruptible power supply (UPS) to ensure the door remains operational during power outages.

Requirements for Installation, Inspection & Maintenance

Common types of automatic doors include swinging, sliding, folding, and revolving. Regardless of the type, automatic doors must be installed, inspected, and maintained in accordance with applicable standards and reasonable care.

Installation

Installation must include proper sensors (motion/safety presence), proper warning signs, proper speed and force limits set. Door installation must be performed by qualified professionals trained to understand the safety features and operation of the door.

Inspection

Daily inspections/safety checks must be performed by facility personnel to verify proper function, that sensors detect approach and presence correctly, that door stops or reverses if obstructed, and that doors operate smoothly and do not slam closed.

Annual door inspections should be performed by a qualified inspector.

Maintenance                                                                                                          

Routine servicing is required to ensure that doors/sensors remain clean, aligned, adjusted, and in proper working order. Maintenance logs should be kept, recording service dates, repairs, and inspections.

Malfunctioning safety devices must be repaired before the door is returned to service. Door maintenance must be performed by qualified personnel.

With limited exceptions, the information discussed in this article will generally apply to all types of automatic doors.

Automatic Sliding Door Injury Expert Investigations

The experts at Robson Forensic have investigated a broad range of incidents involving automatic doors. 

For more information, submit an inquiry or call 800.813.6736.

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Kenneth J. Kutchek, P.E., C.F.E.I., C.M.S.E.

Electrical Engineer & Industrial Controls Expert

Ken is an electrical engineering expert with more than 30 years of hands-on experience in industrial controls, automation, machinery, equipment, industrial safety and machine safeguarding. He applies… read more.