Opening the door to increased safety
April 1st 2008

Used in most modern warehouses and distribution centres, internal and external industrial doors are barriers that separate areas of a facility, yet allow passage through when required. If misapplied, misused or neglected they can be extremely hazardous, resulting in serious injuries, lost productivity and costly lawsuits.

Companies that pay proper attention to industrial door safety benefit from safer, more productive working environments explains Caljan Rite-Hite's Mike Hilton

Industrial door accidents generally fall into one of four categories: Downward impact (door hits person) – These accidents occur when a door comes down on a person standing in or passing through a doorway.

Entrapment – In these accidents, a person is trapped under a door and held down by its weight or the force of the drive system.

Lateral impact (person hits door) – Where a worker, either on foot or in a forklift, collides with the door.

Secondary impact – Where there is a secondary accident, such as when an impact causes the door to break away.

The heavy bottom bar swings outward, hitting someone on the other side.

Choosing a door suited to the application helps prevent accidents. There are many different industrial door types, such as high-speed roll-up, bi-parting, bi-rolling, sectional, rolling steel, screen, curtain and impact. Many of these are suitable for both internal and external use and have the option of manual or automatic activation.

Before choosing, study the application carefully. Is it an internal or external doorway? Is it for pedestrians, vehicles or both? Will the traffic flow be one way or two? Is vehicle speed near the door opening a concern? These are all factors that will have crucial health and safety implications.

Of the four types of accidents, downward impacts are perhaps the most common. Some manufacturers offer lightweight doors, which incorporate the usual safety switches and reversing mechanisms, but feature a soft bottom edge. This buckles upon impact, distributing the force of the blow and reducing the risk of injury. Doors of this type often incorporate infrared area detection sensors for extra safety.

Industrial doors frequently use reversing mechanisms to reduce the risk of entrapment. Reversing mechanisms use a pneumatic or electronic switch to detect an obstruction (i.e.

a person) in the doorway and automatically reopen a closing door. Recently, manufacturers have added fail-safe switches, which monitor reversing mechanisms and increase safety.

Photoelectric safety beams and sensors are available, which detect the presence of a person or forklift approaching or travelling through the doorway and prevent the door from closing.

Lateral impact occurs when workers (usually riding forklifts or other vehicles) collide with the door, or objects adjacent to the door. If the traffic is two way and visibility through the door is poor, forklifts can collide with other vehicles or workers on the other side. Lateral impact, although less common, is extremely dangerous.

Ensuring the traffic flows in one direction and putting plastic window panels into the door to improve visibility reduces the risk of these accidents.

Secondary impact makes initial injuries worse or causes new ones. These accidents can occur in several ways. For example, after an impact the reversing mechanism fully retracts the door. There is a risk the door could drag the injured worker up with it, or strike the worker again on its way. Many industrial doors open much faster than they close, so the secondary impact is likely to have more force. Modern reversing mechanisms retract the door just a few inches, just enough to take the weight off without risking secondary impact.

The door activation system can affect safety and requires careful consideration. Photo-eye sensors, induction loops and motion detectors activate doors automatically as vehicles approach, enabling high-speed travel. However, this could be dangerous if traffic becomes congested or pedestrians use the opening. Manual activation methods, such as radio controls, push buttons and pull cords, moderate traffic speed and increase safety levels.

Adequate staff training is essential. People that use the door must understand how it operates. Many door manufacturers will provide a safety training seminar if requested. Additional equipment, such as mirrors at blind corners and devices that signal an alarm when the door is about to open, may be useful.

Proper inspection and maintenance keeps industrial doors in good working order and reduces the chance of accidents. Facilities managers should ensure servicing takes place on schedule, without exception.

Choosing an industrial door is not easy. Door automation should be a positive feature for any facility, as it increases productivity and working efficiency. However, employers have a duty to protect their workers, so safety is paramount. A good manufacturer will provide a dedicated customer service and assist with initial planning through to design and implementation.

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