Shutting the door on vehicle collisions

Published:  04 June, 2015

Busy loading bays can be frantic places and therefore dangerous, but automation can be the key to maintaining order while ensuring safety and enhancing productivity. Tony Saunders of sara LBS explores the options for optimising operations.

There is a little bit of the Luddite in all of us; we are all capable of wondering if this function or that activity really benefits from automation or whether a manual solution would be just as effective. For instance, nowadays, many high-street shops have doors that open automatically when a customer approaches; it is tempting to think that most people are perfectly capable of pushing the door open themselves. However, ask the facilities’ manager and you will be told about heat loss control, the marketing manager will explain about welcoming in customers and the general manager will highlight wheelchair users, child safety, people carrying shopping or pushing buggies, guide dogs, etc.

When it comes to automating doors, the critical point is usually how frequently they are opened and closed. If they are used a lot, chances are that it will be worth installing a powered actuation mechanism. The actuator will require at the very least an open/close button – from which it is not a giant leap to look at full automation.

Industrial loading bay doors function to provide security, thermal insulation, fire protection and vermin control. And if the loading bay is busy, powered doors are almost a prerequisite. An automated door system is able to monitor its surroundings and adapt to conditions. For instance, in winter it may be essential to keep the door shut as much as possible to keep the heat in, while in summer the opposite may be true. Alternatively, security or hygiene may be the major concern, so minimising open times will be the main objective. In commercial warehouses and manufacturing plants, productivity will be a major concern, so opening will need to be optimised against the arrival of goods, people or vehicles.

In a busy manufacturing or logistics environment, automated loading bay doors can improve flow and increase productivity by reducing bottlenecks.

There are many different technologies available for automatic door operation. Some are suitable for retrofitting to an existing door, others are completely integrated systems; some work by detecting relevant events as they happen (e.g. an approaching vehicle or goods coming down a conveyor belt) others are fed data from say an automated production line or a remote gatehouse. So before selecting a door system, expert advice should always be sought - with future development possibilities being fully considered.

Let us consider some options, starting with probably the simplest – movement detection systems. There are many types of motion sensors available including radar, pressure pads and photoelectric switches. These can detect approaching traffic, goods and pedestrians from any suitable distance (defined by the physical environment and the needs of the application), and activate the doors in a safe and timely manner.

Some applications may require a heightened level of security, only allowing access to authorised personnel. Here, radio or infrared technologies could restrict access to only personnel or vehicles carrying an appropriate transmitter. Elsewhere, a work area may be unsuitable for pedestrian access, in which case weight-sensitive induction loops set into the floor may be best.

In an automated manufacturing environment or a high-speed, high-throughput logistics’ warehouse, a computer system is used to control and coordinate all production operations. Overall, this is highly complicated, but it can be broken down into a series of simple on/off digital data signals, each one controlling a single switch. It is perfectly feasible that such a signal is transmitted to the loading bay control system.

In some situations doors can open slowly; in others, say where fast-moving forklifts operate, speed has to be married to safety if traffic is to flow freely. In such cases the automated detectors must be configured to activate early enough for the doors to open in time. Closing speed is often required to be relatively fast, so that the door is carrying out its primary job of protection for longer.

There are many options for the door activation system and just as many options for the detection and control systems. Identifying the best configuration for any given site is probably best done with expert support, but should result in a solution that allows the door to become a useful tool in effecting site-wide efficiency, rather than a simple protective barrier.

Automated loading bay doors can also help improve site safety. An obvious potential problem is if something or someone gets trapped in the doors as they close. Fortunately, automated doors can be programmed to detect possible obstructions and stop moving, and there are many technologies that provide this protection. Photocells can prevent doors from closing if an object is within their boundary. Self-testing contact edges are also popular, reversing automatically if they make light contact with anything as the doors close.

Loading bay door controls can be integrated with traffic lights, gates and barriers, so that they open automatically as lorries approach. They can also work with fire alarms, intruder alarms, etc. to automatically override normal operations. Other automated systems can prevent machinery inside the building from operating unless the doors are fully closed as a safety feature, or to detect the size of an approaching vehicle and open the door sufficiently to allow clear access, but not excessively, which would allow heat to escape or unauthorised people to enter.

Loading bay door controls can be very sophisticated. An optimal solution will enhance a facility’s operations and help control costs.

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