Plant & Works Engineering
When is a door not a door?
Published:  03 March, 2016

The answer to this question that pops into most people’s head comes from a Christmas cracker, but Louise Nurse, sales manager for sara LBS, is more likely to respond: ‘When it is a part of an industrial or logistics facility.’

There is far more to industrial doors than their domestic counterparts. Consider, for instance, loading bay doors: primarily they provide security and protection for the external weather. But they may also be designed to ensure bio-security and hygiene defences, fire protection, heat and energy barriers, pedestrian access etc. Above all loading bay doors need to be able to open quickly, easily and safely to their full extent.

The optimum design of industrial doors will vary in relation to the needs of each specific situation, but the majority of solutions will be based around a small number of door designs. The main types of door are sectional overhead and roller shutter – which can be further split into solid profile and curtain doors.

Sectional overhead doors are made up of typically five or six full-width panels that are mounted in channels on either side of the door opening. In operation, they slide upwards, usually turning horizontal once clear of the top of the opening so that they are ‘parked’ well above head height. They can be manually, chain or motor driven, and, if the latter, they can be automated so that they open once a lorry has backed into position and close again when it leave to offer maximum efficiency, heat retention (or cold-retention in the case of say a food handling plant), security or bio-protection.

The door panels are typically made of steel or aluminium, but other materials can be used - a popular option is to include windows or to have whole panels that are transparent. They will include elastomer seals and can easily be thermally insulated for improved efficiency. If manually operated a spring mechanism can be included to make operation easier. Normally supplied with locks as standard, they are easily adapted for high security usage by the addition of high quality extra locks.

A pneumatic safety edge can be fitted to the bottom of the door, which will stop movement if it detects an obstruction. They can also be used with light curtains and other safety devices.

Because the door panels fit flush to the wall or ceiling of a warehouse they are particularly well suited to building where tall vehicles or high shelves are present.

Roller shutter doors are similar to sectional doors, but with the panels replaced by many narrow horizontal slats which interlock to provide a secure and weather tight seal. Instead of being parked flat, they are rolled up onto a rotating shaft in a manner similar to a carpet; with a storage housing often provided as an integral part of the system.

Traditional roller shutters, which are manual or motor driven, are the archetypal industrial door found in industrial parks across the country. Typically manufactured from steel slats they are relatively low cost and provide protection from vehicle collisions and break-ins. They are easy to install and can be designed with a secondary ‘pass’ door. They can operate at relatively high speeds (say 0.5m/sec) if motor driven and so provide a very secure option at an affordable cost.

Of course it should be noted that modern developments to the traditional design have seen a dramatic improvement to the performance figures of premium models.

Roller shutter doors are probably the most common choice for use as fire resistance and security doors. Normally open during operating hours, they will close automatically in the event of a fire and are designed to maintain integrity for typically four hours, protecting life and property and preventing fire from spreading.

High-Speed curtain doors in this instance are really the continuation of the roller shutter theme; however, instead of hard profiles, a flexible material (typically PVC, RollTex or NomaTex) is used to cover the doorway. While offering less protection than there roller shutter counterparts, the curtain design can fit to far smaller footprint and often offer faster opening and closing speeds – making them ideal for internal use.

High-Speed roller shutter curtain doors are used across many industries for a host of different applications. From providing speedy access to loading bays for loading/unloading, to specification in cleanroom environments or for machine protection services (using special curtains which protect personnel from machinery or welding splatter.

To conclude, there are as many different door designs and specifications as there applications where doors are required. Of the three basic designs there is no overall winner or loser, it really comes down to individual requirements. Speaking to an industry expert who is familiar with all the options is the best way of ensuring you specify a cost effective solutions which will perform to you requirements reliably and safely.

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