The Association of Loading
and Elevating Equipment Manufacturers

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Double trouble

Continuing the series of articles from The Association of Loading and Elevating Equipment Manufacturers ( ALEM ), Andrew Georgiou, president of ALEM and general manager - loading bay division, Stertil UK Limited, explains how to deal with problems associated with introducing multi-deck trailers.

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Increasingly, ALEM members are being approached by end users, planners and consultants tasked with finding workable and cost- effective solutions for loading bay projects.

However, in recent times, the traditional criteria used to determine the correct loading bay structure and configuration for a wide variety of applications have been complicated by the need to accommodate an increasingly diverse range of road transport vehicles.

The accelerating rise of different types, sizes and shapes of trucks and lorries has been marked by a significant increase in the volume of traffic from overseas. This, in turn, means that a growing number of companies involved in the global supply chain are recognising the benefits of relying on the experience and technical expertise of ALEM member companies.

One of the most common loading bay problems faced by users has arisen through the introduction of double- or multi-deck trailers. Designed to maximise space utilisation within the vehicle, reduce the number of vehicles required and, thus, fuel bills for the user, the increased height of these innovative trailers can cause damage to conventional dock shelters.

Changing to a higher conventional shelter is not always practical as the head curtains are not long enough to cater for lower vehicles. Without an alternative, businesses are faced with a choice of dedicating bays to specific types of vehicle, or accepting energy loss through the poor sealing of conventional shelters.

The proven solution to this annoying, and frequently expensive, problem lies in a dock shelter that features a variable height header curtain, such as an inflatable header, with either inflatable or pvc curtain sides. These can effectively seal from vehicle heights of 5,200mm down to 3,400mm and adjust automatically to the appropriate height.

Another common problem associated with double- or multi-deck trailers is that lips on existing dock levellers are often too short to reach the upper decks on the trailers which, in many cases, are inset slightly.

Faced with this situation, users may request longer lips, but this often proves to be a false economy. Lengthening the lip – either by replacing it or adding to it – can result in one or more of the following detrimental consequences:

  • On the working range of the leveller, the lip will swing out when the platform reaches its top travel but the lip’s bottom position is now the extension length lower, so it can collide with vehicles that it previously missed;
  • The longer lip can collide with loads that are placed at the rear of the previously conventional vehicles, i.e. what you could take out yesterday, you cannot take out today;
  • The original hydraulic system may not be able to lift the extra weight of the new lip;
  • The capacity of the leveller will probably be downrated;
  • Can cause complications with CE marking and testing.

The correct solution is to replace the complete dock leveller with a model that incorporates a telescopic or sliding lip. This type of leveller provides a host of benefits including:

  • Greater operational flexibility and can accommodate many different sizes of vehicle as well as stepped vehicle floors, eg in refrigerated trucks.;
  • The telescopic lip extension can be accurately controlled so that positioning of the vehicle is less critical;
  • The lip can be partially withdrawn to allow use of the full loading area right to the back of the vehicle;
  • Can bridge a vehicle tail-lift if necessary;
  • Permits an external door to be fully lowered in front of the dock to increase thermal efficiency;
  • Can be used for side loading.

One of the most common loading bay problems faced by users has arisen through the introduction of double- or multi-deck trailers.


In summary, dock shelter solutions must be sufficiently flexible to accommodate the widest possible range of vehicle types and sizes from conventional trucks to multi deck trailers. ALEM members have the experience and technical knowledge to advise, recommend and install proven products and equipment that meet all European standards of performance, reliability and safety.

As an Association, ALEM is acknowledged as a world-leading authority on inflatable and curtain shelters and dockseals; wheel guides; mobile yard ramps; tail-lifts, scissor lifts, dock bumpers and vehicle restraint systems, as well as both mechanically- and hydraulically-operated dock levellers.