Dock Planning

How do you know your buying the right Loading Bay? 
  
STEP 1 - Talk to an expert
Usually these are salesmen, but if they're good they will only sell you the right products for your application.
They are seeing distribution companies with problems and applications just like yours every day of the week.

STEP 2 - Have you seen the product?
Make sure that you ask the sales engineer to show you the products first. It's always a good idea to visit a site and talk with a satisfied customer. Let the sales engineer set up a couple of sites and also visit his head office if it's possible. The sales guy can be really good and solve your problems but he doesn't do all of the work.

STEP 3 - Talk to an established supplier.
Most of the really good suppliers are part of a European Group and are manufacturing several thousand dock levellers and dock shelters a year so they have economies of scale whilst turning out good quality products complying with the latest European regulations.

STEP 4 - Ensure that the supplier can install the product
Because of the seasonal and cyclical nature of the retail market, most suppliers use sub-contract installers. Nothing wrong with that providing that they are fully trained in the installation of your supplier's products. An ISO 9000 quality programme usually provides a system of vendor assessment that ensures that all suppliers are inducted, trained and conversant with the company's products, systems and Health and Safety requirements.

STEP 5 - In the afterlife
Once your loading bay is operational it should be regularly maintained to ensure that optimum life and performance is attained. Can your supplier offer routine maintenance contracts with his own service engineers? Can he offer 24-hour callouts? Are all of his engineers trained on all of the products? Do they have access to electronic manuals for some of the older products or those that are less frequently serviced?

WHAT CAN GO WRONG?

There are many things that can go wrong - here are a few examples.

Too small a door or too low a door.
Too steep a slope on the approach to the dock.
Wrong size of dock leveller.
Wrong capacity of dock leveller.

DOOR SIZE

Most HGV's are a minimum of 2400mm wide, with refrigerated trailers up to 2600mm wide. With barn doors swung back, a fridge trailer can be as much as 2900mm wide. Trailer wheel guides (a false economy not to fit them) are set at 2600mm wide to the inside of the tube. Even so, drivers cannot be expected to be exactly on the spot every time. Don't forget the driver is 16 or 17metres away and looking in his mirror! So give the trailer plenty of room inside the doorway.

Smaller delivery vans (7.5T and 12T) especially can be fitted with tail lifts incorporating extra large protruding locking plates that extend as much as 250mm from the back of the vehicle. If the door is not wide enough, the locking plate can (and regularly does) cause real damage to the doorjamb and external cladding.

It is becoming commonplace to see a wide range of vehicles at the dock, with double deck trailers becoming increasingly popular. It therefore pays to discuss your current fleet and contractor's/suppliers vehicles and your likely future fleet with the loading bay sales engineer.

YARD SLOPES

The optimum slope is 1:80 away from the dock - this negates the slope that the "5th wheel" puts on the trailer. That said, many service yards are by no means perfect and compound slopes are much in evidence. This is where two opposing slopes create the required slope. Often a slope away from the dock is formed to a drainage channel and then a slope up to form a compound 1:80.

Steep slopes into the dock cause real problems with rain running of the roofs of trailers into the building as well as wheeled loads tipping out of trailers when the doors are opened. It is also common to find damage to the head of the door because the top of the trailer arrives before the buffers have had the chance to stop it. (See also door size problems)

In this instance, to prevent damage to the building fabric, the first thought is to pack out the dock bumpers. This of course works but then often a longer lip is needed and sometimes the leveller has to be pulled forward as well. The resultant costs are in the several hundreds for each bay. This can be avoided by getting good advice from the outset.

DOCK LEVELLER SIZING

This applies to both the capacity and the dimensions of the dock leveller. Too narrow - and loading and unloading of the first two pallets in the rear of the trailer will be problematic, especially without a fork truck. Too wide - and narrower vehicles cannot be unloaded.

The length is critical in terms of the gradient of the platform. En 1398 requires that the maximum slope be designed to be 1:7 (about 12.5%) although as a rule of thumb 1:10 is quicker to calculate! And errs on the safe side. It is important to calculate the platform gradient excluding the lip of the leveller as this is generally designed to be in a different plane.

Once again, information about vehicles intending to use the dock is most important. Capacity of the dock leveller is rated on the way a load is imposed on the platform. Ask your intended supplier what single axle load has been used to calculate the capacity as this varies. The more robust dock levellers are designed using a single axle load of the rated capacity i.e. 6000kg rated leveller designed on 6000kg single axle load.

So, as you can see, the road to the correct selection of a loading bay contains pitfalls - most can be avoided by talking with the industry.
 
Stertil UK has published a Guide To Loading Bay Design which provides many practical hints and tips both about loading bay design and how to get the information necessary to put the design into practice. Visit www.stertiluk.com