Saturday 10th Dec 2016 - Logistics Manager

Take a load off

A smart loading bay design is a key part of what makes a warehouse successful, but if neglected can be a company’s undoing. Jessica Davies reports.

The face of UK long haul distribution may be changing as more retailers turn to double-deck trailers to reduce journey cycles, fleet size, and fuel and labour costs. This shift has raised fresh challenges to loading bay designs, and the pressure is on to ensure that the most dangerous area of the warehouse remains as safe and efficient as possible.

Double-deck trailers have been in use for years but Mark Adams, managing director of Transdek says that now more big-name retailers are opting to use the lighter, “fixed” rather than “powered” models. This throws up sticky issues regarding the loading bay’s design since powered trailers feature onboard hydraulics, and can therefore marry to a regular loading dock without the need to redesign it. However fixed trailers can’t.

Tesco runs a fleet of 400 fixed double-deckers and has plans to run several hundred more. And Transdek is now working on converting the retailer’s Extra stores to receive double-deckers direct. It has also just finished converting Boots’ UK distribution centres to receive double-deckers, supplying some 50 double-deck lifts. And Adams says that suppliers to the retailers are now following suit.

Transdek has developed surface-mounted hydraulic lifts that are pre-built into chassis along with all working components and electrics. The company says it can convert virtually any loading bay for double-deck trailer loading in as little as 1.5 days.

Its latest 20-tonne capacity double-deck lifts feature high-frequency, low-power lights linked to motion sensors, which can cut electricity consumption by 81 per cent. Operations director Leon Butler says: “Per unit, the cost savings are not massive, but over a hundred units, we estimate annual savings of £36,100 for our customers from the lighting modifications alone.”

They also feature an energy-efficient lowering function. This means the lift’s main motor automatically switches off during lowering, and can help save up to 40 per cent on power use. A series of 24V solenoids are used to return the hydraulic fluid to the tank.

Easilift has seen an increase in the use of dock pods (also referred to as loading houses) in UK distribution centres. These are stand-alone loading bay enclosures, which can be installed directly to the external face of a building. They are suitable for new buildings, extensions, and refurbishments, and feature a dock seal, dock leveller or scissor lift, and a sectional insulated overhead door.

The benefits of the dock pod are that they are quick and easy to install – requiring no hole or pit to be dug into the floor; they can be repositioned easily, and don’t take up any valuable internal warehouse space, and so help avoid contact with cross traffic.

Easilift’s David Whyatt reckons flexibility is one of the key benefits of the dock pod. For example, pods can be equipped with a surface-mounted scissor lift platform, instead of a dock leveller, for use with the latest double-deck trailers now being widely adopted by major high street retailers and logistics companies, he says.

Easilift has supplied hundreds of pods to Tesco, which the retail giant spread across three of its major distribution centres in Livingston, Lichfield, and Goole, in a deal worth some £9 million.

At the one million sq ft Livingston site it fitted 162 of the 179 loading bays with exterior dock leveller pods, all incorporating swing lip type “PowerRamp” dock levellers and insulated, electrically-operated sectional overhead “PowerDoors”. And 17 scissor lift dock pods, designed to integrate with Tesco’s fixed bed double-deck trailers, were also added. These can carry 36 roll cages and an operator safely between the two fixed vehicle beds and the loading dock. Similar systems were supplied to the Lichfield and Goole sites.

When it comes to designing a loading bay a number of things can go wrong. For example, Mike Bunn, managing director of Sara Loading Bay Systems, says that choosing too small or narrow a door, specifying too steep a slope on the approach to the dock, or choosing the wrong size and capacity of dock leveller will create problems.

“Any one of these factors can undo an installation,” he says. “It pays to get things right first time. Having to rectify things later can be very costly and highly disruptive to logistics operations.”

Andrew Georgiou, general manager at loading bay specialist Stertil Stokvis, says that the correctly specified loading dock will reduce lifetime costs and allow flexibility for change, cause less damage to the building, and reduce maintenance on materials handling equipment.

He points to the relationship between vehicle, building construction and dock approach as the key issue when designing a loading bay. “As most buildings have an incline into the loading bay to create the dock, it follows that the top of the vehicle will be closer to the building than the deck of the vehicle. Depending on the gradient of the dock, this means that the top of the vehicle may impact with the cladding above the lintel if the door is too low or narrow, or if it jams,” says Georgiou.

Alan Jenkins, director of Hörmann’s commercial division, says: “With loading bays there are a number of potential hazards, such as forklift trucks falling from the dock. This is caused by truck and trailer creeping away from the loading dock, which can cause the lip of the dock leveller to lose contact with the vehicle bed.”

As a result, the company has developed a wheel-lock system, designed to keep the truck and trailer locked to the dock, only releasing the trailer when the loading/unloading process is complete.

Asda chose Hörmann to supply it with a low energy storage and distribution system for its new 30,000 sq ft distribution centre in Didcot. As a result, Hörmann installed the wheel-lock system, along with 14 high-speed insulated spiral doors, and 1,000mm-long telescopic lip dock levellers for the site’s 57 loading bays.

Asda calculated that the door insulation properties, and the fact that they are programmed to shut automatically after ten minutes without activity, will provide major energy savings and as a result, would pay for the doors within two years.