Bump and grind

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Are there flaws with your floor? It’s probably the most frequently used piece of equipment in a warehouse, but all too often people simply look down on it.    Lucy Tesseras reports.

The warehouse floor may not seem like the most sophisticated piece of kit, but having a cracked, uneven, or dirty surface could reduce efficiency and compromise safety.

In fact, the floor is often so overlooked that it doesn’t even come into consideration when companies begin weighing up why performance levels have dropped.
Steve Richmond, general manager of Jungheinrich UK’s systems and projects division, says if a very narrow aisle storage system is failing to reach optimum levels of efficiency, more often than not the user assumes it is the truck that is underperforming, when in a lot of instances it is actually the surface it is operating on.

He states: “The floor is the point at which the warehouse building and the truck interact and quite simply, a poor floor will result in poor VNA performance.”

The design, specification and final finish of the warehouse floor is absolutely critical to getting the most out of a VNA system, particularly as truck
manufacturers are pushing the physical design of equipment to maximum efficiency.

“You can invest in the best forklift trucks and materials handling equipment on the market,” he explains, “but if your warehouse floor resembles a ploughed field, trucks will never be able to operate at their top speeds of optimum efficiency – think of it as driving a Ferrari down a cobbled street.”

The flatness of the floor also plays a vital role in promoting safety. If there are cracks or bumps, or an unevenness surface the chance of employees tripping and falling increases, as does the risk to staff operating materials handling equipment.

Richmond continues: “Effects from the floor can cause trucks to move from side to side or in a front to back nodding motion as they travel along the length of an aisle…even relatively small difference in the floor level within a racking aisle can have a significant impact when the truck is operating at heights often in excess of 15 metres. The higher the mast height the more pronounced the lean from uneven floors and the greater the potential problem.”

In most cases, damaged floors can be repaired and made fit for purpose again by full aisle grinding or local grinding, depending on the severity of the problem and proper refurbishment can go a long way to boosting performance and safety.

Langdon Industries, a logistics service provider which specialises in temperature-controlled operations, enlisted CG Flooring Systems to get the floor up to scratch at its 11,711 sq ft Bridgwater distribution centre.

To upgrade the floor CG Flooring Systems, working alongside Caer Urfa Consultancy and Project Management, realised the need to remove around 15mm of damaged concrete from the surface of the existing floor slab.

The surface then needed to be mechanically cleaned prior to application of Cemart’s Cemdek Industrial Floor Screed as the newly finished floor surface.

Langdon Industries identified an eight-day window in its operational programme which allowed work to commence.

Before beginning the project, fixed racking and one section of mobile racking had to be removed to increase the size of the open area and reduce downtime.
The team had to be very careful not to damage or knock the system out of alignment when working around it, particularly as some of the steel rails were fixed within the concrete floor.

The first stage of the project involved isolating the steel rails and removing some 200 bolts from within the floor. The damaged concrete was then removed from the surface by a road planner before the newly exposed concrete was mechanically cleaned by captive enclosed shot-blasting. Finally, the temperature of the cold store was increased to 15 degrees centigrade to allow the industrial floor screed to be applied at a thickness of 15mm.

Cracks in the floor can occur as a result of natural shrinkage of the concrete during the drying out process. Paying proper attention to the jointing layout when laying a new floor can go a long way to minimising potential cracks. However, it cannot be guaranteed as a joint is in effect a manmade crack.

Permaban recommends a framework such as its AlphaJoint leave-in-place floor joint system to ensure floor joints are adequately armoured. The flooring specialist recently launched a new version of the AlphaJoint product, with a rigid divider plate to give more stiffness in the horizontal plane, as well as the vertical, which reduces the risk of cracking, while giving load transfer across the free contraction joint.

Andrew MacKenzie of Permaban says: “It is important that this doesn’t interfere at all with the concrete slabs’ ability to move freely in both horizontal planes as constraining movement is a major cause of cracking in concrete floor slabs. All this makes handling and installation of the joints on-site much easier leading to straighter and neater joints.”

The first major project using the AlphaJoint with a rigid divider plate was completed in Leipzig, Germany by flooring contractor IBG Floortec, a company used by property developers ProLogis and Goldbeck in the country.

In the UK, AlphaJoint with rigid divider plate has been used by Stuarts Industrial Flooring for Big Yellow Self Storage’s new depot in Surrey.

Concrete shrinks even more dramatically when it is in a cool location such as a freezer store. If cracks aren’t properly treated forklift trucks travelling over the gaps could be damaged meaning truck bearings need to be replaced more frequently, or the goods being moved may be disturbed.

Permaban recommends using a product such as AlphaSlide, which is designed into the slab at the drawing board stage, to help to minimise the impact. When shrinkage occurs after the floor is laid infill strips are inserted into sockets already set into the AlphaSlide to help maintain a smooth ride.

However, he warns: “There are limitations – the joints are only suitable for straight lines, unlike AlphaJoint which is permitted to go round corners, and strips must be removed before the joints are allowed to close again, for example, if the freezer store is allowed back to ambient.”

The age and condition of a floor is also critical when it comes to applying floor markings as dirty or cracked floors will mean an uneven finish that doesn’t last as long.

ASG Services has developed diamond shaved line markings specifically for use in warehouses and distribution centres where heavy forklift trucks and other materials handling equipment causes traditional line markings to wear away more quickly.

The process involves shaving an area of the concrete floor surface with a diamond blade shod machine to a depth of 1mm – 4mm to reveal fresh concrete and remove any seal or Power Float coating.

A void is created allowing the paint to be applied which physically bonds with the concrete to form a durable product. For the most durable line markings ASG Services recommends a two-part epoxy at a width of 100mm.

Chris Hopkirk of ASG Services, says: “Diamond shaved, which is very different to diamond grinding, will last approximately three times as long as shot blasting, however as usual it depends on usage and the state of the floor.”

Flattery will get you everywhere
Middle Eastern supply chain systems provider Redington Gulf has moved into a new facility in Jebel Ali Free Zone, Dubai, where Face Consultants Middle East has tested and certified what it says is the first ever Defined Movement 1 (DM1) fully compliant floor in the region.

Face Consultants, a UKAS-accredited organisation for flatness compliance, was enlisted by the main contractor to review the approved design for the floor slab.

The Face Middle East engineer team then supervised floor slab construction, testing each panel the day after it was laid with the Face Digital Profileograph. In total 21 very narrow aisle slabs were surveyed and certified as DM1 compliant.

After the racking had been fitted in all VNA areas, Face Middle East installed the wire guidance system, comprising more than 1.2km of wire connected to the line drivers – the frequency generators for the VNA trucks to follow.

S Chidambaram, general manager SCM of Redington Gulf, says: “Floor surface is the most important aspect of a VNA racking facility, especially when the racking has a top beam height of 15 metres.

“The major objective to insist on DM1 flooring was to increase efficiency, better throughput, speed and the safety movement for all our materials handling equipment. We wanted to achieve the best possible result for our flooring surface.”

Redington Gulf was established in 1997 as an IT distributor in the Middle East and Africa and has evolved into a fully integrated supply chain systems provider addressing IT and telecom verticals. Its brand portfolio includes HP, Nokia, Dell, Acer, Samsung and Canon.

The logistics centre in Jebel Ali Free Zone reflects the company’s plans to develop into a supply chain consolidator.Effects from the floor can cause trucks to move from side to side or in a front to back nodding motion as they travel along the length of an aisle.

A mark of safety
Dirt is the main cause of long-term damage to floor markings, so to increase their longevity ASG Services recommends a series of maintenance steps.

  • Sweep the floor with a brush or mechanical cleaner as often as required to avoid dust and dirt accumulating. If a mechanical floor sweeper is used softer bristles are recommended over hard, which tend to be more aggressive and will scratch and dull the paint surface.
  • Wash and scrub the floor regularly using the correct detergent solutions. For general cleaning many industrial cleaning solutions are appropriate and a weekly clean is recommended but areas subject to heavy forklift or other material handling equipment traffic should be cleaned more frequently.
  • Avoid using stiff bristle brushes or caustic and solvent based solutions as they are liable to cause dulling.
  • Place mats at entrance doors to reduce dirt and moisture being transferred to the floor.
  • Avoid sliding or dropping heavy or pointed equipment.
  • Do not drag or push pallets.
  • Repair any significant damage as soon as possible.Concrete shrinks even more dramatically when it is in a cool location such as a freezer store.
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