VNA Warehouse floors – How to get them flat and level

by Tania Wannenburg
RCS Jnl114

In a previous article in Floors Magazine, Royal Consulting Services drew readers’ attention to the fact that the concrete floors in many Very Narrow Aisle (VNA) warehouse facilities fail to meet the applicable international level and flatness criteria needed for safe and efficient truck operation.

Royal Consulting Services offers to survey VNA floors using a UKASaccredited profileograph – as recommended by the United Kingdom Concrete Society Technical Report 34 committee – to either confirm compliance or to expose failure to comply, as the case may be.

The question often arises – Why is compliance with the appropriate level and flatness specification so important? Consider the following scenario: When a truck is stationary in an aisle and there is a difference in floor level under its left and right wheels of 3mm, the mast of the truck will have tilted 33mm out of true vertical at a height of 13 metres above that floor level. This is known as static lean. When the truck is in motion, this static lean becomes dynamic and the departure from true vertical can be up to three times the static value.

Clearance between loaded pallets carried on turret trucks and stored pallets in racks is sometimes as little as 100mm – consequently the risk of load/pallet collision is high. Such collisions can result in catastrophic events – rack collapse, product damaged ordestroyed and injuries to personnel – nightmares no warehouse operator wants to have to face.

If compliance with the requisite specification has not been achieved and these nightmares are closer to reality, what remediation options are available?

The application of a so-called ‘self-levelling’ epoxy screed to the surface of the aisles is a non-starter – simply because no screed product is actually self-levelling. Even if the label on the can is convincing enough to try, be aware that the material constituents of the screed can generate static buildup between the truck wheels and the epoxy surface which may interfere with signals sent to the truck’s on-board computer. Equally true is the fact that over a relatively short period of time the intensity of fixed-path traffic will cause the screed material to break up as it becomes more brittle. This, in turn, necessitates localised repair which is both disruptive to normal operations and is rarely successful.

The solution is to grind the surface until it complies with specification. While this may sound like a simple operation, an effective solution requires the kind of precision which cannot be delivered by manual grinding with a single-head machine. A single-head grinding blade can only be used in a side-to-side motion in the vicinity of a single-wheel track. This means that whilst solving one problem, two others may develop because, in order to guarantee safe truck operation, the left and right wheel track profiles must match.

The CoGri Group, associates of Royal Consulting Services, offers the solution to the problem with its laser grinder system. The grinder unit can be set to grind paths of any width to suit any truck “footprint” within an aisle. It can accommodate compliance with any level and flatness tolerance laid down by any of the international turret truck suppliers. It minimises the amount of concrete to be ground off because it can be set to grind long slopes between waypoints in the aisle without any negative effect on the speed or stability of the truck.

The laser grinder is a totally self-contained motorised unit. If grinding is needed to remedy an in-service facility, there are no trailing power cables to impede normal access in the warehouse. The grinding operation is totally dust-free and whilst the grinding heads are water-cooled, the incorporated suction system automatically pumps the cement slush generated to a storage trailer for disposal outside the warehouse. The engine is quiet-running with a rated exhaust emission so low that by European Union standards the laser grinder can be operated in food storage areas including freezers.

Royal Consulting Services can assist clients by evaluating the level and flatness of the concrete floor in their VNA aisles with the only UKAS-certified profileograph available in South Africa. Coupled with the use of the most highly rated and sophisticated laser grinding system in the world they can guarantee successful remediation of level and flatness characteristics of your problem floor to give you years of safe and efficient VNA operation.

For further information: 011 425 1277 / rcs@mweb.co.za / www.corigroup.com

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