April 11, 2018
Concrete Grinding Ltd, specialists in very narrow aisle (VNA) floor flatness grinding, were recently called to the aid of a world-leading medical products and solutions company who were experiencing problems in one of their newly opened warehouses.
Situated in the Etelä-Savo region of Finland, the warehouse had been operational for a few months, but the Jungheinrich VNA trucks were nearly touching the racks in places and had to be operated at a creep speed; during construction an epoxy screed had been applied on top of the concrete floor, in an attempt to provide a flat surface for the trucks to run on. This had failed badly. In addition, the screed had begun to break-up at the joints.
Paul Altham, Director of Concrete Grinding commented “Although we have other areas within the CoGri Group that specialise in epoxy screeds, we never advocate their use in a VNA application. This is for a variety of reasons, but mainly because it is very difficult to achieve the stringent flatness required and there is a particularly high risk the epoxy will crack, loosen and de-laminate in the tracks of the heavy VNA trucks where repetitive movement takes place. Once this process starts, deterioration continues and can render the aisle un-trafficable.”
Working in conjunction with Face Consultants, a Profileograph survey was initially undertaken to check the existing floor flatness according to the DM1 classification of the EN15620 specification (for racking top beam heights over 13m). The results showed the severity of the situation; the full length of all the aisles were drastically outside this specification and would therefore require remedial flatness grinding.
Due to concerns over the structural integrity of the existing epoxy screed, Concrete Grinding recommended grinding through the screed to completely remove it back to the concrete underneath. Paul added “This approach removed the risk of any remaining screed de-laminating and ensured the trucks had a solid platform to operate on. Our Laser Grinder® machines are able to do this in one pass over the floor without making any airborne dust.”
Before the flatness grinding work could start, there were five steel armoured construction joints crossing the aisles that needed a repair. Paul said “Joint locations often require the most flatness grinding, as they can ‘curl’ upwards during the drying-shrinkage process that follows construction. However, the substantial steel armouring can prevent the joints locations from being ground, and so a repair is required to remove the top section of steel. This also prevents long-term damage being caused to the VNA truck wheels from the hard steel edges of the joints, reducing maintenance costs.”
As the warehouse was operational, a two-aisle rolling programme was established with the client to minimise disruption. After repairing the joints, remedial flatness grinding was carried out to the whole width of the aisles using Concrete Grinding’s Laser Grinder® system. This ensured the aisles easily complied with the DM1 classification of the EN15620 specification whilst allowing adjacent aisles to remain operational.
The Client’s Project Engineer said “Our support from Concrete Grinding Ltd was excellent and during the process we learned a lot about both trucks, floors and how important a flat floor is. We were able to increase the truck speed in the VNA and gained confidence in our personnel with a sense of security. The project was kept to the schedule with minimum disruption to the daily operation of the warehouse. The quality was of high standards, carried out by the skilled and flexible technicians on site. World-class services, easy to recommend.”
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