Materials handling technology is getting more and more sophisticated but it is easy to forget, as you bring in next generation trucks, that they also need next generation floors, or many of the benefits could be lost.
Good quality floors are a key requirement for any materials handling system. If neglected they can cause damage to equipment and reduce warehouse efficiency. In the past they tend to have been overlooked, but awareness of floor performance has improved substantially over the years.
Kevin Dare, managing director of the CoGri Group, says this is thanks to the Concrete Society’s third edition of Technical Report 34, published in 2003, which has standardised floor performance characteristics across the industry.
Floor flatness is vital to the stability and efficiency of very narrow aisle trucks. The development of fork lift technology is resulting in trucks which operate at higher speeds, which in turn increases pallet movement. Theoretically, this should improve productivity, but if the floor isn’t flat enough, the trucks can risk being damaged from bumps in the floor, particularly as VNA trucks have little suspension. Side to side movements also put stresses on bearings and welds. If the trucks are running on wire guidance systems, they can be in danger of going off-wire. So to prevent any accidents or damage to the vehicles they’re forced to operate at reduced speeds.
Ron Farr, VNA manager for truck manufacturer Hyster, says: “In most cases, the floor is not sufficient to jeopardise the safety of the application. Poor floors will result in adjustments to the top speeds, or perhaps a different speed at height to reduce any dynamics.”
Reducing truck speeds may help to avoid accidents and maintenance costs, but it will reduce the movement of pallets per hour. Kevin Dare says this could result in the company having to buy more trucks to achieve the necessary throughput.
This is a problem which affects all warehouse operations, apart from frozen warehouses, where there’s generally less throughput and the speed of operations is slower, owing to the build up of ice on the floors.
Joints are a necessary evil in industrial or warehouse floors as they allow free movement in the concrete, which relieves the stress on the floor slabs. Needless to say, without them, the floor would be prone to random cracking. They also reduce the drying and shrinkage of the concrete. Generally companies don’t favour joints as they need more maintenance. Their edges are vulnerable to damage and can break or erode under impact from wheeled vehicles if not protected. This makes them a real problem to materials handling equipment and can also affect the operators’ health.
The unpopularity of joint induced floors gave way to a new concept – ‘Jointless’ floors.
But, says Kevin Dare, it’s a common misconception to suppose that these floors are functional without joints. Jointless floors eliminate saw-cut joints, which are part of the design of all standard floors, only to be replaced by another type – construction joints. Dare says these are actually bigger than the saw-cut joints, and as a result, more shrinkage occurs.
Wire guidance systems are often embedded in floors for free ranging trucks. Dare points out that these systems, although necessary, can render the floor more vulnerable to cracking. The only way to prevent this would be to keep loads off the floor until it’s had time to settle, so delaying erecting the racking for example. Dare says that 28 days is the standard amount of time the concrete needs to set. Ideally at least three months should be allowed to pass before applying loading. However, Dare points out that this isn’t possible due to the fast pace of the industry, as companies want floors to be ready fast so that the warehouse can be rented out as quickly as possible, to ensure a return on investment.
Health & Safety directives stipulate that forklift traffic and pedestrian areas must be well defined and separated. The usual method is to apply printed symbols or pedestrian-only lines on the warehouse floor. Constant touch ups to the paintwork can become expensive and time-consuming, so durability is the name of the game for line marking companies.
According to David Grundy of ASG Services, floor marking paint is only durable and long lasting on floors which are prepared. He says: “New floors provide the very best surface when painted, whereas older floors give a poor finish and often fall foul of contamination issues which are only realised once the paint is applied.”
Paint can be contaminated from beneath the surface where the slab has previously taken in a chemical. Water damage is more common near walls or the usual sources of water but is generally only serious if left.
Grundy points out that the main benefits of line marking systems are the increase in storage capacity and the improvement of safety. Marking an area identifies the limits of the storage area, once everything has its place, walkways and fork lift truck routes can be created to increase safety.