As when buying forklifts, a sensible purchasing decision on powered doors should be based on life cycle costs, which must take into account their potential to slash energy costs and improve hygiene and worker comfort.
Compared with manually-operated doors they are not cheap but for decades now the warehouse industry has moved away from manually-operated doors because in a fast-changing distribution environment and legislative changes on energy issues they are simply not practical for most operations and also come with back injuries from the lifting and bending each time doors are opened and closed.
There is a wide range of powered doors to suit special needs and rarely are two warehouse operations alike. Likewise, there are many door providers and even wider still is the number of door maintenance contractors whose service quality can vary sharply.
Given the need to justify such investments, therefore, for peace of mind it is advisable to stick with members of ALEM, (Association of Loading and Elevating Equipment Manufacturers). These members will usually conduct energy audits of potential clients’ premises and take them to visit customer sites to gain a view of the doors’ reliability and after-sales service. The latter is important because no matter how good the product may be if the after-sales service is lousy then that risks problems ahead.
The quality of engineering and longevity of high speed doors differs so to avoid disappointment it’s crucial at the early planning stage to study load cycles achievable between service intervals and give that information to the prospective suppliers. Some of the highest quality doors are capable of up to 250,000 cycles a year. Clearly, that lowers the overall annual operational cost through energy savings and the faster the opening and closing speeds the better. These speeds are generally up to 2.5 mt/sec, though one from Effaflex can reach 4 mt/sec. Other savings from top quality doors include fewer service and maintenance visits.
Yet more savings can derive from reductions in accidents. The loading bay is a risky place so door buyers should get advice from their suppliers on the safety add-ons, like motion detectors, door crashout facilities and safety beams that prevent doors hitting pedestrians. Some motion detectors are more effective than others and use laser scanners that only allow door opening if a vehicle is moving directly towards the door.
Many warehouse operators still use a combination of outer traditional, roller shutter security door and an inner, fast-acting PVC roller door. An alternative, however, is the single, thermally insulated spiral door with lath thicknesses that can be varied between 40mm and 100mm. They also offer better than average wind resistance of Class 4 and high operating speeds.
An alternative that should not be overlooked could be an air curtain in combination with a security door where the traffic movement is so high that the door must be kept permanently open during working hours. Such a combination could cut whole building heating costs by up to 30% and they can help keep cool air in. The safety advantages should not be overlooked either when comparing them with fastacting roller and spiral doors, which are prone to forklift hits unless fitted with safety sensors. Leading air curtain suppliers like Airbloc and JS Air Curtains should be able to give prospective users an idea on what energy saving their curtains can achieve.
Warehouse operators place high value on door sustainability and that means reliability, safety and energy conservation. But to achieve that it is essential, after choosing the door, that a robust maintenance regime tailored to one’s own requirements is put in place.