Industrial door selection is no longer a matter of compromise
Industrial contractors and engineers once assumed that choosing industrial doors meant making compromises between energy efficiency, safety and productivity. Fortunately, that is no longer the case. The newest generation of high-speed rolling and bi-parting doors combines energy efficiency with quick and automatic operation, sound safety features and enhanced hygiene control. Some even eliminate the downtime (and energy loss) caused by forklift impacts.
While their cost ranges from $8,000 to $20,000 per opening, they can save facilities as much as $5,000 to $15,000 annually per opening on energy costs. What’s more, both new and retrofit projects are eligible for rebates from a variety of utilities and government entities, allowing them to pay for themselves in as little as one to two years per opening.
Cycle time is the key
Operational speed (cycle time) is at the center of this revolution. Traditionally, R-value (the measure of heat transfer through an object) has been a driving factor in the choice of industrial doors, particularly for cooler and freezer doors. The standard approach for these applications was to install heavy, insulated, rigid doors with a high R-value. While these side-acting doors do a good job of preventing energy loss through the door panels (conduction), they are typically slow moving. This means more infiltration of air and ambient contaminants when open. Warm air infiltration also causes frost and humidity build-up in freezers, which adds to energy costs, hampers productivity and can lead to accidents. In addition, traditional hard-core doors are susceptible to forklift damage.
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Unless the damaged door is quickly fixed, there can be substantial energy losses as a result of poor sealing. Thus, for high-traffic openings, energy losses due to the door being open or a poor seal (infiltration) can represent a significantly larger cost component than energy losses due to conduction. Recent improvements in door technology combine fast cycling with high-efficiency insulation and sealing. These innovations contribute to low, long-term energy costs, improved efficiency and increased safety. In short, high R-value is no longer the main driver in door selection.
Advances in bi-parting doors
Major advances in door design have focused on improved bi-parting doors and insulated upwardacting doors. The newest bi-parting door designs include high speeds to minimize door open time. Some doors can operate up to 84 inches per second, which is up to four times faster than old-style, rigid side-acting doors. Another advantage of newer, more technically advanced bi-parting doors is their ability to withstand forklift impact, by snapping back into their tracks after contact. This feature minimizes maintenance and downtime while maintaining a tight seal throughout the life of the door.
Certain models also offer automatic reversing capability, which eliminates the safety and maintenance concerns of doors that use pneumatic or electrical reversing edges for the same purpose. Additionally, some impactable doors also have high enough R-values to avoid the need for heated panel defrost systems. Thermal air seals around the perimeter also enhance the energy efficiency on many of these doors.
Rolling doors
Similar improvements have been made in the upward-acting
(rolling) design category, including reduced cycle times and the use of insulated door panels. These insulated curtain panels provide the necessary R-value to avoid expensive panel defrost systems. Upward-acting doors can be even faster than bi-parting doors; some operate as fast as 100 inches per second to minimize air infiltration and ensure optimal productivity. As with bi-parting doors, newer upward-acting doors also incorporate a perimeter thermal air seal for added energy savings through a tighter seal.
Industry specific doors
Variations of these high-tech doors are now specially designed and available for specific industries, such as food manufacturing or pharmaceuticals. For example, facilities that must comply with USDA and FDA standards can now take advantage of these new technologies in “clean room” doors. High-tech clean room doors utilize fabrics such as polypropylene, which are highly mold-resistant and have superior washdown qualities, even with harsh cleaning chemicals. Polypropylene also provides higher resistance to acids and bases and a lower water absorption rate than vinyls and urethanes.
Other food industry-specific components include lightweight, easily removable and non-corrosive Lexan and Ultra High Molecular Weight (UHMW) side frames, which meet government guidelines for washdown and bacteria control. Some of these doors also utilize an industry-specific offwall side frame design, which minimizes surfaceto- surface contact, reducing pockets where bacteria can grow. Other food-specific features include sealed, washdown-rated drive systems and controls, as well as tapered bottom edges to push water off to the side, reducing the chance of it dripping on products.
No need to compromise
Industrial door selection is no longer a matter of compromise. Door technology is keeping pace with the increasing demands of metal construction contractors and engineers. This technology has led to more choices of products, which can provide low, long-term energy costs, improved efficiency and increased safety from industrial doors. Better yet, the payback can be remarkably fast, thanks to the many government and utility rebate programs, as well as ongoing energy savings.
Jon Schumacher is director of marketing, Rite-Hite Doors, Milwaukee. For more information, visit www.ritehite.com/products/doors.
