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Industrial doors, such as those found in warehouses and storage facilities, have to meet many performance demands. Key durability issues relate to:

• Operational and mechanical performance - that is, the number of opening and closing cycles for a defined reliability level before maintenance and the costs of interruptions become excessive
• The capacity of the construction materials and finishes to withstand the causes of weathering and use.

Standards

There is a suite of European standards that makes it easier to specify industrial doors that meet those functional requirements. These are:

• Wind load performance BS EN 12424 identifies six classes of wind load resistance from 0 to 5. The higher the class number, the greater the wind load a door can resist.
• Resistance to water BS EN 12425 specifies four classes of resistance to water penetration. Typically industrial doors are class 1, which is tested to resist a 15-minute water spray at a pressure of 30 Pa, and class 2, which is tested to resist a 20-minute water spray at 50 Pa.
• Air permeability BS EN 12426 classifies the air permeability of doors. The seven classes run from 0 to 6. The higher the class, the lower the permeability. A class 1 door has a permeability of 24 m3/m2/h at 50 Pa. Each class has a permeability rate half that of the previous class.
• Safety BS EN 12453 defines safety requirements for power-operated doors. Hazards and risks are identified - for example, crushing between the door leaves and perimeter of opening. Safeguards, design strategies and criteria for avoiding hazards are listed.
• Mechanical requirements and operational durability 

BS EN 12604 specifies the mechanical requirements for industrial doors, such as strength and the factor of safety. This standard is important in assessing potential durability, as it requires manufacturers to state the number of cycles doors have been tested to. Durability is judged by reference to the economic life of the door - in other words, when the costs of maintaining the door are greater than the cost of door replacement.

• Installation and use BS EN 12635 covers the installation and use of industrial doors. This includes the identification of maintenance and repair activities that are essential for lifecycle management and planning.

Other issues

Design issues such as thermal, fire and sound performance should be addressed, as well as security. Wet internal environments will affect specification and durability.

Other issues that directly affect durability include the operating speed of door, the frequency and intervals between operation and who the users are.

Specification options

Door types

• Vertical overhead sectional doors In the most common arrangement, the door leaves slide up under the roof.
• Horizontal folding doors These incorporate sections like vertical overhead sectional doors but open horizontally.
• Roller shutter doors These consist of metal laths that roll up around a high-level barrel above the door opening.

Material options

• Sectional and folding doors may be non-glazed, part-glazed or fully glazed. Single or double-glazed options are available in acrylic or toughened glass.
• Sections or roller shutter laths are usually made from aluminium or low carbon steels, which may be filled with an insulating material for enhanced thermal performance. Stainless steel components may be used for extremely corrosive environments.
• Steel doors have a corrosion protection layer, usually zinc (Z 275 g/m2) or zinc-aluminium (ZA 255 g/m2). Aluminium may be left mill-finished.
• Decorative coatings for both aluminium and steel include PVC plastisol (durability 10 to 30 years), polyvinylidene fluoride PVF2 (10 to 15 years), polyester (five to 10 years) and polyurethane (10 to 15 years). Life expectancies are the period to the first maintenance. Life depends on exposure to coastal, polluted or industrial environments, aspect and orientation, as well as the coating thickness.

Method of operation

• Manual doors are typically operated by means of a chain hoist. Doors larger than 4 × 4 m need to be operated electrically because of their weight.
• Power-operated doors may be triggered by a variety of controls including: push button, pull rope, remote control, magnetic loops, photocells, radar and even mobile phones.