Whole life costing: Automatic doors

Peter Mayer

Doors for retail premises not only have to
look good but neet a host of functional
requirements. Peter Mayer of BLP runs
through the issues and life-cycle costs

Guidance on the specification, design, installation, operation and maintenance of automatic doors for safety, is provided by BS 7036, which comprises five standards.

Automatic doors are operated by some form of presence-sensing device. Positioning of the sensors is critical for effective operation. Operator devices which move the door are typically electrical motor driven, pneumatic or hydraulic. Control units may be required. Where power supply fails doors operate manually. Control systems have lifetimes of between 10 and 20 years.

 

Door types


Swing door Just like a normal hinged door but automatically operated. BS 7036–3 applies. Commonly provided as a low energy swing door (BS 7036–4) powered so that users are unlikely to be harmed if struck by the door.

Sliding or folding door The door leaf of sliding doors may be straight or curved, these slide horizontally across the opening. See BS 7036–2 for avoidance of body traps.

Balanced door For use where space is restricted. The door opens with a combined sliding and swing action. See BS 7036–3.

Revolving door BS 7036–5 gives guidance on maximum revolving speed. Additional safety devices are required for revolving doors with an internal diameter greater than 3m.

 

Door construction


Automatic doors for retail use are constructed from glass or metal-framed glass. Typically aluminium, stainless steel or decorated galvanised steel is used. Timber-framed glass doors are also available.

Aluminium may be mill finished. Anodising is to BS 3987, minimum 25 microns thick, for an expected service life of 30-plus years.

Decorative coatings for both aluminium and steel include PVC plastisol (10-30 years), polyvinylidene fluoride PVF2 minimum 25 microns thick (10-20 years), polyester (five-10 years), polyurethane (10–15 years). Life depends on exposure to coastal, polluted or industrial environments, aspect and orientation, as well as coating thickness.

In a retail environment the door leaf life expectancy is more likely to be related to appearance than physical functionality.

Safety glass is used in framed or frameless doors. Typically toughened glass to BS EN 12150 or laminated safety glass to BS EN ISO 12543. BS 6206 for impact performance of safety glass describes three categories: Class A is the most resistant to impact. Insulating glass units to BS EN 1279 may be used for improved thermal performance.

 

Functional requirements


Safety BS 7036 considers issues such as signage, finger trapping and tripping risk, inclusion of protective barriers, proper operation of safety devices, activation, opening forces and opening times as well as the condition of operating devices and the door. A full hazard analysis and risk assessment should be carried out to guidance from HSE Code of Practice L21 and BS 5304 for safe use of machinery.

Accessibility Disability Discrimination Act applies. Automatic doors and shop entrances may require additional safety measures for people with disabilities or the elderly.

For further guidance go to: Centre for Accessible Environments and BS 8300 for the design of buildings and their approaches for disabled people.

Emergency escape This can be achieved by break-out facility which may be manual or integral to a fire alarm system.

Weathertightness and physical properties of doors are covered in BS EN 14351–1:2006. BS 6375 is still applicable as a guide to specification for weathertightness.

Security Locking systems, ironmongery and hinges should be specified for the expected use and resistance to forced entry.

 

Operation and maintenance


Automatic doors come under the Provision and Use of Work Equipment Regulations 1998. BS 7936–1 gives guidance: regular maintenance and annual inspection.

 

 

Specification options

 

Automatic doors Capital cost £/door assembly Net present value for 60 years £/door assembly
Automatic single swing doorset; 1.2 x 2.2m, operator transom mounted. 3,500 16,300
Automatic double swing doorset; 1.8 x 2.4m; operator transom mounted 8,000 25,600
Automatic sliding single door; 1.2 x 2.2; 5,000 19,600
Automatic sliding double doors; 1.8 x 2.4m 10,000 29,900
Famed glass revolving door; four wing; 2m inside diameter; 2 gear motor integral ceiling structure; Aluminium structure; Stainless steel ground housing. 40,000 62,300

 

Table notes


A discount rate of 3% is used to calculate net present values.

Costs include for complete door polyester powder coated aluminium framed, 10mm safety toughened glass and associated components in prepared opening with electricity supplied. Maintenance costs include for twice annual inspection and servicing to BS 7036. Allowance for minor repairs, responsive call outs and cleaning. Control unit and operator replaced at year 15.

Automatic door assembly replaced at year 30 to coincide with major refurbishment of retail premises. Rates of shop churn or refits are generally shorter 5 – 15 years if automatic doors are part of this replacement cycle life cycle costs would increase proportionately.

Costs are indicative averages. A cost analysis based on project specific information is essential for a realistic best value appraisal.


First published in Building, 2008

 

Further information


BLP provides latent defect warranties for buildings www.blpinsurance.com

Further information contact

 

 

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