Room Data Sheets

Open Plan Office

An open plan office may be situated anywhere in the building. It may be the place of work for many people, possibly a whole company or department.

The environmental conditions of the office are important - people may have to work here all day amongst others who may have different preferences to themselves . Hence all services must be designed with aesthetics, individual comfort, ergonomics and of course health & safety in mind.

Flexibility is important in the open plan office and it is desirable to give occupants at least some form of control over their local surroundings.

Electrical Services Requirements

Main Distribution - The lighting & power requirements of an open plan office are commonly served from a dedicated distribution board. Many users sub-let office space or require that certain areas operate as separate (units) hence separate metering may be employed. In such situations, it may be desirable to have the distribution board serving these areas alone so that maintenance or adaptations to the installation do not have any undue affect on other areas.

A three phase supply may be desired to serve larger areas. However, it should be carefully implemented to avoid possible danger to users through adjacent services being on different phases.

Earthing & Bonding - Equipotential and Supplementary bonding must be installed in accordance with BS7671. In particular, metal rails, and raised floor systems must be bonded.

Clean or functional earth systems may be required for electronic equipment.

Power Services - Socket outlets must be installed in sufficient number to serve general equipment and in particular, the large amount of office & computer equipment common in commercial installations.

The outlets may be installed on dado or skirting trunking, or contained within service floor boxes or poles

It is normal for standard wall mounted outlets to be installed at intervals for use by cleaners etc.

Specialist Power Requirements - The most common requirement within the open plan office is some form of dedicated circuit for essential office equipment or computers.

However, other loads may need consideration. Air conditioning & heating plant may need to be served from separate sources. Printing or copying machines and tea making facilities are often served separately.

Lighting - General - The lighting within the open plan office needs special consideration.

If computer (VDT or VDU) use is extensive, then the lighting must be designed with low glare characteristics. However, over zealous use of low glare luminaires can leave an open plan office looking dim with a dark ceiling. Hence use of uplighters should be considered to brighten up the open plan office.

Task lighting may be required for certain areas as the lighting in an open plan office has to be compromise.

It is common for lighting control systems to be installed to save energy. Daylight linking is common for long well lit offices. Presence detection is highly desirable in an open plan office as large parts of the room may be unoccupied. If an individual is working, then the immediate area only would be illuminated.

It is usual for lighting to be switched centrally.

Due to the large amount of people within an open plan office it is essential to ensure that the lighting is comfortable and pleasing. It is considered by some that poor lighting contributes to sick building syndrome.

Lighting - Emergency - Emergency lighting must be installed to in accordance with BS5266.
Within the open plan office, the escape routes are often hard to define due to the movement of desks and equipment. It is usual to provide illumination firstly along defined escape routes and then across the central walkways of the office.
Separate emergency lighting fittings, surface mounted can look obtrusive, hence it is common for integral packs to be used.

Due to centralised switching often used in an open plan office, test facilities are commonly installed adjacent to the distribution board.

Fire Detection & Alarm - Fire alarm detection and alarms should be installed in accordance with BS5839.

An open plan office will always have some form of defined escape route passing through. Hence unless a manual fire alarm system is to be installed, some form of automatic smoke detection will be required in the area. This may be by detectors in the space or by return air sampling where mechanical extract is used.

Sounders must be installed to give sufficient audibility. However, despite the temptation to provide just one or two very loud sounders, it is best to use several lower output devices. This avoids damage to hearing (which is a requirement of BS5839)

Uninterruptable Power Supplies - Local UPS may be used for standalone equipment. It is occasionally necessary to provide a "secure" circuit to the office to serve essential equipment, a central UPS being used with non-standard outlets to avoid plugging in ancillary equipment.

Cable Containment Systems - Open plan offices can represent a major problem for the electrical designer. Desks and furniture are often well away from walls. If office equipment is required on such desks then means have to be employed to provide services to the middle of the area without causing health and safety hazards associated with trailing cables. Also, of course, the installation must look aesthetically pleasing.

If a raised floor is installed then services can pass underneath using either flexible or fixed wiring systems. Floor boxes containing both power and ancillary services are commonly installed.

If no floor void is present then floor trunking may be installed, again floor boxes would be used.

Where floor access is impractical, power poles may be used to bring services down from the ceiling. These should be carefully used because they can look unsightly if too many are installed.

Perimeter systems such as dado trunking can be used but if desks are extended from the wall, then desk cable management is required.

Data & Communications - Both data and telephone outlets are normally required to each desk as well as other specific locations. The type and format depend upon the type of system used. However, the modern day trend towards structured cabling can present problems in the open plan office due to the large number of cables required.

Special consideration must therefore be given to ensuring sufficient space is allowed in voids, and cable risers to facilitate this cabling.

Outlets can mounted on dado trunking or within floor boxes. In such cases, the depth of the accessory can present problems.

Base Generation - Secure circuits may be used served from autostart generators & UPS in order to ensure no supply disruptions. However such a setup is expensive and is it only used where absolutely necessary.

Security Alarm Systems - The open plan office will have expensive PC and computer equipment installed. Also, office files, possessions and data will all be exposed.  The area is sure to  require security alarm cover, particularly if the room has external windows. A door access system may be required along with  CCTV surveillance.