UK Office Furniture

Ergonomics and Chairs

These guidelines should be followed to assist the user in assuming a correct sitting posture.

Please read the instructions carefully and follow the sequence listed below.

1. When sitting, sit well back into the seat. All adjustments should be made from a seated position.

2. Make sure that the seat is level and the backrest is in an upright position. Adjust the seat height so that there is a 90-degree angle between the upper arm and forearm with the forearm parallel to the work surface. With the feet-resting flat on the floor the angle of the knees should also be 90 degrees. If this is not achievable a footrest may be required.

3. Adjust the back height by lifting the backrest to the required height giving correct support to the lumbar region.

4. Release the seat or back locking mechanism and adjust the body weight tension control (if applicable) to the required pressure. The chair should move freely without having to exert leg pressure.

5. Either lock the mechanism in the required position or leave the seat and back unlocked for synchronised or independent movement.

Please note that these guidelines may vary according to the adjustability of the mechanism and type of swivel chair in question.

Ergonomically correct and comfortable seating should provide stable body support in a variety of postures over a period of time. It should also encourage the maintenance of good health and be appropriate to the tasks or activities, which may be performed by the person sitting on the chair.

  The main requirements for good seating are:

  The ability to accommodate the user population (i.e. enable varying sizes and weights of people to fit the chair).

  The loading stress on the spine is minimized and a modest degree of lower back curvature is maintained.

  The posture requires little muscular effort to maintain and circulation in the thighs is  not restricted.

All good office chairs should have at least the following:

  A backrest with an appropriate size and shape to support the lower and middle back properly.

  A seat cushion that does not create any pressure points but fully supports the user's body weight and does not prevent them from leaning against the backrest because itis too large.

  Seat height adjustment.

  A stable base such as 5 star base with castors or glides depending on the floor covering.

  The facility to add an armrest, if the task requires it.

There are general ergonomic requirements for various aspects of the chair such as:

Seat Height: People should be able to adjust the seat height so that their elbows are level with their keyboard.  Some users may require a footrest to achieve this.

Seat Depth: The user should be able to rest the back against the backrest without pressing their calf muscles against the front edge of the chair as this will restrict circulation to the lower legs and cause discomfort.

Seat Width: People should have enough room to accommodate their hip width.

Back Rest: Should provide support for the lumbar region of the spinal column and for the shoulders. To move synchronously with the back and seat providing a positive tilt when the backrest is reclined.

Arm Rests: Well selected armrests offer not only additional postural support but also assistance in standing and sitting.

Durability: The chair should be strong, stable and must conform to published standards.

Information Kindly supplied by Pledge Manufacturing chairs in the UK from 1970

With over 35 years of proven performance Pledge are confident that all their seating is durable and reliable.

Pledge are active members of FIRA, SATRA, BSI and OFFMA.

All Pledge seating is manufactured to conform to the following standards:-

  BS 5459 (2000) Part 2 - Performance Requirements and Tests.
  BS 4875 (2000) Part 1 - Performance Requirements and Tests.
  BS EN1021-1 (1994) Part 1 - Ignition Source : Smouldering cigarette. 
  BS EN1021-2 (1994) Part 2 - Ignition Source : Match. 
  BS 5852 (1990)  - Section 4 Ignition Source 5 (when treated).
  BS EN1335 (2000) Part 1 - Dimensions - Determination of Dimensions.
  BS EN1335 (2000) Part 2 - Safety Requirements.
  BS EN1335 (2000) Part 3 - Safety Test Methods.

They actively dissuade clients from specifying fabrics that do not conform to all the necessary standards relevant to durability and flammability.