When ordering new chairs or assessing the suitability of existing chairs the following features are recommended.
- Stable base (5 legs). Sometimes chair models offer 6 legs which are also acceptable.
- Adjustable seat height (preferably gas lift)
- Adjustable seat angle (in most cases this should be level, not tilted)
- Seat sloped at front to prevent thigh compression
- Adjustable backrest height,
- Some chairs have a moulded mesh back which moulds to the body shape.
- Some chairs use a ‘ratchet’ style system with a number of levels the back rest can be raised to
- Backrests that adjust and are held up by a knob that tightens are generally not accepted as they do not reliably hold the back rest up over time.
- Backrest padded to provide lumbar support
- Lumbar support can be adjustable on chairs either by raising the back rest height or moving the lumbar support a the back of the chair (depending on chair design)
- Backrest should support the normal curvature of the spine. Poorly adjusted backrests can provide no support and often cause a person to sit away from the back rest causing back issues.
- Adjustable backrest angle
- Should not be positioned forwards as this does not offer back or lumbar support
- Preferably adjustable seat pan depth
- No arm rests for keyboarding work and also where the arm rests prevent good seating posture while performing tasks at the desk.
- Chair padding should be firm but have some give in it to offer support (i.e. should not feel like you are sitting on concrete or a hard surface).
The above list are desirable features and are suitable for general application for most people. In some circumstances, medical conditions may require additional and specific adjustments to the chair to offer the correct support. For more information, refer to your WHS Consultant.
Although not necessarily a consideration of a chair’s suitability, the age of the chair is sometimes raised as an issue. The issue is not necessarily the age of the chair but the amount of use it has had in that time. For instance, a chair can be 15 years old and barely be used with all controls operating effectively and can be perfectly fine. In contrast, a chair that has experienced heavy use and is 5 years old may have worn padding that no longer offers support, which may require replacement.
Glides are recommended if chairs are on linoleum or similar floors, as castors may present a hazard by rolling too freely and slipping out from under the person when attempting to sit down. All suppliers will fit glides if requested when ordering a chair.
Chairs with arms are not suitable if performing keyboard work. They can lead to arm, wrist, shoulder and back problems. For instance, a person may sit further from the desk and have a hunched body posture with arms overstretching to reach the keyboard causing strain to each of these.