Office work is mostly done when sitting – usually over longer periods. A bad coordination of workplace, work equipment (especially visual display units (VDU)) and office chair can lead to one-sided and static postures.
Ergonomic and good seating therefore has a key relevance for the health maintaining. A good office chair should not restrict, it should allow for changing seating positions and should support the body in every position.
Quality criteria for office chairs
- The office chair has a synchronous mechanism.
It is the basis for dynamic seating. When settling back, the back rest smoothly tilt backwards. Simultaneously the seating surface tilts. The office chair follows the natural body movements.
- The “counter-pressure” of the synchronous mechanism is adjustable.
The adjustment can be done manually or via automatic weight recognition technology. The swivel chair can be adjusted, so that the back rest always creates a little “counter-pressure” while allowing for a powerless settling back.
- The back rest is high enough.
For a satisfactory support of the whole body the back rest should be at least as high as the scapulas.
- The back rest has a sufficient lumbar support.
The protrusion of the back rest in the loin region (lower back) supports efficiently in the upright sitting posture. The lumber support should be pronounced, so that the support is notable perceptible. It should not create an unpleasant pressure when leaning back.
- The whole back rest or the lumber support is height adjustable.
A good support of the back can only be accomplished if the lumber support can be adjusted to the individual correct height.
- The seating area is height adjustable.
By adjusting the right seat height, possible blood stasis in the legs can be prevented. It is the basis for a relaxed sitting posture.
- The seating area has a good suspension.
When sitting down the seating area should smoothly back bounce. This prevents unnecessary compressions of the spine.
- The swivel chair has height adjustable arm rests.
Arm rests relieve the shoulder region and prevent tensions. Furthermore they also support intervertebral discs gentle sitting and standing up.
- The arm rests are width adjustable or swivelling.
Hereby it is assured, that every user can make use of the arm rests and is not constrained.
- The star base is equipped with floor matching rolls.
Hard rolls with single sides shall only be used for carpet and other soft surfaces. Soft rolls for wooden or stone floors and other hard floors can be recognized by their bi-coloured sides.
- The swivel chair has a GS-label for proven safety.
The GS-label guarantees the standard safety, stability and durability of the chair. GS-labeled products meet the current standards.
The listed criteria are part of the guideline L-Q 01-06 – Quality criteria for office workplaces, on which basis the QUALITY OFFICE-label is assigned.
Further information on QUALITY OFFICE can be found under www.quality-office.org.
Moreover these requirements on office chairs and other criteria on the evaluation of furnishings and whole office workplaces are part of the office checks. These can be ordered under Info Service or downloaded directly.
All synchronous mechanism are not created equal
The range of swivel chairs with a synchronous mechanism is wide, but also are the variation in quality. The following aspects should be considered when purchasing office chairs:
- Wide opening angle.
Back rests which can only be tilted by a small angle do barely relieve the spine. The back rest should be tiltable backwards by at least 30 degrees.
- No “shirt-off-effect”
When leaning back the arm rest should move precisely accurate with the back of the user. If the back rest “pushes” upwards during the movement, it also pushes the height of the lumber support. This can lead to an unpleasant pressure and the “shirt-off-effect”.
- No raise in seat leading edge.
If the seat leading edge raises noticeable when leaning back, it creates a pressure on the lower part of the thighs. A worse blood circulation is the result.
- Weight adjustment
The counter-pressure of the back rest must be adjustable to the weight of the user. Leaning back must be possible without any physical strength. At the same time the back rest should support the user sit up via a light pressure. The adjustment must be possible during seating. Ideal are adjustment elements which can be controlled during an upright seating posture.
Very important is the stability of office chairs. When leaning back there should be no danger of toppling over backwards. If a chair is save and stable, can be recognized by the GS-label (proven safety) or QUALITY OFFICE-label.