Chairs

The chair is the foundation of office ergonomics. Office ergonomics is similar to building a house, without a good foundation you will not have a safe and structurally sound outcome. Once a person is fitted in the correct chair, and it is set at the correct height, the other aspects of the workstation can be arranged as needed for the user. The term "ergonomic" before "chair", and just about any other item, is often just a marketing ploy and does not promise anything. However there are certain features that can make a chair ergonomically sound.

• The chair must allow the user to make all chair adjustments from the seated position without using undue force or extreme postures.
  
• Seat height is adjustable allowing the user's knees to be slightly lower than the hips, which will promote an opened hip posture and maintains the curvature of the spine while keeping the feet flat on the floor.
  
• Adjustable or fitted seat pan depth to allow users to sit on the seat pan as it was intended, to fit the user leaving no more than three inches, and no less than one inch, of space between the Popliteal and seat pan edge while allowing the user to use the back rest.
  
• The chair should be able to be positioned in recline, flat, forward or rock mode to increase the users ability to sit dynamically.
  
• Seat pan width must be adequate to allow the user to sit on the seat pan as it was intended and have enough room on either side so small shifts in posture can occur throughout the day. Buttock compression on the seat edge or thigh compression on the armrest posts should be avoided.
  
• Armrests should be padded, height adjustable to meet the users elbow height, detachable or break away and preferably at hip breadth distance from each other.
  
• The arm rests should not restrict the users postures.
  
• Backrest should have good lumbar support and be height adjustable with a range of 6-10 inches from the seat pan. The backrest should provide clearance for the buttocks and offer 15° of adjustability from 90° to 105°.
  
• Chair castors used should be appropriate for the floor type.