A chair fitting assessment means documenting the key measurements to select a correctly sized chair for that worker. There are eleven areas to consider when choosing cleanroom chairs or cleanroom stools.

1. Height and Weight: An employee’s overall height and weight are not adequate to properly fit a chair. Employees weighing more than 250 pounds require special considerations for safety purposes.

2. Seat Height and Cylinder Size: The seat of the chair should support the thighs straight with feet resting comfortably on the floor or footrest. The seat’s front edge should match the length of your lower leg. This is also called Popliteal height.

3. Seat Depth: The worker sits in the chair with a space of 1” to 3” between the back of the knees and the seat. Their back will be supported by the backrest. The seat cushion should provide a larger surface for weight distribution for larger people.

4. Seat Width: The seat should be wider than the hips. When using armrests provide an additional 2” to the seat width.

5. Forward Tilt Seat Angle: Most cleanroom technicians will have a forward sitting position. The seat pan angle adjustment should not cause the body to thigh angle to be less than 90 degrees.

6. Seat Cushion: A contour cushion with high density padding is better for weight distribution. A very contoured or saddle seat eliminates the sensation of sliding out of the seat when in a forward sitting position.

7. Backrest: The backrest should support the workers lumbar spinal contours with the backrest contours. Low and narrow backrests (no wider than the width of the waist) are used for tasks which need upper body mobility and arm movement. Tall backrests support the shoulders and should also support the low back area. In a forward sitting position, support for the low back alone is sufficient. Height adjustment of the backrest for women is higher and lower placement for men.

8. Armrest: When armrests are used the length should allow the worker to sit close enough to the cleanroom workstation to perform the task and still maintain contact with the backrest. Armrest placement is important because too narrow interfere with arm movement and too wide will not be useful for support. They should not interfere or catch the cleanroom garment.

9. Casters or Glides: Choose between casters and glides depending on the workstation. Casters are available with a braking option.

10. Upholstery: The cleanroom chair should have a vinyl or polyurethane seat and back. A cloth upholstery should not be used because it will particulate. The cleanroom seat cushion is sealed with a filter in the seat pan. This prevents foam particulates from entering the cleanroom as air escapes when sitting in the chair.

11. Base: The standard cleanroom or ESD chair has a five legged tubular steel, aluminum or a reinforced plastic base.

Stainless Steel Stools

The same height measurements should be used when adjusting the stool. Stainless steel stools are preferable for a research or lab area where cleanroom disinfectants are used to wipe down the equipment.

The cleanroom chair ergonomic assessment documents the key measurements to select the correctly sized chair. Measurements include: knee height, popliteal length, lumbar height, seat pan width and pneumatic cylinder. The cleanroom technician needs to be trained on how to position their chair and their workstation for proper body alignment and posture. When tasks are changed the body position needs to be altered and use rest breaks effectively to eliminate fatigue.

Decisions about the type of chair must take into consideration:

• Variety of tasks which employee will perform
• Adjustability of the other equipment and if there is an adjustable height cleanroom workstation
• Preferred seated position of the employee at the work task.

The cleanroom chair is often one of the most used pieces of furniture so it is important to have a chair assessment done for each technician. When the chair and work surfaces fit together it will enable staff to efficiently accomplish their jobs.