Environmental Health & Safety

Types of Seating

Due to the time that most computer operators spend seated, it is important for them to be equipped with a chair which includes features to help avoid discomfort associated with static postures and slouching. The purpose of this page is to explain the different seating options which are generally available. More specific information is provided on additional pages throughout this web site.


Fig. 1. Examples of "sub-task" Chairs		 "Sub-Task" Seating
Sub-task seating includes but is not limited to simple and rigid chairs, guest chairs, and office chairs. Though they may be of high quality or have ergonomic features, they are usually not sufficient for sitting in over extended periods of time.

Fig. 2. Traditional Task Seating 		Traditional Task Seating
Traditional task chairs allow the operator to set the seat pan tilt and backrest angle to fully support them in the different sitting postures. These chairs rely on knowledge of ergonomic principles and frequent active changes throughout the day to keep the operator comfortable.

Fig. 3. Advanced Task Seating

Advanced Task Seating
A number of modern task chair designs do not fully support the different sitting postures though rely on advanced features to keep the operator comfortable. These chairs also promote spinal health by facilitating frequent posture change with hands-free operation.

Fig. 4. Example of alternative seating		 Alternative Seating
Alternative Seating includes designs that may exploit biomechanical principles, offering advantages over conventional seating. There's usually a compromise involved, such as increased pressure or decreased flexibility that may make these seating options unattractive to most people.

Revised May 7, 2008

This information is made available to assist office workers at Portland State University to maintain safe work practices with respect to office ergonomics. It has been developed to be consistent with current standards, regulations, and research intending to reduce risk factors of work related injuries at video display terminal (VDT) workstations. This guide is not case specific and should be used as a suggestion only. For additional information, contact Jason Mitchell at mitchelj@pdx.edu.