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ERGONOMIC WORKSTATION GUIDELINES

 

RULA and REBA Presentation

Ergonomic Publication References - Pub

Ergonomic Publication References - Hospital

Ergonomic Exercises

Ergonomic Evaluation Form

Introduction

Ergonomics is a scientific discipline, which is concerned with improving the productivity, health, safety and comfort of people, as well as promoting effective interaction among people, technology and the environment in which both must operate.

Responsibility

Departments are encouraged to purchase adjustable equipment for the reasonable accommodation of users. Some users may have special needs, such as left-handedness, color blindness, vision impairment, etc. The goal should be flexibility to accommodate the user population so that personnel may interface effectively with equipment. Equipment should be sized to fit the individual user.

Ergonomic evaluations will be conducted by the Environmental Health and Safety Center. Additional information may be obtained by calling 513-0988 or emailing env-health-ergonomics@ncsu.edu.

Purpose

Ergonomic furniture should be designed to facilitate task performance, minimize fatigue and injury by fitting equipment to the body size, strength and range of motion of the user.

Office furnishings, which are generally available, have adjustable components that enable the user to modify the workstation to accommodate different physical dimensions and the requirements of the job. Ergonomically designed furniture can reduce pain and injury, increase productivity, improve morale, and decrease complaints.

The purchase of equipment should be task specific to eliminate:

(a) static or awkward posture,
(b) repetitive motion,
(c) poor access or inadequate clearance and excessive reach,
(d) display that are difficult to read and understand, and
(e) controls that are confusing to operate or require too much force. Therefore, furniture that is selected should be suitable for the types of tasks performed and be adaptable to multi-purpose use. Office workstations must be designed carefully to meet the need of the staff and to accomplish the goals of the facility.

Design objectives should support humans to achieve the operational objectives for which they are responsible. There are three goals to consider in human-centered design.

    1. Enhance human abilities
    2. Overcome human limitations
    3. Foster user acceptance

To achieve these objectives, there are several key elements of ergonomics in the office to consider.

    1. Equipment - video display terminals
    2. Software design - system design and screen design for greater usability
    3. Workstation design - chairs, work surfaces and accessories
      Environment - space planning, use of colors, lighting, acoustics, air quality and thermal factors
    4. Training - preparing workers to deal with technology
Recommendations

To give departments guidance in selecting office furniture and setting up workstations, the following guidelines are from the American National Standards Institute and the Environmental Health and Safety Center. Included are diagrams and a checklist to guide you through the process.

Chairs

OFFICE CHAIR ADJUSTMENT PROCEDURE FOR A MORE COMFORTABLE, NUETRAL, SEATED POSTURE

Seat Height: Seat height should be pneumatically adjusted while seated. A range of 16 - 20.5 inches off the floor should accommodate most users. Thighs should be horizontal, lower legs vertical, feet flat on the floor or on a footrest. Seat height should also allow a 90 degree angle at the elbows for typing.
Seat Width
and Depth:
A seat width of 17-20 inches suffices for most people and should be deep enough to permit the back to contact the lumbar backrest without cutting into the backs of knees. The front edge should be rounded and padded. The seat slant should be adjustable (0 to 10 degrees). Avoid bucket-type seats. The seat should swivel easily.
Backrest: The backrest should offer firm support, especially in the lumbar (lower back) region, should be 12-19 inches wide, and should be easily adjustable both in angle and height, while sitting. The optimum angle between seat and back should permit a working posture of at least 90 degrees between the spine and thighs. Seat pan angle and backrest height and angle should be coordinated to allow for the most comfortable weight load on the spinal column.
Seat Material: A chair seat and back should be padded enough to allow comfortable circulation. If a seat is too soft, the muscles must always adjust to maintain a steady posture, causing strain and fatigue. The seat fabric should "breathe" to allow air circulation through clothes to the skin.
Armrests: Armrests are optional, depending on user preference and task performed. They should not restrict movement or impede the worker's ability to get close enough to the work surface. The worker should not rest his or her forearms while keying.
Workstation Design

  1. Correct work station height depends upon the user of a work station and upon the chair and other factors that interact with the user and table. The ideal is for the user to be able to sit at the work station with the keyboard in place and be able to easily maintain a 90-100 degree elbow angle and straight wrists while keying. The height of an adjustable keyboard support should adjust between 23" and 28" to accommodate most-but not all-users. 26" is a recommended compromise position while leg clearance must still be considered.
  2. Leg room: Knee spaces should allow a worker to feel uncrowded and to allow some changes of position even with the keyboard support lowered to the correct level for use. The knee space should be at least 30" wide by 19"deep by 27" high to comply with the requirements of the Americans with Disabilities Act. For those using a footrest, clearance must be calculated with the legs in place on the footrest. Likewise, depth of the "clearance envelope" for both legs and toes should be evaluated while the workstation user is in a normal working position at the work station (determined by the design of the seating system and the way the user sits). Drawers and support legs (for furniture) should not go where human legs need to fit.
  3. The work station top should be big enough to allow space not only for all computer-related necessary equipment, but also for paperwork, books, and other materials needed while working at the computer. Working with materials on chairs and at odd angles has the potential for neck and other body strain. Frequently used items should be kept close to avoid long reaches. A general recommendation is that the work area top should be at least as big as the standard office desk - 30 inches by 60 inches. A depth of at least 30 inches allows flexibility in use/reuse of the work area. Usable space may be maximized by good wire/cable management.
  4. Thickness of work surface: one inch
Accessories

Footrest: Situations will arise in which a user is perfectly adjusted for keyboard use and with the monitor at a correct angle, but his/her feet do not rest flat on the floor. A footrest may be used to correct this problem.
Document Holder: Use a document holder instead of resting copy on the table top. This helps to eliminate strain and discomfort by keeping the copy close to the monitor and at the same height and distance from the users face as the screen.
Wrist Rests: Wrists should only be used to support the wrist in pauses between typing if this is comfortable for the individual. Placing the wrists on a wrist rest while typing can create a bend in the wrists and pressure on the carpal tunnel. Wrist rests should have rounded, not sharp, edges and should provide a firm but soft cushion.

Keyboard Tray Adjustment Proceedure


ERGONOMIC CHAIR CHECKLIST

1. Chair has wheels or castors suitable for the floor surface YesNo
2. Chair swivels YesNo
3. Backrest is adjustable for both height and angle YesNo
4. Backrest supports the inward curve of the lower back YesNo
5. Chair height is appropriate for the individual and the work surface height Yes No
6. Chair is adjusted so there is no pressure on the backs of the legs, and feet are flat on the floor or on a foot rest Yes No
7. Chair is adjustable from the sitting position YesNo
8. Chair upholstery is a breathable fabric YesNo
9. Footrests are used if feet do not rest flat on the floor YesNo

MONITOR CHECKLIST

1. Top surface of the keyboard space bar is no higher than 2.5 inches above the work surface Yes No
2. During keyboard use, the elbow forms an angle of 90-100 with the upper arm almost vertical, the wrist is relaxed and not bent, wrist rests are available Yes No
3. If used primarily for text entry, keyboard is directly in front of the operator Yes No
4. If used primarily for data entry, keyboard is directly in front of the keying hand Yes No
5. Top of screen is at eye level or slightly lower Yes No
6. Viewing distance is 18-24 inches Yes No
7. Screen is free of glare or shadows Yes No
8. Images on the screen are sharp, easy to read and do not flicker Yes No