Guidelines

Computer Workstations Design and Adjustment - Guidelines

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1. Purpose and Objectives

The purpose of this guideline is to offer advice to University staff, students and community regarding the set-up of computer workstations in a way that reduces the risk of musculoskeletal disorders.

2. Definitions, Terms, Acronyms

Musculoskeletal disorder - Sprain or strain to soft tissues of the body, including muscles, nerves, tendons, ligaments, blood vessels, and intervertebral discs. Examples: back pain, sciatica, neck strain.

Prolonged period of time - Longer than 2 hours without a period of rest. Usually refers to performing a one specific task for a period of 2-3 hours within an average 7-8 hour shift.

3. Guidelines Scope/Coverage

This guideline applies to all University staff and students who use computer workstations for a prolonged period of time to conduct their work.

4. Guidelines Statement

Use of a computer workstation has been shown to increase the risk of musculoskeletal disorders and therefore the University has developed guidelines on how to best configure computer workstation components to minimise the risk of musculoskeletal disorders to the worker.

This guideline is intended to be used in conjunction with the Computer Workstation Design and Adjustment online training module and Computer Workstations Self-Assessment Checklist.

5. Postural Variation

Regular variation between sitting, standing and walking is vital for back injury management and prevention. Gentle and regular mobilisation of the head, neck, shoulders, arms, hands and upper trunk is also a key injury prevention and management strategy.

Employees are encouraged to vary their posture briefly, every 30 minutes, when working at a computer workstation for prolonged periods (over one hour). It is important that workstation design and adjustment is coupled with regular movement of the body in order to offset the static loading effect on musculature and compressive forces on the spine.

6. General Workstation Characteristics

Any new furniture or seating that is required is to be purchased from the Property and Facilities Furniture Section, as outlined in the Selection and Purchase of Seating and Furniture Policy and Procedures. Occupational Health and Safety Division works closely with the Furniture Section to identify seating and furniture options that meet OHS and ergonomic requirements in order to minimise risk of musculoskeletal injuries associated with poorly designed seating and furniture.

6.1 Workstation dimensions

Optimal workstation dimensions and characteristics described below are outlined in AS/NZ Standards 4443:1997 and Workplace Health and Safety Queensland's Ergonomic Guide to Computer Workstations.

The workstation should be large enough to conduct the required work. Minimum recommended dimensions are 1200 mm (length) x 800 mm (depth) to facilitate optimal viewing monitor distance. The depth of the desk should be sufficient to organise workspace without requiring excessive twisting, reaching or awkward upper body postures while working. The height of seated workstations should be within the standard range of 680 mm-720 mm and allow for adequate leg clearance. Desk thickness should be 25-33 mm.

6.2 Workstation shape

Workstation shapes vary greatly across UQ facilities with an increase in the number of corner, L-shaped and scalloped desks. The shape of some desks may limit the availability of forearm support when keyboarding. Relocating the keyboard, mouse and monitor to a straight portion of the desk or use of a desk lozenge or desk sleeve may improve forearm support. When selecting desks, consider the availability of forearm support and chair access. Refer to the Selection and Purchase of Seating and Furniture Policy and Property and Facilities Furniture Section for additional information regarding workstations.

6.3 Keyboard drop-downs

Keyboard drop-downs on workstations should be stable and large enough to facilitate both keyboard and mouse use. If the keyboard drop-down is not in use, the supports should be removed and the platform secured so it is stable and does not interfere with leg clearance. New furniture requests or refurbishment projects should reconsider the need for workstations with keyboard drop-downs.

6.4 Standing-height workstations and height adjustable workstations

6.4.1 Standing-height workstations

Use of standing-height workstations or height adjustable workstations may help to facilitate increased postural variation. Standing-height workstations can be used with drafting height chairs to allow users to alternate between seated and standing work. Use of a computer on a filing cabinet or bookshelf can be used for short-term or temporary standing needs.

6.4.2 Height adjustable workstations

Height adjustable workstations allow for raising or lowering of the work surface without disruption to workstation equipment. Height adjustable workstations can also accommodate very tall and very short workers who are uncomfortable at standard height workstations. Height adjustability ranges vary across workstations and required heights should be measured prior to ordering. Height adjustable workstations can be purchased through Property and Facilities Furniture Section.

6.4.3 Needs analysis

There may be some medical conditions or instances where standing-height or height adjustable workstations are required or encouraged. In these cases, the worker should consult with their supervisor and local Work Health and Safety Coordinator to determine the most suitable workstation for their needs.

7. Seating

7.1 Chair characteristics

The chair should have a base with five legs and castors appropriate to the work environment (i.e. hard, soft, locking, etc.) and have adjustable features. Minimum adjustments should include seat height, backrest angle and backrest height adjustability.

The seat should be wide and long enough to provide support for the thighs and buttocks without putting pressure on the back of the knees. Some chairs have seat slides or can be ordered with different seat sizes to suit workers of variable heights and leg lengths. Chairs with dynamic backrests (commonly referred to as "mesh-back" chairs) may help to relieve lower back symptoms through increased muscle activation while seated. Due to the dynamic nature of their design, these chairs may have limited adjustability and should be trialed prior to purchase. Most suppliers provide adjustment instruction manuals when chairs are purchased or provide instructions online.

7.2 Adjusting the seat

Adjust the seat height so elbows are aligned to the desk height when bent to 90 degrees. The shoulders and arms should be relaxed when hands are on the keyboard. If the feet are not fully supported on the floor in this position, an adjustable footrest will be needed. Adjust the seat tilt (if applicable) for a flat or neutral tilt to align knees to hips. Workers with lower back pain or leg pain may benefit with a slight forward seat tilt with knees below hip level.

7.3 Adjusting the backrest

While sitting at the very back of the seat, adjust the backrest so the angle between hip and torso is comfortable (usually between 90-100 degrees). Adjust the height of the backrest (if applicable) so the contour of the chair supports the curve in the lower back. Many chairs in use at UQ have a ratchet mechanism where the backrest is lifted from underneath and "clicks" through various height settings. Once at the top, the backrest drops down to the lowest setting. If using a chair with a dynamic mesh backrest, adjust the recline tension so the backrest supports an upright (90-100 degrees) working posture. Many mesh-back chairs have a "recline-lock" function if users do not wish to recline.

7.4 Armrests

Armrests may restrict access to the desk if used with corner workstations or if the armrests do not adjust low enough to slide under the desk. This may encourage forward reaching for keyboard and mouse use or may encourage workers to adjust their chair so that it is too low. If armrests restrict access, they should be removed. Contact Property and Facilities Furniture Section for assistance.

Adjust armrests (if applicable) so they do not restrict close access to the desk. Armrest height should be adjusted to 1-2 cm below relaxed elbow height so as not to encourage shoulder elevation.

8. Adjusting the Keyboard and Mouse

8.1 Keyboard and mouse placement

Keyboard and mouse should be placed within comfortable reach so the spine and upper limbs are in a neutral, relaxed posture. The keyboard and mouse should be placed far enough onto the desk to allow forearm support, but close enough so that the elbows are still close to the body and not extended forward.

8.2 Keyboard selection

The use of a traditional alpha-numeric keyboard with a right hand mouse may result in the right arm being held away from the body, particularly when the user has a smaller shoulder span. This posture may be associated with neck, shoulder and upper limb musculoskeletal disorders. A keyboard without a numeric pad or with the numeric keypad on the left will minimise shoulder abduction and associated risk of musculoskeletal injuries.

8.3 Minimising risks associated with mouse use

Standard computer mice are suitable for most workers, however, some users may develop wrist or hand pain from prolonged, repetitive or intensive mouse use. Mouse design is important but should be coupled with task variation, keyboard shortcuts, use of non-dominant hand for mouse tasks, and other strategies designed to minimise use of the mouse.

High reliance on the right dominant hand is often a contributing factor to hand, wrist and forearm injuries. Changing or varying use with the non-dominant hand is worth consideration for injury prevention and management. The right and left click buttons can be reversed by adjusting mouse settings on the computer.

8.4 Mouse design and selection

People with small hands may experience excessive wrist extension (bending upwards) when using a high profile mouse. This can be minimised through use of low profile or smaller mouse.

A traditional mouse requires the palm to face downward, which may result in sideways wrist movement (ulnar and radial deviation) and wrist upward bending beyond 20 degrees (wrist extension). The use of a vertical mouse where the hand adopts a handshake position minimises forearm pronation and ulnar and radial deviation.

Alternative mouse designs, i.e. trackball, joystick, touchpad may be recommended in cases of wrist or finger injuries but should be addressed on an individual basis.

9. Monitor Placement

Monitors that are too high or too low contribute to awkward neck postures, possibly leading to neck and shoulder tension, eye strain and headaches. To minimise awkward neck postures, the monitor should be 15-50 degrees below eye level. Many monitors have some degree of height adjustability, but a monitor stand may also be required to achieve optimal height.

Monitors placed too close or too far may cause eye strain or forward head postures. Optimal viewing distance is approximately one arm's length away. The monitor should be slightly tilted so the top is slightly further away from the eyes than the bottom of the screen.

9.1 Use of progressive or bifocal lenses

Progressive or bifocal lens wearers need to pay particular attention to the placement of their monitor. The head is often tilted backwards unknowingly to read the screen, potentially causing neck, shoulder and back discomfort. In these cases, it is recommended that dedicated computer glasses are used to minimise awkward head and neck postures.

9.2 Multiple monitor use

Use of multiple monitors may lead to increase neck movement and potential strain. When one monitor is used predominantly, the primary monitor should be centrally aligned and the secondary monitor placed directly beside. When two monitors are used equally, they should be centrally aligned and adjusted to the same height and distance. Multiple monitors may cause neck twisting which over time may develop into neck stiffness, pain and headaches. Widescreen monitors may exaggerate these awkward postures.

Neck twisting can be minimised by angling monitors slightly inward or minimising working documents/programs to use the central sections of the screen. Consider rotating one monitor to portrait orientation (display settings can be adjusted to flip the image) to minimize twisting or consider swapping one or both monitors for non-widescreen models.

9.3 Minimising glare

Placement of the monitor may create glare and reflectance issues, potentially causing eye fatigue. Monitors should be placed perpendicular to windows or large light sources. Window shades and screen filters may be used when the monitor cannot be relocated. Task lamps may be used in areas with poor lighting. Lighting concerns can be addressed by the OHS Division.

9.4 Resolution and display settings

Poor screen resolution or non-optimised display settings may result in eye fatigue or headaches. Adjust brightness and contrast of monitors for comfort. Colour settings may also need adjusting. Screen resolution should be adjusted to highest settings. When two monitors are used, it may be difficult to match screen resolution or display settings. Request assistance from ITS or try to use two similar or identical monitors to minimise this.

10. Laptop Adjustment

10.1 Minimising risks associated with laptop use

Laptops are increasingly used in UQ offices and laboratories and are often associated with musculoskeletal disorders. This is commonly due to the fixed position of the screen, keyboard and mouse in relation to each other, and the awkward postures that result. Use of an external keyboard and mouse with the laptop allows independent adjustment of the controls and computer screen. It is preferable to select and use laptops with the following design criteria:

  • provision of external keyboard and mouse to facilitate independent adjustment
  • capacity to plug in an external keyboard and mouse
  • lightweight and small
  • lightweight carrying case with handle and adjustable shoulder strap

10.2 Traveling with a laptop

When traveling with a laptop, eliminate unnecessary equipment/materials from the case and use a wheeled luggage bag whenever possible. Care should be taken to avoid forcibly pulling, pushing or jerking the bag. When using a laptop in a hotel, pillows can be used to raise seat height when chairs are too low. External keyboards and mice can often be borrowed from the hotel.

11. Paper Documents

Hard copy documents that are viewed during computer tasks should be placed close to the midline of vision and elevated to encourage neutral neck and head position. A document holder or adjustable reading surface should be provided and placed in a position close to the midline between the keyboard and computer screen or adjacent to the computer screen.

12. Telephone Use

Workers who frequently use the telephone and may be required to take notes or use the computer concurrently are likely to cradle the telephone between the neck and shoulder. This posture is associated with a high risk of neck and shoulder strain. Use of a hands-free telephone headset allows simultaneous use of computer and telephone with a neutral posture of the neck and upper limb and is strongly recommended for frequent telephone users.

Voice Networks, Information Technology services (ext. 52200) should be contacted in relation to selection of appropriate telephone headsets.

13. Training and Assistance

13.1 Training

Training in computer workstation set-up is available at the University in the form of an online Blackboard e-Learning training module. All computer users should review the online training module Computer Workstations: Design and Adjustment prior to requesting assistance. In addition, the Computer Workstations Self-Assessment Checklist should be used by the worker in assessing their own workstation to identify any components that may not be at the optimal height or distance.

13.2 Seeking assistance

To seek assistance with individual computer workstation set-up, workers should first review the online training module Computer Workstations: Design and Adjustment and apply the Computer Workstations Self-Assessment Checklist to their workstation. If additional assistance is needed to implement the modifications identified in the checklist or the worker is unsure how to proceed, they should contact their local Workplace Health and Safety Coordinator who can provide initial assistance. If symptoms persist, the situation is complex or there is an underlying medical condition, contact the Ergonomics and Rehabilitation Officer within the OHS Division for specific advice.

14. Contact for Additional Assistance

Ergonomics and Rehabilitation Officer

OHS Division

ohs@uq.edu.au

Custodians
Director, Occupational Health and Safety
Mr Jim Carmichael
Custodians
Director, Occupational Health and Safety
Mr Jim Carmichael