COUNTY OF SAN MATEO Ergonomic Office Standards The following standards have been developed to assist in controlling risk factors known to contribute to muscular-skeletal disorders in the office environment. They are to be used by departments while: designing or redesigning office areas relocating employees whether temporarily or permanently purchasing furniture and equipment The goal of implementing these standards is to create an environment where employees can work safely. Additional resources available in the County to assist departments with ergonomic issues include: Departmental VDT Coordinators Risk Management It is the intent of the Ergonomics Standards Committee to review and update the following standards annually. STANDARDS: I. Workstations: Workstation Height- workstations in the County will be a standard height of 29" and will be a continuous flat fixed surface. If a workstation needs to be adjustable and if it is a Pleion workstation, the fixed support(s) will be changed to adjustable support(s). Work Surface- work surface should have no sharp edges and a depth of 24"-36". Front edge of the work surface should be waterfall edge. Computer Surface- if the computer surface is straight and fixed without a keyboard platform the depth should be a minimum of 36". If the computer surface is straight with a keyboard platform, the depth can be a minimum of 24". If the computer surface is straight with a cutout, it should include a long arm keyboard mechanism and have a minimum depth of 30". Corner Computer Surface- the size of corner work surface is dependent on the side surface but it must accommodate a 30" keyboard platform. Leg Clearance- where there is only one primary task location, e.g. a computer station, the leg clearance envelope should be no less than 29"wide. Where a multiple task location exist, the leg clearance at the primary task point should be no less than 29"wide. The leg clearance envelope at the secondary task points should be no less than 27"wide. ergostandards 1
Where work surfaces are provided primarily to accommodate papers or desktop equipment and no task is intended to be performed, the storage needs of the workers should be the primary concern. Cutouts- workstation cutouts will be large enough to accommodate a 30" X 12" keyboard platform. Free Standing Computer Workstations - may be provided on a case-bycase basis where the work surfaces or office furniture, such as freestanding desks, do not provide space in compliance with the County guidelines for computer workstations. For situations such as training centers and temporary installations, free standing computer workstations may be appropriate. For these situations, the workstation should comply with the County guidelines. Free standing computer workstations in permanent offices or work areas shall meet the general requirements of item Workstations. Free standing computer workstations can have a work surface that is either: split, bi-level and adjustable one piece, either fixed height with an adjustable keyboard arm and platform or height adjustable Examples: SIS Human Factor Technologies Mayline Hamilton Pleion Mill Work and Case Good Furniture (built-ins) - may be appropriate for functional or appearance reasons, such as public walk up counters, high traffic work areas or where no alteration or accommodation of the work surface to individual workers is anticipated. If the mill worked surface is to be used as a seated workstation, the workstation should comply with the County guidelines. Mill worked computer workstations shall meet the general requirement of Workstations in this document. Mill worked counters should provide adequate separation or protection by minimizing long reaches and awkward postures for the workers interacting with people across the counter. For counters where the public stands, the surface should be approximately 42" above the floor. Reaches for workers, whether seated or standing, should be no greater than 24". ergostandards 2
Case Good Furniture (Free Standing) may be appropriate for private offices or shared/intermittent use work areas. Case good/free standing desks are not appropriate as workstations where computer work is more than incidental, i.e., for someone whose computer work consists of checking e- mail once a day. Where paper work or meetings are the primary job responsibilities, freestanding desks may be appropriate. If routine computer work is also part of the worker s responsibilities, then a free standing computer workstation may be necessary. See item Free Standing Computer Workstations in the document. II. Keyboard Platforms- will be straight 28"-30" standard platforms with no split pad. Keyboard platforms need to be available in alternative keyboard shapes. A thirty (30") platform is required with a computer cutout work surface. Keyboard Arms- should have independent controls for adjustment of platform height and angle. The control should require minimal force to adjust and lock the platform position and should present minimal intrusion into leg clearance. The platform should have a vertical adjustment range of at least 4" and an angle of from 0º (flat) to 10º negative. The keyboard platform is not be intended to support the body weight of the operator, but should be able to support the weight of the arms during use. Modular Keyboards (keyboards with a separate numeric keypad) can be provided to allow more comfortable location of the mouse or pointing device. A modular keyboard allows the numeric keypad to be eliminated or placed out of the way so that the mouse can sit closer to the user. Examples: Goldtouch Adjustable Kinesis Maxim Wrist Rest- gel filled should be available for the wrist rest of keyboard platforms. ergostandards 3
III. Task chairs should comply with the following specifications: A pneumatic cylinder with easy operating controls. The range of height adjustment should be a minimum of 5", within a range of 14.5" to 22". A seat depth that permits contact with the backrest in the lumbar region of the spine and be designed to avoid excessive pressure on the backside of the lower leg and knee and the underside of the thigh. Seat pans with overall seat cushion depths up to 19" with a relieved or waterfall leading edge generally will meet this requirement. Seat pans or backrests can be adjusted to meet these criteria. In these cases, the range of depth adjustment should be a minimum of 2" and the minimum depth adjustment should be 17". Seat pans must be wide enough to accommodate the breadth at the thighs of the user when seated. For this reason chairs with differing seat pans are recommended. Minimum width of seat pans should be 18". The chair backrest should provide support to the lumbar region of the spine. If adjustable, the lumbar support should adjust within the range of 6" to 14" above the seat pan. The chair backrest shall permit the user to recline the backrest up to 15 behind the vertical. Chair adjustments should be easily lockable by the user. The chair base should have five points of support with casters appropriate for the floor surface. Chairs should meet BIFMA construction requirements. Upholstered furniture must have a TB133 fire certification. Note: for health care facilities, upholstered furniture must meet healthcare standards. Note: When task chairs are properly adjusted there should be no need for supplemental back cushions/pillows or footrests. Armrests are recommended for tasks that require intensive keystroking/mouse work or where hands or arms are suspended over the keyboard. Armrests should be adjustable in height and width and may pivot inwardly or outwardly to provide support for the users forearms. ergostandards 4
Armrests should adjust to a height of 6" to 9" above the seat pan. Armrest width should adjust from a maximum of 20" to roughly 14". Chairs for high counters or work surfaces should meet the following specifications: Extended pneumatic cylinders. The same seat depth, seat pan, and backrest specifications as listed above. A foot-ring that is height adjustable. Note: High counter or work surfaces should have space to accommodate a height adjustable footrest as the main support surface for the worker s feet. Examples: Standard Workstation Chairs: VIA American Seating Que Chair Grahl Cramer Triton (24 hour users or big and tall) Specialty Chairs: Neutral Posture (certified for 500 lbs.) SOMA Samples of the four standard workstation chairs will be provided by the vendor and kept on-site for sit testing by users. IV. Computer Components h Monitors Monitor Position - should place the top of the screen no higher than the eye height of the operator. The distance between the screen of the monitor and the operator s eyes should be appropriate for the near vision of the operator, whether corrected by glasses or not, i.e., the operator should not have to lean forward, squint or peer at to clearly see the characters on the monitor screen. h CPU/Hard Drives- where possible, when buying or replacing CPU s, a vertical tower is recommended. The CPU tower can be located in a hanging position, suspended by brackets below the workstation. ergostandards 5
The recommended position would be slightly to the side and far enough to the rear to avoid the users bumping the CPU s with their knees, but to still allow easy access for the users to reach controls, CD-ROM, etc., of the CPU. V. Accessories Headsets- are strongly recommended for employees who use the telephone as a normal part of their duties. Headsets are required for employees who work on the computer and telephone simultaneously. To obtain a headset, please contact the Voice Services unit in ISD. Foot Rest- should not be necessary for proper foot support of the computer operator. Footrests may be provided on a case-by-case basis for the comfort of the operator in supporting alternate positions of the foot, ankle and lower leg. Where high counters or work surfaces exist, footrests may be necessary to provide proper foot support for the worker. Glare Screens- should not be automatically provided. Glare screens may be used where glare on a monitor screen cannot be reduced by relocating the monitor or task lights, changing diffusers on overhead light fixtures or using window coverings. Alternative Pointing and Input Devices -should allow for a variety of hardware choices to accommodate specific tasks or physical needs of the employee. In addition to the computer mouse, alternate input devices would include trackballs, touch pad, pen and tablet, and digitizing tablets. Alternative input devices should be adjustable, via software, for speed or accuracy of operation. The input device should be able to be used with relaxed or neutral joint postures and should not have sharp edges that could compress the soft tissue in the wrist or hand. Document Holders In-line Document Holders are most appropriate for frequently viewed documents and/or when it is important that the person keying be able to look forward, rather than having to frequently turn his/her neck. The inline document holder mounts between the monitor and the keyboard. If an employee must handle the source document frequently, an in-line document holder can be used so repetitive over reaching is reduced. ergostandards 6
Examples: VuRyte, model 14SL most appropriate when the tasks involve single sheet documents or 18 SL most appropriate for work papers wider than 14" or open file folders Copy Cat accommodates a surface 1.25" to 1.75" or 1.75" to 2.5 thick Free Standing Document Holders- are most appropriate for infrequently viewed documents or reference documents when space is limited between the monitor and keyboard. A document holder placed directly to the side of the monitor, at screen level, and angled slightly inward toward the screen can be used to hold reference documents. Slant Boards-can be used in situations where reading and/or writing creates a strain on the neck or writing arm from prolonged forward flexion or bending. The examples have a padded edge for normal reading and writing tasks. Example: ISE sizes 13X20 or 15X20 depending on the size of the source documents. Fat Cat angle can be adjusted from 45º to 70º For very thick source documents (i.e. medical records, texts, legal files) a slant board with a high padded wrist rest is necessary to hold the documents in place. These slant boards will not be comfortable for use as writing boards, unless the documents being reviewed are thick, as the padded rest is too high for normal use. Example: WorkRite, standard 18 ¼, large 22 ¾ VI. Lighting Where natural light is available, it should be utilized to its fullest to supplement any artificial light provided. Where natural lighting may increase the light levels beyond an acceptable level of comfort, blinds, shades or the like must be provided to allow employees to control the overall illumination in their work area. Task Lighting-where computer work is the primary task but reading papers is also necessary, an additional task light may be needed if lighting levels in the work station do not provide for high intensity illumination, or if natural lighting is unavailable or insufficient. ergostandards 7
Where visual tasks require long duration or high intensity visual demands, lighting levels above normal office settings may be needed. VII. Cleaning of computer equipment - is the responsibility of the operator and is important for the proper function of the equipment. Cleaning requirements include: Mouse - the underside of the mouse should be cleaned with a damp cloth monthly to remove built-up dirt and assure its easy movement. Ball and rollers - should also be cleaned monthly with rubbing alcohol to maintain the accurate function of the mouse. Keyboards - should be dusted frequently or vacuumed if possible. Liquid cleaners should not be used on keyboards, unless significant build-up exists on the keys. A small amount of rubbing alcohol on a swab or cloth can be used to remove build-up. The operator should take care not to spill ANY liquids on the keyboard. Monitor Screen - should be dusted regularly. Commercial monitor screen cleaners can be used if necessary. Regular glass cleaner shall not be used. If you need assistance with computer maintenance contact your LAN Administrator or VDT Coordinator. ergostandards 8