Under the ADA, an employer is expected to make "reasonable accommodations" for employees with disabilities who can otherwise perform the essential functions of his/her job. This may involve modifying workstation and equipment design or altering the person's job functions. For example, an employee may need a sit/stand adjustable desk to work comfortably due to a back injury or disability. With respect to providing workspace for people with mobility impairments, such as wheelchair users, consider the following Accessibility Guidelines from the ADA: Height of Workstations The tops of accessible tables and workstations shall be from 28 in to 34 in (710 mm to 865 mm) above the finished floor or ground. Furniture with adjustable surface heights maximizes flexibility and can accommodate a range of disabilities and individual users. Knee Clearances If seating for people in wheelchairs is provided at tables or workstations, knee spaces at least 27 in (610 mm) high, 30 in (760 mm) wide, and 19 in (485 mm) deep shall be provided. Components Components should also be adjustable. For instance, worksurfaces and desks designed for computer support should offer adjustable keyboards and mousepads. Seating, work surfaces and tables The height of any type of counter, table or work surface is related to the needs of the wheelchair user rather than the occupancy. Different types of work require different work surface heights for comfort and optimal performance. Light detailed work, such as writing, requires a work surface close to elbow height for a standing person. Heavy manual work, such as rolling dough, requires a work surface height about 10 in. (255 mm) below elbow height for a standing person. The principle of a high work surface for light detailed work and a low work surface height for heavy manual work also applies for seated persons, however, the limiting condition for seated manual work is clearance under the work surface. Size and Approach The minimum clear floor or ground space required to accommodate a single, stationary wheelchair and occupant is 30 in by 48 in(760 mm by 1220 mm). The minimum clear floor or ground space for wheelchairs may be positioned for forward or parallel approach to an object. Clear floor or ground space for wheelchairs may be part of the knee space required under some objects. Forward Reach If the clear floor space only allows forward approach to an object, the maximum high forward reach allowed shall be 48 in (1220 mm). The minimum low forward reach is 15 in (380 mm). Side Reach If the clear floor space allows parallel approach by a person in a wheelchair, the maximum high side reach allowed shall be 54 in (1370 mm) and the low side reach shall be no less than 9 in (230 mm) above the floor. Storage Accessible storage spaces shall be within at least one of the reach ranges specified: the maximum high forward reach allowed shall be 48 in (1220 mm). The minimum low forward reach is 15 in (380 mm); the maximum high side reach allowed shall be 54 in (1370 mm) and the low side reach shall be no less than 9 in (230 mm) above the floor.