Every employer shall -
(a) where reasonably practicable, provide an ergonomically sound seat for every employee whose work can be effectively performed while sitting;
(b) where reasonably practicable, permit an employee whose work is normally performed standing to take advantage of any opportunity for sitting which may occur, and for this purpose the employer shall provide seating facilities; and (c) provide seats with backrests where the nature of work performed by the employees is such that such seats can be used.