Walkways, stairs, platforms and workplaces located at height must be firm and stable at all times and have a design and surface that prevent them from getting slippery.Where practicable, walkways shall be established on structures where the work entails a risk of personal injuries from falls of more than 2 m to a lower level.Walkways, stairs, platforms, floors, decks and similar structures must be provided with guard rails in accordance with Section 2-22 where there is a risk of persons or objects falling down. When the height exceeds 2 m, guard rails or other protective measures must always be in place.Gaps of more than 0.30 m between walls and scaffolds or walkways must be secured. Above permanent workplaces and traffic areas, openings in floors and gratings are only permitted when such openings are passed infrequently, for example in connection with inspection and maintenance.Gangways for ships etc. must have guard rails and safety nets. Quays must have fastening devices for safety nets at appropriate intervals.