attach objects (such as wrenches) to themselves before going onto the catwalk, so that such objects cannot fall and possibly injure someone or damage something. This also prevents objects from falling into a place where they cannot be retrieved, such as between the catwalk floor and the ceiling, or into an HVAC vent. Sometimes, to create better lighting positions or allow more flexibility, catwalks have minimal railings. Because of this, sometimes it is necessary for people working on them to wear fall arrest to satisfy safety requirements, as the railing cannot be considered sufficient. See also Tension grid Fly system Stage lighting Catwalk (disambiguation) Stage lighting Parts of a theatre Fly system Stage terminology