15. Walkways: Walkways inside a building shall:
(1) be kept in good order and free from any obstruction;
(2) be maintained to keep the surface from becoming slippery, even through wear or humidity;
(3) be wide enough to allow the safe handling of materials and be at least 600 mm wide;
(4) be at least 1,100 mm wide if they serve as direct access to an exit;
(5) be clearly marked out by lines traced on the floor or be bordered by facilities, equipment, walls or material or merchandise depots, to permit the safe passage of persons;
(6) have a free space of at least 2 m above the floor unless the danger is made known by means of a visible sign;
(7) be free from any opening capable of causing an accident, unless they are protected with a guardrail or a cover capable of withstanding a load of at least 2,4 kN/m2.