Spent fuel, ash, cinders and other fire debris shall be removed from the fire box at regular intervals, but at least once a day, and, once removed, shall not be stored indoors. Adequate long handle rakes, hoes, scrapers and shovels shall be provided for such removal. When being removed from the fire box, the spent fuel shall be wetted down and cooled with water from the required water supply. Metal containers with covers shall be provided for such spent fuel removal. Such metal containers shall be of a minimum 16 gauge construction and shall be limited in size to a capacity not exceeding 20 gallons (75.7 L), so as to facilitate easy handling by any employee assigned to the task and to enable such containers to easily pass through any door or passageway. The spent fuel shall be placed outdoors in a dumpster or heavy metal container used exclusively for this purpose and kept covered at all times. Such dumpster or container shall be kept separate from combustible construction, and stored combustible materials and combustible waste.