Clearance. Except for a water heater or a modular boiler system, a new or replacement boiler installed in a new or existing building shall be installed consistent with: Or exceeding, the manufacturer's recommendations for clearance; and The space requirements of §A(6) of this regulation. In the event manufacturer recommendations for clearance are not provided, a new or replacement boiler installed in a new or existing building, shall: Have at least 3 feet between: The top of the boiler and the ceiling, and Each side of the boiler and the adjacent wall or other structure; and Comply with the conditions of §A(6) of this regulation. The distance between or around a new or replacement boiler in a modular boiler system installed in a new or existing building shall be in accordance with the manufacturer's recommendations while ensuring: There are 3 feet between each side of the perimeter of the boiler system and the adjacent wall or structure; and The conditions in §A(6) of this regulation are met. The distance between or around a water heater installed in a new or existing building shall be in accordance with the manufacturer's recommendations while ensuring the conditions of §A(6) of this regulation are met. A boiler or pressure vessel having a manhole shall have 5 feet clearance from the manhole opening to any wall, ceiling, or piping that prevents entrance through the manhole. A boiler or pressure vessel shall be located to provide adequate space for: Proper operation of the boiler or pressure vessel and its appurtenances; Inspection of all surfaces, tubes, water-walls, economizers, piping, valves, and other equipment; and Required maintenance and the repair and replacement of tubes. Ladders and Runways. When necessary to afford safe access, a steel runway or platform of standard construction shall be installed across the tops of adjacent boilers or pressure vessels, or at another convenient level. When a valve or appurtenance requiring frequent manipulation cannot be reached or operated from the floor, a platform or other safe means of operation shall be provided. A platform or runway shall: Be at least 24 inches wide; Have standard handrails and toe boards; and Provide at least 7 feet, 6 inches overhead clearance. A runway shall: Have at least two means of exit, located remotely from each other; and Be connected to floor level by: A permanent stairway, or An inclined ladder. Each elevation in a boiler room shall have at least two exits, located remotely from each other, if the room: Exceeds 500 square feet floor area; and Contains one or more boilers having a fuel-burning capacity of 1,000,000 Btu per hour, or equivalent electrical heat input.