Michigan Administrative Code (Last Updated: November 16, 2016) |
Department LR. Licensing and Regulatory Affairs |
Bureau of Construction Codes |
Chapter Construction Code - Part 9A. Mechanical Code |
Part 9A. MECHANICAL CODE |
Section 408.30927a. Equipment and appliances on roofs or elevated structures.
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a. Section 306.5 of the code is amended to read as follows:
306.5 Equipment and appliances on roofs or elevated structures. Where equipment or appliances requiring access are located on an elevated structure or the roof of a building so that personnel will have to climb higher than 16 feet above grade to access this equipment or appliances, an interior or exterior means of access shall be provided. Such access shall not require climbing over obstructions greater than 30 inches high or walking on roofs having a slope greater than 4 units vertical in 12 units horizontal (33- percent slope). Such access shall not require the use of portable ladders. Where access involves climbing over parapet walls, the height shall be measured to the top of the parapet wall.
Permanent ladders installed to provide the required access shall comply with all of the following minimum design criteria:
(1) The side railing shall extend above the parapet or roof edge not less than 30 inches.
(2) Ladders shall have rung spacing not to exceed 14 inches on center. The uppermost rung shall be a maximum of 24 inches below the upper edge of the roof hatch, roof, or parapet, as applicable.
(3) Ladders shall have a toe spacing not less than 6 inches deep.
(4) There shall be a minimum of 18 inches between rails.
(5) Rungs shall have a minimum 0.75-inch diameter and be capable of withstanding a 300-pound load.
(6) Ladders over 30 feet in height shall be provided with offset sections and landings capable of withstanding 100 pounds per square foot. Landing dimensions shall be not less than 18 inches and not less than the width of the ladder served. A guard rail shall be provided on all open sides of the landing.
(7) Climbing clearance. The distance from the center line of the rungs to the nearest permanent object on the climbing side of the ladder shall be a minimum of 30 inches measured perpendicular to the rungs. This distance shall be maintained from the point of ladder access to the bottom of the roof hatch. A minimum clear width of 15 inches shall be provided on both sides of the ladder measured from the midpoint of and parallel with the rungs, except where cages or wells are installed.
(8) Landing required. A ladder shall be provided with a clear and unobstructed bottom landing area having a minimum dimension of 30 inches by 30 inches centered in front of the ladder.
(9) Ladders shall be protected against corrosion by approved means.
(10) Access to ladders shall be provided at all times.
Catwalks installed to provide the required access shall be not less than 24 inches wide and shall have railings as required for service platforms.
Exception 1: An approved, permanent building mounted ladder receiver which prevents the ladder from sliding sideways off the building or slipping backward and meets the ladder safety standard of OSHA regulations (Standard - 29 CFR) Ladders. - 1926.1053 (b)(1) may be installed on buildings under 20 feet in height above grade to access such equipment or appliances.
Exception 2: This section shall not apply to group R-3 occupancies.
306.5.1 Sloped roofs. Where appliances are installed on a roof having a slope of 3 units vertical in 12 units horizontal or greater and having an edge more than 30 inches above grade at such edge, a level platform shall be provided on each side of the appliance to which the access is required for service, repair, or maintenance. The platform shall not be less than 30 inches in any dimension and shall be provided with guards. The guards shall extend not less than 42 inches above the platform, shall be constructed so as to prevent the passage of a 21-inch-diameter sphere, and shall comply with the loading requirements for guards specified in the Michigan building code. Access to appliances shall not require climbing over obstructions greater than 30 inches high or walking on roofs having a slope greater than 4 units vertical in 12 units horizontal permanent ladders, or equivalent, shall be provided on both sides requiring access in accordance with the ladder requirements of section 306.5.
Exception: This section shall not apply to group R-3 occupancies.
History: 1989 AACS; 1995 AACS; 2007 AACS; 2010 AACS; 2013 AACS.