306.5
Mechanical equipment and
appliances on roofs or elevated structures. Where mechanical equipment
or appliances requiring periodic inspection, service, or maintenance are
installed on roofs or elevated structures, a permanent stair shall be provided
for access.
Exception: A portable ladder may be used for
dwellings, replacement equipment and appliances, on existing buildings, and
exterior roof access points not exceeding 16 feet (4.9 m) above grade, unless
the building official determines that the unique shape of the roof does not
allow safe access with a portable ladder.
The permanent stair shall, at a minimum, meet the
following:
1. The stair shall be
installed at an angle of not more than 60 degrees measured from the horizontal
plane.
2. The stair shall have flat
treads at least 6 inches (152 mm) deep and a clear width of at least 18 inches
(457 mm) with equally spaced risers at least 10.5 inches (267 mm) high and not
exceeding 14 inches (356 mm).
3.
The stair shall have intermediate landings not exceeding 18 feet (5.5 m)
vertically.
4. Continuous handrails
shall be installed on both sides of the stair.
5. Interior stairs shall terminate at the
under side of the roof at a hatch or scuttle of at least 8 square feet (0.74
m2) with a minimum dimension of 20 inches (508
mm).
6. When a roof access hatch or
scuttle is located within 10 feet (3.0 m) of a roof edge, a guard shall be
installed in accordance with IMC section
304.11.
7. Exterior stairs shall terminate at the
roof access point or at a level landing of at least 8 square feet (0.74
m2) with a minimum dimension of 20 inches (508 mm).
The landing shall have a guard installed in accordance with IMC section
304.11.
306.5.1
Sloped roofs. Where
appliances, equipment, fans, or components that require service are installed
on a roof having a slope of 3 units vertical in 12 units horizontal (25-percent
slope) or greater and having an edge more than 30 inches (762 mm) above grade
at such edge, a level platform shall be provided on each side of the appliance
to which access is required for service, repair, or maintenance. The platform
shall be at least 30 inches (762 mm) in any dimension and shall be provided
with guards. The guards shall extend at least 42 inches (1067 mm) above the
platform, shall be constructed so as to prevent the passage of a
21-inch-diameter (533 mm) sphere and shall comply with the loading requirements
for guards specified in Minnesota Rules, chapter 1305.
306.5.2
Electrical requirements.
A receptacle outlet shall be provided at or near the equipment or appliance
location in accordance with the Minnesota Electrical Code.
306.5.3
Permanent ladders. Where
a change in roof elevation greater than 30 inches (762 mm) but not exceeding 16
feet (4.9 m) exists, a permanent ladder shall be provided. The ladder shall be
vertical. The ladder must, at a minimum, meet the following:
1. Width shall be at least 16 inches (406
mm).
2. Rung spacing shall be a
maximum of 14 inches (356 mm).
3.
Toe space shall be at least 6 inches (152 mm).
4. Side railings shall extend at least 30
inches (762 mm) above the roof or parapet wall.
