Fire Code of the Philippines Ebook - SafetySignsPH.com Fire Code of the Philippines eBook - SafetySignsPH | Page 81

c. The total cumulative occupant load assigned to a particular stair
shall be that stair’s prorated share of the total occupant load, as
stipulated in (d) and (e), calculated in proportion to the stair width.
d. For downward egress travel, stair width shall be based on the total
number of occupants from storeys above the level where the width
is measured.
e. For upward egress travel, stair width shall be based on the total
number of occupants from storeys below the level where the width
is measured.
C. Curved Stairs
Curved stairs shall be permitted as a component in a means of egress,
provided that the depth of tread is not less than two hundred eighty
millimeters (280 mm) at a point three hundred five millimeters (305 mm)
from the narrowest end of the tread and the smallest radius is not less than
twice the stair width.
D. Spiral Stairs
1. Where specifically permitted for individual occupancies by Divisions 8
to 17 of this Chapter, spiral stairs as a component of means of egress
shall comply with the following:
a. Riser heights shall not exceed one hundred eighty millimeters (180
mm).
b. The stairway shall have a tread depth of not less than two hundred
eighty millimeters (280 mm) for a portion of stairway width sufficient
to provide egress capacity for the occupant load served in
accordance with Section 10.2.5.2 para C of this IRR.
c. At the outer side of the stairway, an additional two hundred sixty-
five millimeters (265 mm) of width shall be provided clear to the
other handrail, and this width shall not be included as part of the
required egress capacity.
d. Handrails shall be provided on both sides of the spiral stairway.
e. The inner handrail shall be located within six hundred ten millimeters
(610 mm), measured horizontally, of the point where a tread depth
of not less than two hundred eighty millimeters (280 mm) is
provided.
f.
The turn of the stairway shall be such that the outer handrail is at
the right side of descending users.
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