building commences.]
1.2.2.8
Deflection
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NOTE: For buildings with masonry, infill, limit
frame sway 1/600th of building eave height and
consider limiting wall purlin deflection to 1/600th
of span. The designer should also consider weight
handling systems and building finishes when
specifying deflection limits.
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a.
Structural Members: The maximum deflection of main framing
members shall not exceed 1/240th of their respective spans. The
maximum deflection due to live load in roof panels and purlins
shall not exceed 1/180th of their respective spans.
b.
Roof Panels: UL 580, Class 90. The design analysis shall
establish that the roof when deflected under dead plus live or
snow loads, will not result in a negative gradient. Maximum
deflections shall be based on sheets continuous across two or more
supports with sheets unfastened and fully free to deflect. In
addition, the roof decking shall be designed for a 90 kg 200-pound
concentrated load at midspan on a 300 mm 12 inch wide section of
deck. Panels thinner than 0.8 mm 0.03 inches are not permitted
for diaphragms used to resist seismic loads in Seismic Zones 2
through 4.
c.
Wall Panels: The maximum deflection due to wind on wall panels
and girts shall be limited to 1/120th of their respective spans
except that when interior finishes are used the maximum allowable
deflection shall be limited to 1/180th of their respective spans.
d.
Openings: Limit deflections of steel framing above and along the
side of rolling door openings to a maximum of 1/2 the allowable
movement in the telescoping top roller of the doors to ensure
proper operation. Frame all equipment openings over 300 by 300 mm
12 by 12 inches.
1.2.2.9
Provisions for Gutters and Downspouts
Gutters and downspouts shall be designed according to the requirements of
SMACNA Arch. Manual for storms which should be exceeded only once in 5
years and with adequate provisions for thermal expansion and contraction.
Supports for gutters and downspouts shall be designed for the anticipated
loads. Roof drainage system to withstand rainfall intensity of [_____]
mm/hour inches per hour, with 5 minute duration.
1.2.2.10
Provisions for Louvers
Louvers shall be [fixed-blade] [adjustable] type designed for a minimum net
open area of [_____] square meters, square feet, to be rainproof, and to
resist vibration when air is passed at the rate of [_____] cubic meters per
second.cubic feet per minute.
1.2.2.11
Ventilators
a.
Circular Ventilators:
Circular roof ventilators shall be gravity
SECTION 13120
Page 14
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