each end by folding in to 24 gage sheet metal or by metal collar frames.
3.1.10
Installation of Supports
3.1.10.1
Selection
Select duct and equipment support system taking into account the best
practice recommendations and requirements of SMACNA Rectangle Duct Const,
SMACNA Rnd Duct Const, and NFPA 91; location and precedence of work under
other sections; interferences of various piping and electrical work;
facility equipment; building configuration; structural and safety factor
requirements; vibration and imposed loads under normal and abnormal service
conditions. Indicated support sizes, configurations, and spacings are the
minimal type of supporting component required for normal loads. Where
installed loads are excessive for the normal support spacings, provide
heavier duty components or reduce the element spacing. After system
start-up, replace or correct support elements which vibrate and cause noise
or possible fatigue failure. Exercise special care to prevent cascading
failure.
3.1.10.2
General Requirement for Supports
**************************************************************************
NOTE: See Section 15070, "Mechanical Sound,
Vibration, and Seismic Control," for guidance given
in guide specification technical notes. Definite
requirements should be specified in contract
specification for bidders' information.
**************************************************************************
Securely attach supporting elements to building structural steel or
structural slabs. Where supports are required between building structural
members provide supplementary structural steel as specified for work under
this section. On submittals show location of supports and anchors and
loads imposed on each point of support or anchor. Do not hang ductwork or
equipment from piping, or other ducts or equipment. Attach supports to
structural framing member and concrete slab. Do not anchor supports to
metal decking unless a means is provided and approved for preventing the
anchor from puncturing the metal decking. Where supports are required,
between structural framing members, provide suitable intermediate metal
framing. Where C-clamps are used, provide retainer clips. A maximum span
of 3 meters 10 feet shall exist between any two points, with lesser spans
as specified or as required by duct assemblies, interferences, and loads
imposed or permitted. Provide a minimum one set of two vertical support
elements for each point of support and each length of duct, except as
otherwise specified. Install supports on both sides of all duct turns,
branch fittings, and transitions. Cross-brace hangers sufficiently to
eliminate sway. Perforated strap hangers are prohibited. Where ductwork
system contains heavy equipment, hang such equipment independently of the
ductwork. [Duct supports shall be vibration isolated from structure at
points indicated.] [Provide vibration isolators in indicated discharge
ducting system for a minimum distance of [15 meters] [50 feet][_____]
beyond the fan. Coordinate deflection of duct and equipment mountings and
conform to Section [15070N] MECHANICAL SOUND VIBRATION AND SEISMIC
CONTROL.] [The location of supporting elements shall be limited by the
allowable load on the purlin which shall be limited to that no greater than
the moment produced by 4450 Newton one Kip load at mid-span of purlin.
When the hanger load exceeds these limits, provide reinforcing of purlin[s]
or additional support beam[s]. When an additional beam is used, the beam
SECTION 15801N
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