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STANDARD CONSTRUCTION
This standard construction is suitable for use up to a maximum pressure
of 4 KPa.
-casing shall be constructed from prime quality pre-galvanised mild steel
sheet, and will be the following
thicknesses: -1.0 mm up to 1000 mm
-1.2 mm up to 1000 mm to 2400 mm
-1.6 mm over 2400 mm
The case will be in one piece up to 1500 mm in length, over this the case
may be made in two pieces although the acoustic splitters will always
be made in one continuous section.
-end flanges: shall be either rolled steel angle section or knock-on type
-attenuating splitters: shall be arranged within the casing to provide
optimum acoustic and aerodynamic
performance by the use of asymmetric thickness and spacing of the splitters.
The splitters shall be constructed from 0.9 mm pre-galvanised sheet steel
and retained within the casing by
either rivets or self tapping screws.
The acoustic infill shall be retained with 0.6 mm perforated pre-galvanised
steel sheet.
Acoustic infill shall be either fibreglass or rockwool suitable faced
to prevent fibre erosion at passage velocities
up to 40 m/s.
CARE AND MAINTENANCE
Being a static item of equipment once installed there is no regular or
periodic maintenance to carry out on duct mounted attenuators located
inside the building. Inspection for corrosion would be part of a long
term program and should be commenced at a time suitable to the operating
environment. If the air stream is subject to a heavy dust load than a
regular internal inspection of the perforated metal for dust build up
should be carried out.
The splitters can be cleaned in most cases by brushing and vacuuming the
perforated metal. Oil or grease build up should be removed by steam cleaning.
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