"ALL PLASTIC" Corrosion Resistant Fume Exhaust Systems
and Duct Fittings
Polyvinyl Chloride (PVC)
Chlorinated Polyvinyl Chloride (CPVC)
Polypropylene (PPRO)
Complete Pre-Engineered or Component Systems
Designed for Durability and Cost Efficiency
Thermoplastics Reduce Weight and Increase Reliability
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Suggested Standard Specifications
For PVC Ducting
Applicability of ASTM standards as it pertains to PVC
Ducting
A) ASTM-D1784 Compounds utilized in the manufacture
of base components, which covers Type I and/or Type II material
B) ASTM-D-635 Flammability UL94V-9 (Self
Extinguishing)
C) ASTM-E-84 Flame Spread (10-25) Fuel Contribution
(0)
EXHAUST DUCT
All ventilation duct components to be fabricated
of PVC Type I, Grade I (dark gray) and/or PVC Type II, Grade I (light gray)
material. The PVC Type II, Grade I material can be rolled without heating,
resulting in a lower cost for the finished product. Selection of materials
of construction shall be at the purview, unless otherwise specified by
the Buyer.
ROUND DUCT
Round PVC duct will be seamless and extruded in sizes
6" through 24". Below 4", Schedule 40 gray PVC pipe will be utilized.
Nominal wall thickness for 6" through 18" will be
.187"; 20" size will be .219" and 24" size will be .250". Nominal wall
thickness, 4" and below, will conform to ASTM Standard D-1785 for Schedule
40 pipe.
Round PVC duct above 24" will be cold rolled from
Type II Grade I extruded PVC sheet material. The seam will be thermal fused
utilizing a computerized welding machine. The sheet edges are heated and
pressed together pneumatically achieving 100% weld strength using no filler
rod. Wall thickness will be 3/16" for sizes up to 32" diameter. Above 32"
diameter...1/4" material will be used, unless otherwise specified.
Elbows will have an approximate centerline radius
of 1-1/2" times duct diameter, 90° elbows can be either 3-piece or
5-piece mitre, 45° elbows, 2 or 3 piece mitre. Specific job requirements
will determine which type is used. If no preference is given, 3-piece 90°
elbows and 2-piece 45° elbows will be provided.
Transitions will be tapered, cone-type only. The
cone will be the same material thickness as the duct material. Transitions
will be concentric, unless otherwise specified.
Branches will enter the main ducting at a 45°
angle, unless otherwise specified.
Couplings for sizes up to 24" can be either sleeve
type (no stop) or standard with a stop. Only sleeve couplings are available
in sizes above 24". Socket depth for both to be 3".
Flanges for size 6" through 20" will be heat formed
from PVC duct or cut from flat sheet stock. Flanges for 24" and above will
be formed from PVC Type I extruded angle. Leg size will either 1-1/2" x
3/16" for diameters up to 30" or 2" x 1/4" for sizes above 30".
Bolt holes will be 5/16" diameter on approximate
4" centers. Suggested bolting can be either galvanized or 304 SS. Both
should be 1/4"-20 x 1-1/4" long with a nut and two washers provided for
each bolt.
Suggested gaskets should be 1/8" thick, closed cell
neoprene for duct sizes up to 24"; above 24", 3/16" thick neoprene should
be used.
Suggested flexible connections should be 3/16" neoprene,
6" wide, with two SS draw bands.
Quadrant dampers or blastgates will be provided with
a locking device for permanently setting after balancing.
End caps can be either permanently welded in place
or fabricated to allow removal.
Access panels and/or view ports can be provided with
clear PVC material or Plexiglas and will be held in place with SS self-tapping
screws.
Reinforcements, if required, will be per SMACNA,
Second Edition, January 1995, or greater, for the particular water gauge
specified.
Installation (joining) can be accomplished with the
bell and spigot (cementing) method, flanging or thermal welding.
RECTANGULAR DUCT
Rectangular duct will be formed from Type I Grade
I PVC extruded sheet material. Corners will be heat bent and seams thermal
fused where applicable. Where heat bending and thermal fusion is not possible,
corner welding with PVC filler rod will be utilized.
Where the developed length is 120" or less, 3/16"
material will be used. Above 120", 1/4 sheet will be used.
Both 45° and 90° elbows will be 2 pieces,
square throat. The 90° elbows will have turning vanes made from PVC
extruded duct material.
Transitions will be tapered and will be the same
material thickness as the duct. They will be concentric unless otherwise
noted.
Branches will enter main run at 45° angle only
unless otherwise specified.
Couplings will be sleeve type only. Overall length
is 6" and will be the same thickness as the duct.
Flanges for 3/16" wall duct will be 1-1/2" x 3/16"
PVC Type I angle. Flanges for 1/4" wall duct, 2" x 1/4" Type I PVC angle
will be used. Bolt holes will be 5/16" diameter on approximate 4" centers.
Bolting, gaskets and flexible connections will be
the same as the round duct standards.
End caps and access panels will be the same as the
round duct standards.
Reinforcement, if required, will be per SMACNA Second
Edition, January 1995, for the particular water gauge specified.
Joining can also be accomplished with the bell (coupling)
and spigot method, flanging or field welding.
WELDING FOR ROUND AND RECTANGULAR
DUCT
Welding will be accomplished by using either the
hot gas fusion method using fill rod or thermal fusion. The rod will be
5/32" or 3/16" thick.
All joints will have a minimum of one weld bead to
a maximum of three. This includes elbows, transitions, branches, couplings,
flanges and end caps.
The foregoing information is based on our 30 years
experience as a plastic fabricator. Particular engineering requirements
may alter any of the above. However, we feel these are proven shop methods
which produces a reliable product for many years of trouble free service.
BASIC GUIDE
TO SPECIFYING AND ORDERING
The following information represents a basic product
guide to assist with both specifying and ordering a wide range of standard
products readily available from PEP.
CORROSION RESISTANT EXHAUST SYSTEMS
thermoplastic chemical and corrosion resistant fume
exhaust systems are pre-engineered to save you both time and money. We
can provide you with the component parts, such as straight duct and fittings
or a complete turnkey system including exhaust fans and scrubbing equipment.
The efficiency and effectiveness of exhaust systems are important to you
and the maintenance of air quality standards. All duct systems are designed
in accordance with the recommended practice of the American Conference
of Governmental Industrial Hygienists and fabricated in accordance with
Sheet Metal and Air Conditioning Contractors National Association, Inc.
(SMACNA) manual for Thermoplastic Construction.
DUCT AND PIPE FITTINGS
Our 55,000 square ft. facility maintains a complete
line of duct and fittings from 6" through 24" diameter. The unusual is
standard at PEP. We are able to manufacture to 96" diameter with square
and rectangular duct also available. While our specialty is to prefabricate
entire fume duct systems manufactured to your specifications, we also manufacture
and supplies fume duct pipe, fittings, dampers, rain caps, blast gates,
etc. for field assembly.
MATERIALS
Thermoplastics are the answer to your most difficult
design problem adding lightweight, versatility, durability, corrosion resistance
and cost efficiency. We offer a wide range of corrosion resistant plastics
including: PVC, Corzan® (CPVC) and Polypropylene.
PVC & CPVC (Belled End) Duct Fittings Conforming
to ASTM-D-1784 Material Standard
 
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