ASTM D3982-98
(Specification)Standard Specification for Contact Molded "Fiberglass" (Glass Fiber Reinforced Thermosetting Resin) Duct and Hoods
Standard Specification for Contact Molded "Fiberglass" (Glass Fiber Reinforced Thermosetting Resin) Duct and Hoods
SCOPE
1.1 This specification covers ducts and hoods fabricated by contact molding intended for use in handling corrosive fumes and process gases. Special attention is given to equipment that operates at temperatures over 180°F (82.2°C) with regard to strength and corrosion resistance.
1.2 The material of construction shall be "fiberglass" consisting of a polyester, vinyl ester, or other qualified resin-matrix systems with fiber reinforcement in accordance with Specification C582.
1.3 This specification is not intended to cover selection of resins and reinforcements for specific chemical environments.
1.4 All descriptions and limitations in this specification are to include both ducts and hoods, where applicable.
1.5 This specification covers ducts and hoods up to a design pressure of +5 psig (34.5 Pa).
1.6 The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are for information only.
General Information
Relations
Standards Content (Sample)
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Contact ASTM International (www.astm.org) for the latest information.
An American National Standard
Designation: D 3982 – 98
Standard Specification for
Contact Molded “Fiberglass” (Glass Fiber Reinforced
Thermosetting Resin) Duct and Hoods
This standard is issued under the fixed designation D 3982; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope F 436 Specification for Hardened Steel Washers
2.2 NFPA Standard:
1.1 This specification covers ducts and hoods fabricated by
NFPA 91 Installation of Blower and Exhaust Systems for
contact molding intended for use in handling corrosive fumes
Duct, Stack and Vapor Removal or Conveying
and process gases. Special attention is given to equipment that
operates at temperatures over 180°F (82.2°C) with regard to
3. Terminology
strength and corrosion resistance.
3.1 Definitions:
1.2 The material of construction shall be “fiberglass” con-
3.1.1 The definitions used in this specification are in accor-
sisting of a polyester, vinyl ester, or other qualified resin-matrix
dance with definitions in Terminologies D 883 and F 412,
systems with fiber reinforcement in accordance with Specifi-
unless otherwise specified.
cation C 582.
3.2 Definitions of Terms Specific to This Standard:
1.3 This specification is not intended to cover selection of
3.2.1 calculated thickness—this description is in accor-
resins and reinforcements for specific chemical environments.
dance with the standard laminate composition tables for Types
1.4 All descriptions and limitations in this specification are
I and II in Specification C 582.
to include both ducts and hoods, where applicable.
3.2.2 contact molding—includes the “hand layup” and the
1.5 This specification covers ducts and hoods up to a design
“spray up” methods of manufacture.
pressure of 65 psig (34.5 Pa).
3.2.3 flange cant—the angle that an entire branch is off
1.6 The values stated in inch-pound units are to be regarded
from being perpendicular to the main run centerline (see Fig.
as the standard. The SI units given in parentheses are for
1).
information only.
3.2.4 flange flatness—maximum deviation, (see Fig. 2)
2. Referenced Documents from the actual flange face not including warpage or perpen-
dicularity.
2.1 ASTM Standards:
3.2.5 flange offset—the amount that an entire branch is off
C 581 Practice for Determining Chemical Resistance of
the main run centerline (see Fig. 3).
Thermosetting Resins Used in Glass Fiber Reinforced
3.2.6 flange perpendicularity—maximum angle that the
Structures, Intended for Liquid Service
plane (see Fig. 2) of the flange inside diameter makes with the
C 582 Specification for Contact-Molded Reinforced Ther-
perpendicular plane to the duct’s centerline.
mosetting Plastic (RTP) Laminates for Corrosion Resistant
3.2.7 flange warpage—the amount that a flange outside
Equipment
3 diameter pulls back from the plane of the inside diameter
D 883 Terminology Relating to Plastics
during the cure of the material (see Fig. 2).
D 2583 Test Method for Indentation Hardness of Rigid
4 3.2.8 hand layup—application of glass plies in sheet form
Plastics by Means of a Barcol Impressor
by hand. Resin can be applied by either brushing, rolling, or
D 2584 Test Method for Ignition Loss of Cured Reinforced
4 spraying.
Resins
3.2.9 minimum thickness—take six thickness readings. The
F 412 Terminology Relating to Plastic Piping Systems
average of the six readings shall be a minimum of 85 % of the
calculated thickness. This must contain the required layers of
glass.
This specification is under the jurisdiction of ASTM Committee D-20 on
3.2.10 spray up—fiberglass roving is chopped and blown
Plastics and is the direct responsibility of Subcommittee D20.23on Reinforced
Plastic Piping Systems and Chemical Equipment. onto the mold in conjunction with resin and catalyst.
Current edition approved Feb. 10, 1998. Published November 1998. Originally
published as D 3982 – 81. Last previous edition D 3982 – 1992.
Annual Book of ASTM Standards, Vol 08.04.
3 5
Annual Book of ASTM Standards, Vol 08.01. Annual Book of ASTM Standards, Vol 15.08.
4 6
Annual Book of ASTM Standards, Vol 08.02. Available from National Fire Protection Assn., 470 Atlantic Ave., Boston, MA
02210.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 3982
FIG. 1 Flange Cant
FIG. 3 Flange Offset
ascertain its compatibility with the corrosive environment when this has
been reported to him by the purchaser.
4.1.3 Fire-retardant additives may be added to resins if
required to reduce flame spread.
NOTE 2—Because the addition of fire-retardant agents may interfere
with visual inspection of laminate quality, they should not be used in the
inner surface or interior layer unless their functional advantages would
outweigh the loss of visual inspection.
4.1.4 Where static electricity has been determined to be a
problem by the engineer, the inner surface of the ductwork
shall be grounded with a maximum resistance to ground of 10
FIG. 2 Flange Tolerance Description
V. The grounding method shall be determined by the manu-
facturer and the purchaser.
3.3 Abbreviations:Symbols and Abbreviations:
4.2 Reinforcement—Glass reinforcing material with a
3.3.1 M =1 ⁄2 oz/ft chopped-strand mat.
binder and sizing compatible with the resin to be used. Fiber
3.3.2 R = 24 oz/yd woven-roving witha5by4 weave.
reinforcements shall be in accordance with and meet the
3.3.3 V = glass or synthetic veil, 0.010 in. (0.25 mm)
requirements of Specification C 582 including composition
calculated thickness.
requirements for Type I and Type II laminates.
3.3.4 For additional symbols and abbreviations specific to
4.2.1 Corrosion Barrier—Consists of the inner surface
design requirements, see 6.2.1.
followed by the interior layer which has a minimum total
calculated thickness of 0.096 in. (2.4 mm).
4. Materials and Manufacture
4.2.1.1 Inner Surface—Surfacing veil with approximately
4.1 Resin—The resin used shall be a commercial-grade
90 % resin and 0.010 to 0.020-in. (0.25 to 0.50-mm) calculated
thermoset that has either been evaluated in a laminate by test in
thickness.
accordance with Practice C 581 or that has been determined by 1
4.2.1.2 Interior Layer—A minimum of two plies of 1 ⁄2 oz/
previous documented service to be acceptable for service
ft chopped-strand mat or chopped roving equivalent with a
conditions. Where service conditions have not been evaluated
compatible sizing system with approximately 75 % resin and
a suitable resin may be selected by agreement between the
0.086-in. (2.2-mm) calculated thickness minimum. Fiber
manufacturer and the end user. 1
length shall be ⁄2 in. (12.7 mm) minimum to 2 in. (50.8 mm)
4.1.1 The resin may contain fillers or pigments in accor-
maximum.
dance with Specification C 582.
4.2.2 Structural Layer—Shall consist of chopped-strand
1 1
4.1.2 A thixotropic agent may be added up to 5 % by weight
mat plies of nominally 1 ⁄2 oz/ft and have a ⁄2 in. (12.7 mm)
of resin.
minimum to 2 in. (50.8 mm) maximum fiber length, or shall
consist of a chopped roving equivalent in the spray-up method.
NOTE 1—The addition of a thixotropic agent may reduce the resistance
When necessary, woven-roving plies shall be used and shall
of many resin systems to certain corrosive chemical environments. It is the
responsibility of the fabricator, using a thixotropic agent in the resin to consist of 24 oz/yd with a five by four weave or a suitable
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 3982
equivalent agreed on by the end user and the fabricator. If result:
Woven-roving shall be applied alternately with a minimum of
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,
a1 ⁄2 oz/yd mat or chopped roving equivalent, finishing with
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a mat layer.
Then use:
4.2.3 Outer Surface—Shall be coated with a resin-rich layer
2.2E T
and containing 0.2 to 0.6 % paraffin wax with a melting point
P 5
S D
F D
of 122 to 126°F (50.0 to 52.2°C), except when not required as o
determined by the engineer.
If result:
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5. Physical Properties
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5.1 Minimum wall of (V, M, M, M) shall be maintained
Then use:
under any circumstances.
2.5
5.2 Laminates or portions of laminates comprised only of
2.6E T
S D
chopped-strand mat shall have a 25 to 30 % glass content by F D
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P 5
0.5
weight when tested by Test Method D 2584. L T
2 0.45
S D
D D
5.3 Minimum mechanical properties of standard laminates o o
shall be in accordance with Specification C 582.
6.2.4 Stiffeners to Withstand External Pressure:
6.2.4.1 Required Moment of Inertia:
6. Design Requirements
PL ~D ! F
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6.1 Design Limitations:
I 5
24E
6.1.1 Safety Factor—Use five for external pressure, use ten
for internal pressure and all other design calculations.
6.2.4.2 Material used to attach ring stiffener to cylinder wall
6.1.2 Maximum Permissible Deflection Under Design
may be included when calculating the actual moment of inertia
Load—Use 1 % of the span for laminates not exposed to a
of the stiffener as well as the portion of the cylinder wall
chemical environment and use ⁄2 % of the span for allowable
beneath the stiffener and attachment material up to a width of
deflection when a chemical environment will be in contact with
2 x (stiffener width).
the laminate.
6.3 Rectangular Duct:
6.1.3 Secondary Bond Strength—When the load is along the
6.3.1 The largest flat panel shall be designed to withstand
surface, use 2000 psi (13.79 MPa) ultimate shear stress for the
the loading conditions and not exceed the design limitations
bonding surface area. Use a safety factor of ten when calcu-
(see 6.1.2). This can be accomplished with a sufficient wall
lating allowable secondary bonding stresses.
thickness alone or by the incorporation of stiffening ribs to
6.1.4 When an extra corrosion barrier is specified, do not
reduce the required wall thickness.
include this thickness in the design calculations.
6.3.2 Appropriate calculations shall be run for wall thick-
6.1.5 Increase all calculated wall thicknesses to the nearest
ness and stiffening ribs as determined by the manufacturer and
standard wall thickness. Treat these standard wall thicknesses
the purchaser. Minimum wall thickness in all cases for rectan-
as minimum dimensions.
gular duct shall be as in Table 1, substituting the longer side for
6.2 Cylinder Wall Design:
the diameter.
6.2.1 Symbols and Abbreviations:
6.3.3 The radial sides of a rectangular elbow shall be
6.2.1.1 P—Actual design pressure, psi (MPa).
designed as a round cylinder with the same radius.
6.2.1.2 PA—Allowable pressure, psi (MPa).
6.4 Follow the requirements of NFPA Bulletin 91, Section
6.2.1.3 D —Outside diameter of cylinder, in. (mm).
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510 when it is required by law or the engineer.
6.2.1.4 D—Inside diameter of cylinder, in. (mm).
6.5 Shop Drawings and Design Calculations—The fabri-
6.2.1.5 S—Ultimate tensile strength, psi (MPa).
cated structure shall be in accordance with the design and
6.2.1.6 F—Safety factor (see 6.1.1).
construction details shown on shop drawings and design
6.2.1.7 T—Cylinder wall thickness, in. (mm).
calculations prepared by the manufacturer and approved by the
6.2.1.8 E—Tensile modulus of elasticity, psi (MPa).
6.2.1.9 L—Cylinder length between joints or elements that purchaser. Details to be covered include, but are not limited to,
the following:
qualify as a stiffener, in. (mm).
6.2.1.10 I—Required moment of inertia for an element to
6.5.1 Materials, including a definition of the fiber-resin
3 3
qualify as a stiffener, in. (mm ). system, in accordance with types of resins and reinforcing
6.2.2 Internal Pressure:
materials of Specification C 582,
6.5.2 Dimensions,
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6.5.3 Size and location of stiffening ribs,
6.5.4 Location of field joints and flanges, and
6.2.3 External Pressure (Internal Vacuum):
6.5.5 Type and location of supports, if supplied by the
Calculate: manufacturer.
0.5
6.6 All stiffeners, access openings, lifting devices or other
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1.73
S D
T appurtenances shall be included as part of the duct design.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 3982
TABLE 1 Typical Flange Dimensions and Hanger Spacing
NOTE 1—1 in. = 25.4 mm
1 lb/ft = 1.488164 kg/m.
A A B CD
Calculated Cylinder Flange Flange Recom- Maximum Maximum
Inside Flange Bolt Bolt Hole Number Bolt
Wall Thick- Wall Thickness, Outside mended Bolt Bolt Torque, Hanger
Diameter, in. Circle, in. Diameter, in. Holes
ness, in. Construction min, in. Diameter, in. Torque, ft/lb ft/lb Spacing, ft
3 3 7
1 0.14 Type I ⁄8 5 ⁄8 4 ⁄16 4 20 30 8.0
1 3 5 1 7
1 ⁄4 0.14 Type I ⁄8 5 ⁄8 4 ⁄4 ⁄16 4 20 30 8.0
1 3 7 1 7
1 ⁄2 0.14 Type I ⁄8 5 ⁄8 4 ⁄2 ⁄16 4 20 30 8.5
1 3 7
2 0.14 Type I ⁄2 6 ⁄8 5 ⁄16 4 25 40 8.5
1 1 7 1 7
2 ⁄2 0.14 Type I ⁄2 6 ⁄8 5 ⁄2 ⁄16 4 25 40 9.0
1 3 7
3 0.14 Type I ⁄2 7 ⁄8 6 ⁄16 4 25 40 9.5
1 3 7
4 0.14 Type I ⁄2 8 ⁄8 7 ⁄16 4 25 40 10.0
1 3 7
6 0.14 Type I ⁄2 10 ⁄8 9 ⁄16 8 25 40 10.5
1 3 7
8 0.14 Type I ⁄2 12 ⁄8 11 ⁄16 8 25 40 11.0
1 3 7
10 0.14 Type I ⁄2 14 ⁄8 13 ⁄16 12 25 40 11.5
1 3 7
12 0.14 Type I ⁄2 16 ⁄8 15 ⁄16 12 25 40 11.5
1 3 7
14 0.14 Type I ⁄2 18 ⁄8 17 ⁄16 12 25 40 12.0
1 3 7
16 0.14 Type I ⁄2 20 ⁄8 19 ⁄16 16 25 40 12.5
1 3 7
18 0.14 Type I ⁄2 22 ⁄8 21 ⁄16 16 25 40 12.5
1 3 7
20 0.14 Type I ⁄2 24 ⁄8 23 ⁄16 20 25 40 13.0
1 3 7
24 0.18 Type I ⁄2 28 ⁄8 27 ⁄16 20 25 40 15.0
5 3 7
30 0.18 Type I ⁄8 34 ⁄8 33 ⁄16 28 35 50 15.5
5 3 7
36 0.18 Type I ⁄8 40 ⁄8 39 ⁄16 32 35 50 16.0
5 3 7
42 0.22 Type II ⁄8 46 ⁄8 45 ⁄16 36 35 50 19.0
5 3 9
48 0.22 Type II ⁄8 54 ⁄8 52 ⁄16 44 35 50 19.5
5 3 9
54 0.22 Type II ⁄8 60 ⁄8 58 ⁄16 44 35 50 20.0
5 3 9
60 0.30 Type II ⁄8 66 ⁄8 64 ⁄16 52 35 50 24.0
3 3 9
72 0.30 Type II ⁄4 78 ⁄8 76 ⁄16 60 40 60 25.0
3 3 9
84 0.30 Type II ⁄4 90 ⁄8 88 ⁄16 72 40 60 25.5
3 3 9
96 0.30 Type II ⁄4 102 ⁄8 100 ⁄16 80 40 60 26.0
A
Based on 10 ft (3.0 m) between stiffeners for 5-in. (127.0 mm) H O vacuum service. See Specification C 582 for wall construction.
B
The flange thicknesses are based on practical experience to resist maximum bolt torquing since these thicknesses are sufficient to resist process conditions. Minimum
flange thickness shall be measured in the spot-faced area.
C
Special design consideration must
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