1、NOVEMBER 24, 20041SUBJECT 2399OUTLINE OF INVESTIGATIONFORMETAL VENTING SYSTEMS FOR HOUSEHOLD CLOTHES DRYERSIssue Number: 2November 24, 2004Summary of TopicsThe Second issue of Subject 2399 is being issued to update thereference to the Standard Specification For Steel Sheet, ZincCoated (Galvanized) o
2、r Zinc-Iron Alloy-Coated (Galvannealed) bythe Hot-Dip Process, ASTM A525. This issue also includes othereditorial changes.The UL Foreword is no longer located within the UL Outline of Investigation. Forinformation concerning the use and application of the requirements contained inthis Outline of Inv
3、estigation, the current version of the UL Foreword is located onthe ULStandardsInfoNet at http:/ 2004 UNDERWRITERS LABORATORIES INC.NOVEMBER 24, 2004SUBJECT 23992No Text on This PageCONTENTSINTRODUCTION1 Scope .52 Components 53 Units of Measurement .54 Undated references .65 Glossary .6CONSTRUCTION6
4、 General 77 Materials .78 Polymeric Materials .88.1 General .88.2 Flammability .89 Assembly 810 Joints .911 Thimbles 912 Support Assembly 1013 Vent Termination and Caps 10PERFORMANCE14 General 1015 Test Installation .1116 Temperature Measurement 1516.1 Thermocouples 1516.2 Vent gas temperatures 1516
5、.3 Other temperatures .1517 Temperature Test .1918 Vertical Support Test 1919 Strength Tests 2019.1 Impact test 2019.2 Longitudinal pull test 2320 Torsion Test .2421 Leakage Test 2422 Pressure Test 2523 Operation Test .2524 Resistance to Corrosion Test .2625 Permanency of Marking .2625.1 General .26
6、25.2 Air-oven aging test .2725.3 Humidity test .2725.4 Specific-condition exposure test 27MARKINGS26 General 27NOVEMBER 24, 2004 SUBJECT 2399 3MANUFACTURING AND PRODUCTION TESTS27 General 2828 Longitudinal Pull Force and Torsion Test 29INSTRUCTIONS29 General 2930 Installation Instructions 3031 User-
7、Maintenance Instructions .32APPENDIX AStandards for ComponentsA1NOVEMBER 24, 2004SUBJECT 23994INTRODUCTION1 Scope1.1 These requirements apply to venting systems, constructed of rigid metal, for venting householdelectric clothes dryers and Type 1 gas-burning household clothes dryers as defined by the
8、 Standard forGas Clothes Dryers, ANSI Z21.5.1 and the National Fuel Gas Code, NFPA 54.1.2 Venting systems covered by these requirements are intended to convey exhaust air containingmoisture, lint, and the byproducts of combustion from household clothes dryers to the outside atmosphereor to an existi
9、ng permanent duct provided as part of the building structure. These venting systems areintended for use with clothes dryers that have been installed in accordance with the manufacturersinstructions, National Fuel Gas Code, NFPA 54, National Electrical Code, NFPA 70, and state or localcodes.1.3 These
10、 requirements do not cover flexible venting systems.2 Components2.1 Except as indicated in 2.2, a component of a product covered by this outline of investigation shallcomply with the requirements for that component. See Appendix A for a list of standards coveringcomponents used in the products cover
11、ed by this outline of investigation.2.2 A component is not required to comply with a specific requirement that:a) Involves a feature or characteristic not required in the application of the component in theproduct covered by this outline of investigation, orb) Is superseded by a requirement in this
12、outline of investigation.2.3 A component shall be used in accordance with its rating established for the intended conditions ofuse.3 Units of Measurement3.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory orapproximate information.NOVEMBER 24, 2004 SUBJEC
13、T 2399 54 Undated references4.1 Any undated reference to a code or standard appearing in the requirements of this outline ofinvestigation shall be interpreted as referring to the latest edition of that code or standard.5 Glossary5.1 For the purpose of these requirements, the following definitions ap
14、ply.5.2 CLOTHES DRYER An appliance used to dry wet laundry by means of heated air derived fromthe combustion of fuel, electric heating elements, or steam.5.3 COMBUSTIBLE MATERIAL Material made of, or surfaced with, wood, compressed paper, plantfibers, or other material that ignites and burns, as app
15、lied to materials adjacent to or in contact withheat-producing parts of a clothes dryer, vent connectors, and venting systems. Such material shall berated as combustible even though flameproofed, fire-retardant treated, or plastered.5.4 CONCEALED SPACE A space rendered inaccessible by the structure
16、or finish of the building.5.5 PRODUCT As used in these requirements, refers to all venting systems or any part thereofcovered by these requirements unless specifically noted otherwise.5.6 THIMBLE The part of a venting system that is intended to provide a means for routing the ventingsystem through a
17、 combustible wall in a horizontal installation.5.7 EXHAUST VENT CONDUIT The part of a venting system that is directly exposed to exhaust andis a continuous conveyer of the exhaust from the clothes dryer outlet to the outside atmosphere.5.8 VENT INPUT TEMPERATURE The exhaust vent temperature at the l
18、ocation where the ventingsystem attaches to a clothes dryer.5.9 VENT TERMINATION OR CAP The part of a venting system that terminates exterior to thebuilding and is intended to resist the entrance of debris and rain into the exhaust vent conduit.5.10 VENTING SYSTEM A complete assembly, external to a
19、clothes dryer, comprised of all field-installed component parts required to convey exhaust from a clothes dryer to the outside atmosphere orto an existing permanent duct provided as part of the building structure.NOVEMBER 24, 2004SUBJECT 23996CONSTRUCTION6 General6.1 Single-wall metal pipe shall be
20、used only for runs directly from the space in which the clothes dryeris located, through the exterior wall, to the outer air. See 30.9(i).6.2 Single-wall metal pipe shall not pass through any attic, inside wall, concealed space, or any flue orceiling. See 30.9(j).6.3 A venting system shall be constr
21、ucted so that clearances to combustible materials are maintained.6.4 An edge, projection, corner, opening, frame, guard, or a similar part shall not be sharp enough toconstitute a risk of injury to persons during installation or maintenance.6.5 A venting system duct shall have a diameter of 4 inches
22、 (101.6 mm) or a cross-sectional area of 12in2(77.4 cm2).7 Materials7.1 A venting system shall be constructed of rigid metal.Exception: As specified in 8.1.1, polymeric materials are not prohibited from being used for parts notsubject to contact by vent exhaust or exhaust vent conduit.7.2 A venting
23、system shall be made of corrosion resistant materials, or have a corrosion resistant finishin areas subject to corrosion due to condensate, and shall be made of materials rated for the temperaturesanticipated during normal operations. Metals shall not be used in combinations that result in galvanica
24、ction at any location within the system.7.3 The thickness of sheet metal, including any coatings, shall not be less than specified in Table 7.1unless otherwise specified.Table 7.1Minimum metal thicknessMetal Inch (mm)Aluminum alloys (1100, 3003) 0.012 (0.30)Steel coated 0.016 (0.41)Galvanized steel
25、(G90 coating class) 0.018 (0.46)Aluminum-coated steel 0.40 ounces persquare foot (0.12 kg/m2)0.018 (0.46)Stainless steel (430, 446) 0.012 (0.30)7.4 An exhaust vent conduit shall be of a material having the rigidity, durability, and resistance to heatrequired for the intended application. Stainless s
26、teel and aluminum, shall comply with the requirementsfor the applicable tests described in these requirements. See Performance, Sections 14 24. Parts incontact with vent exhaust or subjected to condensate shall be of material having the durability andresistance to heat equivalent to Type 1100 or Ser
27、ies 3000 aluminum or Types 430 and 446 stainlesssteel.NOVEMBER 24, 2004 SUBJECT 2399 77.5 Parts of a venting system subject to contact by vent exhaust at or beyond the terminus of the exhaustvent conduit shall be of a material equivalent to the exhaust vent conduit. See 7.4.7.6 Galvanized steel used
28、 for structural parts or other components or subassemblies shall have azinc-coating complying with the coating designation G90 (former coating class 1.25 commercial) in theWeight (Mass) of Coating Requirements table of the Standard Specification for Steel Sheet, Zinc-Coated(Galvanized) or Zinc-Iron
29、Alloy-Coated (Galvannealed) by the Hot Dip Process, ASTM A653, with not lessthan 40 percent of the zinc on any side, based on the minimum single spot test in ASTM A653. The weightof zinc coating shall be established in accordance with the Standard Test Methods for Weight of Coatingon Zinc-Coated (Ga
30、lvanized) Iron or Steel Articles, ANSI/ASTM A90. Aluminum coated steel shall be ofType T1-40 (regular) 0.40 ounce per square foot (0.12 kg/m2).7.7 The surface of metallic materials which are coated shall be free of sharp edges, burrs, or protrusionscapable of scratching mating parts in a manner that
31、 reduces the thickness of the coating.8 Polymeric Materials8.1 General8.1.1 With reference to the Exception to 7.1, polymeric materials for use in a venting system shall complywith Flammability, Section 8.2.8.2 Flammability8.2.1 Polymeric materials for use in a venting system shall comply with the r
32、equirements for a Class 5VAmaterial, as specified in the Standard for Tests for Flammability of Plastic Materials for Parts in Devicesand Appliances, UL 94.9 Assembly9.1 A venting system shall include all the parts for a complete assembly (see 5.9). Each part of a ventingsystem shall be constructed
33、for assembly without requiring alteration, cutting, threading, drilling, welding,or similar tasks.Exception: An assembly or part intended to be cut to length or fitted by the installer meets the intent ofthe requirement when means are furnished for joining any altered part to a companion part or ass
34、embly.All fasteners required to complete the assembly shall be provided with the venting system or shall bespecified in the manufacturers installation instructions and be readily available.9.2 Two or more parts of a venting system that are to be used in a specific relationship to each other inthe in
35、tended application shall:a) Be arranged and constructed to be incorporated into the complete assembly withoutalteration or alignment and only in the correct relationship with each other,b) Be assembled and shipped from the factory as one unit, orc) Be provided with a permanent marking showing the pr
36、oper alignment when companion partsare secured separately to the building structure and clothes dryer during installation.NOVEMBER 24, 2004SUBJECT 239989.3 Each individual part, such as a pipe section, elbow, vent cap, coupling, or similar part shall becompletely assembled by the manufacturer at the
37、 factory.Exception: A part is not required to be completely assembled at the factory when the final assembly isable to be made by a simple means without the use of tools, cutting, welding, brazing, or soldering.9.4 A venting system shall not be assembled with sheet metal screws or other fastening me
38、ans whichextend into the duct and that catch lint or otherwise restrict exhaust flow.9.5 Mating parts that overlap when assembled shall overlap a minimum of 1 inch (25.4 mm).Exception: Crimp joints shall have a minimum of a 1-1/2 inch (38.1 mm) contact lap.10 Joints10.1 Joints and seams in a venting
39、 system shall be gas-tight as determined in accordance with LeakageTest, Section 21.10.2 Parts of a venting system shall be joined and secured so that they do not disengage when tested inaccordance with Longitudinal Pull Test, Section 19.2, and Torsion Test, Section 20.10.3 Where cement, tape, screw
40、s, or similar materials are required for sealing vent joints, they shall beprovided or shall be specified in the manufacturers installation instructions and be readily available.10.4 Where screws are used for field-joint assemblies, the assemblies shall provide for the use of screwswithout being fie
41、ld-punched or drilled.10.5 A joint shall not reduce the cross-sectional area of the exhaust vent conduit.11 Thimbles11.1 A venting system intended for horizontal installation shall be provided with a ventilating thimbleconstructed to enable the venting system to penetrate an exterior vertical wall c
42、onstructed of combustiblematerial unless the venting system is investigated with zero clearance to combustible construction.11.2 A thimble shall have the strength and bearing surface to maintain the required clearance from theventing system parts to the wall studs and inner surfaces of walls.11.3 A
43、thimble installed for protection of combustible materials shall maintain the temperature rise of suchcombustible materials to not more than 50C (90F) above ambient.NOVEMBER 24, 2004 SUBJECT 2399 912 Support Assembly12.1 A support assembly shall establish and maintain a minimum clearance of 6 inches
44、(15 cm) betweena venting system and adjacent combustible construction.Exception: The minimum clearance is reducible when the product complies with Temperature Test,Section 17, at the reduced clearance.12.2 A support assembly shall be capable of supporting the weight imposed upon it by all the ventin
45、gsystem parts as determined in accordance with Vertical Support Test, Section 18.12.3 A support assembly secured by nails or screws shall be constructed so that the load on the securingmeans is a shear or compressive load.12.4 Supports and hangers shall be provided with the system kit or shall be sp
46、ecified in the installationinstructions and shall accommodate both longitudinal and lateral vent movement. The maximum length ofthe duct between supports and hangers shall be specified in the manufacturers installation instructions.13 Vent Termination and Caps13.1 A vent termination or cap shall be
47、constructed so that snow, leaves, and debris falling or blown ontoit are not retained so as to obstruct vent exhaust or cooling air passages.PERFORMANCE14 General14.1 Following the tests specified in Sections 17 25, as applicable, a venting system shall comply withthe following:a) No part of the ven
48、ting system shall be damaged or permanently distorted to an extent that itor the assembly does not continue to function as intended.b) The effectiveness of any required protective coating or finish shall not be impaired.c) The reflectivity of a surface shall not be impaired when the reflectivity of
49、such surface isutilized to reduce the risk of fire.d) Sealing materials or tape at joints shall not show evidence of deterioration to an extent thatthe assembly does not continue to function as intended.14.2 Where venting system sections are of uniform grade, thickness, and cross section, such as squareor round, the tests are to be performed on the largest and the smallest sizes. Square or round sections,varying in grade and thickness with size, shall also be tested in the intermediate size range. Rectangular
