1、Designation: D1998 13D1998 15Standard Specification forPolyethylene Upright Storage Tanks1This standard is issued under the fixed designation D1998; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe
2、r in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers flat-bottom, upright, cylindrical tanks molded in one-piece seamless construction by rotationalmolding. The tanks
3、 are molded from polyethylene for above ground, vertical installation and are capable of containing aggressivechemicals at atmospheric pressure. Included are requirements for materials, properties, design, construction, dimensions,tolerances, workmanship and appearance. Tank capacities are from 1900
4、 L (500 gal) up.1.2 This specification does not cover covers the design of stationery vessels intended for use at pressures other than atmosphericpressure. Furthermore, this specification does not cover the design of portable tanks. It is also not for vessels atmospheric pressureintended for use wit
5、h liquids heated abovebelow their flash points, or temperatures abovepoints and continuous servicetemperatures below 66C (150F) for Type I tanks and below 60C (140F) for Type II tanks for continuous service. tanks. NFPAStandards 30 and 31 shall be consulted for installations that are subject to the
6、requirements of these standards.1.2.1 NFPA Standards 30 and NFPA 31 shall be consulted for installations that are subject to the requirements of thesestandards.1.3 Special design considerations not covered in this specification shallFor service requirements beyond the scope of thisspecification (1.2
7、 be given to vessels subject to superimposed mechanical forces, such as seismic forces, wind load or agitation;to vessels subject to service temperature in excess of 23C (73.4F); and vessels subject to superimposed pressure exceeding 25.4cm (10 in.) of water or 2.5 10), such as externally imposed me
8、chanical forces, internal pressure or vacuum, higher temperatureservice, etc., other relevant sources of standards, for example, local and state building codes, NFPA, ASME, ARM, etc., shall beconsulted.3 MPa (0.36 psi).1.4 The values stated in SI units are to be regarded as the standard. The values
9、given in parentheses are for information only.NOTE 1ISO 13341:2005+A1:2011 and ISO 13575:2012 are similar, but not equivalent to this standard.1.5 The following precautionary caveat pertains only to the test methods portion, Section 11, of this specification: This standarddoes not purport to address
10、 all of the safety concerns, if any, associated with its use. It is the responsibility of the user of thisstandard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for
11、Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD1693 Test Method for Environmental Stress-Cracking of Ethylene PlasticsD2837 Test Method for Obtaining Hydrostatic Design Basis for Thermoplastic Pipe Materials or Pressure Design Basis forThermoplastic Pipe ProductsD3892 Practic
12、e for Packaging/Packing of PlasticsD4703 Practice for Compression Molding Thermoplastic Materials into Test Specimens, Plaques, or SheetsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodF412 Terminology Relating to Plastic Piping Systems1 This specific
13、ation is under the jurisdiction ofASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.19 on Film, Sheeting, and MoldedProducts (Section D20.15.01).Current edition approved Oct. 1, 2013Sept. 15, 2015. Published October 2013October 2015. Originally approved in 1991. Las
14、t previous edition approved in 20062013as D1998 - 06.D1998 - 13. DOI: 10.1520/D1998-13.10.1520/D1998-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards
15、 Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, A
16、STM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, P
17、O Box C700, West Conshohocken, PA 19428-2959. United States12.2 OSHA Standard:29 CFR 1910.106 Occupational Safety and Health Administration, Flammable and Combustible Liquids32.3 ANSI Standard:B-16.5 Pipe Flanges and Flanged Fittings42.4 NFPA Standards:30 Flammable and Combustible Liquid Code531 Ins
18、tallation of Oil Burning Equipment52.5 ISO Standards:6ISO 13341:2005+A1:2011 Static Thermoplastic Tanks for the Above Ground Storage of Chemicals Blow Moulded orRotationally Moulded Polyethylene Tanks Requirements and Test MethodsISO 13575:2012 Static Thermoplastic Tanks for Above Ground Storage of
19、Domestic Heating Oils, Kerosene and Diesel Fuels Blow Moulded and Rotationally Moulded Polyethylene Tanks and Rotationally Moulded Tanks Made of AnionicallyPolymerized Polyamide 6 Requirements and Test Methods3. Terminology3.1 DefinitionsDefinitions are in accordance with Terminologies D883 and F412
20、 and the Association of Rotational Molders(ARM) Glossary of Terms,7 unless otherwise indicated.3.2 Definitions of Terms Specific to This Standard:3.2.1 bottom knuckle radius, nthe outside corner radius.3.2.2 impact failure, nany crack in the test specimen resulting from the impact and visible in nor
21、mal room lighting to a personwith normal eyesight.3.2.3 rotational molding, na three-stage commercial process consisting of loading the mold with powdered resin, fusing theresin by heating while rotating the mold about more than one axis, and cooling and removing the molded article.3.2.4 service fac
22、tor, na number less than 1.0 (that takes into consideration all the variables and degrees of safety involved ina polyethylene storage tank installation) that is multiplied by the hydrostatic design basis to give the design hoop stress.4. Classification4.1 Tanks meeting this specification are classif
23、ied according to type as follows, and it is the responsibility of the purchaser tospecify Type I or Type II:4.1.1 Type ITanks molded from cross-linkable polyethylene.4.1.2 Type IITanks molded from non-cross-linkable polyethylene.5. Materials5.1 This specification is based upon the use of 100 % virgi
24、n polyethylene intended for the rotational molding process. Any useof regrind, recycled or reprocessed materials, or combinations of such materials, shall not rely upon the performance data of theiroriginal constituents, but must meet the requirements of this specification in its own right.5.1.1 The
25、 polyethylene shall have a stress-cracking resistance of 500 h minimum F50 in accordance with Test Method D1693,Condition A, full-strength stress-cracking agent. The test specimens shall be compression molded or rotational molded. Ifcompression molded, Procedure C of Annex A1 of Practice D4703 shall
26、 be followed for both types of polyethylene with aminimum platen temperature of 177C (350F) forType II materials.The temperature forType I (cross-linkable) polyethylene shallbe 197C (390F) and the platen shall be kept closed under full pressure for five minutes at the specified temperature in order
27、tobring about the crosslinking reaction. If the test specimens are rotational molded, the conditions for rotational molding shall besimilar to the conditions used for molding a tank from this polyethylene.NOTE 2The stress-cracking test is not used as an indicator of general chemical resistance of a
28、polyethylene. Refer to the polyethylene suppliers ormolders chemical-resistance chart for information on the resistance of the polyethylene to specific chemicals or products, or test specific products orchemicals prior to use.5.2 All tanks used for outdoor installation shall contain an ultraviolet s
29、tabilizer at a level adequate to give protection for theintended service life of the tanks. This stabilizer shall be compounded into the polyethylene.5.3 Any pigments added must be compatible with the polyethylene and shall not exceed 0.5 % dry blended, and 2 %compounded in, of the total weight.3 Av
30、ailable from Occupational Safety and Health Administration (OSHA), 200 Constitution Ave., NW, Washington, DC 20210.4 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.5 Available from National Fire Protection Association (NFPA), 1 Batterymarch
31、 Park, Quincy, MA 02269-9101.6 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.7 Available from Association of Rotational Molders, 800 Roosevelt Road, C-312, Glen Ellyn, IL 60137, tel: 630-942-6589.D1998 152NOTE 3The use
32、of dry-blended pigments may have an effect on physical properties, that is, impact strength.5.4 Each resin used in designing tanks covered by this specification shall have hydrostatic-hoop-stress data available.6. Design Requirements for Both Type I and Type II Tanks6.1 Cylinder Shell (Unsupported P
33、ortion of Tanks)The minimum required wall thickness of the cylindrical shell at any fluidlevel (F) shall be determined by the following equation,equations, but shall not be less than 4.7 mm (0.187 in.) thick. The toleranceindicated in 9.1.2 applies to these dimensions.T 5P 3OD/2 SD (1)HL 5HM 2F (1)w
34、here:HL = head at level F, m (ft),HM = maximum fluid head, m (ft), andF = any fluid level, m (ft).For illustration, see Fig. 1.T 5P 3OD/2 SD (2)where:T = wall thickness, mm (in.),P = pressure, MPa (0.0098 MPa/m-H2O SG H(m), or psi (0.433 psi/ft-H2O SG H(ft),P = pressure, MPa (0.0098 MPa/m-H2O SG HL
35、(m), or psi (0.433 psi/ft-H2O SG HL (ft),SG = specific gravity of fluid,H = fluid head, m (ft),HL = head at level F, m (ft),OD = outside diameter of tank, mm (in.), andSD = hydrostatic design stress, MPa (psi).6.1.1 The hydrostatic design stress that is used to determine the minimum wall thickness a
36、t any fluid level must be based onhoop stress data for the resin. The hoop stress data, obtained in accordance with the procedures of Test Method D2837, providea hydrostatic-design-basis for the resin. The hydrostatic-design-basis must be reduced by a service factor to determine the actualhydrostati
37、c design stress. The maximum service factor shall be 0.5 for wall thicknesses less than 9.5 mm (0.375 in.). Forthicknesses equal to or greater than 9.5 mm (0.375 in.), the maximum service factor shall be 0.475. For example, if thehydrostatic-design-basis for the resin is 8.7 MPa (1260 psi), the hydr
38、ostatic design stress for a tank with wall thickness greater than9.5 mm (0.375 in.) is 0.475 8.7 = 4.1 MPa (or 0.475 1260 = 600 psi).6.1.2 Tank hoop stresses shall be derated for service above 23C (73.4F).6.2 Cylinder Shell (Externally Supported Tanks)The minimum required wall thickness for the cyli
39、nder straight shell must besufficient to support its own weight in an upright position without any external support, but shall not be less than 4.7 mm (0.187in.) thick. The tolerance indicated in 9.1.2 applies to these dimensions.FIG. 1 Illustration of Cylinder ShellD1998 1536.3 Top HeadMust be inte
40、grally molded with the cylinder shell. The minimum thickness of the top head shall be equal to thetop of the straight wall.6.4 Bottom HeadMust be integrally molded with the cylinder shell. The minimum thickness for a full-supported flat-bottomhead shall be 4.7 mm (0.187 in.). The radius of the botto
41、m knuckle of a flat-bottom tank shall not be less than 25.4 mm (1 in.)for tanks with a diameter less than 1.8 m (6 ft) and 38.1 mm (1.5 in.) for a diameter greater than 1.8 m (6 ft). The minimumthickness of the radius shall not be less than the maximum thickness of the cylinder wall.6.5 Bottom Knuck
42、le RadiusThe minimum thickness of the outer radius shall not be less than the maximum thickness of thecylinder wall.NOTE 4Since it is difficult to control the absolute radius dimension and, in the absence of any FEA or scientific analysis, it is recommended that theoutside radius of the bottom knuck
43、le of a flat-bottom tank not be less than 25.4 mm (1 in.) for tanks with a diameter less than 1.8 m (6 ft) and 38.1 mm(1.5 in.) for a diameter greater than 1.8 (6 ft).6.6 Open-Top TanksThe top edge of open tanks shall be reinforced by design to maintain its shape after installation.7. Fittings7.1 Fa
44、bricated nozzles, gaskets, and other fitting accessories must be chemically compatible with the materials to be handledin the tanks.7.2 Openings that are cut in tanks to install fittings must not have sharp corners. Holes shall have minimum clearance to insurebest performance of fittings.7.3 The siz
45、e, location, and specification, and so forth, for manways and fittings shall be agreed upon between the purchaser andthe manufacturer.7.4 The vents must comply with OSHA 1910.106 (F) (iii) (2) (IV) (9) normal venting for atmospheric tanks, or other acceptedstandard, or shall be at least as large as
46、the filling or withdrawal connection, whichever is larger but in no case less than 25.4 mm(1 in.) nominal inside diameter.7.5 Fittings installed in tanks shall be of appropriate strength to meet manufacturer and purchaser specifications.7.6 Bolts securing mechanical fittings must be manufactured of
47、materials compatible with tank contents.7.7 Provisions shall be made to attach hold-down devices to the tanks for outdoor service.7.8 For all flanged connectors, the flange drilling and bolting shall be in accordance with ANSI/ASME B-16.5 for 150 psi (1MPa) pressure class straddling the principal ce
48、nterline of the vessel.8. Performance Requirements8.1 The following performance requirements shall be met by Type I and Type II tanks:8.1.1 Low-Temperature ImpactLow-temperature impact shall be determined using the test method described in 11.3. Therequirements for Type I and Type II tanks are as fo
49、llows:Wall thickness, mm (in.) Impact energy,min. J (ft-lb)4.7 mm (0.187 in.) to and including 6.4 mm (0.25 in.) 122.0 (90)6.6 mm (0.26 in.) to and including 12.9 mm (0.50 in.) 135.5 (100)12.9 mm (0.51 in.) to and including 19.3 mm (0.75 in.) 203.2 (150)19.3 mm (0.76 in.) to and including 25.4 mm (1.00 in.) 271.0 (200)Greater than 25.4 mm (1.00 in.) 271.0 (200)8.1.2 Percent Gel, for Type I Tanks OnlyThe percent gel level shall be determined using the test method described in 11.4.The percent gel level for Type I t
