48519030636616849 INTERNATIONAL ISO STANDARD 12091 First edition 1995-12-01 Structured-wall thermoplastics pipes Oven test Tubes en matieres thermoplastiques a parois structurées - Essai a I'étuve ISo Referencenumber ISO12091:1995(E) COPYRIGHT 2ooo International Organization For Standardization Information Handling Services, 2ooo - 4851903 2T99E90 785 ISO 12091:1995(E) Foreword ISo (the I International Organization for Standardization) is, a_worldwide federationofnationalstandardsbodies(isOmemberbodies).Theworkof represented on that committee. International organizations, governmental and non-governmental, in liaison with IsO, also take part in the work. IsO collaborates ciosely with the International Electrotechnical ( Commission (lEC)onallmattersofelectrotechnicalstandardization. Draft international Standards adopted by the technical committees are circulated tothe memberbodies forvoting.Publicationas an International a vote. International Standard ISO 12091 was prepared by Technical Committee ISO/Tc 138, Plastics pipes, fittings and valves for the transport of fluids, Subcommittee Sc 5, General properties of pipes, fittings and valves of plastic materials and their accessories - Test methods and basic specifi- cations. Annex A forms an integral part of this International Standard. Annexes B and C are for information only. @ISO1995 All rightsreserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including pnotocopying and microfiim, witnout permission in writing from the pubisher. International Organization for Standardization. Case Postale 56 . CH-1211 Geneve 20 . Switzerland Printed in Switzerland i Standardization Information Handling Services, 2oo0 - E06t59h TT99E90 INTERNATIONALSTANDARD ISO ISO 12091:1995(E) Structured-wall thermoplastics pipes - Oven test Scope Apparatus This International Standard specifies a method for as- 4.1 Air-circulation oven, thermostatically con- sessingthe pipewall homogeneityofnon-smooth, trolled, with a heating power such that it is capable of structured-wall thermoplastics pipes by inspection of operatingatthetemperature specified inannexAfor the effects of heating in an oven. the material under test and re-establishing this tem- perature within 15 min after the introduction of the The method is not applicable to the testing of pipes testpieces. with a smooth external surface. The oven shall be equipped with a thermostat capable This test does not include of maintaining the temperature to within ± 2 C of the NOTE1 emeasurementofthe longitudinal reversion (see annex C). specified temperature. 5 Testpieces Definitions 5.1 The sampling procedure for obtaining test pieces shall be as specified in the referring standard. For the purposes of this International Standard, the following definitions apply: 5.2 Each test piece shall comprise a pipe of length 300 mm ± 20 mm. The test piece may be cut longi- 2.1 wall separation: Separation between the layers tudinally into two equal-sized sections if the outside di- in multilayer designs. ameter is less than or equal to 400 mm, or four equai- sized sections if the outside diameter is greater than NOTE 2 Wall separation is normally recognized as the 400 mm. formation of visible bubbles in the surface layer of the pipe. Separation of layers at the cut ends is not considered to NOTE 3 The referring standard should define the optional constitute a failure. procedure for cutting the test piece into sections. This will depend on the wall structure of the pipe. 2.2 blister: Separation of a pipe wall layer internally in the form of a bubble. 5.3 The number of test pieces shall be as specified in the referring standard. However, it is recommended to use at least three test pieces. 3 Principle 6 Procedure A piece of pipe of given length is heated in an oven at 6.1 Condition the test pieces (or test piece sections) a specified temperature for a specified length of time