1、BRITISH STANDARDBS ISO 17455:2005Plastics piping systems Multilayer pipes Determination of the oxygen permeability of the barrier pipeICS 23.040.20g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g
2、3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58Incorporating corrigendum March 2007 National forewordThis British Standard is the UK implementation of ISO 17455:2005, incorporating corrigendum March 2007.The start and finish of text introduced or altered by corrigendum is indicated in the text by ta
3、gs. Text altered by ISO corrigendum March 2007 is indicated in the text by .The UK participation in its preparation was entrusted by Technical Committee PRI/88, Plastics piping systems, to Subcommittee PRI/88/4, Test methods.A list of organizations represented on this subcommittee can be obtained on
4、 request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.BS ISO 17455:2005This British Standard was published u
5、nder the authority of the Standards Policy and Strategy Committee on 29 June 2007 BSI 2010ISBN 978 0 580 65213 4Amendments/corrigenda issued since publicationDate Comments 31 May 2010 Implementation of ISO corrigendum March 2007Reference numberISO 17455:2005(E)INTERNATIONAL STANDARD ISO17455First ed
6、ition2005-10-01Plastics piping systems Multilayer pipes Determination of the oxygen permeability of the barrier pipe Systmes de canalisations en plastiques Tubes multicouches Dtermination de la permabilit loxygne de la couche barrire dun tube BS ISO 17455:2005ii iiiContents Page Foreword iv Introduc
7、tion v 1 Scope . 1 2 Principle. 1 3 Terms and definitions. 1 4 Symbols and abbreviated terms . 2 5 Apparatus 3 6 Test piece 4 7 Preconditioning. 4 8 Calibration of the test assembly . 4 9 Preparation for testing . 4 10 Measuring procedure . 5 11 Calculation of flux. 7 12 Test report . 8 A n n e x A
8、(informative) Oxygen solubility as a function of temperature . 9 Bibliography . 10 BS ISO 17455:2005iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normal
9、ly carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the
10、 work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare I
11、nternational Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some o
12、f the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 17455 was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for the transport of fluids, Subcommittee SC 5, General
13、properties of pipes, fittings and valves of plastic materials and their accessories Test methods and basic specifications. BS ISO 17455:2005vIntroduction In response to the worldwide demand for specifications, requirements and test methods for multilayer pipes, WG 16 of ISO/TC 138/SC 5 was created a
14、t a meeting held in Kyoto, Japan, in 1998. The working group then started drafting three test standards (including ISO 17455) for multilayer pipes: ISO 17456, Plastics piping systems Multilayer pipes Determination of long-term strength; ISO 17454, Plastics piping systems Multilayer pipes Test method
15、 for the adhesion of the different layers by using a pulling rig. Only multilayer pipes are dealt with in this International Standard and for these purposes cross-linked polyethylene (PE-X) as well as adhesives are to be considered as a thermoplastics material. BS ISO 17455:2005blank1Plastics piping
16、 systems Multilayer pipes Determination of the oxygen permeability of the barrier pipe 1 Scope This International Standard specifies two test methods for determining the oxygen permeability of barrier pipe: the dynamic (Method I) and the static (Method II). In principle, both methods give the same r
17、esults. The method to be applied is not application-dependent, but can be specified in the referring standard. 2 Principle The principle is measurement of the oxygen transfer through the wall of the test piece under specified conditions. The oxygen increase is measured in a system of which the test
18、piece forms part. Oxygen can only be transported through the wall of the test piece. Therefore, the increased amount of oxygen in the closed system is the result of the functioning of the barrier layer of the test piece. NOTE A certain continuous oxygen permeation through the barrier layer is allowe
19、d. 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 multilayer pipe pipe comprising layers of different materials 3.2 multilayer M pipe multilayer pipe comprising layers of polymers and one or more metal layers NOTE The wall thickness of the p
20、ipe consists of at least 60 % polymer layers. 3.3 multilayer P pipe multilayer pipe comprised of two or more polymer layers 3.4 inner layer layer in contact with the liquid or gas 3.5 outer layer layer exposed to the outer environment BS ISO 17455:20052 3.6 embedded layer layer between the outer and
21、 inner layer NOTE There can be more than one embedded layer. 3.7 barrier layer layer intended to prevent or greatly diminish oxygen transport from outside the pipe into the inside water NOTE For multilayer P pipes, the barrier layer is normally not stress-designed. 3.8 closed system system which com
22、prises stainless steel pipes, couplings and a tap, as well as the test piece, allowing only oxygen to permeate from the outside to the inside of the test piece 3.9 flux oxygen permeability of the barrier layer of the pipe 4 Symbols and abbreviated terms Abarroutside surface of the barrier layer, in
23、square metres (m2) Cox, toxygen concentration after time , in grams per cubic metre (g/m3) Foxflux expressed in oxygen transfer per unit per area (of the barrier layer),in grams per square metre per hour (g/m2 h) T test temperature (40C or 80C), expressed in degrees Centigrade Vappvolume of the clos
24、ed system, excluding the volume of the test piece, in cubic metres (m3) Vpipevolume of the test piece (pipe sample), in cubic metres (m3) dboutside diameter of the barrier layer, millimetres (mm) demanufacturers nominal outside diameter, expressed in millimetres (mm) diinside diameter of the test pi
25、ece (pipe), in millimetres (mm) l length of the test piece, in metres (m) Pastandard atmospheric pressure (1 000 mbar at 20C), expressed in bar1)Pfinatmospheric pressure at the end of the measurement, expressed in bar Pinitatmospheric pressure at the start of the measurement, expressed in bar t test
26、 period, in hours (h) prdimensionless correction factor to atmospheric pressure 1) 1 bar = 0,1 MPa = 105Pa; 1 MPa = 1 N/mm2BS ISO 17455:2005Rox,tot total rate of transfer of oxygen through the pipe wall, expressed in grams per hour (g/h) 360fin2,O total amount of oxygen after six hours, in grams (g)
27、 = 060initO,H2O total amount of oxygen in the water at the start of the test, in grams (g) 5 Apparatus The test assembly shall include the following main elements: NOTE 1 The test temperature (40C or 80C) is specified in the relevant product- or system standard. NOTE 2 1 ppb = 1 g/m3. 5.1 Oven, capa
28、ble of maintaining a constant temperature of (40 0,5) C and/or (80 0,5) C. 5.2 Test rig, a closed system consisting of stainless steel parts of pipes, couplings, valves (only for Method II) and taps, including the test piece. 5.3 Water circulation pump, capable of a variable delivery with a capacity
29、 range of from 0,15 dm3/m in to 0,5 dm3/m in. 5.4 Oxygen sensor, Capable of functioning at (40 0,5) C and/or (80 0,5) C, with a range of from 0,1 ppb to 20 ppm2). 5.5 Water pressure meter, with a range of (1 0,1) to (4 0,1) bar. 5.6 Atmospheric pressure meter, with a range of from (965 1) mbar to (1
30、035 1) mbar. 5.7 Water flow meter, with a range of from (0,15 0,05) dm3/min to (0,5 0,05) dm3/min. 5.8 Water temperature meter, capable of functioning at (40 0,05) C and/or (80 0,05) C. 5.9 Air temperature meter, capable of functioning at (40 0,05) C and/or (80 0,05) C. 5.10 Airtight vessel, for pre
31、paration of water with an oxygen concentration of 10 ppb (nominally oxygen-free) NOTE 3 Normally, sink plates or nitrogen are used to remove the oxygen from the water by purging. 5.11 Test medium, deionized water with PH 7 (demi/water). 5.12 Registration device, capable of registering (graphical wri
32、ter or computer) oxygen concentration as a function of time. 2) “Parts per billion (ppb)” and “parts per million (ppm)” are used exceptionally in this International Standard in order to correspond to other, closely related and already published standards. The accepted SI form for the expression of a
33、 volume fraction is in units of microlitres per litre (l/l), or, alternatively, as 106, or as a percentage by volume (% by volume); for mass fractions it is expressed in micrograms per gram (g/g). See ISO 31-0:1992, 2.3.3, and ISO 31-8-15:1992. BS ISO 17455:20054 6 Test piece 6.1 Number of test piec
34、es Unless otherwise specified, the number of pipe test pieces shall be one. 6.2 Preparation The test piece shall have a free length of (20 0,5) m. Prepare the test piece in accordance with the manufacturers instructions, taking into account the minimum free length. The free length between the coupli
35、ngs as well as the inside diameter of the test piece shall be measured and recorded. 7 Preconditioning The test piece shall be preconditioned in accordance with the referring product or system standard. When the relevant product or system standard gives no conditioning time, the conditioning time in
36、 relation to the wall thickness according ISO 1167 1is recommended. 8 Calibration of the test assembly 8.1 Connect the closed system, without the test piece, to the oxygen sensor and pump. 8.2 Remove all air (bubbles) from the system, which has been filled with water. 8.3 Using the vessel, circulate
37、 the water at a maximum of 0,5 dm3/min to produce water with an oxygen concentration of 10 ppb. NOTE 1 dm3/min = 0,0016 m3/s. 8.4 Stop the production of this water after the oxygen sensor shows a steady state concerning the oxygen concentration in the water. 8.5 After at least 15 min stop the calibr
38、ation procedure. 9 Preparation for testing 9.1 Installation procedure 9.1.1 Connect the test piece in the closed system using the relevant stainless steel couplings. 9.1.2 Fill the closed system with water and remove all air (bubbles). 9.1.3 Establish the required pressure and temperature. 9.2 Remov
39、ing the oxygen 9.2.1 Using the vessel, circulate the water through the closed system to produce water with an oxygen concentration of 10 ppb. BS ISO 17455:200559.2.2 Stop the production and circulation of this water after the oxygen sensor shows a level of u 220 ppb (220 g/l) for a test temperature
40、of 40 C, or 100 ppb (100 g/l) for a test temperature of 80 C. NOTE As long as the final oxygen concentration is much smaller than the solubility values per Annex A, the driving force of the transfer of oxygen can be considered as being constant. 10 Measuring procedure 10.1 General For measuring the
41、oxygen increase, two different methods are allowed: Method I and Method II. NOTE With Method I the water is circulated; whereas, in Method II it is stagnant. 10.2 Dynamic test method (Method I) (see Figure 1) 10.2.1 Circulate the water continuously with a volume flow of maximum 0,5 dm3/min through t
42、he system without refreshment. Maintain the temperature of the water as well of the surrounding air at the specified values. Maintain the inside water at the specified pressure. 10.2.2 Using the oxygen sensor, continuously measure the total amount of the oxygen in the water. 10.2.3 After one hour, s
43、tart the measurement of the oxygen concentration in the inside water. NOTE During 5 h, the rate of change in oxygen concentration in the inside water is constant (Stage 2 in Figure 1). 10.2.4 Repeat the procedure according to 9.2 before each measurement. 10.2.5 Only when three measurements in succes
44、sion have values within 5 % of each other during Stage 2, calculate the value of oxygen concentration in the inside water, Fox. 10.3 Static test method (Method II) (see Figure 2) 10.3.1 After the step according to 9.2.2 (the water circulation has been stopped), close the valves on both sides of the
45、test piece to isolate (make airtight) the test piece from the closed system. To prevent a possible vacuum, first close the outlet valve and then the inlet valve. 10.3.2 Maintain the temperature of the water as well of the surrounding air at the specified values. Maintain the pressure of the inside w
46、ater at the specified pressure. NOTE The water is stagnant inside the test piece without refreshment. 10.3.3 Leave for a period of 6 h to let oxygen diffuse into the stagnant water. 10.3.4 After 6 h, open the valves on both sides of the test piece and force the oxygen-free water (coming from the ves
47、sel) out the pipe. 10.3.5 Using the oxygen sensor, measure the total amount of oxygen that issues. NOTE 1 The water coming from the vessel forces out the stagnant water. NOTE 2 When the observed concentration of oxygen is displayed as a function of time in Figure 2, the integration of the curve show
48、s the total amount of oxygen flowing past the sensor. 10.3.6 Repeat the procedure according to 9.2 before each measurement. 10.3.7 Only when three measurements in succession have values within 5 % of each other, use the value of the total amount of oxygen in the inside volume of water for calculatin
49、g Fox. BS ISO 17455:20056 Key X time t, h Y oxygen concentration, g/m31 stage 1 2 stage 2 3 stage 3 NOTE When the oxygen increase in time is graphically shown, as here, there are three different stages. In Stage 2, the rate of oxygen increase is constant. In Stage 3 the maximum solubility is reached. Figure 1 Oxygen increase in a closed system Method I Key X time t, h Y oxygen concentration, g/m3Figure 2 Oxygen concentration in a closed system Method II BS
