NMI R 137-1 & 2 GAS METERS. PART 1 - NATIONAL MEASUREMENT INSTITUTE.docx
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1、(OIML R 137-1 & 2:2012(E), MOD)The English version of international standard OIML R 137-1 & 2 Gas Meters. Part 1: Metrological and Technical Requirements and Part 2: Metrological Control and Tests is adopted as the modified national standard with the reference number NMIR137-1 & 2NMI R 137 Gas Meter
2、sPart 1: Metrological and Technical RequirementsPart 2: Metrological Controls and Performance Tests Commonwealth of Australia 2013First editionOctober 2013National Measurement InstituteBradfield Road, Lindfield, NSW 2070PO Box 264, Lindfield, NSW 2070T(61 2) 8467 3600F(61 2) 8467 3610Wwww.measuremen
3、t.gov.au1.SCOPENMI R 137 specifies the metrological and technical requirements for the pattern approval of gas meters used to measure the quantity of gas that has passed through the meter at operating conditions. The quantity of gas can be expressed in units of volume or mass.2.CONTENTSNMI R 137-1 &
4、 2 (2013) is a modified version of OIML R 137-1 & 2 Gas Meters. Part 1: Metrological and Technical Requirements and Part 2: Metrological Control and Tests published by the International Organisation of Legal Metrology (OIML). These modifications are listed in clause 4.3.INTERPRETATIONSThe following
5、interpretations shall apply to NMI R 137: The national authority for the pattern approval of gas meters is the National Measurement Institute (NMI). The authority issuing the pattern approval certificate for a gas meter is NMI. The pattern evaluation authority or authority responsible for (the) patt
6、ern evaluation is the Chief Metrologist or a person or organisation appointed as an approving authority by the Chief Metrologist in accordance with Regulation 76 of the National Measurement Regulations 1999. For references to national regulations refer to the National Measurement Act 1960, National
7、Measurement Regulations 1999 and the National Trade Measurement Regulations 2009. References to this Recommendation are taken as being NMI R 137.4.MODIFICATIONSNMI R 137 has been modified from the original OIML R 137 such that deletions are indicated with a red strikethrough and additions are indica
8、ted in blue text. All the modifications to OIML R 137 that appear in NMI R 137 are described below: In all instances the use of the term “” has been replaced with the relevant Australian legal unit of measurement for the quantity indicated. In all instances the term ”type approval”, and all associat
9、ed references concerning the testing, evaluation and certification of gas meters, have been changed to the equivalent term “pattern approval”. For ease of readability the deleted “type” has not been indicated with a red strikethrough. The following Note has been included in clause 3.2.10Note:Durabil
10、ity tests are also commonly referred to as endurance tests, the two terms should be considered interchangeable. The definition of overload conditions (clause 3.4.3) has been amended to include:conditions outside the rated operating conditions (including flow rate, temperature, pressure, humidity and
11、 electromagnetic interference) that a gas meter is required to withstand without deterioration to its metrological performance when subsequently returned to rated operating conditions The following amendment has been made to clause 4.1:All quantities shall be expressed in SI units 3 or as other Aust
12、ralian legal units of measurement 4. unless a countrys legal units are different. In the next section the unit corresponding to the quantity indicated is expressed by . The ambient temperature range of -10 C to +55 C has been adopted. See clause 5.1. The following item has been included in clause 5.
13、1:k)Maximum pressure lossAs specified by the manufacturer The Note relating to Table 2 has been deleted. The maximum permissible errors for subsequent verification specified in Table 2 are adopted for use in Australia. However no re-verification period is defined for gas meters in Australia. The fol
14、lowing amendments have been made to clause 5.4:After repair of components of the gas meter which affect the metrological behavior or after damage to the seals, the meter shall be verified before being returned to service. The maximum permissible errors shall comply with the errors on for initial ver
15、ification as stated in Table 2, as well as the maximum permissible weighted mean error as stated in Table 3 shall apply. The following sentence has been inserted into clause 5.8 concerning the maximum working pressure:In addition, the minimum value of pmax shall be 25 kPa. The following sentence has
16、 been added to clause 5.10:It should be noted that the successful completion of durability testing and compliance with relevant acceptance criteria does not provide any guarantee in relation to meter life expectancy. The following amendment has been made to clause 5.13.6:For types of gas meters of w
17、hich some components are intended to be interchangeable for operational purposes (e.g. ultrasonic transducers or meter cartridges), the fault due to the interchange of such a component shall not be more than one third of the maximum permissible error (applicable during type evaluation), while the er
18、ror shall in no case exceed the maximum permissible error for that range.The use of interchangeable components will not be approved by NMI without subsequent verification of the meter. The following clause, 5.13.9, has been included concerning the maximum pressure loss allowable for diaphragm meters
19、:The maximum pressure loss of the meter at Qmax (when tested on air) shall be defined by the manufacturer. The following amendment has been made to clause 6.1.2:The case of a gas meter shall be gas-tight as specified according to national or international standards and requirements concerning safety
20、 and at least up to 1.5 times the maximum working pressure of the gas meter. If a meter is to be installed in the open air it shall be impermeable to run-off water. The following sentence has been included in clause 6.1.3:The indication of the meter must be easily readable during exposure to its rat
21、ed operating conditions. The following amendment has been made to the Note in clause 6.1.5:Note:National or regional requirements may contain provisions to guarantee access to the data for customers and consumers Customers and consumers that receive a bill or charge based on the reading of a meter s
22、hould have access to (i.e. be able to physically read) the primary indicating device of that meter. The following amendment has been made to clause 6.1.8:Components of the meter may only be exchanged without subsequent verification if the type evaluation establishes that the metrological properties
23、and especially the accuracy of the meter are not influenced by the exchange of the components concerned (see 5.13.6). Such components shall be identified by the manufacturer by their own unique part numbers/identifiers.Note:National bodies may require components to be marked with the model(s) of the
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