Legal Metrology Act, 2014 (Act No. 9 of 2014)RegulationsLegal Metrology Regulations, 2017Part XI : Measuring instruments and containers used for prescribed purposes115. Gas meters for domestic use |
| (1) | A new gas meter must be of a positive displacement type. |
| (2) | A gas meter must be made of such material as will effectively preclude inaccurate measurement owing to any corrosive or other injurious property of the gas being measured and must be sufficiently strong to withstand, without distortion, the maximum pressure at which it is designed to work. |
| (3) | A gas meter must be so constructed that— |
| (a) | there is no external leakage of gas when the meter is subjected to an internal pressure of 1,25 times the maximum pressure at which it is designed to work or of 5 kPa, whichever is the greater, for a period of not less than two minutes; and |
| (b) | its indicator moves continuously when the meter is subjected to an inlet pressure, equivalent to the maximum pressure at which it is designed to work or to 1,25 kPa, whichever is the greater, and when gas is passing through the meter at a rate of 0,2% of its maximum rate of flow. |
| (4) | The direction of flow of gas through a gas meter must be marked clearly and indelibly on the meter by means of an arrow or by means of the word "IN" at the inlet. |
| (5) | The counter of a new gas meter must, for the purpose of testing, be provided with a graduated indicator by means of which the quantity of gas measured is continuously indicated and the value represented by the smallest graduation on the test indicator must be not more than the quantity of gas passed through the meter during one working cycle. |
| (6) | A separate test indicator need not be provided on a gas meter on which the value of the smallest graduation on the main quantity indicator is not more than the value specified in subregulation (5). |
| (7) | The value represented by the smallest graduation on the quantity indicator of a gas meter, excluding the test indicator referred to in subregulations (5) and (6), must be not more than 0,05 of that quantity which will pass through the meter in one hour at the maximum rate of flow, provided that this value must be 1 x 10n of 1 m3, where "n" is a positive or negative whole number or zero. |
| (8) | On any gas meter provided with a multi-pointer type of quantity indicator, the index pointers must move in a clockwise direction only for increasing quantities. |
| (9) | Any ancillary device, such as a pressure or flow rate controller, recording device, automatic or coin operated shut-off mechanism or a similar device, must not be used on or in conjunction with a gas meter, unless any such ancillary device is approved in terms of section 22 of the Act. |
| (10) | Where a gas meter has any protruding shaft or other working part for the attachment of an ancillary device and such shaft or part is not in use it must be enclosed with a sealed cover. |
| (11) | The following information must be legibly, indelibly and permanently marked on a gas meter or on a plate permanently attached thereto: |
| (a) | the maker's name or trade mark, type designation and serial number; |
| (b) | the approved model number; |
| (c) | the maximum rate of flow at which the meter is designed to operate, in cubic metres per hour, which may be expressed as "Q max……….. m3/h"; |
| (d) | the capacity of the meter per revolution or working cycle, which may be expressed as "V……..m3" or "V………dm3"; and |
| (e) | any other information which may be required on approval of the model in terms of section 22 (1) of the Act. |
| (12) | The actual capacity of a gas meter per revolution or cycle of operation must not differ by more than 5% from the marked capacity per revolution. |
| (13) | Subject to the provisions of subregulation (14), any difference between the pressure at the inlet and the mean pressure at the outlet of a gas meter must not exceed 0,125 kPa when the meter is tested at any prescribed rate of flow and when the pressure at the inlet of the meter is 0,5 kPa: Provided that in the case of a gas meter fitted with an automatic or coin-operated shut-off mechanism the requirements of this subregulation must not apply during the automatic shutting-off period. |
| (14) | When a gas meter is tested as described in subregulation (13) and there is any oscillation of pressure between the highest and the lowest pressure at the outlet such oscillation must not exceed 0,075 kPa. |
| (15) | Except where a gas meter is tested in situ or in other special circumstances, air may be used as the testing medium. |
| (16) | Unless other means or conditions for testing a gas meter have been approved by the National Regulator, such a meter may be tested for accuracy and constancy by passing air through the meter from a measurement standard holder that comply with the requirements in Part III of these regulations at a pressure of 0,5 kPa. |
| (17) | The tests of a gas meter must be carried out at— |
| (a) | the marked maximum rate of flow of the meter, or, if this rate is greater than the maximum operating rate of the measurement standard holder, at the maximum attainable rate; |
| (b) | one-half of the marked maximum rate of flow of the meter; |
| (c) | 0,6% of the marked maximum rate of flow of the meter; and |
| (d) | any other rate of flow, not less than 0,6% of the marked maximum, which the market surveillance inspector or verification officer may consider necessary. |
| (18) | The temperature of the testing medium must not differ by more than 1°C from that of the surrounding air, the meter being at the same temperature as the surrounding air. |
| (19) | Any error on a gas meter must not exceed the amounts shown in Table 24 |
1 |
2 |
3 |
4 |
5 |
TABLE 24 |
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Rate of flow |
For new or repaired meters |
For meters in use |
||
In excess (under-registration) |
In deficiency (over registration) |
In excess (under- registration) |
In deficiency (over registration) |
|
Any prescribed rate of flow |
3% |
2% |
5% |
5% |
| (20) |
| (a) | The verification mark must be applied in a position as described in the type approval documentation, if not described it shall be applied in a conspicuous, essential and accessible part of the gas meter housing. |
| (b) | Protective marks (seals) must be applied to the measuring instrument to prevent unauthorised access to any adjusting device or to the working parts, in a position as described in the type approval documentation. |