S-02—Application of specifications for statistical sampling and measurement uncertainty in the verification and reverification of electricity and gas meters

Category: Statistical methods
Issue date:
Effective date:
Revision number: 5
Supersedes: S-02 Rev.4

1.0 Purpose

This bulletin establishes Measurement Canada's (MC) policy on the application of specifications for statistical sampling and measurement uncertainty in the verification and reverification of electricity and gas meters.

2.0 References

3.0 Definitions

Acceptance sampling
(échantillonnage d'acceptation)
The process of accepting or rejecting a lot of meters by inspecting a sample in accordance with a predetermined sampling plan. The object is to ensure that lots of acceptable quality have a high probability of acceptance.
Compliance sampling
(échantillonnage de conformité)
A specialized form of acceptance sampling of isolated lots of meters in service, having the object of ensuring that lots of unacceptable quality have a high probability of rejection.
Multiple customer metering system
(système de mesurage à clients multiples)
A metering system that requires on-site central processing of metrological information for more than one metering point.
Ultrasonic domestic gas meter
(compteur de gaz domestique à ultrasons)
An ultrasonic gas meter which includes a battery-powered register and associated processing circuitry, all enclosed within the same meter case and used to measure volumes of gas at working pressures up to a maximum of 200 kPa.

4.0 Specifications for verification and reverification

4.1 General

Specifications for the verification and reverification of the types of meters identified in this bulletin are listed in section 2.0.

4.2 Diaphragm gas meters

As of , for the purposes of verification and reverification of large diaphragm gas meters by 100% inspection, the upper specification limit for the measure of absolute deviation from target was reduced from 0.80 to 0.60.

5.0 Application of specifications for acceptance sampling (S-S-01, S-S-03 and S-S-04)

5.1 General

Any inspection of isolated lots and short series of lots of meters by acceptance sampling is to be conducted in accordance with specifications S-S-01, S-S-03 and S-S-04, the supporting guidelines of bulletin S-01, and the specifications for verification and reverification of the particular type of meter.

5.2 Scope of application

Inspection by acceptance sampling is currently limited to the following types of meters:

Note: Additional types of meters will be added to this list as specifications for their verification and reverification are established or revised to provide for inspection by acceptance sampling in accordance with specifications S-S-01, S-S-03 and S-S-04.

6.0 Application of specifications for compliance sampling (S-S-01 and S-S-06)

6.1 General

Any inspection of isolated lots of in-service meters by compliance sampling is to be conducted in accordance with specifications S-S-01 and S-S-06, the supporting guidelines of bulletin S-01, and the specification for verification and reverification of the particular type of meter.

6.2 Scope of application

While specification S-S-06 was designed to apply to all types of meters, inspection by compliance sampling is currently limited to the following:

Note: Additional types of meters will be added to this list as specifications for their verification and reverification are established or revised to provide for inspection by compliance sampling in accordance with specifications S-S-01 and S-S-06, or as otherwise authorized by MC.

6.3 Multiple customer metering systems

Any MCMS whose conformity to the requirements of specification S-E-04 has not been assessed and confirmed can't be included in a lot that is to be inspected by compliance sampling.

7.0 Application of specifications for measurement uncertainty (S-S-02)

7.1 100% inspection

Subject to section 7.5, prior to 100% inspection of the following types of meters, the combined standard uncertainty associated with their performance test results must first be determined in accordance with the requirements of specification S-S-02 and the supporting guidelines of bulletin S-01:

Note: Additional types of meters will be added to this list as specifications for their verification and reverification by 100% inspection are established or revised to provide for the application of measurement uncertainty in the conformity assessment of performance test results.

7.2 Acceptance sampling

Subject to section 7.5, prior to inspection of the types of meters listed in section 5.2 by acceptance sampling, the combined standard uncertainty associated with their performance test results must first be determined in accordance with the requirements of specification S-S-02 and the supporting guidelines of bulletin S-01.

7.3 Compliance sampling

7.3.1 Lot of meters

Measurement uncertainty is not required to be applied when determining the number of marginally conforming and nonconforming meters in the assessment of a lot of meters for the purposes of extending its reverification period.

Note: The application of measurement uncertainty in the assessment of a lot of meters subjected to inspection by compliance sampling is to be considered a risk management decision left to the discretion of the meter owner. However, MC recommends that meter owners give serious consideration to their compliance assurance obligations when the application of measurement uncertainty is being considered.

7.3.2 Individual sample meters

Subject to 7.5, assessment of the acceptability of individual sample meters of a type listed in sections 6.2 and 7.1 requires the combined standard uncertainty associated with their performance test results to be determined in accordance with the requirements of specification S-S-02 and the supporting guidelines of bulletin S-01.

7.4 Measurement dispute investigations

Subject to section 7.5, for measurement dispute investigations conducted in accordance with bulletin GEN-43, the application of measurement uncertainty (determined in accordance with specification S-S-02 and the supporting guidelines of bulletin S-01) is limited to the verification conformity assessment portion for the types of meters listed in section 7.1.

7.5 Diaphragm gas meters

For diaphragm gas meters, a default combined standard uncertainty value of 0.267% may be used until the actual uncertainty value has been determined by the authorized service provider or MC.

8.0 Revisions

The purpose of revision 5 was to:

The purpose of revision 4 was to include the:

Date modified: