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A-2 — Calibrations of standards and measuring apparatus owned and used by authorized service providers to conduct inspections

Date:
Bulletin: A-2, rev. 11
Category: Programs for authorized service providers
Document(s): Criteria for the Accreditation of Organizations to Perform Inspections Pursuant to the Electricity and Gas Inspection Act and the Weights and Measures Act (S-A-01); Registration Program Terms and Conditions; Conditions and Administrative Requirements for the Recognition Program of Calibration Results from CLAS Laboratories Program (RC-01); Weights and Measures Act and Regulations; Electricity and Gas Inspection Act and Regulations
Supersedes: A-2, rev. 10


Table of content


1.0 Purpose

The purpose of this bulletin is to outline how Measurement Canada (MC) determines the number of standards and measuring apparatus owned by authorized service providers (ASPs) that are calibrated by MC for use by ASPs to conduct inspections (examinations). It also sets out ASPs' responsibilities in this regard and the conditions under which weights and measures calibrations are carried out by MC free of charge.

2.0 Scope

This bulletin applies to standards and measuring apparatus owned and used by ASPs to conduct inspections (examinations) in accordance with the Electricity and Gas Inspection Act and the Weights and Measures Act. Information on the calibration of other standards can be found in bulletin GEN-08. Bulletin GEN-08 cannot be used to circumvent the requirements of the present bulletin.

3.0 Definitions

Note: For the purposes of this bulletin, the term "inspection" is used in a generic manner and is intended to include verifications and reverifications under the Electricity and Gas Inspection Act and examinations under the Weights and Measures Act.

Calibration

A comparison between a standard under test and a reference standard for the purpose of determining if the value of the standard under test is within the specified tolerances.

Note: The term "calibration" does not necessarily include the adjustment of a standard required to ensure it meets specified tolerances.

Standard

Any standard designated as a local standard by the Minister under section 13 of the Weights and Measures Act.

Measuring apparatus

An apparatus required for the measurement of electricity or gas, or the examination of meters.

4.0 Responsibilities of authorized service providers

ASPs are responsible for the following:

No later than December 15 of each year, ASPs must submit a list of the standards and measuring apparatus they would like MC to certify and designate during the next calendar year to the Regional Coordinator, ASD for acceptance. The Regional Coordinator, ASD, must also approve any addition to the list. These lists help MC provide calibration services within service standards.

Weights and measures standards used to perform inspections are calibrated and certified as local standards by MC free of charge, in accordance with section 59 of the Weights and Measures Regulations. See Appendix 1 for the maximum number of weights and measures standards that can be calibrated and designated as local standards by MC free of charge.

Measuring apparatus used to conduct inspections in accordance with the Electricity and Gas Inspection Act are calibrated and certified in accordance with section 47 of the Electricity and Gas Inspection Regulations. At this time, there is no maximum number of measuring apparatus that can be accepted by the Regional Coordinator, ASD. Fees apply to the calibration of electricity and gas measuring apparatus.

5.0 Accuracy requirements

6.0 Types of standards and measuring apparatus and their calibration location

6.1 Dimensional

6.2 Electrical

6.3 Gas

6.4 Gravimetric

6.5 Temperature

6.6 Volumetric

Calibration locations:

  1. MC
    ACSL
    Standards Building
    151 Tunney's Pasture Driveway
    Ottawa, Ontario K1Y 1G9
  2. MC district offices (various locations)
  3. National Research Council of Canada (NRC), Ottawa
  4. CLAS (Calibration Laboratory Assessment Service) Type I laboratories recognized by MC
  5. On-site calibration by MC's ACSL
  6. CLAS laboratory or laboratory recognized by the NRC providing traceability to the definition of the metre as per the Weights and Measures Act.

7.0 Information on standard types

7.1 Gravimetric standards

Mass standards that are used to inspect Class III, IIIHD and IIII weighing devices must meet the tolerances prescribed in Part III or IV of Schedule IV of the Weights and Measures Regulations. These tolerances are roughly equivalent to International Organization of Legal Metrology (OIML) Class M1 tolerances.

Mass standards used to inspect Class II weighing devices must meet the tolerances prescribed in Part I of Schedule IV of the Weights and Measures Regulations. These tolerances are roughly equivalent to OIML Class F2 tolerances.

Weight kits that are calibrated by the ACSL must meet one half of the prescribed tolerances in order to be certified. The purpose of this provision is to ensure that, during the certification period, the error of mass standards does not exceed the tolerance prescribed in the Weights and Measures Regulations.

Please consult the MC Regional Gravimetric Specialist for advice on the selection of mass standards 5 kg and greater or the ACSL for all other weight kits.

7.1.1 OIML Class M1 mass standards of 5 kg or larger

Mass standards (usually cast iron or fabricated weights) of 5 kg or larger (10 lb or larger) must meet all requirements, including those relating to construction, material and fabrication defined in OIML R111-1 and Appendix 2 of this document. It is recommended that organizations consult the local MC Regional Gravimetric Specialist prior to the purchase or fabrication of any new weight design.

Before being submitted for calibration and certification, mass standards must be cleaned and prepared in accordance with the procedure described in Appendix 2 of this document. Mass standards which deviate from the nominal value (error) by more than two thirds of the prescribed tolerance will have to be adjusted as close as possible to the nominal value. ASPs must provide the necessary personnel to assist in making these adjustments. The purpose of adjusting mass standards as close as possible to the nominal value is to ensure that, during the certification period, the error of mass standards does not exceed the tolerances prescribed in the Weights and Measures Regulations.

7.1.2 OIML Class M1 mass standards of 5 kg and smaller

These standards are also known as "inspector weight kits". They consist of weights of 5 kg (10 lb) to 10 mg (0.001 lb or 1/32 oz) and are used to inspect Class III, IIIHD and IIII devices.

These weight kits must meet all of the requirements found in the Laboratory Manual for the Evaluation of Weight Kits. Weight kits that do not meet these requirements, including those that are not properly cleaned, marked or adjusted as required, will be returned to their owner without being certified. MC's ACSL does not provide weight cleaning, stamping or adjustment services. More information can be found in the Laboratory Manual for the Evaluation of Weight Kits.

7.1.3 OIML Class F2 or better mass standards of 20 kg and smaller used to inspect Class II devices (high precision weight sets)

These standards are also known as "precious metal weight kits". They consist of weights of 20 kg to 1 mg and are used to inspect Class II devices. They must only be used for the inspection of legal for trade Class II devices; otherwise, the integrity of the weights may be compromised and they may be outside the prescribed tolerance before the end of their calibration cycle.

These weight kits must meet all of the requirements found in the Laboratory Manual for the Evaluation of Weight Kits. Weight kits that do not meet these requirements, including those that are not properly cleaned, marked or adjusted as required will be returned to their owner without being certified. MC's ACSL does not provide weight cleaning, stamping or adjustment services. More information can be found in the Laboratory Manual for the Evaluation of Weight Kits.

7.1.4 Recognition Program of Calibration Results from CLAS Laboratories

High precision weight sets (section 7.1.3) are not presently open to the Recognition Program of Calibration Results from CLAS Laboratories. All high precision weight sets used for the inspection of legal for trade Class II devices must be sent to MC for calibration and certification.

Mass standards that are suitable for the inspection of Class III, IIIHD and IIII weighing devices (section 7.1.2) must be submitted to MC for the initial evaluation. Only subsequent evaluations can be performed by a recognized CLAS Type I Laboratory under the Recognition Program of Calibration Results from CLAS Laboratories.

ASPs utilizing the services of a laboratory recognized under the Recognition Program of Calibration Results from CLAS Laboratories for the calibration of their weights and weight sets must meet the requirements of sections 4.1, 4.6 and 4.9. The requirements of section 4.6 are applicable to weights and weight sets certified and designated as standards and not to other weights and weight sets ASPs may need to have calibrated. The requirements of sections 7.1.1 and 7.1.2 must also be met. Mass standards can be cleaned, stamped and adjusted by a CLAS Type I Laboratory.

All weights and weight sets sent to a CLAS Type I Laboratory must be properly packaged to ensure adequate protection during shipping. They must also be accompanied by a correctly completed Calibration Services Request form and the last calibration certificate issued by MC.

7.2 Volumetric standards

Volumetric standards must meet all requirements, including those relating to construction set out in MC's Guidelines for the Calibration and Certification of Volumetric Standards, available from your MC contact. It is recommended that organizations consult the MC Regional Volumetric Specialist prior to the purchase or fabrication of any new standards design and equipment not included in the Guidelines for the Calibration and Certification of Volumetric Standards.

Before being submitted for calibration and certification, volumetric standards must be cleaned. Walls must be free of greasy or oily residue, dirt and rust. The coating on the inside surface of standards must be in good condition with no obvious peeling. The standards must be free of flammable or noxious vapours.

The ACSL and MC district offices do not clean volumetric standards. Volumetric standards that do not meet construction requirements or are not properly cleaned will be returned to their owner without being certified.

7.3 Temperature standards

Temperature standards must meet the accuracy requirements set out in Schedule IV to the Weights and Measures Regulations. It is recommended that organizations consult the local MC Regional Volumetric or Gas Specialist prior to the purchase of temperature standards.

For the specified application, thermometers must have a minimum resolution and range as follows.

Table 1: Thermometers
Application Minimum range Minimum resolution
General field inspection −30 °C to +50 °C 0.1 °C
Calibration of a thermometer used in a gas prover for temperature correction 0 °C to +35 °C 0.01 °C
Temperature correction in gas measuring apparatus 0 °C to +35 °C 0.1 °C
Bell prover air temperature 0 °C to +35 °C 0.1 °C

Thermometers intended for field use must be stored in a hard protective carrying case with foam inserts cut to the shape of the thermometer and the probes or similar means to protect them. The carrying case must have sufficient padding to prevent breakage of the thermometer and the probes.

The following information must be permanently marked, or be capable of being displayed on thermometers: manufacturer's name, model number and serial number. In the case of thermometers with multiple probes, each probe must be marked by a unique identifier.

Where the instrument is capable of being calibrated or adjusted, access to the adjustments must be easily detectable or sealable.

8.0 Revisions

The initial version of this bulletin became effective January 28, 2004.

8.1 The purpose of revision 1 (May 3, 2004) was to:

8.2 The purpose of revision 2 (February 3, 2006) was to clarify:

8.3 The purpose of revision 3 (November 17, 2006) was to:

8.4 The purpose of revision 4 (January 7, 2008) was to:

8.5 The purpose of revision 5 (July 21, 2008) was to:

8.6 The purpose of revision 6 (June 9, 2010) was to:

8.7 The purpose of revision 7 (March 11, 2013) was to:

8.8 The purpose of revision 8 (October 31, 2013) was to clarify:

8.9 The purpose of revision 9 (October 1, 2014) was to:

8.10 The purpose of revision 10 (October 1, 2015) was to:

8.11 The purpose of revision 11 (March  13, 2019) was to:

9.0 Additional information

For additional information regarding this bulletin, please consult the contact us section of the MC website or your departmental contact. The copy of this document located on MC's website is considered the controlled copy.

Appendix 1—Number of standards certified and designated as local standards by Measurement Canada free of charge for weights and measures authorized service providers

The maximum number of standards MC can certify and designate as local standards free of charge for weights and measures ASPs is set out below.

When the number of standards to be submitted by an ASP exceeds the limits listed above, the ASP must provide a written justification to the local Regional Coordinator, ASD, explaining the reason why the additional standards require MC certification and designation.

MC can also designate any supplementary standards calibrated by a recognized laboratory under the Recognition Program of Calibration Results from CLAS Laboratories as long as they are used to inspect devices.

1.0 Gravimetric standards

Mass standards of 5 kg or larger:

Large test weights (gravimetric standards in excess of 100 kg):

Mass standards of 5 kg and smaller (inspector's weight kit):

Mass standards of 20 kg and smaller used to inspect Class II devices (weight set):

2.0 Temperature standards

Thermometer

3.0 Volumetric standards

Definition

Narrow neck standard

A local standard of volume or capacity that has, on or adjacent to the narrow neck of the standard, a mark indicating the volume or capacity of the standard, or that has a machined rim that indicates the volume or capacity of the standard. These standards are typically used to check specialized test equipment.

  1. Twenty-litre test measure used to inspect volumetric meters:
    • Two test measures of a given nominal volume for every recognized technician. One additional test measure for every two recognized technicians per ASP.
  2. Prover used to inspect volumetric meters:
    • As per historical data. Addition of new provers requires agreement from MC.
  3. Hydrometer / LPG dispenser:
    • Two hydrometers / LPG dispensers for every recognized technician. One additional hydrometer per ASP.
  4. Narrow neck 20 L standard:
    • One narrow neck 20 L standard for every recognized technician. One additional narrow neck 20 L standard per ASP point of service.
  5. Test measure and prover of 100 L and less used to calibrate other provers or used to certify ASPs' pipe provers:
    • As per historical data. Addition of new test measure requires agreement from MC.

Appendix 2—Calibration procedures for standards of mass

The information that follows is an excerpt from RP-01 Field: Calibration Procedures for Standards of Mass (sections 2.4 to 2.72). The section numbering has been modified for use in this document.

1.0 Material and fabrication requirements for mass standards

For specifications regarding material, construction, shape, density, surface conditions, etc., of mass standards, the international recommendation OIML R111-1: Weights of Classes E1, E2, F1, F2, M1, M 1–2, M2, M2–3 and M3 should be consulted. Questions regarding design or acceptability of standards 5 kg and larger and industry weights should be addressed to the Gravimetric Specialist and, when necessary, the Gravimetric Engineer. Questions regarding design or acceptability of mass standards 5 kg and smaller (inspector's weight kit) and any high precision weights should be addressed to the ACSL. Requirements for these types of weights can be found in the Laboratory Manual for the Evaluation of Weight Kits.

To ensure consistency with past practice, the following should be observed in addition to the requirements of OIML R111-1 for standards equal to or larger than 10 kg.

1.1 Design

The construction of standards of a nominal value equal to or greater than 10 kg must be either "solid", "layered" or "filled", as defined below:

Note: The use of industry weight baskets or weight racks is prohibited.

1.2 Seams

All exposed seams must be joined with a continuous weld to form a closed system (with the exception of the seal and plug). Where seams may come in contact with other objects during normal use, the weld on these seams must be ground smooth and flush with the surrounding metal.

All welds must be sufficiently strong to withstand, without breaking or cracking, all forces encountered during normal use.

1.3 Shape

The shape of the standard must be simple without undue sharp angles, and any exterior corners must be rounded to a radius no smaller than 6 mm.

1.4 Surface roughness

The entire surface must be smooth and reasonably free from grooves and/or indentations in which foreign matter may accumulate.

1.5 Density

The density of any material used to construct standards must be such that when the actual air density at calibration is ± 10% away from the conventional value of 1.2 kg/m³, the total density of the standard does not cause a change in the calculated value of the conventional mass exceeding 1/3 of the tolerance for the standard being calibrated or certified.

Although Table 5 of OIML recommendation R111 (2004) states the minimum and maximum densities of various classes, all standards equal to or larger than 10 kg used by MC should have the following minimum and maximum densities:

MC imposes more stringent requirements for density because otherwise the effect of the variations in air density and of the uncertainty due to the material density of the standard would make its combined uncertainty too large.

Note that grey cast iron has an approximate density of 7 000 kg/m³ and the lowest density for cast iron is 6 000 kg/m³.

1.6 Material hardness

The material used must not be softer than brass and must be of suitable hardness and ductility to resist stress, wear and chipping to which standards may be subjected under normal use.

1.7 Adjustment cavities

Standards must have one but no more than two adjustment cavities. The total volume of the cavity must be as close to, but must not exceed, 5% of the total volume of a standard.

Cavity enclosure must result in a closed system with provisions made for the imprint of an inspection mark. To ensure that no liquids can enter and accumulate in cavities, adequate means for sealing must be provided with an undercut opening or other to ensure that lead is securely held in place to seal the opening. No lead must project beyond the surface of the standard.

1.8 Flaws

A cast iron standard must be examined to ensure there are no cracks or flaws and the adjustment cavities are free of foreign matter.

The Rz (maximum height of roughness profile) of the surface finish of any new cast iron standard must not exceed 12.5 μm (500 μin). The Ra (mean height of roughness profile) of the surface finish must not exceed 2.5 μm. A further examination must be made to ensure that the standard does not contain casting defects. Any depression deeper than 2 mm from the surrounding surface and at any point wider than 4 mm must be filled by welding to prevent accumulation of added weight after calibration. The use of foundry putty or body filler is not acceptable.

1.9 Nominal values

Standards should be constructed to represent nominal values of mass of denominations of 1, 2 and 5 x 10n, where "n" is a positive or negative whole number or zero. Standards not represented by nominal values of mass of denominations of 1, 2 and 5 x 10n can be certified as standards, but the appropriate tolerance must be determined.

2.0 Care and maintenance of mass standards

When not in use, standards should be covered or stored in their carrying cases. These cases must have appropriate compartments for each weight of a series. The interior of the case must be such that the standards are protected against any wear, abrasion or shock that may be encountered during transportation.

When stored, carrying cases should be kept off the floor to protect them from dampness, which can affect the stability of the standards.

Standards must be protected from drafts and dust.

Stainless steel reacts with the chrome salts used in the manufacturing process of chamois, especially if the chamois is left in contact with the standards over a long period of time. Usually, a chamois is kept with the standards in a closed box, where it may remain for months at a time. Any new chamois must therefore be washed with soap and water, rinsed thoroughly and dried before use.

2.1 Adjustment of mass standards

When field standards being calibrated or verified are not within 2/3 of their applicable tolerance, they are adjusted. The adjustment is made so that the standard's value is now within 1/3 of the applicable tolerance.

Inspector weights are adjusted using lead because it is malleable and its density is very high (11 340 kg/m³). The adjustment cavity is then closed and an MC inspection mark is applied. Whenever large quantities of adjusting material are added, the adjusting material should be of the same material as that from which the standards were fabricated.

2.2 Cleaning and refurbishing standards

Inspector weights are cleaned by scrubbing off excess rust, flaking paint, etc. Oil and dirt may be removed by using a cloth moistened with mineral spirits. In this case, the cleaning solution must be allowed to evaporate over a 24-hour period prior to calibration taking place.

When a weight is made of a material that oxidizes such as cast iron, it is important that the surface finish be disturbed as little as possible to maintain weight stability. Once the surface acquires its initial oxidation coat, any further corrosion significantly slows. Therefore, the less the new surface is exposed to fresh oxidation, the more stable the standard. It is also important to use a surface finish with good flow and self-adhesive properties to fill minor gaps, seal the surface, and securely bond with previous coats of paint.

2.2.1 New cast iron standards

New standards must be kept unfinished for two weeks prior to any finishing material being applied.

Before painting, new standards should be lightly cleaned with a wire brush to loosen surface rust, wiped with a cloth moistened with mineral spirits to remove dust, loosened rust, surface oils, etc., and then painted with a primer/sealer and allowed to dry thoroughly.

Two coats of metallic rust-preventative paint (aluminum based) should be applied with a brush or sprayed in very thin layers and then the required markings should be applied for identification.

A coating of paint is only recommended once for the bottom of standards greater than 5 kg and having recessed bottoms.

When two different colours are used to differentiate between avoirdupois and metric weights, it is recommended that metric standards be painted with gold aluminum paint and avoirdupois standards with silver aluminum paint.

The standard should be allowed to dry overnight, as a minimum, prior to calibration to ensure that the solvents have completely evaporated from the paint.

It is good lab practice to test the paint on one standard first and then test for adhesion before applying to the full set.

2.2.2 Refurbishment of cast iron standards

Under no circumstance should a cast iron standard be sandblasted. Regular maintenance as described below will ensure that the surface coatings do not become excessively thick.

As a minimum, the standard must be:

A coating of paint is recommended for the bottom of standards greater than 5 kg and having recessed bottoms. When two different colours are used to differentiate between avoirdupois and metric weights, it is recommended that metric standards be painted with gold aluminum paint and avoirdupois standards with silver aluminum paint.

The standard should be allowed to dry overnight, as a minimum, prior to calibration to ensure that the solvents have completely evaporated from the paint.

Date modified: