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V-24 (rev. 1) Relevant Local Standards of Volume
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Relevant Local Standards of Volume, in PDF format, 89 KB
Table of Contents
1.0 Purpose
2.0 Scope
3.0 Background
4.0 Definitions
5.0 General Requirements for Volumetric Local Standards
6.0 Relevant Local Standard against which Volumetric Devices may be Certified
7.0 Revision
8.0 Additional Information
Date: 2005-07-01
Bulletin: V-24 (rev. 1)
Category: Volume
Supersedes: V-24
Documents: W&M Act, Section 25; W&M Regulations, Section 266, 267 and 268
1.0 Purpose
Section 25 of the Weights and Measures Act prohibits an inspector from certifying any device for use in trade, without comparing it to a relevant local standard. The purpose of this bulletin is to define what relevant local standards are for particular types, sizes and classes of volumetric device. It is also intended to detail general requirements for volumetric standards and any special conditions of use, where applicable.
2.0 Scope
This bulletin defines what are the relevant local standards to be used when calibrating or certifying volumetric measuring devices. In the event that new technology or circumstances warrant a deviation from the normal approach, inspectors should consult with their regional specialist to determine what relevant local standard will be appropriate in each such case.
3.0 Background
Not applicable.
4.0 Definitions
Not applicable.
5.0 General Requirements for Volumetric Local Standards
5.1 All local standards must meet the design requirements defined by the Measurement Canada Volumetric Standards Calibration Manual or as defined by the Measurement Canada Volumetric Engineer.
5.2 All local standards of volume must be certified within the time frame stated in section 56 of the Weights and Measures Regulations.
5.3 Each local standard of volume must be accompanied by a Certificate of Designation, signed by a person delegated to do so, by the authority of the Minister.
5.4 Each local standard of volume must be used in accordance with any and all applicable conditions stated on the certificate.
5.5 The internal coatings and seals of any volumetric prover must be compatible with the product being tested. If there are any questions regarding this, consult the regional Volumetric Specialist.
5.6 Local standards of volume must employ some means to indicate to the operator what product was last contained therein. The previous product must be known to reduce the possibility of product contamination. This can take the form of a product identification tag conspicuously located on the prover to notify the operator of the product last contained.
6.0 Relevant Local Standard against which Volumetric Devices may be Certified
6.1 Dispensers for Motor Fuels: With a flow rate less than 91 lpm - Section 265 of the regulations, which defines the limit of error (LOE) for these devices does not stipulate any particular known quantity or time frame for the test delivery. Convention has been to use 20 litre measures, however, larger provers can be used.
6.2 High Speed Refuellers: With a flow rate greater than 90 lpm, used to deliver motor fuel - Section 266(4) of the Weights and Measures regulations stipulates that the limits of error are applicable to quantities of liquid equal to or greater than that delivered in one minute at maximum operating rate. As these meters are typically 65mm (2.5 inches) in diameter or smaller, section 266(2) of the Weights and Measures Regulations dictates a minimum known volume or prover size of 225 litres and a maximum of 900 litres. Convention is to use a 250 litre prover for these meters, however, larger provers can be used.
6.3 Large Capacity PD and Turbine Meters: Stationary or truck mounted, used to deliver petroleum products - these meters can be tested with a suitably-sized open neck prover or with a suitably-sized pipe prover.
6.3.1 When using open neck provers, they must be of a sufficient size to contain a quantity equal to or greater than one minute’s flow at maximum operating rate. In accordance with section 266 of the regulations, provers used with meters 65 mm (2.5 inches) in diameter or smaller must have a capacity between 225 litres and 900 litres. For meters which are 75 mm (3 inches) in diameter or larger, the prover volume must be greater than or equal to 1350 litres. When testing meters of 75 mm or larger, with outlets which are restricted to a flow rate of less than or equal to 500 lpm, a 500 litre prover may be used. If the results of tests conducted with the 500 litre prover indicate errors greater than three times the limit of error, in favour of the trader, tests must be repeated with a prover of a size of 1350 litres or greater. Where systems are equipped with more than one outlet, the prover size must be appropriate for the flowrate from that outlet, and respect the conditions described above.
6.3.2 When using uni-directional or bi-directional pipe provers without acceptable means of pulse interpolation, they shall receive 10,000 or more unaltered pulses during each pass. An unaltered pulse is defined as a pulse generated from an actual event. This can be an opening and or closing of a switch in the case of a mechanical switch; the opening and or closing of a window in the case of an optical switch; or the rising intersect point and or declining intersect point with a threshold with an electromagnetic switch type pulser. Pulses cannot be multiplied by electronic means.
In addition, in order to prevent excessive displacer by-pass or switch “bounce”, the velocity of the displacer should not exceed 1.5 m/s for bi-directional provers (ball type); or 3 m/s for uni-directional provers; or 1.0 m/s for bi-directional piston type provers. If it is determined that the displacer velocity is in excess of these limits, the regional volumetric specialist should be consulted to determine if the prover can be used.
6.3.3 Small Volume Pipe Provers - Pipe provers which generate less than 10,000 pulses per pass can be used, provided the means of pulse interpolation is done by recognized equipment in a recognized manner. The velocity of the displacer shall not exceed the manufacturer’s specified limit.
6.4 Turbine and PD Meters Measuring Liquified Gases
These meters may be tested using a pipe prover, a gravimetric prover or a vapour displacement prover.
6.5 Mass Flow Meters / Coriolis Meters
When the unit of trade on these devices is mass, these devices must be tested with a reference scale. If the unit of trade is in terms of volume, the device may be tested with a reference scale and an appropriate means to determine density, or a suitably sized volumetric standard and an appropriate means to determine density.
6.5.1 When a reference scale is used, it and the vessel must be of a capacity adequate to contain a quantity of liquid, such that the applicable LOE is at minimum five times greater than the minimum increment of the reference scale, or one minutes actual flow of the device under test, which ever is the greater. Reference scales must be a class III/IIIHD, or better. The reference scale must be tested immediately prior to, and following the inspection, in accordance with the Field Inspection Manual for Non-automatic Weighing Devices. The results of the reference scale test must be within the applicable LOE for the device, in the range it will be used.
6.5.2 Adequate means of determining density are certified pycnometer used with an appropriate scale and certified mass standards, or a certified floating instrument (normally a hydrometer).
6.5.3 Open neck volumetric standards, must be of a size adequate to contain a volume equal to one minute flow at the actual full capacity.
6.5.4 Pipe provers may only be used after consultation with the regional volumetric specialist or volumetric engineer, to determine the appropriateness of the standard.
6.6 Heated Products such as Bunker or Asphalt
The preferred means of testing these meters is with a pipe prover. They may, however, be proved with open provers, provided that all residue is rinsed from the vessel after each run. Equipment used in these applications should be insulated.
7.0 Revision
The original bulletin was issued on April 1, 2004.
The purpose of Revision 1 is to change the criteria when large open provers must be used; to add criteria regarding proving meters used with heated products and to correct some minor errors.
8.0 Additional Information
For additional information regarding this bulletin, please contact the Senior Program Officer responsible for volume measurement.
Dennis Beattie
Senior Program Officer, Volumetric
Weighing and Measuring Division
Program Development Directorate
Tel: (204) 983-8910
Fax: (204) 983-5511
Dennis Beattie
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Measurement Canada
