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Mass Standards - Calibration Services
Ordering Calibrations Services
Mass pieces, or weights, are calibrated using a wide variety of balances and comparators. These devices are force comparators and provide the raw data for mass comparisons. Computational tools, notably software developed at NRC, permit accurate, traceable calibration of weights. The computations take into account important environmental influences, particularly air density. The most significant determinations are the estimates of variances and their propagation through the mass chain.
The Mass Standards Group calibrates all stable materials, particularly brass and stainless steel. Weights must be in good condition and must not be too sensitive to environmental conditions, e.g., not porous, and of adequate surface finish.
Calibration Range Uncertainties Fees for Service
Contact:Dr. Claude Jacques Tel. (613) 993-9330
The normal mass calibration range is from 1 mg to 50 kg. Uncertainties of measurement range from 40 parts in 109 at 1 kg to 2 parts in 107 at 50 kg. Calibration at routine higher uncertainties should be arranged through laboratories accredited by the Standards Council of Canada (SCC) and the NRC's Calibration Laboratory Assessment Service (CLAS). A list of these laboratories is available. Sets of weights typically range from 1 mg to 100 g. They are calibrated by closed orthogonal designs using NRC standards.
The results of all mass calibrations normally represent conventional mass, i.e., the mass an artifact would appear to possess at an air density of 1.2 kg/m3. All uncertainties are expressed so as to relate the calibrated mass value to that of the international prototype of the kilogram. Absolute masses (the mass that a weight would appear to have a vacuum) are also determined when the densities are known.
Uncertainties on the order of 2 parts in 106 or better require a separate determination of density. This information can either be supplied by the client or established by NRC as a separate procedure. NRC will be the sole arbiter of acceptability of any density estimate from an external source. NRC does not calibrate, repair, or certify balances or comparators.
The uncertainties quoted in the descriptions below are expanded uncertainties representing a confidence level of approximately 95%, except where otherwise indicated. They were obtained assuming a normal distribution and multiplying the standard uncertainty (one standard deviation) by a coverage factor of k = 2.
Ordering Calibrations Services
NEW procedures effective March 23, 2006.
A33-05-00-00 Custom Mass Standards Measurements or Services Fee on request |
Contact Dr. Claude Jacques for further information |
A33-05-00-01 Handling Fee $250 |
A charge is levied for any instrument or artifact found to be unsuitable for calibration. This fee covers opening, inspection and return and is based on the work done prior to discovery of the fault. |
Mass Magnetic Susceptibility of Weights Hydrometers, Density & Volume Pressure Flow
Mass |
A33-05-01-01 Single Weights $173 |
Single weights in the range of 1 mg to 50 kg are calibrated in terms of the working standards of NRC with an uncertainty of one part in 105, by direct one-on-one comparison. |
A33-05-01-03 Loading Weights for Dead Weight Gauges $88 |
Calibration of loading weights for dead weight gauges is carried out directly traceable to national standards with an uncertainty of 1 part in 104. |
A33-05-01-06 Reference Kilograms $680 |
Reference kilograms of adequate quality are compared with NRC primary stainless steel reference standards using the NRC primary kilograms comparator. Conventional corrections are supplied with an uncertainty of 40 µg (40 ppb). |
A33-05-01-08 Reference Kilograms, Comprehensive $1368 |
Includes mass calibration as per A33-05-01-06 plus determinations of density, height of centre of mass, and magnetic susceptibility. The variation of the height of the centre of mass can effectively alter the apparent mass of the 1 kg weight by 3 µg to 5 µg. High magnetic susceptibility renders a weight unfit for calibration. |
A33-05-01-10 Weight Set $3284 |
Calibration of a set of OIML E1 weights, 1 mg to 100 g. |
A33-05-01-20 Centre of Mass $170 |
Determination of the height of the centre of mass of a kg reference weight. See A33-05-01-08. |
The accuracy of mass measurement can be greatly affected by the magnetic susceptibility of weights. For high accuracy and conformance to a class (E1 to E2 and some ASTM classes), it is important to verify that magnetic susceptibility is sufficiently small.
A33-05-01-30 Disc Samples $201 |
Determination of magnetic susceptibility of a disc sample greater than 30 mm in diameter. |
A33-05-01-32 Additional Disc Sample $133 |
As per A33-05-01-30, for each additional disc sample of the same dimensions when supplied at the same time. |
A33-05-01-34 Light Weights $201 |
Determination of magnetic susceptibility of an OIML- or ASTM- shaped weight (50 g to 2 kg). |
A33-05-01-36 Additional Light Weight $133 |
As per A33-05-01-34, for each additional weight of the same dimensions when supplied at the same time. |
A33-05-01-38 Heavy Weight $269 |
Determination of magnetic susceptibility of an OIML- or ASTM- shaped weight (3 kg to 10 kg). |
A33-05-01-40 Additional Heavy Weight $184 |
As per A33-05-01-38, for each additional weight of the same dimensions when supplied at the same time. |
A33-05-01-42 $50 (set-up)+ $10/weight |
Magnetic susceptibility - Test for compliance |
The derived quantity of density is generally measured in terms of the water or silicon standards. The densities of liquids and solids, particularly weights, are determined. Precision pycnometers are calibrated traceable to primary base SI quantities. Air densities are routinely computed and are used in aerostatic density measurements, when necessary. Results are based on calculations made at 20 °C unless otherwise requested by the client.
Hydrometers are calibrated only during the first week of May. Densities of weights are determined only during the second weeks of May and September.
NRC calibrates sensitive hydrometers graduated in any type of unit. Each hydrometer must have a serial number and be made of either glass or metal. Hydrometers in the density range of 475 kg/m3 to 1800 kg/m3 are calibrated with an uncertainty of 1 part in 103, depending on the quality of the hydrometer. Calibrations are carried out by hydrostatic weighing in doubly distilled de-ionized water. If the hydrometer reading is affected by the surface tension of the liquid into which it is placed, the applicable surface tension value must be specified.
A33-05-02-00 Setup $340 |
Preparation and installation of a batch for calibrations. |
A33-05-02-01 Hydrometers $236 |
Calibration of one hydrometer at 3 measurement points. |
A33-05-02-02 Additional point on a hydrometer $84 |
Additional points on the stem are measured on a hydrometer calibrated through A33-05-02-01. |
A33-05-02-03 Densities of Weights $519 |
Densities of weights in the range of 7 500 kg/m3 to 17 000 kg/m3 with masses of 10 g to 1 kg are determined hydrostatically with an uncertainty of 2 parts in 103. The densities are traceable to the water density standard and the national prototype of the kilogram. Lower levels of uncertainty may be obtained by special arrangement. |
A33-05-02-03A Additional Weights $170 |
As per A33-05-02-03, for each additional weight of approximately the same mass when supplied at the same time. |
A33-05-02-04 Densities of Liquids 600 kg/m3 - 2000 kg/m3 $334 |
Densities of liquids in the range of 600 kg/m3 to 2000 kg/m3 are determined by hydrostatic weighing using de-ionized doubly distilled water as a density standard and fused silica artifacts as solid transfer standards. Samples must be clearly marked. Special arrangements must be made for samples which are corrosive, volatile at ambient temperatures, toxic or very viscous. Solutions of thallium compounds are not accepted for calibration. |
A33-05-02-05 Densities of Liquids 1000 kg/m3 - 1800 kg/m3 $624 |
Densities of liquids in the range of 1 000 kg/m3 to 1 800 kg/m3 are determined as in A33-05-02-04 or gravimetrically using pure water as a reference standard by means of calibrated pycnometers. |
A33-05-02-06 Determinations of Volume Fee on request |
Determination of the volume of volumetric glassware, pycnometers, constant volume delivery devices, syringes, and other devices is performed gravimetrically. Due to the variety of such devices and the range of complexity in their volumetric calibration, this work is undertaken only by special arrangement. |
The primary pressure standard is embodied in a mercury manometer which serves as the means of realization of the derived SI unit of pressure, the pascal (Pa). Dead weight piston gauges, also known as piston gauges, piston-cylinder gauges or pressure balances, provide traceable overlapping standards to higher pressures.
Preparation and Shipping
Clients should refer to "Ordering Calibration Services" in the Calibration Services pages for general information about shipping. In addition, the following points should be observed when sending pressure balances to NRC for calibration.
- It is generally unnecessary to ship the frame of the device.
- Separate the piston from the cylinder and clean both thoroughly, using warm soapy water. Rinse well and finish cleaning using 95% reagent grade ethanol or isopropanol.
- Pack the piston and cylinder carefully and separately in their own container or containers. This is particularly important when they are shipped with the loading weights.
- If the piston and weight carrier can be separated, be sure that the carrier is included in the shipment. NRC personnel will not attempt to separate seized assemblies that appear to have an interference fit.
Pneumatic Pressure Calibrations
(A33-05-03-01 to A33-05-03-06)
A33-05-03-01 Dead Weight Gauges, medium accuracy $1339 |
Routine evaluation of the areas of dead weight assemblies (piston-cylinder assemblies) are carried out, with uncertaintaies > 0.01%, by comparisons with reference dead weight gauges traceable to the primary mercury manometer. |
A33-05-03-01A Dead Weight Gauges, high accuracy $2635 |
Routine evaluation of the areas of dead weight assemblies (piston-cylinder assemblies) are carried out, with uncertainties < 0.01%, by comparisons with reference dead weight gauges traceable to the primary mercury manometer. |
A33-05-03-06 Pneumatic Pressure Gauges $1740 |
Vibrating cylinder gauges, quartz bourdon gauges, liquid-in-glass manometers, and barometers and micromanometers are calibrated with an uncertainty of 0.01%. |
Hydraulic Pressure Calibrations
(A33-05-03-21 to A33-05-03-24)
High pressure calibration is performed in the range from 200 kPa to 280 MPa using either a primary pressure balance or a reference dead weight standard with the indicated uncertainties. Zero and general stability tests, linearity tests, and points in excess of 10 required can be done for an additional fee. Please inquire directly about these and other special calibration requirements.
A33-05-03-21 Hydraulic Pressure Gauges $1790 |
Vibrating cylinder gauges, quartz bourdon gauges, etc., are calibrated with an uncertainty of 0.01% using reference dead weight tester. |
A33-05-03-22 Dial Gauges $650 |
Bourdon type gauges are calibrated using reference dead weight testers. Calibration uncertainty depends upon the gauge being calibrated. |
A33-05-03-23 Dead Weight Gauges <100 MPa $2575 |
Routine evaluation of the areas of piston-cylinder assemblies are carried out, with uncertainties < 0.01% by comparisons with reference dead weight gauges traceable to the primary mercury manometer. |
A33-05-03-24 Dead Weight Gauges > 100 MPa $1295 |
Routine evaluation of the areas of piston-cylinder assemblies are carried out, with uncertainties > 0.01% by comparisons with reference dead weight gauges traceable to the primary mercury manometer. |
Gas flow is measured using a volume displacement apparatus using air or inert reference gases such as nitrogen or argon. Because of the nonlinearity of flow devices, ten calibration points are recommended over the useful range of an instrument.
A33-05-05-01 Gas Flow Gauge $620 (set-up) + $105 per point |
Gas flow gauges are calibrated for flows of 1 ml per minute to 50 standard litres per minute, with an uncertainty of 2%. |
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