GASES
     
MOLE FRACTION AIR HUMIDITY
       
     
MOLE FRACTION IN GASEOUS PHASE
       
  Quantity - mole fraction of component in gas mixture
  Unit - mol/mol.
  Tasks
      The main task is the realisation of mole fraction scale for different gas mixtures and its transfer into gas reference materials.
  International comparisons

year comparison type of comparison subject of comparison

1998

CCQM K3

key

CO, CO2, propane in nitrogen

2000

EUROMET 485

key

CO, CO2, propane in nitrogen

2000

CCQM P23

supplementary

3 mixtures of CO in nitrogen

2001

EUROMET 580

key

ethanol in air

2001

CCQM K16

key

natural gas


Euromet 485 results:
Measured component in
CRM of CO, CO2, propane in N2
measured mole fraction
mmol/mol
relative difference from reference value
carbon monoxide
31.030
0.046 %
carbon dioxide
132.05
0.020 %
propane
2.090
0.22 %

Euromet 580 results:
Measured component in
CRM of ethanol in air
 measured mole fraction
µmol/mol

relative difference from reference value

etanol

118.88

0.17 %

CCQM K16 results:
Measured component in CRM of natural gas measured mole fraction
mmol/mol		 relative difference from reference value measured mole fraction
mmol/mol		 relative difference from reference value
methane
820.8
0.49 %
817.9
- 0.46 %
ethane
7.570
1.1 %
109.72
- 0.34 %
propane
2.9432
0.99 %
44.780
- 0.35 %
n-butane
2.0309
0.24 %
0.9832
- 0.86 %
iso-butane
2.0334
0.84 %
0.9974
- 0.39 %
n-pentane
0.5035
1.1 %
0.3469
0.44 %
iso-pentane
0.4890
0.60 %
0.3452
- 0.04 %
neopentane
0.512
3.0 %
0.511
2.2 %
n-hexane
0.5060
- 0.02 %
0.1963
- 0.48 %
nitrogen
121.45
0.20 %
11.91
- 0.35 %
CO2
40.60
0.38 %
7.953
- 0.11 %

 
    Available metrological services
      - verification tests and type approvals of cehicle exhaust emissions gas analysers
- verification tests and type approvals of breath analysers
- preparation of primary RM of gas mixture for sale
- certification measurement of RM of gas mixtures
     
Gas mixture Component Mole fraction range of component
in PRM / in measured gas mixture		 Expanded uncertainties of
certified mole fraction (k=2), % rel.
mmol/mol in PRM in gas mixture analysed at SMU
from to from to from to
CO2 in N2 CO2 10 180 0.20 0.15
0.30
 0.25
CO in N2 CO 8 100 0.20 0.15
0.30
 0.25
propane in N2 propane 0.1 10 0.30 0.20
0.60
 0.50
CO, CO2, propane
in N2
 CO2 60 140 0.20 0.20
0.35
 0.30
CO 5 35 0.30 0.25
0.90
 0.35
propane 0.1 2 0.40 0.40
1.0
 0.60
ethanol in N2/air ethanol 0.075 0.8 0.5 0.5
1.2
 0.8
         natural gas  methane 650 990 0.20 0.20
0.50
 0.50
ethane  2.5 90 0.25 0.20
1.1
 0.40
propane  1 100 0.35 0.25
1.0
 0.40
n-butane  0.3 7 0.50 0.30
0.90
 0.50
iso-butane  0.3 7 0.50 0.30
0.90
 0.90
n-pentane  0.2 3 0.50 0.40
1.1
 0.60
iso-pentane 0.2 3 0.50 0.40
0.80
 0.40
n-hexane  0.2 2 1.0 0.50
1.1
 0.60
CO2 2 170 0.35 0.20
0.95
 0.25
N2 1 140 0.30 0.20
0.50
 0.30
 
Methods of measurement:
     

Preparation of PRM of gas mixtures is based on keeping the newest ISO standards: ISO 6142 (2001) gas analysis - preparation of calibration gas mixtures - Gravimetric method and ISO 6143 (2001) Gas analysis - determination of the composition of calibration gas mixtures - Comparison methods. Each PRM undergoes validation process in analytical comparison against maintained appropriate set of PRMs at SMU. Cylinders (5 L volume) used for PRMs fulfil the highest requirements for gas mixture stability. SMU provides 2 years stability guarantee for most of its gaseous PRMs. All certification measurements of gas mixtures consist of several automatic comparisons against maintained appropriate set of PRMs at SMU.

 
       
    Instruments in use
      Automated balance for cylinders Laboratory is maintaining National standard equipment as collection of filling station, balances, NDIR analyzers, gas chromatographs, FTIR spectrometer, autosamplers, roller and set of PRMs of gas mixtures.
 
     
Contact
Dr. Stanislav Musil Mr. František Chromek Mrs. Eva Juranyiová Dr. Zuzana Repiská
phone: + 421 2 60294 211 phone: + 421 2 60294 523 phone: + 421 2 60294 229 phone: + 421 2 60294 240
musil@smu.gov.sk chromek@smu.gov.sk juranyiova@smu.gov.sk repiska@smu.gov.sk
   
     
AIR HUMIDITY
       
  Quantity - dewpoint temperature and relative humidity.
  Unit - °C for dewpoint temperature; % for relative humidity.
  Tasks
      The main task is the realisation of dewpoint temperature and relative humidity scale.
  International comparisons
      The standard instrument is traceable through the accredited laboratory of Michell Instruments, U.K. to the National Physical laboratory U.K. Teddington.
    Available metrological services
      Calibration of dew point temperature instruments based on different measurement principles in the range from -70°C to +20°C laboratory conditions (mirror, capacitance, resistant, etc.). Calibration of relative humidity hydrometers based on different measurement principles in the range from 0 % to 95 % (mechanical, capacitance, resistant, etc.)
 
Methods of measurement:
      - mirror dewpointmeter is used for reproduction of quantities dewpoint temperature (°C) and by calibration of instrument with other dewpointmeters of the other countries.
 
Quantity Mark Range Expanded Uncertainty (k=2)
dewpoint temperature Dp -70 to +20°C 0.4°C to 0.1°C
relative humidity RH 0 to 95 % 0.6 %
     
The Laboratory performances of theoretical workshop with practical training for workers in the field of air-conditioning and cooling techniques, compressors and others.
       
    Instruments in use
      Air humidity standard Air humidity standard consists of mirror dewpointmeter from Michell Inst., which is built-in to compact instrument called calibration system designated for calibration of air humidity hygrometers and sensors.
Working range: -75°C to +30°C of dewpoint temperature; 0 - 99 % relative humidity.
Accuracy: U = ± (0.4 - 0.08)°C temperature of dewpoint in a measuring range of (-75 up to +20)°C, U <=0.35 % rh.
 
     
Contact
Mrs. Eva Juranyiová
phone: + 421 2 60294 229
e-mail: juranyiova@smu.gov.sk