Bilateral inter-comparison in the gas flow range from 0.002 m3/h to 2.5 m3/h with sonic nozzles

Project Description

Sonic nozzles (7 pieces) with nominal flow rates 2 L/h, 16 L/h, 60 L/h, 250 L/h, 600 L/h, 1600 L/h, 2500 L/h will be used to compare primary low-pressure test facilities.
The laboratories should carry out the calibration using their common procedures.
The procedure described in PTB Testing  Instruction Volume 25: Gas meters – Test rigs with critical nozzles is recommended to be used.
The parameters  QV,20,tr,1000[L/h] and cpE[-] are required to be determined for each sonic nozzle.
Each laboratory will be responsible for the transfer of the sonic nozzles to the next laboratory.
No other costs are expected.

Test conditions:

  • Test gas: air
  • Upstream sonic nozzle pressure: near atmospheric
  • Test temperature:  (19.5 ÷ 22.5) °C


Flow (F)
Coordinating Institute
CMI (Czech Republic)
Participating Partners
PTB (Germany)