Accreditation Scope

Overview

Analyt MTC's calibration laboratory seeks DAkkS accreditation for the calibration of gas flow measuring instruments. The scope covers two measurands under the category flow measurement quantities:

• Standard volumetric flow (dV/dt) — the volume of gas per unit time referenced to standard conditions
• Mass flow (dm/dt) — the mass of gas per unit time

These two measurands represent the same physical quantity expressed in different units. Standard volumetric flow and mass flow are related through the gas density at reference conditions: conservation of mass implies conservation of standard volumetric flow. This is fundamentally different from actual volumetric flow, which depends on local pressure and temperature conditions. Both measurands are calibrated using the same fundamental method. For background on these concepts, see Mass Flow and Volumetric Flow.

Reference Conditions

All standard volumetric flow values are referenced to:

• Temperature: 273.15 K (0 °C)
• Pressure: 1013.25 hPa (101.325 kPa)

Calibration medium: air.

Calibration Technologies

The laboratory uses two reference standard technologies:

Laminar flow elements (MolBloc L series)

Transfer standards based on the principle of laminar pressure drop across a precisely characterized flow element. Cover the lower flow range. See principle of operation.

Sonic nozzles (MolBloc S series)

Transfer standards based on the principle of choked (critical) flow through a precisely characterized nozzle. Cover the upper flow range.

CMC — Standard Volumetric Flow

Calibration and measurement capabilities (CMC) for standard volumetric flow of gases (dV/dt).

Measurement range at reference conditions: 273.15 K; 1013.25 hPa.

CMC — Mass Flow

Calibration and measurement capabilities (CMC) for mass flow of gases (dm/dt).

Measurement range at reference conditions: 273.15 K; 1013.25 hPa.