A measuring station, or measuring cross, is used in a ventilation system to measure the actual air volume.
Material quality and thicknesses
For normal comfort ventilation, measuring stations are manufactured from the following materials:
- Casing: Sendzimir galvanised steel;
- Measuring points: Sendzimir galvanised steel or aluminium;
- Other choice of material, depending on the application, in consultationwith the supplier.
The measuring station is available with circular and rectangular connections.
The available nominal dimensions of the intermediate measuring stations are standardised to NEN-EN 1505 (rectangular connections) and NEN-EN 1506 (circular connections) and can be selected as indicated in the tables for standard dimensions, as given in this Guide under chapters 188.8.131.52 (rectangular connections) and 184.108.40.206 (circular connections). They refer to the internal dimensions with a tolerance of +0 to -5 mm. The dimensions depend on the manufacture.
Measuring stations shall be installed in accordance with the manufacturer's instructions. If present, they must at least comply with the requirements of paragraph 3.1.4.
The measuring station should be mounted so that the arrow on the casing points in the air direction. This is very important for proper operation.
A minimum distance from or to a bend, fan, valve, etc. must be taken into account. For circular measuring stations a minimum distance of 2 x the connection diameter is recommended. For rectangular constant volume controllers a distance of 2 x the duct width is recommended.
Measuring stations with circular connections, fitted with rubber seals, can be efficiently connected to air ducts and contribute to the airtightness of the air duct system, if the fittings have sufficient airtightness in accordance with NEN-EN 15727.