Ideal Solution for EN ISO 16911:2013

The European Norm EN ISO 16911:2013 recently substituted the UNI 10169:2001.

The norm specifies the method to determine periodically the axial velocity and the flow rate of emission gases in ducts and chimneys. It is composed of 2 parts: the first is related to the manual reference method, the second to the automatic measurement systems.

The ISO 16911 introduces different news: the controls to perform before the sampling, the modifications related to the Pitot tubes and the references to other norms to determine the measurement points (EN 15259) and to measure the humidity (EN 14790) and the oxygen (EN 14789).

Particularly, when you use an electronic device to measure the pressure, as for example the Flowtest St produced by Tecora (Italy), the norm requires to control the measured values, through the comparison with a liquid pressure gauge or a calibrated pressure sensor. The multifunction calibrator Flowcal Air, produced by Tecora, is the ideal solution which allows to execute the controls required by the norm EN ISO 16911:2013.

The resolution of the electronic measurement device should be of at least 2 decimal per Pascal: Flowtest St can comply to this requirement simply making a software update via USB.

Further, regarding the Pitot tube, contrary to the previous standard, it is not possible to use the constants derived only from their design’s criteria.

The formula used by the norm to calculate the fumes’ velocity keep into consideration the density of the gas, its humidity and the pressure and temperature into duct.

Using Isostack G4 and Flowtest St, both produced by Tecora, it is possible to obtain the automatic calculation of the fume density, knowing the oxygen (to be measured using the paramagnetic method, according to the new norm) and CO₂ concentration.

Once the fume humidity is determined, the instruments calculate the velocity, showing the same results obtained applying the equations expected by the norm: so, Isostack G4 and Flowtest ST are in compliance with EN ISO 16911-1.