BS/EN 14134-2019 pdf download.Ventilation for buildings – Performance measurement and checks for residential ventilation systems.
8 Functional measurements
8.1 General
The purpose of the functional measurements is to provide information needed to assess whether the system complies with the design specifications with respect to the following aspects of performance:
— air flow rate and direction; and
— static pressure; and
— running time.
Methods for mechanical air flow measurement apply also for hybrid ventilation systems when the fan is mechanically driven.
Other aspects of performance may be handled under special measurements.
8.2 Air flow rate and direction
8.2.1 Mechanical ventilation
8.2.1.1 Principle
At all air terminal devices (ATDs):
— the air flow rate shall be measured; and
— the direction of air flow shall be determined.
The measurement can be performed by different methods, e.g.:
— pressure compensating air flow device;
— vane anemometer;
— constant injection tracer gas;
— pilot static tube;
8.2.1.2 Equipment
Uncertainty due to the measuring instrument has an important impact on total uncertainty of the measurement.
Measured values shall be within the measuring interval of the equipment.
NOTE Regular verification of calibration of measuring instruments is essential, see ISO/IEC 17025.
Air flow measuring instruments shall respect a maximum permissible measurement error of 10 % of the measured value or 1 1/s whichever is the greater.
8.2.1.3 Control settings
If there is no manual control available to the end user, measurement shall be performed in the current setting.
If there is a manual control available to the end user, measurement shall be performed at beforehand agreed control settings, if any.
If no control settings are agreed then measurement shall be performed at the maximum setting of the manual control (e.g. highest number or largest pictogram available on a multi position switch, most open position of an air terminal device (ATD)).
8.2.2 Natural ventilation
No measurement required.
NOTE For natural ventilation, air flows on site depend on environmental conditions (e.g. wind speed, temperature difference), location of the device and geometry of the building.
8.3 Static pressure
8.3.1 Mechanical ventilation
8.3.1.1 General
For automatically controlled ATD (e.g. humidity control ATD), a static pressure measurement at air terminal devices is appropriate to assess the systems runs with sufficient airflow. Indeed, veriI’ing that the static pressure is consistent with the design pressure range can be more accurate than airflow measurement. In particular, static pressure measurement is appropriate when the air flow rate is low or the humidity is unknown for humidity control devices.
NOTE For humidity control ATDs. the static pressure measurement is appropriate to verify the functioning of the ATDs for any air humidity situation.
— a measuring tube inserted in the ATDs. The tube shall be positioned in the ducts upstream the regulating part of the ATD.
Possible methods for pressure measurement are described in EN 16211.
8.3.1.3 Equipment
Uncertainty due to the measuring instrument has an Important impact on total uncertainty of the measurement.
Measured values shall be within the measuring interval of the equipment.
NOTE Regular verification of calibration of measuring instruments is essential, see ISO/IEC 17025.
Pressure measuring instruments shall respect a maximum permissible measurement error of 2 % of the measured value or I Pa whichever is the greater.
8.3.1.4 Control settings
If there is no manual control available to the end user, measurement shall be performed in the current setting.
If there is a manual control available to the end user, measurement shall be performed at control settings as previously agreed.
If no control settings are agreed then measurement shall be performed at the maximum setting of the manual control (e.g. highest number or largest pictogram available on a multi position switch, most open position of an air terminal device (ATD)).
8.3.2 Natural ventilation
No measurement required.
8.4 Running time
Functional measurements of the system running times apply to both natural and mechanical ventilation systems if they incorporate devices which automatically control air flow rate by means of times switches and/or run-on timers.
Where a ventilation system or air terminal device (ATD) incorporates a time switch, the running time shall be determined by reading the durations of all “oN” periods from the time switch dial/display.
Where a ventilation system or air terminal device (ATO) incorporates a run-on timer then the duration of the run-on time shall be determined by operating the control switch and measuring the run-on time (e.g. using a stopwatch).BS/EN 14134-2019 pdf download.