The Mensura Powered Flow Hood is commonly used by installers and service engineers to accurately measure supply and airflow rates. Moving from supply to extract airflows is easy, as there is no need to change the unit configuration. Airflow direction is automatically detected. No calculations are needed when checking airflows, as system pressure within the airflow meter is automatically compensated for. Flow measurements are easily read and accessible from a digital screen which is built-in to the adjustable handle.

Unit Accuracy: +/- 3% of reading / +/- 1 metre cubed per hour. 

Unit Range: 10 - 400 metres cubed per hour400  (3.7 - 111.1l/s).

Approximate battery life: 8 hours while measuring 75 metres cubed per hour (20.8 l/s)

The complete kit consists of:

• 1 x Powered flow hood with handle and built-in display.
• 1 x Battery charger.
• 1 x Extension transparent hood (315 x 315 x 220mm).
• 4 x AA size rechargeable batteries.
• 1 x Datalogging SD card (2Gb).
• 1 x User manual.
• 1 x Ridged transport case.

Note: This unit is un-calibrated. UKAS certificate of calibration must be purchased separately using part number: 90001146.  The addition of a UKAS certificate of calibration will mean a minimum of 4 additional weeks lead time.

An introduction to the Mensura Powered Flow Hood

The Mensura Powered Flow Hood provides a simple and accurate way to measure airflow when testing and commissioning domestic ventilation systems. Unlike traditional anemometer-based measurement, the Mensura uses powered zero-pressure technology to compensate for the resistance created by the measurement equipment. This helps prevent the measuring device from affecting the ventilation system and eliminates the need for fan- and instrument-specific correction factors.

Powered vs. traditional airflow measurement

Traditional anemometers and non-powered hoods can introduce resistance or back pressure into the ventilation system. This means the measured airflow can be different from the system's normal operating airflow, requiring specific correction factors based on the fan and measurement equipment being used.

The Mensura actively compensates for this resistance, allowing airflow to be measured using the unconditional measurement method (Method A).

BSRIA BG 46/2022 identifies the unconditional method using a powered flow hood as the preferred method for domestic ventilation airflow measurement because of its accuracy and simplicity.

Why use a powered flow hood?

• Zero-pressure measurement – minimises the effect of the measuring equipment on system airflow.
• Accurate readings – provides a direct airflow measurement without fan-specific correction factors.
• Simple to use – reduces the calculations and adjustments associated with traditional methods.
• Supply and extract – automatically detects airflow direction, allowing both to be measured.
• BSRIA Method A – follows the preferred unconditional measurement approach described in BG 46/2022.

What does BSRIA BG 46/2022 say?

BSRIA identifies three methods of airflow measurement: unconditional (Method A), conditional (Method B) and minimum benchmark (Method C).

The conditional method (Method B) can be used with equipment such as vane anemometers, but requires the effects of the measuring equipment and the specific fan performance to be taken into account. BSRIA states that specific correction factors for both the instrument and fan are required.

The unconditional method (Method A) uses a powered flow hood to achieve a zero-pressure balance, providing a measurement that is independent of site-specific fan and instrument characteristics.

Measure airflow the smarter way

Choose the Mensura Powered Flow Hood for accurate, straightforward domestic ventilation testing and commissioning.