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AP – Air Permeability (m
Achieved Pressure Range (Pa)
A test ID will also be displayed, this should be noted for records.
At the end of the test the results are automatically captured in the unit's memory. These may be exported as .csv
or .Pat file (depending on the version of Pulse unit and software you are running) by plugging in a USB and
following export guidelines in section 8.3.
Alongside all results, feedback on the quality of the test is also presented. This feedback is informed by a number
of test quality indicators and includes the following advice:
Feedback
Comment
Valid test
A high quality successful test, proceed accordingly
Warning:
A test status warning is given where the achieved pressure range does not span 4Pa. The
Low
warning will state 'low pressure' if the maximum of the range is below 4Pa and 'high pressure'
achieved
if the minimum of the range is above 4Pa. This does not invalidate the test but means that the
pressure
result at 4Pa has had to be inferred based on the available data. This is then reflected in the
calculation uncertainty. Where these instances occur, the closer the achieved pressure range is
to 4Pa, the better.
A low achieved pressure is as a result of the building under test being either too big and or too
leaky for the Pulse equipment in use. To increase the achieved pressure, the air receiver should
be charged to a higher starting pressure and if this was already the case, an additional air
receiver should be added in order to increase the total air flow release.
Warning:
A test status warning is given where the achieved pressure range does not span 4Pa. The
High
warning will state 'low pressure' if the maximum of the range is below 4Pa and 'high pressure'
achieved
if the minimum of the range is above 4Pa. This does not invalidate the test but means that the
pressure
result at 4Pa has had to be inferred based on the available data. This is then reflected in the
calculation uncertainty. Where these instances occur, the closer the achieved pressure range is
to 4Pa, the better.
A high achieved pressure is as a result of the Pulse equipment releasing too much air into the
building under test for its given size and/or leakiness. In these instances the operative could use
fewer air receivers and/or carry out the test from a lower air receiver charge level i.e. fewer
bars.
Invalid r²
The correlation coefficient, or r², is indicative of the accuracy with which a curve fitting
Threshold
equation can be applied to a set of results. With high frequency 50Hz data collection, 25
reference points are collected per step and it is recommended that an overall r² value of
greater than 0.96 is required for a test to be deemed valid. Where all combinations of the test
steps are analysed yet none are able to achieve the minimum 0.96 threshold, the test is
flagged as invalid. The quality of the data points and trendline can be viewed in the 'Air Flow'
chart of the View Test page of Pulse Online, with poor r² tests typically presenting a distorted
series of data points.
These distortions will typically be as a result of either:
Adverse environmental conditions e.g. strong gusting winds;
Poor test conditions e.g. a loose or moving element of the building fabric that is
constantly moving and changing or reacting to the Pulse of air inconsistently;
Sub-standard test setup e.g. distorted air flow and reverberations as a result of the air
receiver or controller being too close to a wall or window.
3
2
/m
h)
Page 17 of 28
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