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What do the results mean?

Pulse test results are presented as various metrics at both 4 Pa and 50 Pa, including:

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Air Leakage Rate (Q)

The volume of air that exits the building per hour, when the building is pressurised to the cited pressure difference.Units: m³/h rounded to nearest whole number

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Air Permeability (AP)

The air leakage rate normalized to the envelope area of the building. It represents air leakage rate per hour per square metre of building envelope area at the cited pressure difference.Units: m³/h.m² rounded to 2 decimal places
Air Permeability (AP) = Air Leakage Rate (Q) ÷ Envelope Area (A)

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Air Changes per Hour (N)

The air leakage rate normalized to the building volume. This metric represents the number of times that the total air volume in a room, space or building is completely removed and replaced in an hour when the building is pressurised to the cited pressure difference.Units: 1/h also known as ACH rounded to 2 decimal places
Air Changes per Hour (N) = Air Leakage Rate (Q) ÷ Volume (V)

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Effective Leakage Area (ELA)

An estimate of the area of a hole that would produce the same amount of leakage as the building envelope at the cited pressure difference. This value is calculated in accordance with ISO 9972:2015.Units: m² rounded to 4 decimal places

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Calculation Uncertainty

The uncertainty in the air leakage calculation, excluding instrument and on-site building measurement uncertainty.Units: ± % rounded to 2 decimal places

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What are the calculation details?

The calculation details give advanced diagnostic information about a Pulse result:

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Coefficient of Determination (R²)

The coefficient of determination is indicative of the accuracy with which a curve fitting equation can be applied to a set of results.With high frequency 50 Hz data collection, 25 reference points are collected per step and an overall R² value of greater than 0.96 is required for a test to be deemed valid.Tests that do not obtain this minimum value may be due to adverse environmental conditions or poor test conditions or techniques.Rounded to 4 decimal places

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Air Flow Exponent (n)

The air flow exponent is used to describe the airflow regime through the gaps and holes in the building fabric. Values must range between 0.5 and 1.0.An n value approaching 0.5 signifies turbulent flow, representing high flow through large apertures. An n value approaching 1.0 will indicate a more laminar flow, characteristic of more airtight structures or those with much smaller gaps and holes.Rounded to 2 decimal places, with confidence interval

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Air Flow Coefficient (CENV)

The air flow coefficient is a measure of the efficiency with which air flows through the gaps, cracks and holes in the structure at an internal to external pressure difference of 1 Pa.Rounded to 3 decimal places, with confidence interval

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Air Leakage Coefficient (CL)

The air leakage coefficient is obtained by correcting the air flow coefficient to standard conditions (i.e. 20°C and 101,325 Pa).Rounded to 3 decimal places, with confidence interval

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What are the test timings?

The timings allow advanced users to view and adjust the Pulse data analysis routine:

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Steady State

The Steady State phase is the period over which a polynomial fit is performed to determine a smoothed curve and a derivative of the air pressure and tank pressure.The Steady State Offset is the start of the defined period, offset from the point the valve opens. This defaults to 0.5-secs but may be manually adjusted to >= 0.3-secs.Steady State Duration must be >= 0.4-secs and the sum of the Steady State Offset + Steady State Duration must not be longer than the total Pulse valve open duration (typically 1.5-secs or 3-secs when testing more airtight enclosures).

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Narrow State

The Narrow State phase sits within the Steady State and is the period when data samples of air pressure and air leakage are collected for analysis.The sum of the Narrow State Offset + Narrow State Duration must be <= Steady State Duration.