Smoke Test Result Calculator

Input Form

Enter measured conditions and observed smoke behavior.

White theme • Responsive grid • Exports

Test setup

Test type

Choose the system being smoke tested.

Unit system

Auto-refreshes labels for units.

Test duration (min)

Total observation time under steady conditions.

System volume (m^3)

Approximate internal volume being filled with smoke.

Pressure differential (Pa)

Approx. applied or measured test pressure.

Smoke output rate (m^3/min)

Rated smoke generation or injection flow.

Fill factor (1.00–2.00)

Extra volume allowance for mixing and losses.

Observed smoke behavior

Observed intensity

Qualitative smoke visibility at leak points.

Leak points observed (count)

Count distinct leak locations or defects.

Average leak diameter (mm)

Estimated average opening size across leaks.

Largest leak diameter (mm)

Used for context; model uses average diameter.

Visibility distance (m)

Distance smoke remains visible from the leak source.

Leak location criticality

Used for the risk index to prioritize repairs.

Environment

Temperature (C)

Informational; can affect buoyancy and visibility.

Relative humidity (%)

Higher humidity can change plume appearance.

Wind / air movement (m/s)

External wind can mask or disperse smoke rapidly.

Acceptance criteria

Criteria preset

Choose a decision rule for PASS/FAIL.

Custom allowable leakage (L/s)

Used only when you select the custom option.

Advanced parameters

Discharge coefficient (Cd)

Typical sharp-edged orifice values range 0.60–0.65.

Air density (kg/m^3)

Approx. 1.2 kg/m^3 at standard conditions.

Inspector notes (optional)

Included in exports for reporting.

Clear

Example data table

Sample entries showing how inputs affect modeled results and decisions.

Scenario	System Volume	dP	Leak Points	Avg Diameter	Intensity	Modeled Leakage (L/s)	Decision
Vent stack joints	30 m^3	25 Pa	1	1.5 mm	Wisps	0.13	PASS
Duct access panel	55 m^3	50 Pa	3	3.0 mm	Steady	2.46	FAIL
Envelope penetration	120 m^3	10 Pa	6	2.0 mm	Heavy	1.62	FAIL
Minor fitting seep	25 m^3	15 Pa	2	1.0 mm	None	0.07	PASS

Example values are illustrative. Always apply the project’s governing specifications and inspection procedures.

Formula used

This tool combines simple screening equations with your observed intensity.

A = n · pi · (d/2)^2
Q = Cd · A · sqrt( 2·dP / rho )
Q(L/s) = Q · 1000
ACH = (Q · 3600) / V
FillTime = (V · FillFactor) / SmokeOutput

Where n is leak count, d is average leak diameter, dP is test pressure, rho is air density, and V is system volume.

Equivalent Leakage Area sums openings from your leak estimate.
Modeled leakage estimates flow for quick comparison between tests.
Decision uses your chosen preset or custom leakage limit.

How to use this calculator

Pick the test type and select the unit system you will enter.
Enter the system volume, test duration, pressure, and smoke output rate.
Record leak count, estimated average opening, and observed intensity.
Select an acceptance preset or set your own allowable leakage limit.
Click Calculate Results to see PASS/FAIL and KPIs.
Use Download CSV or Download PDF for reporting.

Tip: Use conservative estimates for leak diameters when uncertain, then verify with targeted repairs and retesting.

Smoke testing purpose in construction verification

Smoke testing is commonly used to reveal unintended pathways in plumbing vents, ductwork, shafts, and envelope penetrations. A visible plume indicates a pressure-driven connection between the test zone and a leak point. This calculator converts those field observations into screening metrics (modeled leakage, ACH, and a severity label) to support consistent documentation and retest planning.

Key inputs that drive meaningful comparisons

Results are most comparable when the applied pressure differential and test duration are stable. Leak count and average opening size define the Equivalent Leakage Area used in the flow estimate. The smoke output rate and fill factor estimate how quickly a zone can reach visible concentration. Criticality helps prioritize repairs in life safety or occupied areas where small leaks still matter.

Interpreting modeled leakage and air change rate

The modeled leakage uses an orifice approximation: a simplified relationship between area, pressure, and flow. Use it to rank scenarios and track improvement after sealing. ACH represents how quickly air would be exchanged at the modeled flow rate. Higher ACH often aligns with stronger visible streams, but wind and geometry can disperse smoke and lower apparent intensity.

Acceptance decisions and reporting discipline

Many projects define acceptance as “no visible smoke” at joints and penetrations. Others allow minor wisps if leakage is within a specified limit. This tool supports preset decisions and a custom leakage threshold. Exported CSV and PDF summaries are designed for closeout packages, daily reports, and communication between inspectors, subcontractors, and owners.

Example dataset for consistent field logs

Use a simple log format so crews can repeat tests under similar conditions. Example (metric):

System Volume: 55 m^3, Duration: 15 min, dP: 50 Pa, Output: 2.5 m^3/min, Fill Factor: 1.15
Leak Points: 3, Avg Diameter: 3.0 mm, Intensity: Steady, Criticality: High
Modeled Leakage: ~2.46 L/s, ACH: ~0.16, Decision (minor wisps preset): FAIL

FAQs

1) Does the modeled leakage replace project specifications?

No. It is a screening estimate to compare tests and track improvements. Always apply the governing specification, inspection procedure, and authority requirements for acceptance.

2) Why does pressure differential matter so much?

Leakage flow increases with the square root of pressure. If dP changes between tests, results are not comparable. Keep the same dP when verifying repairs.

3) What should I enter for average leak diameter?

Use a conservative estimate based on visible opening size. If uncertain, assume smaller diameters for pinholes and larger for gaps, then validate by sealing suspected points and retesting.

4) Why include smoke output rate and fill factor?

They estimate how quickly the test volume reaches visible concentration. Low output or high volume can delay visibility, which may be mistaken for a pass unless adequate time is allowed.

5) How should wind or ventilation be handled?

Air movement can disperse smoke and hide small leaks. Reduce ventilation where safe, note wind conditions, and repeat tests under calmer conditions for critical findings.

6) What does the risk index mean?

It combines modeled leakage, observed intensity, and criticality to help prioritize repairs. Use it to sort work orders, not as a code compliance metric.

7) What is a good workflow for retesting after repairs?

Document baseline inputs, seal identified paths, then retest with the same duration and dP. Compare leakage and severity trends, and export reports for closeout documentation.