Enter measured values when possible. If you only have estimates, keep the ranges realistic and compare scenarios.
This calculator converts inspection and test data into a normalized integrity index from 0 to 100.
- V = L × W × H (room volume, m³)
- A = 2(LH + WH) + 2(LW) (envelope area, m²)
- ACH = Q / V where Q is leakage flow (m³/h)
- Measure the room dimensions and record wall material and thickness.
- Run a leakage or decay test and enter the leakage flow value.
- Enter design and measured differential pressure if your process requires it.
- Count openings and penetrations, then rate sealing quality from 1 to 5.
- Record cracks, surface condition, moisture ingress, and corrosion level.
- Fill in temperature, humidity, and vibration values from recent logs.
- Press Calculate Integrity to view the index and sub-scores.
- Use the recommendations to target the lowest component first.
- Download CSV/PDF to document audits and compare scenarios.
Example scenarios illustrate how changes in leakage and sealing can shift the integrity index.
| Scenario | L×W×H (m) | Class | Leakage (m³/h) | Design/Measured ΔP (Pa) | Doors/Windows/Penetrations | Cracks (m) | Seal Avg (1–5) | Typical Index |
|---|---|---|---|---|---|---|---|---|
| Baseline audit | 6×4×3 | High | 18 | 15 / 14 | 1 / 0 / 6 | 0.8 | 4.0 | ~80 (Good) |
| Improved sealing | 6×4×3 | High | 10 | 15 / 15 | 1 / 0 / 6 | 0.4 | 4.7 | ~90 (Excellent) |
| Degraded envelope | 6×4×3 | High | 35 | 15 / 11 | 2 / 1 / 12 | 2.5 | 2.7 | ~55 (Poor) |
Integrity Index Meaning
The integrity index summarizes how well a room maintains its intended boundary under normal operation. It combines leakage, pressure, structure, sealing, defects, environmental stability, and maintenance into a 0–100 score. Higher values suggest a tighter, more reliable envelope with fewer failure paths. Treat the index as a screening KPI for audits, not a regulatory certificate, and confirm critical spaces using your validated test procedures. In commissioning, pair the index with smoke visualization and tracer gas checks to validate boundary behavior reliably onsite.
Leakage and Air Changes
Leakage flow is normalized by volume to estimate air changes per hour (ACH). ACH indicates how quickly the room air can be replaced through uncontrolled paths when pressure is applied. The calculator compares measured ACH to a class target and maps the ratio to a sub‑score. Reducing ACH usually requires sealing joints, tuning doors, and controlling service penetrations, then repeating the same test method to verify improvement.
Pressure and Containment
Differential pressure supports containment by driving flow in the intended direction. The pressure compliance score compares measured ΔP to the design requirement, helping identify underperforming fans, blocked filters, or unbalanced dampers. If door cycles cause large swings, investigate control stability and door hardware. For rooms with no defined ΔP target, you can still use ΔP as a trend metric to detect drift over time.
Defects, Seals, Openings
Crack length is converted to a density using the envelope area, providing a consistent defect indicator across room sizes. Counts of doors, windows, and penetrations add an opening penalty because every interface introduces leakage risk. Seal ratings capture workmanship and gasket condition at typical leak paths. Use these sub‑scores to prioritize fixes: repair cracks, standardize sleeves, and upgrade gaskets before chasing minor control tweaks.
Using Results for Planning
Start with the lowest sub‑score because it usually yields the fastest index gain per hour of work. Export CSV or PDF to compare scenarios, document remedial actions, and build a maintenance history. Recalculate after each change set so your team sees measurable progress. Over time, use the trend to plan refurbishments, budget seal replacements, and justify preventive inspections for high‑criticality rooms.
1) What does the Integrity Index represent?
The index is a weighted 0–100 score combining leakage, pressure, structure, sealing, defects, environment, and maintenance. Use it for screening and trending. For critical acceptance decisions, confirm with your formal test method and criteria.
2) Which leakage value should I enter?
Enter the leakage flow from your leakage or decay test at the procedure pressure. Use m³/h. If you have multiple runs, use the stabilized average from the same setup and instrumentation.
3) How do I choose the integrity class?
Select Standard for general spaces, High for controlled environments, and Critical for high‑risk containment. The class mainly sets the ACH target heuristic. Match the choice to your internal specification and risk assessment.
4) Why is pressure compliance low?
Low compliance usually means measured ΔP is below the design value. Common causes include clogged filters, insufficient fan capacity, unbalanced dampers, door leakage, or unstable controls. Correct the cause, then log ΔP again.
5) Can I use this for cleanrooms or isolation rooms?
Yes, as a preliminary integrity and improvement tool. It does not replace cleanroom classification, HVAC commissioning, or clinical isolation requirements. Always follow your governing standard, documentation needs, and acceptance limits.
6) How often should I recalculate?
Recalculate after sealing work, HVAC adjustments, or preventive maintenance, and during periodic audits such as monthly or quarterly. Tracking the index over time reveals drift and supports budgeting for refurbishments.