Leak Rate

What this report does

Calculates the leak rate for the selected unit(s), broken down by unit and component type. For each combination of unit and component type, the report shows the number of components with leaks and the resulting leak rate as a ratio.

The report covers a single inspection type (M21 (EPA Method 21) or AVO (Audio, Visual, and Olfactory)) per run. It counts all inspections of that type performed within the date range, then determines what fraction of the inspected components had a leak. This report is in the Leak folder on the Reports tab.

When to use it

• Producing a leak rate summary for a monitoring period to compare against thresholds or track trends over time.
• Comparing leak rates across component types or across units in a single run.
• Tracking whether leak rates are trending up or down across periods.

⚠ Verify the formula before regulatory submission. This report uses a general formula: components with leaks ÷ components inspected. Many regulations define leak rate differently (e.g., based on total monitored components, not just those inspected in the period, or with specific exclusions). Confirm that this formula matches your regulation's requirements before submitting results to an agency. For HON compliance submissions, use the HON Leak Report.

Parameters

Columns

What's included and excluded

Included:

• All inspections of the selected inspection type (M21 or AVO) with a date performed within the date range.
• Only components assigned to the selected regulation(s).
• Only components in the selected unit(s) and of the selected type(s).

Excluded:

• Inspections of any type other than the selected inspection type.
• Components not assigned to the selected regulation(s).
• Components outside the selected unit(s) or type(s).
• The Inspection Type parameter in Chateau offers M21 and AVO only — OGI is not available as a selection. If you need a leak rate for an OGI-monitored population, refer to Simplified Leak History to count OGI leaks and inspected components manually.

Note on "components inspected": The denominator is the count of distinct components that had at least one qualifying inspection in the period — not the number of inspections. A component inspected multiple times counts once. The denominator is not shown as a column in the report. To back-calculate it, divide Number of Leaks by Leak Rate (where Leak Rate > 0). For rows with a 0.0000 rate, the denominator cannot be derived from the report output — check Chateau inspection records to confirm how many components were inspected.

How key values are calculated

Leak Rate formula

Leak Rate = Leaks Found ÷ Total Monitored Components

The result is expressed as a proportion (for example, 0.0200 = 2%). This is the number of components found leaking during the period divided by the total number of components monitored.

Denominator

The total number of monitored components (the denominator) is not displayed in the report output. To verify the Leak Rate calculation manually, cross-reference the monitored component count from the Periodic Inspection Summary or Component Count by Regulation for the same regulation and date range.

Number of Leaks

The count of distinct components that had at least one qualifying inspection linked to an open leak during the date range. A component that leaked and was inspected multiple times counts once.

Leak Rate

Number of Leaks divided by the total number of distinct components that had at least one qualifying inspection in the period. The result is expressed as a decimal (e.g., 0.0200 = 2%).

⚠ The Leak Rate is a proportion, not a percentage. A result of 0.0200 means 2%. Multiply by 100 when reporting to agencies or comparing to percentage-based thresholds.

If no inspections were found in the period, Leak Rate shows 0 rather than producing an error from dividing by zero.

Regulation filtering

Components are first scoped to the selected unit(s), then filtered to only those assigned to the selected regulation(s). This means a component must be both in a selected unit and assigned to a selected regulation to appear in results.

Tips and common questions

• "Leak Rate is shown as a decimal like 0.0200 — is that 2%?" Yes. The report expresses the rate as a proportion (0.02 = 2%). Multiply by 100 to get a percentage when reporting to a regulatory agency or comparing against a percentage-based threshold.
• "When should I use M21 vs. AVO as the Inspection Type?" Choose M21 when reporting a leak rate based on instrument monitoring (Method 21 or equivalent). Choose AVO when your regulation is based on audio, visual, and olfactory inspections. The two should not be mixed in a single run because they represent different monitoring programs with different regulatory definitions of a "leak."
• "My leak rate seems lower than expected — is there a data problem?" Check whether all inspections from the period have been entered in Chateau. The denominator counts only components that had at least one qualifying inspection recorded in the system. Uninspected components are excluded entirely — they do not lower the rate, but missing inspection records mean your denominator (and therefore your rate) is based on incomplete data. Regulatory leak rates calculated on incomplete inspection records may not be valid. Verify inspection entry completeness before using this report for compliance submissions.
• "A row shows a Leak Rate of 1.0000 — does that mean every component was leaking?" Yes. A rate of 1.0000 means every component of that type in that unit that was inspected during the period had a leak. This is a legitimate result for small populations — for example, if only 2 pumps were inspected and both had leaks, the rate is 1.0000 (100%). It does not indicate a reporting error.
• "A row shows 0 leaks and a rate of 0.0000 — does that mean no inspections were done?" Not necessarily. A 0.0000 rate means inspections were performed but none resulted in a leak. The row appears because at least one component of that type was inspected during the period. If you suspect no inspections occurred, verify against Chateau inspection records.
• "What's the difference between this and HON Leak Report?" HON Leak Report implements the specific HON formula with deactivation credits, excess DORs, and D90 subtractions, and is run separately by component type (Valves, Pumps, Connectors). Leak Rate uses a simpler formula (components with leaks ÷ components inspected), covers any regulation, and can include multiple component types in a single run.
• "The report comes back empty." Confirm that the selected unit has components mapped to the selected regulation, that the selected inspection type (M21 or AVO) was performed during the date range, and that those inspections are recorded in Chateau.

Related reports

• HON Leak Report — Valves / Pumps / Connectors — HON-specific leak rate reports (one per component type) with deactivation credits, excess DORs, and D90 exclusions; use when you need the HON compliance formula specifically.
• Simplified Leak History — shows individual leak records; use when you need to see which specific leaks are behind the rate.

Sample output

What the rows illustrate:

• ALKY Connector and PRV (0) — inspections were performed but no leaks were found; rate shows 0 rather than 0.0000 as displayed in the report.

• ALKY PUMP (0.3932) — 2 leaks found; back-calculated denominator = 2 ÷ 0.3932 ≈ 5 inspected pumps.

• ALKY VALVE (0.3742) — 1 leak found; back-calculated denominator = 1 ÷ 0.3742 ≈ 3 inspected valves.

• CRUDE PUMP (0.141) — same component type as ALKY PUMP with the same number of leaks (2), but a lower rate reflecting a larger inspected population; back-calculated denominator = 2 ÷ 0.141 ≈ 14 inspected pumps.

• CRUDE VALVE (0.002) — 1 leak found across a large inspected population; back-calculated denominator = 1 ÷ 0.002 = 500 inspected valves. The same number of leaks as ALKY VALVE (1) produces a dramatically lower rate due to the larger denominator.

• TANK FARM COMPRESSOR, Connector, and PRV (0) — zero leaks across all three types; inspections were recorded but none produced a leak.

• TANK FARM PUMP (0.1667) — 1 leak found; back-calculated denominator = 1 ÷ 0.1667 ≈ 6 inspected pumps.

• TANK FARM VALVE (0.0298) — the highest raw leak count in the report (13 leaks) but a moderate rate, reflecting a large inspected valve population; back-calculated denominator = 13 ÷ 0.0298 ≈ 436 inspected valves.

Output format

Compact tabular output. Suitable for on-screen review, PDF, and Excel export.