What counts as cleanliness verification?

The checks that confirm the assembly is clean before release: particulate counts, wipe or swab results, visual inspection under the required lighting, and the records that capture them. Your cleanliness procedure defines the exact steps for the part.

Why does clean assembly need its own rate?

Because gowning, clean handling and verification make a controlled build slower than the same assembly on a standard bench. Using the standard rate hides that time until the schedule slips.

What does the window represent?

The assembly hours the schedule can give this batch, planned at the same crew size used for the completion rate. A shorter window does not change the work, only the time available to finish it.

Can the allowance cover rework?

Only rework tied to cleanliness control, such as a failed verification that needs a re-clean. Rework from assembly errors belongs in a separate estimate, not in this allowance.

Nuclear & Critical Infrastructure Manufacturing calculator

Clean Assembly Labor Calculator

Estimate clean assembly labor before the build starts. Base hours come from the assembly count and completion rate, then an allowance covers cleanliness control and verification.

What this calculator does

Hours for controlled clean assembly, including cleanliness control and verification, and whether the batch fits the available window.

Formula used

Base assembly hours = assemblies to build ÷ assemblies completed per hour
Cleanliness and verification hours = base assembly hours × cleanliness allowance ÷ 100
Required assembly hours = base assembly hours + cleanliness and verification hours
Hours over the window = required assembly hours − available assembly hours (signed)
Window use = required assembly hours ÷ available assembly hours × 100, blank at a zero window

Inputs explained

Assemblies to Build: Units in this clean build batch that need controlled assembly.
Assemblies Completed per Hour: Clean assembly rate from a recent controlled build time study.
Cleanliness Control and Verification Allowance: Extra time for gowning, contamination control and verification steps.
Available Assembly Hours: Staffing hours this batch can use on the controlled line.

How to use the result

Best suited to sizing a clean bay build batch, staffing a controlled assembly shift, comparing clean and standard assembly hours.
First-article cleanliness qualification and re-clean after a failed check sit outside the allowance. Cleaning room entry and exit time is blended into the completion rate.

Common questions

What counts as cleanliness verification? The checks that confirm the assembly is clean before release: particulate counts, wipe or swab results, visual inspection under the required lighting, and the records that capture them. Your cleanliness procedure defines the exact steps for the part.
Why does clean assembly need its own rate? Because gowning, clean handling and verification make a controlled build slower than the same assembly on a standard bench. Using the standard rate hides that time until the schedule slips.
What does the window represent? The assembly hours the schedule can give this batch, planned at the same crew size used for the completion rate. A shorter window does not change the work, only the time available to finish it.
Can the allowance cover rework? Only rework tied to cleanliness control, such as a failed verification that needs a re-clean. Rework from assembly errors belongs in a separate estimate, not in this allowance.

Last reviewed 2026-10-01.