How do you calculate a vacuum leak risk score?

Multiply the severity, occurrence, and detection difficulty ratings together. With severity 7, occurrence 5, and detection 4 the score is 140 on a raw scale (shown here as a scaled 5.55 score).

What is a good vacuum leak risk score?

Lower is better. There is no universal threshold, but teams usually set an action line — for example, anything in the top quartile of scored failure modes gets a corrective action regardless of absolute value.

What does a high detection score mean?

It means the leak is hard to catch before cure — for instance a slow seep at a complex bag pleat that a standard drop test misses. High detection difficulty inflates risk because the failure escapes to the autoclave undetected.

Why use severity times occurrence times detection?

Because risk is the product of how bad, how often, and how invisible a failure is. A high-severity leak that is rare and obvious may rank below a moderate leak that happens often and hides until cure.

How is this different from a simple leak-rate test?

A leak-rate test measures one bag's actual drop in inHg per minute. This score is a prioritization tool across failure modes and tools, telling you where to invest prevention before leaks ever occur.

How do I lower the score after scoring it?

Attack the largest driver. If detection difficulty is the worst factor, add leak-down tests or thermocouple-side vacuum monitoring; if occurrence dominates, redesign the bagging detail or train the sealant technique.

Composites, Fiberglass & Advanced Materials calculator

Vacuum Leak Risk Calculator

Vacuum Leak Risk applies the classic FMEA risk-priority-number logic to one of the most failure-prone steps in composites manufacturing: holding vacuum integrity in the bag through debulk and cure. Process engineers and quality teams score how bad a leak would be (severity), how often it tends to happen on a given tool (occurrence), and how hard it is to catch before cure (detection), then multiply them. The result ranks bagging failure modes so a quality team can attack the worst tools and details first. A dropped vacuum mid-cure can scrap a six-figure aerospace part, so prioritizing prevention pays for itself fast.

What this calculator does

Estimate vacuum leak risk for bagged composite layups, infusion tools, or cure bags.
prioritizing leak checks before infusion or cure
It multiplies severity, occurrence, and detection difficulty ratings into a single risk-priority score for a specific vacuum-bagging failure mode.

Formula used

Vacuum Leak Risk = vacuum leak severity score × vacuum leak occurrence score × vacuum leak detection difficulty score

Inputs explained

Leak severity rating:
Leak occurrence likelihood rating:
Leak detection difficulty rating:

How to use the result

Use it during process FMEA reviews, after a vacuum-related scrap event, or when prioritizing which tools and bagging details to re-engineer first.
The score is only as good as the ratings; multiplication makes it sensitive to scale calibration, and equal scores can mask very different real-world consequences, so treat it as a ranking aid rather than an absolute hazard measure.

Current U.S. benchmarks

The producer price index for plastic resins and materials stands at 319.371 (BLS, May 2026), up 19.5% from a year earlier. Quotes priced off last quarter's material cost miss this move.
Steel mill PPI stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. New factory orders are up 2.3% year over year (Census).

Common questions

How do you calculate a vacuum leak risk score? Multiply the severity, occurrence, and detection difficulty ratings together. With severity 7, occurrence 5, and detection 4 the score is 140 on a raw scale (shown here as a scaled 5.55 score).
What is a good vacuum leak risk score? Lower is better. There is no universal threshold, but teams usually set an action line — for example, anything in the top quartile of scored failure modes gets a corrective action regardless of absolute value.
What does a high detection score mean? It means the leak is hard to catch before cure — for instance a slow seep at a complex bag pleat that a standard drop test misses. High detection difficulty inflates risk because the failure escapes to the autoclave undetected.
Why use severity times occurrence times detection? Because risk is the product of how bad, how often, and how invisible a failure is. A high-severity leak that is rare and obvious may rank below a moderate leak that happens often and hides until cure.
How is this different from a simple leak-rate test? A leak-rate test measures one bag's actual drop in inHg per minute. This score is a prioritization tool across failure modes and tools, telling you where to invest prevention before leaks ever occur.

Last reviewed 2026-05-12.