How is warranty exposure scored?

Each input is rated 1-10, then weighted: severity at 0.40, occurrence at 0.35 and detection at 0.25. For severity 6, occurrence 4 and detection 3 the score is 4.55 on a 10-point scale.

Why is field failure severity weighted highest?

A fielded heat exchanger failure usually triggers a service call, refrigerant or coolant loss and possible secondary damage, so its cost dwarfs a caught-in-house defect. The 0.40 weight reflects that asymmetry versus occurrence and detection.

What is a good warranty exposure score?

On this scale, under 3 is low exposure, 3-5 is moderate and worth monitoring, and above 6 demands action like added leak testing or a design change. The example score of 4.55 sits in the moderate band.

How is this different from a standard FMEA RPN?

A classic RPN multiplies severity, occurrence and detection into a 1-1000 number that overweights small changes. This uses a weighted average on a 0-10 scale, which is more stable and easier to compare across programs.

How do I lower pre-shipment detection risk?

Add or tighten end-of-line controls: helium mass-spectrometer leak testing, 100% pressure decay testing, or vision inspection of braze joints. Cutting detection from 3 to 1 in the example would pull the score from 4.55 down to 4.05.

What counts as expected warranty occurrence?

It is a rated likelihood that units in the field generate a warranty claim, informed by historical claim rates, process capability on critical joints, and the duty cycle the exchanger sees in service.

Heat Exchanger, Coil & Radiator Manufacturing calculator

Warranty Exposure Calculator

Warranty exposure is the quiet killer on coil and radiator programs: a leaking braze joint or a corroded tube in the field can mean a unit pull, refrigerant recovery and a customer who never reorders. This calculator turns three FMEA-style judgments — how bad a field failure is, how often warranty claims are expected, and how likely a defect slips past final pressure and leak testing — into one weighted exposure score. Reliability engineers and quality managers use it to rank programs and decide where to add helium leak detection or burst testing. Unlike a flat RPN multiply, this weights severity highest because a fielded heat exchanger failure carries outsized cost and reputational damage.

What this calculator does

Score warranty exposure for heat exchangers, coils, radiators, condensers, evaporators, and oil coolers using severity, occurrence, and detection ratings.
Use it when leak risk, corrosion, vibration fatigue, fin damage, pressure failures, gasket issues, or field returns need to be ranked before corrective action.
It blends field failure severity, expected warranty occurrence and pre-shipment detection risk into a single 0-10 weighted warranty exposure score.

Formula used

Warranty exposure score = field failure severity × 0.40 + expected warranty occurrence × 0.35 + pre-shipment detection risk × 0.25

Inputs explained

Field failure severity:
Expected warranty occurrence:
Pre-shipment detection risk:

How to use the result

Use it during design review, PPAP, or program ranking to flag which heat exchanger lines warrant tighter end-of-line leak and pressure testing.
Scores are subjective judgments; two engineers can rate the same braze process differently, so calibrate against historical claim data where you have it.

Current U.S. benchmarks

The producer price index for copper and brass mill shapes stands at 559.593 (BLS, May 2026), up 76.8% from a year earlier. Quotes priced off last quarter's material cost miss this move. Global copper trades at $13,484 per tonne (IMF via FRED, May 2026).

Common questions

How is warranty exposure scored? Each input is rated 1-10, then weighted: severity at 0.40, occurrence at 0.35 and detection at 0.25. For severity 6, occurrence 4 and detection 3 the score is 4.55 on a 10-point scale.
Why is field failure severity weighted highest? A fielded heat exchanger failure usually triggers a service call, refrigerant or coolant loss and possible secondary damage, so its cost dwarfs a caught-in-house defect. The 0.40 weight reflects that asymmetry versus occurrence and detection.
What is a good warranty exposure score? On this scale, under 3 is low exposure, 3-5 is moderate and worth monitoring, and above 6 demands action like added leak testing or a design change. The example score of 4.55 sits in the moderate band.
How is this different from a standard FMEA RPN? A classic RPN multiplies severity, occurrence and detection into a 1-1000 number that overweights small changes. This uses a weighted average on a 0-10 scale, which is more stable and easier to compare across programs.
How do I lower pre-shipment detection risk? Add or tighten end-of-line controls: helium mass-spectrometer leak testing, 100% pressure decay testing, or vision inspection of braze joints. Cutting detection from 3 to 1 in the example would pull the score from 4.55 down to 4.05.

Last reviewed 2026-05-12.