Coating Failure Analysis Calculator

Evaluate coating system integrity from adhesion tests, thickness measurements, and service conditions to predict failure risk and identify failure modes.

Inputs

Pull-off adhesion (PSI)

Cross-cut rating (0-5)

Specified DFT (mils)

Measured DFT max (mils)

Measured DFT min (mils)

Years in service

Environment (1-5)

Tab to move between fields

Results

Failure risk score (0-100)

Remaining life (years)

Adhesion margin (%)25

DFT ratio (%)117

Thickness variation (%)42.9

Service life used (%)30

Cross Cut Name4B (Good)

Cross Cut PassYes

Risk LabelMODERATE

How to Use This Calculator

Enter Pull-off adhesion (PSI), Cross-cut rating (0-5), and Specified DFT (mils).
Set Measured DFT max (mils), Measured DFT min (mils), and Years in service.
Adjust Environment (1-5) as needed.
Review Failure risk score (0-100) and Remaining life (years).
Use Adhesion margin (%) and DFT ratio (%) to inform your decision.

How the result changes with Pull-off adhesion (PSI)

Pull-off adhesion (PSI)	Failure risk score (0-100)	Remaining life (years)
300	80	7
1,050	45	7
1,950	45	7
2,700	45	7

What each input means

Pull-off adhesion (PSI): ASTM D4541 pull-off adhesion test result in PSI.
Cross-cut rating (0-5): ASTM D3359 rating: 0=5B perfect, 5=0B failed.
Specified DFT (mils): Coating system specified dry film thickness.
Measured DFT max (mils): Maximum measured dry film thickness.
Measured DFT min (mils): Minimum measured dry film thickness.
Years in service: How long the coating has been in service.
Environment (1-5): 1=Indoor, 2=Outdoor mild, 3=Industrial, 4=Marine, 5=Immersion/Chemical.

What each result means

Failure risk score (0-100): Overall coating failure risk. Higher = more risk.
Adhesion margin (%): How far above/below minimum adhesion requirement.
DFT ratio (%): Measured vs specified DFT as percentage.
Thickness variation (%): Spread between min and max measured DFT.
Remaining life (years): Estimated remaining service life.
Service life used (%): Percentage of expected coating life consumed.

How this is calculated

Worked example, using the default values

Identify Input Parameters
4 parameters
Pull-off adhesion (PSI) = 500, Cross-cut rating (0-5) = 1, Specified DFT (mils) = 6, Measured DFT max (mils) = 7 = 7 input(s) provided
Calculate Failure risk score
50 = 50
Calculate Remaining life
Remaining life = max(0
7 = 7
Calculate Adhesion margin
Adhesion margin = ((adhesionPsi - requiredAdhesion) / requiredAdhesion) * 100
25 = 25
Calculate DFT ratio
DFT ratio = measuredDftMils / max(0.1, specifiedDftMils)
117 = 117