API RP 581 - 3rd Ed.2016 - Add.2-2020 - Risk-Based Inspection Methodology

RISK-BASED INSPECTION METHODOLOGY, PART 2—PROBABILITY OF FAILURE METHODOLOGY 2-143
20.9 Figures
STEP 1: Do administrative
controls prevent pressurizing below
some temperature CET?
No
STEP 2: Determine CET, the Part 3, API
579-1/ASME FFS-1
Yes
Use this CET
Material Type
(Carbon Steel or
Low Alloy Steel)
STEP 3: Determine T ref from Table 20.3 and
Exemption Curve in Table 20.1
Exemption Curve
A, B, C, D
Material Minimum
Yield Strength, YS
STEP 4: Calculate CET - T ref
STEP 5:
Determine base
Damage Factor
Using Table 20.4
No
Post-weld
heat treated?
Yes
Determine base
Damage Factor
Using Table 20.5
STEP 6:
Determine adjustment factors:
• Service Experience
Determine Damage Factor
Using Equation (2.86).
Figure 20.1—Determination of the Brittle Fracture DF