Testing

Module from the Piping Engineering Curriculum curriculum.

Module 9 — Examination, NDE & Pressure Testing · Learning Objectives · 1. Apply B31.3 §341 examination requirements by fluid service · 2. Compute hydrostatic test pressure per B31.3 §345.4.2: P_T = 1.5 × P_D × (S_T/S_D) · 3. Identify when pneumatic testing is allowed (§345.5) and use caution · 4. Select NDE methods (VT, PT, MT, RT, UT, PAUT) for the service category · 5. Perform a sensitive leak test per §345.8 (pneumatic, bubble, halogen) · Examination Requirements by Service (B31.3 §341.4)

Service	VT	RT Weld %	PT / MT	Hardness	Notes
Category D	5% spot	0%	As specified	N/A	Least rigor
Normal	100% VT	5% random	Per WPS	Usually N/A	Default service
Severe cyclic	100% VT	100% RT	PT or MT 100%	As req	Fatigue critical
Category M	100% VT	100% RT	PT or MT all socket	If sour/hydrogen	Hazardous
High pressure (Ch. IX)	100% VT	100% RT	100% PT or MT	Always	Above Class 2500
Hydrogen > 600 °F	100% VT	Per spec	PT / MT	200 HB max	HTHA sensitive
Sour service (NACE)	100% VT	Per spec	PT or MT	22 HRC max	Prevent SSC
Hydrostatic Test Pressure Example (CS, Class 300, SDesign = 20 ksi, STest@70°F = 20 ksi)
P_T = 1.5 × P_D × (S_T/S_D) = 1.5 × 285 psig × (20/20) = 428 psig minimum. Hold for 10 minutes minimum. Increase to field full test if owner requires. Vent all high-point air. Provide safe venting. Drop pressure below yield if cold-flowed assembly.
NDE Method Applicability
Method	Detects	Surface / Volume	Typical Use	Limits	Standard
VT (Visual)	Surface flaws, workmanship	Surface	All welds	Surface only	ASME V Art. 9
PT (Dye penetrant)	Surface cracks	Surface	Non-ferromagnetic, finish machined	Surface only	ASME V Art. 6
MT (Magnetic particle)	Surface + slight subsurface	Surface	Ferromagnetic CS & CrMo	Can't use on SS	ASME V Art. 7
RT (Radiography)	Volumetric porosity, LOF	Volume	Butt welds	Density limits, crew safety	ASME V Art. 2
UT (Ultrasonic)	Volumetric defects	Volume	Thickness, fatigue cracks	Operator skill	ASME V Art. 5
PAUT	Improved UT coverage	Volume	Alternative to RT	Calibration block required	ASME V Art. 4
Hardness (Brinell/Rockwell)	Post-PWHT verify	Surface	Sour service, PWHT check	Avg 4 readings	ASTM E10/E18

Source: Piping_Engineering_Curriculum_v1.xlsx · Sheet: Testing

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