ASNT NDT III LT case studies
ASNT NDT III LT · Put your knowledge to work in context.
The ASNT NDT Level III (LT) designation is a professional credential in nondestructive testing offered within the certification programs administered by the American Society for Nondestructive Testing. Level III is the highest of the three NDT qualification levels, and it is aimed at experienced leak testing personnel who develop, qualify, and administer procedures, interpret codes and standards, and take responsibility for the technical adequacy of a leak testing program rather than performing routine inspections alone. The ASNT NDT III LT case studies are 5 cases and about 1,852 words.
1Detecting a Slow Leak in a Helium-Traced Vacuum Chamber
A vacuum chamber with a design leak-rate limit of 1×10⁻⁷ atm·cc/s is tested by the helium spray (hood) method against a mass spectrometer leak detector. The chamber is pumped to 5×10⁻⁶ torr and the detector is calibrated with a certified calibrated leak.
419 words, about 2 min2Qualifying a Pressure-Decay Test Procedure for a Small Vessel
A procedure for pressure-decay leak testing of a 2-liter aluminum vessel specifies pressurizing to 150 psig with dry nitrogen, stabilizing for 5 minutes, then measuring pressure drop over 10 minutes with a gauge having 0.1 psi resolution. The acceptance criterion is a pressure drop of no more than 0.5 psi.
403 words, about 2 min3When a Calibrated Leak's Certificate Expires Mid-Project
A leak-testing lab's helium leak detector is calibrated daily with a calibrated leak certified at 1×10⁻⁷ atm·cc/s. The certificate for the calibrated leak expires in three days.
336 words, about 2 min4Helium Versus Air for a Large, Rough-Surface Casting
A large cast aluminum housing (about 0.5 m³ internal volume) must be leak tested to a maximum allowable leak rate of 1×10⁻⁴ atm·cc/s of air. The casting has a rough, porous surface and several blind holes.
360 words, about 2 min5Level III Certification Records and a Recertification Dispute
An NDT Level III certified under a written practice based on SNT-TC-1A has been performing leak testing method duties for five years. The employer's written practice requires recertification every five years, consisting of a practical examination and a documented review of the Level III's continuing experience.
334 words, about 2 min