Instructions for Ultrasonic Thickness Measurement

Before Beginning of Thickness Measurement

1. Check ambient temperature. Temperature shall be < 60 oC

2. Check job surface for cleanliness / preparation requirement.

3. Check if surface is curve or flat. Select probe accordingly.

4. Select two thickness(es), such that one thickness is less and the other thickness is more than the expected job thickness.

During Thickness Measurement

1. Calibrate thickness measurement instrument.

2. Apply couplant on job surface. Same couplant is to be used which was used for calibration of instrument.

3. Clean surface, if required.

4. Take thickness measurement readings at locations specified in drawing or follow below given check list

5. Record values in Thickness Measurement Report Format : UT/01 Rev. 0

6. If total time of thickness measurement is more than 2 hrs., after calibration of instrument, check instrument calibration and subsequently after every 2 hrs.

7. Report results to UT level II or UT level III/

After Thickness Measurement

1. Check calibration at end of thickness measurement.

2. In case oil or grease is used as coolant, remove the same by solvent used for Penetrant Testing.

Thickness Measurement Check List

Plate : At least at 3 locations along plate length and at longitudinal axis centre.

Pipe : Use curvature probe for small diameters. Take thickness measurement, depending upon diameter, at 120o apart at pipe ends and at mid-centre.

Elbows : At 120o apart at ends and at the centre of outside radius of elbow.

Dished Ends

: At 4 locations, 90o apart, on knuckle, crown and straight face.

Vessel : As specified in the drawing.

Issue by UT Level III

Exhibit No. : UT/Instructions/01, Rev 0