Calibration of used Penetrameters

[BPVN]

Hi All,
Could any body guide me that, how to calibrate Penetrameter after using more than a year?
Only Visual Inspection for damage is acceptable or require to check/measure hole sizes too?
If yes How to measure/calibrate used penetrameters?
Any code reference states that, calibration of penetrameter must require?
Pls. guide me.
Thanks in advance.
BPVN

 

[apiguy]

Why do you have to calibrate it? I wonder if someone meant to say certify it.

The APIGUY....