Download WI 111-03

NDT & Corrosion Control Services
Work Instruction
Document # WI 111-3
Page 1 / 2
Approved By:
Issue: 1/1
Date: 20 / 4 / 2000
Title: Calibration of Densitometer
REFERENCE:
ASME Sec V- SE 1079
Densitometer Manual
OPERATION:
1.
2.
Connect the power source 9 V dry battery at the rear side of the instrument’s
battery chamber.
(OR)
DC 9V power source through adapter by inserting phone plug into jack in
densitometer.
Turn the power switch “ON” and allow a minimum of 30 minutes warm
- up time (OR manufacture’s recommendation) to stabilize circuitry before
starting the calibration.
3.
Place the densitometer on a light table.
4.
Adjust indication to 0.00 using “Zero” adjustment dial.
5.
Select and position for reading the neutral density closest to 0.30, 3.0 and
3.9 on the NBS (National Bureau of Standards.) calibrated step tablet or the step
wedge film.
6.
Place the neutral density step wedge film under the measuring spot of the
instrument with emulsion side up and measure the actual densitometer readings
of each neutral density 0.3, 3 and 3.9 of step wedge film or step tablet.
7.
Find the variation if any between the actual densitometer reading and
neutral density.
8.
This variation should not be more than  0.05 density units stated on the
step wedge film.
9.
If the variation is more than  0.05 density units the instrument should be
corrected prior to measuring the densities on production radiographers and
recalibration is required.
10.
Record the calibrated readings in the format qf-111-5.
NDT & Corrosion Control Services
Work Instruction
Document # WI 111-3
Page 2 / 2
Approved By:
Issue: 1/1
Date: 20 / 4 / 2000
Title: Calibration of Densitometer
11.
A pressure sensitive label (or) tag that indicates the calibration date,
calibration due date and the identification of the person performed the calibration
should be attached to the instrument.
12.
Periodic calibration should be performed at the beginning of each shift,
after 8 hours continuous operation or change of operator or change of apertures.
DOCUMENTATION:
The calibrated Densitometer shall have a tag depicting the Sr. No. and date
of calibration and due for calibration.
A Test certificate shall be made and it should posses the following
minimum details.
1)
2)
3)
4)
5)
Model & Sl. No.
Date of calibration
Details of calibration
Validity of calibration
Signature of the person performing the
calibration
6)
Signature of the person authorizing the
calibration.