Standard Calibration Procedure
Doc. No. Call/SCP/012 Rev. 00 May 01, 2015
Dead Weight Tester
STANDARD CALIBRATION PROCEDURE
DEAD WEIGHT TESTER
Prepared by
Muhammad Ajlan Signature Date : 01.05.2015
Reviewed by
Muhammad Sarwar Signature Date : 01.05.2015
Approved by
Qaswar Mahmood Signature Date : 01.05.2015
Controlled Copy No. Uncontrolled Copy
Issued to :
Page 1 of 4
Standard Calibration Procedure
Doc. No. Call/SCP/012 Rev. 00 May 01, 2015
Dead Weight Tester
This document is the property of Qstar Engineering, and is issued only for persons or entity as
written on this document. It is not to be retransmitted, printed or copied without prior written
permission of company.
Table of Contents
Sr. No. Title Page No(s).
1.0 Scope 03
2.0 Standard Equipment 03
3.0 Preliminary Operations 03
4.0 Calibration Procedure 03~04
5.0 Related Documents 04
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Standard Calibration Procedure
Doc. No. Call/SCP/012 Rev. 00 May 01, 2015
Dead Weight Tester
1.0 Scope
This procedure provides guidelines for calibration of Dead Weight Tester.
2.0 Standard Equipment
2.1 Dead Weight Tester with a valid certificate of calibration traceable to international
standard in accordance with an industrial code or a regulation shall be used as a
standard for calibration.
2.2 The standard shall be kept under controlled environmental conditions e.g. dust free
environment and Lab temperature 22°C ± 3°C. Lab Humidity 60%RH ± 20%RH.
3.0 Preliminary Operations
3.1 The details of Dead Weight Tester received for calibration shall be entered in the
Calibration Job Form (Form: Call/001).
3.2 It shall be ensured that the Pressure Port of Dead Weight Tester is not blocked.
3.3 The Dead Weight Tester shall be inspected and marked () in relevant block of
equipment's primary inspection section of Calibration Data Sheet (Form: Call/013).
4.0 Calibration Procedure
4.1 The Dead Weight Tester to be calibrated shall be maintained at same place of standard
(Dead Weight Tester) for 06 hours minimum.
4.2 Ensure weight carrier is level. adjust four leveling screws if necessary.
4.3 Attach the instrument under test, using bonded seals on any connections A copper or
leather washer can be used for the bonded seal at the IUT. Dirty or contaminated
instruments under test shall be thoroughly cleaned before connection to the DWT.
Failure to observe this precaution could severely damage the piston assembly.
4.4 The reference level of the piston assembly must be level with the base of the (Instrument
under Test)
4.5 If necessary switch on the Instrument under Test.
4.6 Ensure Instrument indicates zero pressure, & adjust if necessary. Any adjustment at this
point must be carried out with reference to appropriate instrument manufacturer
instructions.
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Standard Calibration Procedure
Doc. No. Call/SCP/012 Rev. 00 May 01, 2015
Dead Weight Tester
4.7 Note the input pressure required on the blank calibration data sheet and selects the
appropriate weight for the lowest value of pressure. Remember to include the weight on
the weight carrier.
4.8 Carefully mount the weight on top of the piston assembly located on the left of the Dead
Weight Tester.
4.9 Load the weight carrier with the weight equivalent to the desired pressure taking into
account the weight of the carrier. Each weight is marked with two pressures; one for the
low-pressure range and one for the high pressure range.
4.10 Apply pressure by turning the capstan screw clockwise until the piston rises and the
piston skirt is floating within the indicated mark. Rotate the weights gently by hand. It is
essential that the weights be spinning freely whilst taking readings.
Note: The piston head should stay in this floating position for several minutes without it being
necessary to further adjust the screw press. On initial setting up however, there may
be some air trapped in the base of the piston / cylinder unit and as this air leaks out,
the piston will fail slightly for a few minutes until all the air has escaped. If the weights
continue to fall, check the system for leaks.
4.11 After the test, stop rotation and wind back the capstan screw as far as possible, open
reservoir valve.
4.12 The relevant section of Calibration Data Sheet (Form: Call/013) shall be marked.
4.13 The readings of Dead Weight Tester shall be recorded in observed value column against
the standard readings in set value column of Calibration Data Sheet (Form: Call/013).
4.14 Calibration Certificate (Form: Call/002) shall be issued for calibrated Dead Weight
Tester as per Calibration Data Sheet Record (Form: Call/013).
4.15 A Calibration Sticker (Form: Call/003) containing following information shall be affixed
on the calibrated Dead Weight Tester.
a) Item code
b) Calibrated on
c) Next calibration date
5.0 Related Documents
All the latest formats are documented in Master List of Document / Record and placed in CQF
file for reference.
All the latest Standard Calibration Procedures (SCP) are controlled and issued to concerned
Calibration Engineers.
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