METHOD STATEMENT OF GATE Affective
Date
VALVES AUG 19, 2019
Project Title Document
Code
SHUQAIQ IWPP ARC-102-MS-002
METHOD STATEMENT OF GATE VALVES
Customer: Nomac
Project Name: Shuqaiq Independent Water & Power plant
Location: Abha, Kingdom of Saudi Arabia
Rev. No.
Project Engineer Project Manager Operations Manager
Name
Date
Sign
Page 1 of 8
METHOD STATEMENT OF GATE Affective
Date
VALVES AUG 19, 2019
Project Title Document
Code
SHUQAIQ IWPP ARC-102-MS-002
TABLE OF CONTENT
1. Scope of Work ................................................................... Error! Bookmark not defined.
2. Applicable Regulations and Standards ............................ Error! Bookmark not defined.
3. Responsibilities...................................................................................................................3
4. Equipment’s........................................................................................................................3
5. Consumables ..................................................................... Error! Bookmark not defined.
6. Type of Actuator ............................................................... Error! Bookmark not defined.
7. Precautions ....................................................................... Error! Bookmark not defined.
8. Inspection for the Gate Valves ......................................... Error! Bookmark not defined.
9. Checklist for Pneumatic Gate Valve of Steam-Water System ........................................8
Page 2 of 8
METHOD STATEMENT OF GATE Affective
Date
VALVES AUG 19, 2019
Project Title Document
Code
SHUQAIQ IWPP ARC-102-MS-002
1. Scope of Work
The purpose of this Method statement is to provide a controlled procedure for overhauling and
testing of gate valve in line with industry standards.
2. Applicable Regulations and Standards
API 6D - Design, Manufacturing, Testing of Valves
API 598 - Valve Inspection and Testing
ASME B16.5 - Pipe Flanges and Flanged Fittings
ASME VIII - Pressure Vessels & Inspection.
3. Responsibilities
A. Test Engineer
Coordinates with the client. Supervises the overall activities. Allocating time for each job and
maintaining the outage time
B. Supervisor
Identifying the nature of repair work to be carried out. Execution of job. Maintaining the right
methodology of work. Coordinating work, the technicians and the engineer. Recording all the
work carried out.
C. Technician
Performing the inspection, disassembling and assembling job with expertise
4. Equipment’s
Lapping machine
Multimeter
Hart Communicator.
General Spanners
Box spanner
Chain Block
Page 3 of 8
METHOD STATEMENT OF GATE Affective
Date
VALVES AUG 19, 2019
Project Title Document
Code
SHUQAIQ IWPP ARC-102-MS-002
Eye bolt
Torque wrench
Gland puller
Seat ring puller
V block
Magnetic stand
Dial gauge
5. Consumables
Cleaning Agent – WD 40, Diesel
High Temperature Grease – Molykote HSC
Emery Paper – 220 Grade
6. Type of Actuator
Single acting pneumatic actuator
Double acting pneumatic actuator
Motor Operated Actuator
7. Precautions
Before dis assembling the valve , make sure there is no pressure in the valve body.
Removing the packing without removing the actuator is difficult and is not recommended
Do not try to blow out the old packing rings by applying pressure to the lubricator hole in
the bonnet.
Careful that the stem threads do not damage the packing rings
Stem threads should not be damaged while working
While boxing up make sure the inside should be free of foreign particles which will
damage the seat
8. Inspection for the Gate Valves
The gate valves will undergo general visual inspection.
Valve accessories like positioners, relays, boosters, limit switches, will be inspected and
reported
Careful examination of the valve body, flange face will be carried out.
Page 4 of 8
METHOD STATEMENT OF GATE Affective
Date
VALVES AUG 19, 2019
Project Title Document
Code
SHUQAIQ IWPP ARC-102-MS-002
i. Initial Functional Test
Actuator functional test is carried out first. The actuator will be given min and max
operating pressure. The findings will be recorded
Stroke test is carried out for positioners and the travel of the valve stem is noted at open
and close by giving 4-20 mA signal through the feeder.
ii. Disassembling
Prior to dismantling the valve will be punched.
Remove the accessories & tubing’s from the actuator and positioner.
De couple the coupling and remove actuator from valve body
Remove compression on actuator spring by screwing spring adjuster until the actuator
tension is free.
Loose the bolts of the Actuator casing and remove the actuator.
Remove O-rings, seals and any soft parts
Remove the bonnet or side casing from the valve body.
Take out the complete stem set from the body along with the gate
Separate out gasket, packing, valve trim components and place them is separate trays for
inspection.
iii. Inspection Stage
All the parts will be carefully inspected and the inspection findings will be entered in the report.
Necessary repair work will be carried out.
a) Internal Inspection
Carefully examine contact area and seating area of the gate
Conduct Blue matching for the seating surface
Lapping will be carried out if required for the gate and seating faces
Examine stem gland area.
Examine stem thread area.
Examine gasket sealing surface.
Inspect for spindle bend by checking the runout and check the run out is with in the limits
Page 5 of 8
METHOD STATEMENT OF GATE Affective
Date
VALVES AUG 19, 2019
Project Title Document
Code
SHUQAIQ IWPP ARC-102-MS-002
b) Body inspection:
External and Internal body is carefully examined for cracks and cavitation.
Examine seat pocket area.
Examine gland area and gland packing. Replace gland packing if necessary.
Examine gland studs, gland follower, gland bush.
Examine all the greasing point and apply grease where ever necessary.
Examine body studs and nuts.
c) Actuator Inspection:
Check for bends and score marks.
Advice for painting if it’s in bad condition.
Check for corrosion
Check for cracks in casing.
Check for conditions of pressure and sealing soft goods.
Diaphragm condition
Spring tension for the single acting actuator
Loop checking for the actuator
d) Gear Box Inspection
Gear Drive Inspection
Hear the noise
Measure the clearance (backlash)
See the condition of tooth flank for surface damage
Surface damage could be in the form of pitting, spalling, scoring, ridging, rippling or other
visual sign of deterioration.
Check the gearbox oil level
Check the bearings
Check alignment of gears, lubrication with semi synthetic oil or grease
iv. Overhauling Stages
All parts will be placed in separate trays. Trays will be tagged by the valve tag No or serial number
for identification. Heavy valve body will be placed in separate stand in upright position.
Page 6 of 8
METHOD STATEMENT OF GATE Affective
Date
VALVES AUG 19, 2019
Project Title Document
Code
SHUQAIQ IWPP ARC-102-MS-002
a) Cleaning
All the parts will undergo cleaning by using appropriate cleaning agent.
b) Soft spares:
Bonnet Gasket
Packing
c) Assembly
Identifying the spares
Assemble the stem set, gate
Conduct the final blue matching for the seating surface
Place the gland packing and gland follower.
Close the bonnet of the valve with all the soft parts installed.
Apply Molykote HSC on all threaded parts
Assemble the actuator on the valve body.
Place the O ring on the actuator stem.
Place the diaphragm plate and the diaphragm.
Close the casing.
Adjust the spring tension screw.
Tighten the yoke lock nut screw.
Recalibrate the actuator.
d) Final Testing
Actuator functional test is carried out first. The actuator will be given min and max
operating pressure. The findings will be recorded
Record the readings for full open and full closing for the valve
The findings will be recorder in test report.
Page 7 of 8
METHOD STATEMENT OF GATE Affective
Date
VALVES AUG 19, 2019
Project Title Document
Code
SHUQAIQ IWPP ARC-102-MS-002
9. Checklist for Pneumatic Gate Valve of Steam-Water System
KKS NAME LOCAL REMOTE TIME REMOTE DATE SIGNATURE REMARKS
POSITION
Direction Feedback O C
Correct Correct
LAE13 DS/HTG
AA001 1 SPRAY
I-VALVE
LAE14 DS/HTG
AA001 1 SPRAY
S/OVAL
VE
LAE15 DS/HTG
AA001 2 SPRAY
S/OVAL
VE
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