Flushing Procedure

1. SYSTEM / PACKAGE: Rev.
1. GENERAL
The purpose this procedure shall be applied to general or service flushing and cleaning of piping work
and process units in Water or Wastewater treatment system during pre-commissioning stage before
start up equipment and process units of commissioning.
2. SCOPE
This procedure covers the guideline for cleaning and flushing of piping work and process unit.
This procedure shall not be applied if the following cases are mentioned.
a) Where customer's instructions are existing, flushing work shall be performed by following
such procedure
b) When supplier's instructions / manuals are available, flushing work shall be performed
following such procedure.
3. RESPONSIBILITY
Site manager or site engineer/supervisor is responsible for controlling and checking the flushing
WATER and WASTEWATER TREATMENT SYSTEM PAGE:
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WATER TREATMENT SYSTEM
GOSHU KOHSAN
PROJECT DIVISION PIPE-LINE and UNITS
FLUSHING and CLEANING PROCEDURE DATE: 29-Jun-20
work done by installation or pre-commissioning teams.
4. DEFINITION
None
5. DETAILED PROCEDURE
Selection of Flushing Method
5.1.1 Flushing method shall be selected in following method, considering the kind of service
fluid, pipe material and conditon on internal surface of piping to be cleaned.
Flushing method and extend of flushing to be applied will be instructed in the flushing
plan* (or Flushing Diagram).
*Flushing Plan shall include the following documents:
- Flushing/cleaning test package (Package No., Pipeline/ or equipment list)
- Diagram or Piping and Instrument Diagram (P&ID) marked-up
Note: (1) Including instrument air and utility air service
(3) For H2SO4 only, the First step shall be cleaning used by the humane and second step
shall be used for air flushing or air blow.
5.1
Service
Air flushing
Water flushing or Cleaning surface -
-
Flushing Method Note
(1)
(3)
Chemical (3) (Fume)
Water
Air (1)
Chemical (2) (not Fume)
Cleaning surface only. not wet condition
Water flushing or Air flushing
PJMD-P-FCOM-001

2. SYSTEM / PACKAGE: Rev.
5.1.2 Any pping that requires special cleaning and flushing, such as chemical (acid or alkalin)
cleaning, oil flushing, pig flushing, etc.shall be instructed definitely in the flushing plan.
General requirements for Cleaning and Flushing
5.2.1 Cleaning at fabrication work
(a) Vinyl caps or other end protection which cover the ends of piping components
shall not be removed until fabrication work is started
(b) For valves, fittings and other components, the same as above item (a) shall be
observed.
(c) Inside surface of fabricated pipings shall be made free from slag, scale and
other foreign materials by using grinder, chisel, wire brush, etc. and shall be air-blown
after completion of the cleaning, then ends of the piping shall be covered with caps until
the installation in the fields.
(d) When installing pipings in place, the cleanness of piping shall be examined.
Re-cleaning with power tool or air blowing shall be done as necessary
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5.2
GOSHU KOHSAN FLUSHING and CLEANING PROCEDURE
PROJECT DIVISION PIPE-LINE and UNITS
WATER and WASTEWATER TREATMENT SYSTEM PAGE:
29-Jun-20
DATE:
Re-cleaning with power tool or air blowing shall be done as necessary
prior to the piping installation. Proper care shall be taken so as not to allow
any foreign materials into the piping and equipment during installation and
assembling.
5.2.2 Preparation for Flushing
(a) The following preparation work shall be carried out in accordance with the flushing
plan.
(1) Temporary piping work
(2) Countermeasure for safety
(3) Coordination procedure and assignment of man concerned
(4) Prevention of public nuisance
(5) Cooperation with operator
(6) Judgement criteria of flushing
(7) Treatment of piping accessories
(8) Setting of spring hanger, etc.
(9) Confirmation of support (slide or fix)
(b) Support shall be attached to existing piping to prevent accident caused by the
reaction force during flushing
Water Flushing
5.3.1 Water for flushing
(a) Pure water, service water, steam condensate, industrial water, etc. will be used.
5.3
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3. SYSTEM / PACKAGE: Rev.:
5.3.2 Degree of Water Flushing
(a) Flushing shall be performed until the water become free from foreign materials,
scale, etc. This shall be decided by Cutomer and/or Owner upon visually observing the
turbiddity of water taken out into beaker or cup.
5.3.3 Procedure for Water Flushing
(a) Water flushing shall be performed in the method of running pressurized water, or
rapid draining of water.
(b) When instrument are included in the piping system to be flushed, the instruments shall,
as a rule, be removed and spool pipe (distance piece) shall be inserted instead of the
instruments. When flushing is carried out in the condition with control valve connected,
the procedure shall be as follows.
(1) Disconnect the companion flange at upsteam side of control valve and cover
opening of the control valve.
(2) Flush the piping of upstream side.
(3) Connect the control valve with piping of upstream side after completetion of
DATE: 29-Jun-20
PROJECT DIVISION PIPE-LINE and UNITS
PAGE: 3
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GOSHU KOHSAN FLUSHING and CLEANING PROCEDURE
WATER TREATMENT SYSTEM
WATER and WASTEWATER TREATMENT SYSTEM
(3) Connect the control valve with piping of upstream side after completetion of
the flushing.
(c) Criteria acceptable for flushing
- Velocity: More than (>) 0.75 m/s
- Volume: More than (>) 2 time of pipe flushed volume
- Quality : Turbidity at outlet point shall be close to that of inlet point
Air Flushing
(a) Degree of Flushing
Air flushing shall be performed until the there remain no scale in the piping, Customer
and/ or Owner shall judge whether the result of the flushing is satisfactory or not.
(b) Procedure for Air Flushing
(1) Air flushing shall be performed in the method of blowing pressurized air.
(2) Line air flushing shall, as a rule, be performed for each piping from equipment to
adjacent equipment whether the equipment is to be included in the piping or not
considering the shape, internal construction and packing of the equipment
and also according to Flushing Plan .
(3) Treatment of instruments shall conform to the conditions specified in Par. 5.3.3(b).
Special Cleaning and Flushing
Detailed procedure of special cleaning and flushing, such as chemical (acid or alkali) cleaning,
oil flushing, pig flushing, etc. shall be described in a separate Manual/Inspection.
5.4
5.4
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4. SYSTEM / PACKAGE: Rev.:
6. RE-INSTALLATION (RE-INSTATEMENT)
Upon completion of cleaning/flushing, the valve, control valve, blind flange, etc, shall be reinstalled as
previously disconnected lines are re-connected.
After flushing out has been completed, the water shall be thoroughly drained.
7. TEMPORARY UNIT AND UTILITY (If required)
- Temporary air compressor (or service air supply from plant air if available)
- Temporary short piece of pipe spool
- Temporary pipe or hose connection
- Service water (or original service water supply if available)
- Equipment & tools and material, etc,…
8. SERVICE FLUSHING ***
The service flushing is generally similar to flushing activity of piping system, except that the service
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WATER TREATMENT SYSTEM
GOSHU KOHSAN FLUSHING and CLEANING PROCEDURE
DATE: 29-Jun-20
PROJECT DIVISION PIPE-LINE and UNITS
flushing shall be firstly performed at up-stream piping system of equipment before the start-up and
operation of equipment so that it starts with a low water quality feed into the equipment (e.g. Clarifier, Micro-Filter)
Then, the equipment (e.g. MF: Micro-Filter) can start-up to treat the water until the required water quality is met.
The flushing of succeeding down-stream piping system up to the equipment or through the equipment
shall follow using the treated water from up-stream until the effluent is clear, then the equipment can
start-up to prepare the system until ready for service and supply.
The piping system and equipment unit to be applied for sevice flushing/start-up shall be marked-up or
highlight in P&ID and shall be submitted to Customer or Owner for information/acceptance.
The media, chemical loading, and equipment unit start-up function shall be referred to the
pre-commissioning and commissioning procedure
Remark: *** if necessary and accepted by Customer or Owner
The media, chemical loading, and equipment unit start-up function shall be referred to the
pre-commissioning and commissioning procedure
Remark: *** if necessary and accepted by Customer or Owner
PJMD-P-FCOM-001

5. SYSTEM / PACKAGE: Rev.:
9. DETAILED METHOD FLUSHING, CLEANING, LEAK TEST and POINT INSPECTION
Type and Selection of Method
9.1.1 Tank (Water, Chemical (Fume and not Fume), Precess Tank)
Clrifier body, Sludge Thickener body, Filtrated Water Sump, Screw Press
Water Tank
Full capacity tank and drain
Detail of Cleaning
1 The instruments are installation included in the tank will be closed first such as a level transmitter, level gauge,
analyzer, etc.
2 Closed valve : suction line, bottom drain or valve affects water loss when water fills to the tank.
* in case the tank have manhole can consider open for cleaning inside the tank before water fill up step
3 Fill up water by service water or more than quality until full capacity tank or can recheck water at overflow line
4 Make sure water level high capacity and open bottom drain for remove water with particles inside the tank
until water level low
Remark : The tank can repeat step more than 1 time for cleaning by the full water capacity method
Detail of Recheck Condition During Cleaning
PAGE:
GOSHU KOHSAN FLUSHING and CLEANING PROCEDURE DATE: 3-Apr-20
PROJECT DIVISION PIPE-LINE and UNITS
9.1
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Equipment
Type
Method
WATER TREATMENT SYSTEM
WATER and WASTEWATER TREATMENT SYSTEM
1 Between drain out from high level and low lovel. Inspection by white cotton or filter bag at drain out point.
recheck white cotton or filter bag, not big particle size.
Detail of Leak Test
1 After cleaning by the full water capacity method and rechek white cotton or filter bag, not big particle size.
2 Fill up water by service water or more than quality until full capacity tank
3 Open valve a level gauge or level transmitter for making sure
4 Hold step not activity around 12 - 24 hr. after that visual check for connect point (flange, man hole) and
connecting point (flange, manhole) and recheck the water level.
- water level not reduce assume the tank not have point leak
9.1.2 Tank (Chemical - not Fume),
Aluminum chlorohydrate storage tank, Polymer peparering tank
Chemical Tank
Full capacity tank and drain
Detail of Cleaning
1 The instruments are installation included in the tank will be closed first such as a level transmitter, level gauge,
analyzer, etc.
2 Closed valve : suction line, bottom drain or valve affects water loss when water fills to the tank.
* in case the tank have manhole can consider open for cleaning inside the tank before water fill up step
3 Fill up water by service water or more than quality until full capacity tank or can recheck water at overflow line
4 Make sure water level high capacity and open bottom drain for remove water with particles inside the tank
until water level low
Remark : The tank can repeat step more than 1 time for cleaning by the full water capacity method
Equipment
Type
Method
PJMD-P-FCOM-001

6. SYSTEM / PACKAGE: Rev.:
Detail of Recheck Condition During Cleaning
1 Between drain out from high level and low lovel. Inspection by white cotton or filter bag at drain out point.
recheck white cotton or filter bag, not big particle size.
Detail of Leak Test
1 After cleaning by the full water capacity method and rechek white cotton or filter bag, not big particle size.
2 Fill up water by service water or more than quality until full capacity tank
3 Open valve a level gauge or level transmitter for making sure
4 Hold step not activity around 12 - 24 hr. after that visual check for connect point (flange, man hole) and
connecting point (flange, manhole) and recheck the water level.
- water level not reduce assume the tank not have point leak
9.1.3 Tank (Chemical - Fume (H2SO4)),
Sulfuric acid storage tank
Water Tank
Dry cleaning
Detail of Cleaning
1 The instruments are installation included in the tank will be closed first such as a level transmitter, level gauge,
analyzer, etc.
GOSHU KOHSAN FLUSHING and CLEANING PROCEDURE DATE: 3-Apr-20
PROJECT DIVISION PIPE-LINE and UNITS
Equipment
Type
Method
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WATER TREATMENT SYSTEM
WATER and WASTEWATER TREATMENT SYSTEM PAGE:
analyzer, etc.
2 Open manhole for man power cleaning inside tank
3 Use cloth for cleaning surface for dirty or particle after cleaning will have to take out and keep dry condition only
or when using a wet cloth or use water cleaning inside the tank after that have to make sure the condition inside
the tank must dry before close manhole
3 Recheck for the manhole has not a big particle between the connecting point.
Detail of Recheck Condition During Cleaning
1 Visual check inside tank
Detail of Leak Test
1 Deu to H2SO4 is an iron tank and it is tested by hydro test already. So, This tank will not be considered
to leak test
PJMD-P-FCOM-001