NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

Contractor Doc. No.
VV3120-008-A-137

Rev.1

METHOD STATEMENT OF LEAK TEST FOR MANHOLE
(DOCUMENT CLASS: X)

Issue Purpose

For Construction

Rev

Date

Page

Description

Prep'd

Chk'd

App'd

1

March/3/2015

All

For Construction

L.V.S

C.N.T

D.M.C

0

Feb/24/2015

All

For Approval

L.V.S

C.N.T

D.M.C

Operation Centre JOB Code:
Responsible Company:

Vinaconex E&C

Operation Centre Doc. No.:
Prepared by:

Checked by:

Approved by:

Le Van Son

Cao Nguyen Thang

Do Minh Chau

Page 1 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

Contractor Doc. No.
VV3120-008-A-137

Rev.1

CONTENTS


1

PURPOSE............................................................................................................................................. 3

2

SCOPE OF WORK......................................................................................................................... 3

3

REFERENCES DOCUMENTS........................................................................................................ 3

4

ORGANIZATION CHART............................................................................................................... 5

5

MACHINERY AND EQUIPMENT.................................................................................................... 5

6

MATERIALS..................................................................................................................................

6

7

MANPOWER.................................................................................................................................


7

8

RESPONSIBILITIES......................................................................................................................

8

9

PROCEDURE AND SEQUENCE.................................................................................................... 9

10

INSPECTION AND TESTING....................................................................................................

18

11

HEALTHY, SAFETY AND ENVIRONMENT (HSE)....................................................................

18

12

WORKING IN CONFINED SPACE.............................................................................................

19


13

APPENDIX.....................................................................................................................................

24

Page 2 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

1

Contractor Doc. No.
VV3120-008-A-137

Rev.1

PURPOSE
The purpose of this Method Statement is to describe the methodology involved in the works of
Leak Test for Manholes and Pipe and detail the steps to be taken in meeting the technical
standards and HSSE requirements of NSRP Complex Project.

2

SCOPE OF WORK
This Method Statement covers the works related to inspection and leak detection (if any) for all the

manholes which are located at the areas of C200 and C300 to ensure that the entire execution
stages of work is done in line with good JGCS’s Engineering practices and compliance with JGCS’s
Engineering standard practices, national and local codes.

Page 3 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

3

Contractor Doc. No.
VV3120-008-A-137

Rev.1

REFERENCES DOCUMENTS
3.1

Project specifications
S-000-1312-1001V

3.2

Construction Specification for Site Preparation and Earth Work

S-000-1310-0001V


Detailed Engineering Design Data for Civil and Structure

S-000-1320-1001V

Construction Specification for Concrete Works

S-000-1671-0916V

Inspection and Test plan for Site Concrete Work

Drawings for construction
D-000-1320-1001V

Concrete Works General Notes

D-000-1320-1002V to 1004V
D-000-1320-1005V

Standard Details for Rebar Arrangement
Standard Details for Concrete Structures General
Arrangement

Construction Drawings for Manholes.
Construction drawing for Pipes.
3.3

Standards and Codes

TCVN 4453


Concrete structure and Reinforced Concrete Technical
Requirements

BS 8110

Structural Use of Concrete

BS EN 12390

Testing Hardened Concrete

BS EN 12350

Testing Fresh Concrete

Page 4 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

BS EN 13263-1

Contractor Doc. No.
VV3120-008-A-137

Rev.1


Testing Concrete in Structures - Part 1: Cored Specimens.
Taking, Examining and Testing in Compression

BS 1881

Testing concrete

Page 5 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

4

Contractor Doc. No.
VV3120-008-A-137

Rev.1

ORGANIZATION CHART

Project Manager: Vu Ba Dat
Milestone schedule
QS section for contract, quantity, payment

Site Manager: Do Minh Chau

Directly in charge for daily schedule,
mobilization of equipment, materials supply
capacity.

QC Section
QC Manager: CN Thang
QC field Eng.: NV Thu,
PH Tien
ITP, Laboratory, Inspection,
Records

Batching plant,
material supply
- Batching plan
- Capacity of supply,
access in and out,
record, quantity
control, store

Site Engineer
LN Hoan, VD Sang, TN
Thach, NQ Hieu
Survey, daily schedule,
location of work, equipment
control, labor for each kind of
works

Construction Team
- Foremans
- Labors for works

- Minor tool and
equipment, submaterials, form and
scaffolds.

HSSE
HSSE Manager: PN Giang
HSSE Supervisor: LH Trung,
VN Hai,HD Bach, DT Ninh
Equipment HSSE control,
Permit, access way, Traffic,
Labor entry, HSSE training,
HSSE at work place

Const. Equipment
Condition and number
of Equipment, fuels,
drivers, transportation,
traffic control, signal,
service.

Page 6 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

5


Contractor Doc. No.
VV3120-008-A-137

Rev.1

MACHINERY AND EQUIPMENT
•

Prior to using any machineries/equipment at site, it will be inspected and certified by
qualified person.
•

Periodic Preventive Maintenance will be made by all equipment and machineries.
0

All operators and drivers are to be educated with valid driver's license/operator's license or permit
from

1

concerned government agency.
•

Only authorized drivers and operators are allowed to operate equipment and machinery.
•

Only authorized signalman will be assigned together with the driver or operator.
Equipment Name, Capacity

N


Year of

o

Manuf.

Origin

s
1

Excavator

0

2010

Japan

1994

Japan

2
2

Crane truck 5T

0


Page 7 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

Contractor Doc. No.
VV3120-008-A-137

Rev.1

1
3

Tamping rammer MIKASA

0

2001-2011

Japan

2010

China

2000


China

2012

Vietnam

2012-2014

China

2013

Japan

2010

Japan

2010

Japan

2008-2011

Japan, Vietnam

2008-2010

Korea, China


2008-2010

Japan

2010

Japan

2010

Japan

2
4

Air compressor

0
1

5

6

Bending and Cutting machine,

0

D32


2

Welding machine, 250A

0
3

7

Needle concrete vibrator

0
3

8

Water pump

0
3

9

Survey instrument NIKON

0
2

10


11

Automatic Leveling machine:

0

NIKON

2

Batching plant

0
5

12

Concrete agitator truck 8 m3

0
8

13

Concrete pump car 60 m3/h

0
3


14

Bulldozer

0
2

15

Roller

0
2

Page 8 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

6
•

Contractor Doc. No.
VV3120-008-A-137

Rev.1


MATERIALS.
All material shall conform to the appropriate specification or standards listed above
unless/otherwise approved by Contractor.

•

All material shall either carry a quality certificate from the approved source or be tested to the
satisfaction and approval of Contractor.
6.1

Concrete Brick

0

Concrete brick shall be used for construction of Temporary wall for plugging opening

1

holes on Manholes, it shall be removed after completion of Leak test.

6.2

Rebar (Reinforcement)
Rebar for Concrete work (at the connection location between RC Pipes and Manholes)
shall comply with ASTM A-615 Grade 60 and approved by JGCS (refer to D-000-13201001V Drawing).

6.3

Structure Concrete
Concrete using for installation of Pipes (GRP Pipes or RCP Pipes) is concrete type

Mix-A which comply with Specification S-000-1320-1001V and Drawing D-000-13101Q01V.

6.4

Formwork
The contractor shall use Plywood or steel formwork. All the formwork surface need
coated by dedicated oil for avoid adhesive to concrete element surface.

6.5

Joint Materials
All joint materials shall be approved by JGCS and the Employer prior to use.

7

MANPOWER
-

Prior to working any work at site, all workers will be trained safety and certified by JGCS’
HSE.

-

All workers must to have name card for travel on the site.
Table 7.1: LIST OF MANPOWER FOR LEAK TEST WORK

Page 9 of 43


NGHI SON REFINERY AND

PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

8

Contractor Doc. No.
VV3120-008-A-137

Rev.1

No.

Manpower

Equipment (ea)

Manpower

1

Driver of excavator

1

2

2

Driver of Mobile crane


1

2

3

Driver of Concrete truck

1

2

4

Leveler, Total Station

2

2

5

Water pumper

2

2

6


Mechanic

2

7

Electrician

1

8

Guard

2

9

Flagman

2

10

General workers

10

Note


RESPONSIBILITIES

It is overall responsibility of Project Manager to organize resources prior to perform construction
activities as per project specification in compliance with the quality, schedule & safety
requirements.

HSSE Manager will ensure in coordination with Site JGCS’s Engineer that all measure/construction
taken shall be maintained till completion of job.

It is the responsibility of Construction Manager/Site JGCS’s Engineer that construction activities are
executed according to the relevant project specification in compliance with the safety, quality &
schedule requirements.

It will be ensured that all works are performed safely according to the attachment.

The relevant Supervisor will ensure that the work is carried out in accordance with this method
statement and project specification.

Page 10 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

Contractor Doc. No.
VV3120-008-A-137


Rev.1


The QC Inspector will ensure that the work is executed according to the Project requirements and
quality dossier is fulfilled.

Page 11 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

9

Contractor Doc. No.
VV3120-008-A-137

Rev.1

PROCEDURE AND SEQUENCE
9.1

Mobilization

9.1.1
Obtain valid permit to work (PTW) and other required certificate related for
the works.
9.1.2

Prior to enter the working area, all equipment and machinery will be
inspected by safety personnel.
9.1.3
All machineries, equipment and material shall be entering using the
designated entrance gate.
9.1.4
Ensure that Vinaconex E&C shall comply with traffic management plan and
safety transportation plan.
9.2

Equipment setting-up
9.2.1
All material, machineries and equipment shall be located at designated
area.
9.2.2
Setting-up of equipment will be done by Supervisor by adhering to all safety
measurement and requirement outline.
9.2.3
Upon completion of set-up, joint inspection will be carried out to satisfy all
parties and ensure all relevant equipment/machineries shall be complied
with safety rules and regulation.

9.3

Setting out
9.3.1
Prior to the work commencement, construction drawing will be reviewed to
check of its latest issuance for construction and all essential details are given. It

will


be checked that the intermediate dimension agree with the overall dimension.
9.3.2
The setting-out will be made at the beginning stage of the work by referring

Page 12 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

Contractor Doc. No.
VV3120-008-A-137

Rev.1

to the construction drawing and all reference points will be made necessary for the
entire work. This will be acquired and develop method of checking and cross-checking
on all setting-out operations. When principal lines and levels have to be set-out, it would
be advised to be the relevant persons.
9.4

Layout Marking
Layout and marking will be marked using surveying equipment having a valid calibration
certificate and will be verified by QC.

9.5


Execution of Leak Test for Manhole
Depend on the actual condition of construction site as well as the planning of the contractor,

the
system of pipes connect to Manhole shall be executed at the same time or at another time with
the work for construction of Manhole. The method statement of Leak test for manhole shall be
divided into cases based on actual conditions of construction activities on site.
A.

CASE1 : MANHOLES AND PIPES ARE- EXECUTED AT DIFFERENT TIMES

In case the pipes system is installed in other stage with Manholes, the excavation and
installation work for pipes shall be carried out separately after finishing construction work
for manholes (Box out shall be left on the manhole wall to wait for installing of Pipes)

The sequence of Leak Test for Manhole and Pipe shall be in compliance with the chart as
following:
Preparation
(Equipment& Material Mobilization, Setting out…)

Plugging the Openings of Manhole-exclude pipe
between 2 manholes leak test
(Using Masonry block with Plastering Surface)

Leak test - Phase 1
(Leak test at position of Construction joint of Manhole

Page 13 of 43



NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

Contractor Doc. No.
VV3120-008-A-137

Rev.1

Backfilling Work for the Manhole and Removal the Sheet pile
(After Complete of Leak test-Phase 1)

Excavation work and Installation Work for the
Pipes Connect to the Manhole

Leak test - Phase 2
(Leak test at Position of Connection Joint between
Pipes and Manhole

Backfilling Work for Pipes
(After Completion of Leak Test)

Table 9.5.1: SEQUENCE FOR EXECUTION OF LEAK TEST FOR MANHOLE AND PIPES
(CASE 1)

Page 14 of 43


NGHI SON REFINERY AND

PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

Contractor Doc. No.
VV3120-008-A-137

Rev.1

9.5.1
Preparation Work
10
Plan preparation
11
Clear and re-survey for total plan of working area. Setting out shall be carried out in
accordance with the relevant IFC Drawings.
12
The Contractor shall install sign board, site regulation and safety notice in
the construction site in accordance with the Project specification
13
The suitable safety barricade shall be installed around construction area
and approved by JGCS engineer prior to starting work.
14
The contractor shall contact with security for approval of transportation of
vehicle get in the construction site.
15
Equipment, Manpower and Material mobilization
16
Equipment, man power and material for execution of Masonry Work, Pipe
installation and Leak Test shall be mobilized and really for using prior to

construction
activities.
16.1.1
Plugging the Openings of Manhole (excluding pipe between two manhole)
17
Process to construct a temporary wall of concrete brick for plugging the
openings of the manhole which shall be Leak Tested afterward.
18
The internal side of temporary wall shall be cover with cement plaster.
19
Check for the tightness of wall and the quality of plastering layer for ensuring that
there is no leakage able to happen through the wall as well as the connection with
the manhole wall.

Page 15 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

Contractor Doc. No.
VV3120-008-A-137

Rev.1

har d bar r icade
har d bar r icade
access and egr ess way

Top of paving
el

Sheet pil e

Masonr y bl ock
W/ pl ast er ing l ayer

Sheet pil e

Concr et e br ick
st air wit h handr ain
pl ast er ing l ayer

CONSTRUCTION MASONRY BLOCK FOR PLUGGING THE OPENING

19.1.1
Leak Test- Phase 1
After finishing masonry work for the temporary wall and the plastering layer reach the
required strength, process Leak Test for the Position of Construction Joint of Manhole.
The Leak test shall be carried out as the following steps:


Step 1: Fill water to top of manhole or upper 1.5m from soffit pipe (which is lower)
in 1h for stabilization



Step 2: Leak test in 8 h




The work will be accepted as satisfactory when a visual inspection for water

Page 16 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

Contractor Doc. No.
VV3120-008-A-137

Rev.1

tightness reveals no leaks or external damp patches and:


L1 > 5(m) ; L < L1/500 (m)

L1 < 5(m) ; L1 < 0.01 (m)

Page 17 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK

TEST FOR MANHOLE

Contractor Doc. No.
VV3120-008-A-137

Rev.1

19.1.2
Backfilling Work for the Manhole and Removal of Sheet pile (apply with deep Manhole)
20

Execution of Backfilling works shall be executed in compliance with Contractor

Doc. No. VV3120-008-A-117: "Method Statement for Excavation works".
21

The backfilling work shall be carried out layer by layer to the ground level. When
finishing the work, Vinaconex.EC shall remove existing sheet pile around the

manhole.
22

The work for removal of sheet pile shall be executed sequential and under the
supervision of JGCS Engineer.

har d bar r icade

har d bar r icade

Top of paving


Page 18 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

Contractor Doc. No.
VV3120-008-A-137

Rev.1

BACKFILLING WORK FOR MANHOLE (PHASE 1)

22.1.1
Excavation Work and Installation Work for the Pipes Connect to Manhole
23

Depend on the actual condition of construction site as well as the planning of the
contractor, the system of pipes connect to Manhole shall be executed at the same

time or at another time with the work for construction of Manhole. In case the pipes
system is installed in other stage with Manhole, the excavation and installation work
for pipes shall be carried out separately.
24

The temporary wall shall be removed prior to starting the pipe work. Detail for


connecting Pipes to Manhole is in accordance with design drawing.

Page 19 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

Contractor Doc. No.
VV3120-008-A-137

Rev.1

har d bar r icade

el :

el :

INSTALLATION PIPE INTO MANHOLE
24.1.1
Leak Test - Phase 2
After finishing installation and connection Pipes between two manholes, the contractor
shall carry out Leak test for manholes to check the leakage at positions of connection
joints with pipes.
25



The Leak test shall be carried out as the following steps:
Step 1 : Fill water into the manhole up to a specific level which not exceeding 1,5
meters above the pipe soffit level.



Step 2: Until the water level shall be made up to produce the required test head
mentioned above, the test shall commence. Time for process of leak test shall be at

Page 20 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

Contractor Doc. No.
VV3120-008-A-137

Rev.1

least one hour after filling the test section unless otherwise having a specific time
from instruction of the Jgcs Engineer.


The system is deemed to have passed during the test period if the leakage is less
than the following values:
1,0xD litter/Linear metre run of Pipe (Per one hour)
With: D - Pipe diameter (m).


har d bar r icade

har d bar r icade

WATER LEVEL FOR LEAK TEST

el :

el :

el :

LEAK TEST FOR CONNECTION JOINT OF MANHOLE

Page 21 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

Contractor Doc. No.
VV3120-008-A-137

Rev.1

25.1.1
Backfilling work for pipe

When finishing Leak test and no leakage is detected as well as having the approval
from JGCS Engineer, the back filling work shall be conducted. It means that leak test
procedure for the manholes is completed.
Execution of Backfilling works for the pipes & manholes shall comply with Contractor
Doc. No. W3120-008-A-117: “Method Statement for Excavation works”

har d bar r icade

har d bar r icade

har d bar r icade

el :

el :

pIPE
SOFFIT

BACKFILLING WORK FOR PIPES
25.1.2
For the Precast Manhole
26

The Leak test will carry out for manholes on casting area as item 9.5.3

B.

CASE 2: MANHOLES AND PIPES ARE EXECUTED AT THE SAME TIME


In case the pipes system is installed in the same stage with Manholes, the excavation and
installation work for pipes shall be carried out continuously after finishing construction work for
Preparation
(Equipment& Material Mobilization, Setting out…)

Page 22 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

Contractor Doc. No.
VV3120-008-A-137

Rev.1

manholes. In this case, the leak test for Manholes shall be proceeded one time for both the
construction joints and connection joints. The test is started after finish installation work of Pipes.
The sequence of Leak Test shall be in compliance with the chart as following:

Installation Work for the Pipes Connect to
Manholes
(After finish Execution of Manholes)

Leak test
(Leak test for Position of Construction Joints of
Manholes and position of Connection Joints between
pipes and Manholes)

Backfilling Work for Pipes and Manhole, Removal of Sheet
pile (if any)
(After Complete of Leak Test)

CHART 9.5.2: SEQUENCE FOR EXECUTION OF LEAK TEST FOR MANHOLE
(CASE 2)

Detail for each work in the above sequence shall be as the same work that shown in Case 1.

27

INSPECTION AND TESTING
The Site Inspection and Test Plan (ITP) for this work summarize various characteristics to be
checked. The concerned Site Engineer/Foreman will be responsible to ensure stage wise
compliance for these operations and the Site QA/QC Engineer/Inspector will carry-out quality
control checks and report the inspection results.

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NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

Contractor Doc. No.
VV3120-008-A-137

Rev.1


Page 24 of 43


NGHI SON REFINERY AND
PETROCHEMICAL PROJECT
Title: METHOD STATEMENT OF LEAK
TEST FOR MANHOLE

28

Contractor Doc. No.
VV3120-008-A-137

Rev.1

HEALTHY, SAFETY AND ENVIRONMENT (HSE)
28.1

Responsibilities
The Safety Manager is responsible for the overall safety of the construction site. His manhours
worked and ensuring all works are carried out in the safest possible manner consistent with
good
construction practices. In case of imminent danger the site supervisor has to stop the work
immediately.

28.2

Safety measures

29

All staffs and workers on site have to be HSSE trained before entering the project. They must
study carefully Job Safety Analysis and Risk Assessment for the works before starting, participate
at Tool Box meeting in every morning.
30
Safety and security staffs of our management team strictly complied with the regulations on
HSSE issued for the project. Sufficient Persona! Protective Equipment (PPE) for workers such as
glove, hard-hat, safety boots, glass, protective clothing should be provided. Electrician shall have
rubber insulation gloves etc. All workers, during construction must wear uniformed PPE.
31
Provide sufficient lighting for construction works at night-time.
32
For construction equipment, prior to construction, it is necessary to check equipment’s
operation and carry out trial run. The equipment, before being used shall be verified and shall get
the verification certificate from the JGCS HSSE’s team. The equipment and machine shall be
maintained at a periodical basis in accordance with the specified regime. The warning system
must be kept during the construction activities.
33
For explosion/fire prevention work at fuel storehouses, and other inflammable areas, the
sub-contractor will provide fre fighting device, slogan and instruction to remind workers on the
safety assurance, install fire fighting notice sign.
34
The Contractor organizes a first-aid force on site and signs a contract with local medical
hospital to get ready to give emergency-aid and treatment when accident at work is happened.
34.1

Environmental protection measures

Page 25 of 43