007-CIVIL-MS for Dewatering.pdf

Pearl GTL Project

LINDE ENGINEERING

Shell Project No: HP-3000-QAT Contractor Project No : 5887 Project Document Number: T- 4.234.077 Project Rev.: A Page 2 of 17

Purchase Order Number: 2MH127

Tag/Item Number(s): N/A

Unit(s): ASU

PCWBS: Z

QATAR SHELL GTL PROJECT (PEARL) C2 AIR SEPARATION UNITS CONSTRUCTION

D A 21.05.2008 Issued for Company Comments IO BU AG ICC

C O 03.12.2007 Issued for Company Comments IU IO/UA MC/ZG ICC

B 03.12.2007 Issued for Review IU IO/UA MC/ZG IFR

A 27.11.2007 Issued for Internal Review IU IO/UA MC/ZG IIR

GAMA Rev.

Project Rev Date Description

Prepared By

Checked By

Approved By Status

No. No. ORIGINATOR

Company

LINDE ENGINEERING AG

Document Title:

METHOD STATEMENT FOR DEWATERING

Document No. GAM MTS CIV GTL 007 D

LOC470 Contractor

Gama Qatar Co. W. L. L. Org.

Code Doc. Type

Disc. Code

Geogr. Area

Seq. No

Rev. No Vendor Code

Project Document Number: T-4.234.077

Rev No: A

Doc. Title : GAM-MTS-CIV-GTL-007 Rev. D Method Statement for Dewatering Date : 26 May 2008

T-4.234.077 Rev. A Page 4 of 17

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TABLE OF CONTENTS

1. PURPOSE _____________________________________________________________ 5

2. SCOPE _______________________________________________________________ 5

3. HSSE_________________________________________________________________ 5

4. REFERENCES _________________________________________________________ 6

5. DEFINITIONS __________________________________________________________ 6

6. RESOURCES __________________________________________________________ 7

6.1. Responsibility ____________________________________________________________ 7 6.1.1. Site Manager __________________________________________________________________7 6.1.2. Civil Works Manager ____________________________________________________________7 6.1.3. Site Engineer __________________________________________________________________7 6.1.4. Work Supervisor________________________________________________________________7

6.2. Equipment & Manpower ____________________________________________________ 8 6.2.1. Equipment ____________________________________________________________________8 6.2.2. Manpower ____________________________________________________________________8

7. METHOD OF EXECUTION ________________________________________________ 9

7.1. General __________________________________________________________________ 9 7.2. Pre-Commencement Works _________________________________________________ 9

7.2.1. Existing Underground Facilities ____________________________________________________9 7.2.2. Access Roads _________________________________________________________________9 7.2.3. Barricades, Safety Signboards & Night Activities ______________________________________9

7.3. Construction of Evaporation Ponds (Embankments)____________________________ 10 7.4. Dewatering System _______________________________________________________ 11 7.5. Other ___________________________________________________________________ 11

8. QUALITY ASSURANCE _________________________________________________ 11

9. ATTACHMENTS _______________________________________________________ 12

9.1. Job Safety Analysis _______________________________________________________ 13 9.2. Location of Dewatering Ponds ______________________________________________ 16


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1. PURPOSE

This document describes the methods proposed to be used for the dewatering operations that will be carried out as part of ASU Construction Works of Qatar Shell GTL Plant (Pearl) in Ras Laffan Industrial City of Qatar including similar works in TSF Area.

2. SCOPE

It is possible to encounter the Groundwater Table and/or other means of seepage during Excavation and/or Backfilling activities (although it is almost impossible to make an accurate estimated as to the level of Water Table, it is estimated somewhere between 0.00 m QNHD and +0.50 m QNHD). Whenever encountered, water inside the trenches will be pumped out to evaporation ponds, as described in the following sections, with diesel-powered pumps as required. Water in the ponds will be allowed to either sock back into the ground or evaporate as well as being pumped into tankers to be used for dust control.

3. HSSE

All works will be in compliance with the State of Qatar laws and regulations, Ras Laffan Industrial City and international standards/codes, and Company and Client requirements and instructions.

All personnel will go through Gama, Company and Client Safety Induction courses as well as other trainings as identified by their supervisor. Please see Document Number GTL-GM-001-A-5635 for details.

A Job Safety Analysis (JSA) specific for this work including a Risk Assessment, is prepared as per Gama procedure GTL-GM-001-A-5626 and is attached herein. Such JSA addresses the hazards associated with each task within the scope of this Method Statement and introduces the controls that will be implemented to reduce the associated risks to acceptable levels. The JSA will be used by the Site Supervisor as the basis of his TSTI / TSTO and Toolbox Talks.

All personnel will have PPE required for their specific tasks in addition to the minimum PPE (coveralls, safety goggles, safety shoes, high-visibility vests, gloves) at site at all times as required.

In the event of a release, fire or explosion, employees will secure their area and evacuate to the nearest muster point. Once all employees are evacuated the supervisor will conduct a headcount to verify all employees are out of harms way. The supervision will report this to Company. Emergency Contact numbers for Company, Contractor and Client will be posted onsite.

All vehicles and equipment used for the subject work will be inspected and certified as required.

Drivers and operators will be competent and will have attended all required trainings set forth in project procedures and specifications.


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4. REFERENCES Qatar Construction Standard DEP 34.19.20.31-Gen : Reinforced Concrete Foundations and Structures DEP 34.14.20.31-Gen : Drainage and Primary Treatment Facilities

T-13.376.358 : Amendments and/or Supplements to Reinforced Concrete Foundations and Structures

DEP 34.11.00.11 : Site Preparation and Earthworks including Tank Foundations and Tank Farms

T-13.376.352 : Amendments and/or Supplements to Site Preparation and Earthworks including Tank Foundations and Tank Farms T- 4.234.069 MS for Excavation T- 4.234.074 MS for Backfilling Other related documents

5. DEFINITIONS Client : QSGTL and/or its PMC Company or Linde : Linde Engineering AG Contractor or Gama : Gama Qatar Co. W. L. L. Contract : QSGTL Pearl Plant C2 ASU Construction Works QCP : Quality Control Procedure ITP : Inspection and Test Plan QA/QC : Quality Assurance / Quality Control JSA : Job Safety Analysis


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6. RESOURCES

6.1. RESPONSIBILITY

6.1.1. Site Manager

The site manager will provide inputs to the project execution plan to ensure that strategies & philosophy are properly addressed.

6.1.2. Civil Works Manager

The Civil Works Manager is responsible for the overall management of the project construction team to ensure that safe and effective operations are conducted and properly documented.

6.1.3. Site Engineer

He will be overall responsible for safe execution of the whole job including:

Confirming the installation location from schedule of approved construction drawings. Organizing of equipments and tools needed for the job. Assigning skilled personnel for the job. Sequence of activities to be carried out for the work as per this method of statement. Conduct inspection and surveillance. Ensure all Client and Company regulations are followed. Ensure all personnel involved are in safe working condition.

6.1.4. Work Supervisor

He will be responsible for safe execution of the following activities: Conduct TSTI with the concerned work force prior to start the work. Ensure that relevant work permits for the job are obtained prior to start the work. Conduct daily toolbox talks for the entire work force prior to start day work. Assigning a competent work crew for specific activities, details of activities and task

information will be given to the work crew.

Organizing tools and equipment needed to the work site. Inspection and supervision of work. Ensure all Client and Company safety regulations are followed as applicable.


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6.2. EQUIPMENT & MANPOWER

All equipment will be inspected and approved by Company and/or Client, when required, and all personnel will be inducted and trained before and during mobilization.

6.2.1. Equipment

Dewatering Pumps (Diesel and/or Petrol Powered, 4 6 inch) Hoses, Clamps, etc. (for the Pumps) Boom-Truck (for carrying the pumps) Excavator (for embankment) Water Tanker (for dust control)

6.2.2. Manpower

Site Engineer Foreman (Work Supervisor) HSE Officer(s) Dewatering Pump Operator(s) Common Labourer(s)

If the above-listed equipment and/or manpower proves not sufficient for the timely completion of the facilities and project; additional will be provided to complete the works on time and in line with rules, regulations and specifications of Client, Company and RLIC.


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7. METHOD OF EXECUTION

7.1. GENERAL

The water will be pumped from the excavations to the evaporations ponds (embankments) by means of pumps; and will be allowed to either soak back into the ground or evaporate. The water accumulated in the pond may also be pumped to Water Tankers to be used for Dust Control.

However, should this system proves ineffective and/or insufficient; it may be changed to cope with the water volume. Such change will be subject to approval from the Contractor and the Company.

The pumps will be operated only during the working hours and the water will be let accumulate in the excavation pit; except for backfilling where the laid material should be kept dry until compaction.

7.2. PRE-COMMENCEMENT WORKS

7.2.1. Existing Underground Facilities

Prior to work commencement, the existing and possible underground structures and installations will be checked by means of As-Built Drawings issued by the Contractor or the Company. The locations of such installations will be marked at site and posted with signs. After the area has been barricaded, possible relocation or removal applications for the same will be studied. Same studies will be submitted to the Contractor and the Company for approval. Should any underground facility be encountered in spite that they have not been pointed out in the drawings, Contractor will be informed immediately; and approval of Contractor and Company will be waited before proceeding with the relocation or removal of the same. The barricades for such activities will be temporary.

7.2.2. Access Roads

The locations of access roads within the execution area will be pointed out by the Contractor. These access roads will be used for the planning of concrete activities within the area. However, the access roads may be diverted for some periods during the execution of the works in order to ensure smooth execution of the works in the area. Nevertheless, no such diversion will take place without prior written consent of the Contractor or the Company. After the locations of access roads have been excavated, they will be backfilled to allow traffic in and within the area.

7.2.3. Barricades, Safety Signboards & Night Activities

All work areas will be barricaded and posted with signs before any work starts. Barricades will be formed by black pipes (steel); and the signboards will be placed as needed. Barricades will be kept in place until the work done and the areas have been filled.

All night activities, should there be any, will be carried out as per the Method Statement for Night Works (T-4.234.081).


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7.3. CONSTRUCTION OF EVAPORATION PONDS (EMBANKMENTS)

Embankment will be formed by an Excavator using the material excavated from the nearby pits. The excavator will place the material in a circular pattern; and then arrange the same to form an embankment around itself. It then will compact the embankment with the back of the bucket.

Once the embankment is completed the excavator will leave the embankment, and repair the section of the embankment it used on the way out.

The size (diameter and height) of the embankment will be determined according to the amount of water; however, in no case the depth will be more than 1.20-m; and maximum water height inside the pond will not exceed 1.00-m. Initial diameter of the pond will be 10-m, which will be adjusted according to the conditions on site.

The pond will be located between the 2 pits, so that it can be used for both. However, such location can be adjusted according to site conditions.

The area will be barricaded and posted with safety signs. Such signs and barricades should have high-visibility, or be reinforced with high-visibility tapes to ensure their visibility at night.

Typical Cross-Section of a pond is shown in below figure, initial locations of the ponds in given in Attachment 2. However, the locations (and the dimensions) of the ponds are not final and may be adjusted according to the conditions on site.


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7.4. DEWATERING SYSTEM

Sufficient number of 4 and 6 diesel-powered dewatering pumps will be provided. The number of required pumps will be determined according to the conditions on site. Each system will have the following as a minimum in addition to the pumps:

1 Drip-tray for spill control for each pump, 1 Inspected Fire extinguisher for each pump (The tag showing the inspection will be put on the

extinguisher)

1 Set of Spill Kit (2 Plastic sacks (heavy duty), 10 Absorbent pads, 1 kg absorbent Granules, Plastic Drip Tray, Shovel (small)) for each pump,

1 trained operator for each pump in operation 7.5. OTHER

The water accumulated in the pond can be pumped into water tankers to be used for dust control only. It will never be used for construction and/or potable water. Hence, the tanker used for such job should be marked properly stating that the water inside is not potable.

In order to prevent seepage into the excavation pit, the embankment will be located at least 20-m away from the edge of the nearest excavation.

8. QUALITY ASSURANCE

A Quality Assurance System will be operated conforming to related standards.


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9. ATTACHMENTS


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9.1. JOB SAFETY ANALYSIS


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9.2. LOCATION OF DEWATERING PONDS


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Documents

007-CIVIL-MS for Dewatering.pdf