SA04C2-00-MET-MS-00007 MS Excavation and Backfilling

SHUQAIQ 3 INDEPENDENT WATER PROJECT

Transmittal No.: SA04C2-T-MET-AAG-00075 Submission Date:

TRANSMITTAL

Internal Code: Submitted To:

31-Jan-2021

Subject: Technical Query Method Statement for Excavation and Backfilling

AAG

Received by: AAG

Submitted From: MET

DISCIPLINE: Civil

General

Process

Mechanical

Instrumentation

Project Management

Quality

Electrical

Piping

Safety and Environment.

DOCUMENT ISSUED FOR: For Client Review

For Construction

For Information

As Built

ACTION TAKEN A: Reviewed with comments

D: Reviewed, no comments

G: Documents listed below

B: Approved with comments

E: Approved, no comments

H: Comments on Attachment

C: Not approved

F: Comments noted below

I: Document list attached Others (Specify)

Document List: 1: SA04C2-MS-MET-AAG-0007 MS Excavation and Backfilling.

Comments:

PROJECT TITLE: Shuqaiq 3 Independent Water Project.

P NO: CO-SA04C1-Z06BD-079

Document No: SA04C2-00-

Method Statement for Excavation & Backfilling

MET-MS-00007

Rev :0 Date: 31/01/2021 Page 1 of 8

METHOD STATEMENT FOR

EXCAVATION AND BACKFILLING

PROJECT TITLE: Shuqaiq 3 Independent Water Project. Method Statement for Excavation & Backfilling

P NO: CO-SA04C1-Z06BD-079

Document No: SA04C2-00MET-MS-00007 Rev : 0 Date: 31/01/2021 Page 2 of 8

Revision Record

Rev

00

1.

This cover page is a record of all revisions of the document identified above by number and title. All previous cover pages are hereby superseded and are to be destroyed.

2.

The contractor has the full right to modify, amend or change Method Statement and supporting documents as required or as deemed necessary. All such documents will be submitted to the “CONSULTANT” for approval.

Date

31/01/2021

Prepared By

Reviewed by

Approval for Issuance by

Benigno Saleem Ahmad Manuel Muñiz Sanchez Iglesias Sanmartin

Description & page Number of Revision

PROJECT TITLE: Shuqaiq 3 Independent Water Project. Method Statement for Excavation & Backfilling

Contents 1.0

Purpose

2.0

Scope

3.0

References

4.0

Definitions and Abbreviations

5.0

Responsibilities

6.0

Materials

7.0

Equipment & Tools

8.0

Safety & Health

9.0

Procedure

10.0 Attachments

P NO: CO-SA04C1-Z06BD-079

Document No: SA04C2-00MET-MS-00007 Rev : 0 Date: 31/01/2021 Page 3 of 8

PROJECT TITLE: Shuqaiq 3 Independent Water Project. Method Statement for Excavation & Backfilling

1.0

P NO: CO-SA04C1-Z06BD-079

Document No: SA04C2-00MET-MS-00007 Rev : 0 Date: 31/01/2021 Page 4 of 8

PURPOSE The purpose of this method statement is to clarify excavation and backfilling works to be carried out for the project.

2.1

SCOPE This method statement covers general excavation works for foundations and other structures requiring straightforward excavations. It generally encompasses the following: o Machineries for earthwork, delivery, transportation, handling and storing at site. o Survey o Stockpiling and disposal of excavated material o All necessary safety measures o Testing, preparing ground surface to final grade and levels

. 3.1

REFERENCES ➢ ➢ ➢ ➢ ➢

4.0

Project specifications Contract Drawings Approved Shop Drawings NOC from the Concerned Authority Project Quality Plan

DEFINITIONS& ABBREVIATIONS PM: CM: PE: SE: QCE: QA QC: HSE:

5.1

Project Manager Construction Manager Project Engineer Site Engineer Quality Control Engineer Quality Assurance and Quality Control Health Safety Environment

RESPONSIBILITIES ➢ Project Manager is responsible for overall project execution, quality and safety. Adopt a leading role with respect to Contractor’s quality and safety procedures. The PM is responsible for the overall implementation of this method statement. The Project Manager shall ensure that the key personnel are well aware of the specifications and method statement.

PROJECT TITLE: Shuqaiq 3 Independent Water Project. Method Statement for Excavation & Backfilling

P NO: CO-SA04C1-Z06BD-079

Document No: SA04C2-00MET-MS-00007 Rev : 0 Date: 31/01/2021 Page 5 of 8

➢ CM / Project Engineer shall arrange all materials, equipment, safety related items & manpower & direct the Site Engineers & Foremen to resort appropriate action for the smooth execution of the works. ➢ Safety Engineer shall be responsible for safe working environment & conditions. Coordinate with Site Engineer to identify potential hazards before works and advise methods of safe working from new developments. ➢ Surveyor shall be responsible for setting out for levels, layout, and lines & establish top levels. Ensuring setting out books are properly maintained and filed when completed. To coordinate with the CONSULTANT surveyor in determining coordinates, levels, and limits. ➢ QA/QC Engineer shall be responsible for ensuring that execution of works are complying with approved method statement; specifications, approved shop drawings and ensure ITR are submitted based on ITP requirements. ➢ Site Engineer shall ensure that all works are carried out according to approved shop drawings. He shall direct the surveyor for the setting out lines & levels in concurrence from the Construction Manager/Senior Civil Engineer. ➢ MEP Coordinator / Engineer shall be responsible for proper execution of MEP works involved before, during and after the works. 6.0

MATERIALS

➢

Approved Materials for backfilling

7.1

EQUIPMENTS& TOOLS Below is the equipment involved in the subject works included the following: ➢ ➢ ➢ ➢ ➢ ➢ ➢ ➢ ➢ ➢ ➢ ➢

Excavator Power shovel Motor Grader Dump Truck Plate and Roller Compactor Front End Loader JCB` Water Tanker Hand tools (Shovels, Spade, rake etc.) Dewatering Equipment (if required) Total station, level Shoring materials (if required)

PROJECT TITLE: Shuqaiq 3 Independent Water Project. Method Statement for Excavation & Backfilling

P NO: CO-SA04C1-Z06BD-079

Document No: SA04C2-00MET-MS-00007 Rev: 0 Date: 31/01/2021 Page 6 of 8

The capacity / size and quantity of the above equipment shall be judged in accordance with site conditions, requirements, and availability at the time of execution. 8.1

SAFETY & HEALTH ➢ Site HSE Management shall be applied. ➢ All personnel involved will use necessary PPE as required such as safety helmet, glasses, coverall, shoes, gloves, ear plugs etc. ➢ HSE officer to ensure that excavated area is barricaded. Adequate warning tapes and warning signs are provided. All access from adjacent play ground to extension area shall be closed and monitored. ➢ Though the excavation is minor in nature a hazard analysis table is attached for excavation activities. All major possible risks/ hazards are highlighted. ➢ The workers will be made aware of safety requirements related to this activity through daily tool box and safety talk. ➢ All required work permits will be acquired and kept available at respective work site hanged clearly in plastic folders. ➢ Safety notice board will be installed.

9.1

PROCEDURE EXCAVATION: ➢ Ensure the availability and validity of documents such as Excavation Permits, NOC and approved drawings. ➢ Ensure the availability of MEP clearance, risk assessment, shoring and dewatering permits etc. ➢ Before commencement of work ascertain the nature and location of all existing (above and underground) services on site by visual survey or by reviewing the service layout drawing. ➢ If any protection, rerouting, termination or removals of services are required for the smooth processing of work, it shall be discussed and written approval shall be obtained from the Engineer as appropriate. ➢ The surveyor will set out line / coordinates as per relevant construction drawings. ➢ The surveyor will inform area / excavation foreman of these lines & levels.

PROJECT TITLE: Shuqaiq 3 Independent Water Project. Method Statement for Excavation & Backfilling

P NO: CO-SA04C1-Z06BD-079

Document No: SA04C2-00MET-MS-00007 Rev: 0 Date: 31/01/2021 Page 7 of 8

➢ Banks man will be deployed with all mechanical excavation equipment & dump trucks to guide the operators. ➢ The excavation / area foreman will direct the excavation equipment in an agreed sequence. ➢ Dumping of unsuitable material will be done to disposal point, as notified by CLIENT & material fit for backfilling will be stock piled separately at a suitable agreed location. ➢ Barricading of the excavated area will be done as work proceeds. ➢ Where ever there are chances of sliding, the sides of excavation will be sloped ➢ The bottom of all excavated areas shall be trimmed, leveled and rammed. ➢ While excavation is in progress, excavation area foreman will continuously monitor the level to avoid over excavation. ➢ The surveyor will check the lines & levels upon completion of excavation. ➢ Upon acceptance of survey, the area will be released for subsequent activities. ➢ If excavation goes below the adjacent structures, shoring will be carried out. BACKFILL & FILL: ➢ CM/PE will ensure that particular area/structure has been cleared for backfilling by QC department. ➢ Upon approval for backfilling the PE will instruct concerned foreman to conduct this activity. ➢ The backfill material will be sourced from suitable stock pile or from excavated material. ➢ The backfill material will be placed in layers according to the specification. ➢ The layer will be moisturized and compacted. ➢ Generally compaction will be done by rollers / compactors. ➢ Compaction must be monitored and judged by regular tests for density which should not be less than 95% Maximum Dry Density. ➢ Once test results are satisfactory to the specification subsequent layer shall be precede. ➢ In narrow places and corners where roller can’t reach, a plate compactor shall be used to complete the job. ➢ Precede the subsequent layer with the same procedure until the required level obtained. ➢ Upon completion of backfill activity, the area will be cleaned of waste materials. ➢ Safety barriers will be removed to safety store.

PROJECT TITLE: Shuqaiq 3 Independent Water Project. Method Statement for Excavation & Backfilling

P NO: CO-SA04C1-Z06BD-079

Document No: SA04C2-00MET-MS-00007 Rev: 0 Date: 31/01/2021 Page 8 of 8

DEWATERING: 1. The Trench will be dewatered using a well point system, if excavation depths extends below the water table. The proposed dewatering method will be submitted together with shoring proposals. Depending on trench width, working area, and site conditions for the trench, well points may be made inside or outside the trench. 2. Holes will be drilled for the well points to a sufficient depth to enable the ground water to maintain at 0.5m below the formation level of the excavation (bottom of the Excavation). The Dewatering Pipes will be inserted in the well Points and the Space around the Pipes filled with 10mm drainage stone. The Dewatering pipes will be connected to a 6 inches header pipe system. 3. Dewatering Pumps powered by diesel will be installed and connected to the Header system at an appropriate location. All pumps will be placed on steel drip trays that will be periodically emptied by a registered approved waste contractor who will dispose the contaminated effluent. 4. The Environmental Engineer from Acciona will analyze the and determine if it needs treatment prior to discharge if deemed safe the water will be pumped to the nearest evaporation pound. 5. The Dewatered level table will be maintained at a minimum of 0.5m below the excavation level. 6. The Dewatering system will be disconnected once the uplift pressure is neutralized and upon the appropriate level of backfilling being reached. 7. For safe operation all personal will not be directly involved with the dewatering operations will be kept. 8. For safe operation, all personal not directly involved with the dewatering operations will be kept clear of the working area. A demarcated observation area will be established to enable safe monitoring and observation area. 10.1

ATTACHMENTS ➢ ITP ➢ Checklist ➢ Manufacture Recommendation.

Field Service Installation Package Client: Project: SHUQAIQ 3 Independent Water Project ‐ RO Plant Contractor: ACCIONA.

Field Services Department

INSTALLATION GUIDELINE UNDERGROUND PIPE SYSTEM

Document Number: FPI-KSA-FSV-IG-UG Revision: 0

Field Services Department

Revision & Approval Control DOCUMENT CONTROL Title

INSTALLATION GUIDELINE

Document Number

FPI-KSA-FSV-IG-UG

UNDERGROUND PIPE SYSTEM

Issue Date

24-11-2019

REVISION CONTROL Revision 0

Date

Description

Comments

24-11-2019

Issued for Review

N/A

APPROVALS Name

Position

Signature

Date

Name

Position

Signature

Date

Luqman Ali

Field Service Supervisor

PREPARED BY

24-11-2019

REVIEWED BY Name

Position

Saeed Mustafah

Field Service Engineer

Signature

INSTALLATION GUIDELINE UNDERGROUND PIPE SYSTEM | FPI-KSA-FSV-IG-UG

Date 24-11-2019

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Terms of use The use of the contents and the data published in this brochure have been licensed to Future Pipe Industries L.L.C. This document contains confidential and proprietary information. Reproduction or disclosure of any part of this document is only allowed with written authorisation by Future Pipe Industries L.L.C. Future Pipe Industries L.L.C. reserve the right to change the data published in this brochure without any prior notification. All information was correct at the time of going to press. However, we reserve the right to alter, amend and update any products, systems and services described in this document. We accept no responsibility for the interpretation of statements made. For any technical query please consult Future Pipe Industries L.L.C.

INSTALLATION GUIDELINE UNDERGROUND PIPE SYSTEM | FPI-KSA-FSV-IG-UG

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TABLE OF CONTENTS 1. INTRODUCTION 2. REFERENCES 3. HANDLING 4. TRENCH SPECIFICATIONS 5. SPECIAL UNDERGROUND REQUIREMENTS 6. BACKFILL AND INSTALLATION SELECTION 7. SYSTEM ASSEMBLY 8. SPECIAL REQUIREMENTS 9. PIPE DEFLECTION 10. FIELD HYDROSTATIC TESTING 11. AIR IN PIPELINES, AIR VALVES, AND SURGE CONTROL 12. HSE REQUIREMENT

INSTALLATION GUIDELINE UNDERGROUND PIPE SYSTEM | FPI-KSA-FSV-IG-UG

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1. GENERAL This manual deals with installation of Glass Reinforced Plastic pipes and fittings manufactured by Future Pipe Industries (FPI). It is to be used in conjunction with the Glass Reinforced Plastic Product Data, Method statements, etc. and is intended to assist the installer in understanding the requirements and procedures for the successful handling, laying and testing of Glass Reinforced Plastic pipes and fittings for underground installation. This manual should be carefully read by the Contractor responsible for laying the pipe as well as the pipeline Design Engineer. This information should be considered only as a guide. The Engineers or others involved in pipeline design or laying should establish for themselves the procedures best suited to the actual site conditions. Sound engineering practices should always be followed. This document mainly addresses the usual circumstances that may be encountered in the field. Unique situations requiring special considerations are not addressed and should be resolved in coordination with the manufacturer. The instructions in this document are as complete as possible. However, it is not possible to describe all circumstances that might be encountered in the field. Therefore, our experienced Field Service Representatives can opt for an alternative method to achieve an optimum solution using the latest installation techniques and processing methods. Besides, our Field Service Representatives may be consulted for clarification of statements made in this document and for advice about specific problems encountered in the field. Definition of words used in these instructions: - The word “shall” indicates a requirement. - The word “should” indicates a recommendation.

2. REFERENCES •

AWWA-M45 Manual

-

Fiberglass Pipe Design

•

ASTM D1586

-

Standard method for Penetration Test and Split Barrel sampling of soils.

•

AWWA C950

-

Standard Specification for Fiberglass pipes

•

ASTM D2487

-

Classification of soils for Engineering Purposes.

•

ASTM D3839

-

Standard Practice for underground Installation of “Fiberglass Pipe”

•

BS8010 Part 1:89

-

Pipe Lines on Land-General

•

BS8010 Part 2.5:89

-

Pipe Lines on Land-Design Construction & Installation-GRP Pipe Lines.

INSTALLATION GUIDELINE UNDERGROUND PIPE SYSTEM | FPI-KSA-FSV-IG-UG

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•

BS8010 part 3:93

-

Pipe Lines- Sub-sea: Design, Construction & Installation.

3. HANDLING 3.1 Receiving Generally, pipes will be handed over to the Contractor or his representative at the factory or at the job site or as agreed upon in the Contractor’s purchase order. In case of Ex-works delivery, the pipes and fittings shall be loaded on the Contractor’s trucks, by the factory loading staff. If the loading staff considers the transport unsuitable they will advise the contractor or his representative accordingly. Inspection is thoroughly made by the factory loading staff of the goods being loaded. Nevertheless, the contractor or his representative should make their own inspection of the goods during dispatch. The Contractor should make the following inspection at the time of reception of the goods: a. All pipes and fittings should be inspected upon receipt at the job site to ensure that, no damage has occurred during transport. b. Total quantity of pipes, couplings, rubber rings, fittings, lubricant, etc. should be carefully checked against the delivery notes. c. Any damaged or missing item must be pointed out to the dispatcher or driver and noted on the delivery note. d. Materials that have been damaged during transportation should be isolated and stored separately on site, until the material is checked by our site representative and repaired or replaced. Note: Damaged or defective material must not be used before it is repaired or replaced. 3.1.1 Repair Pipes with minor damage can be repaired at the job site by a qualified technician. If in doubt about the condition of the pipe, do not use it. The site services representative can help to determine whether repair is required, possible and practical. Repair method can vary due to pipe thickness, wall composition, application, and the type and extent of the damage. Therefore, do not attempt to repair a damaged pipe without consulting the manufacturer first. Repairs must be made by a trained repair technician. Improperly repaired pipes may not perform as intended. 3.2 Unloading Pipe Unloading the pipe at the job site must be carried out carefully under the control and responsibility of the Contractor. Do not drop the items and extreme care should be taken to avoid impact the pipe with any solid object (i.e. other pipes, ground stones, truck side etc.).

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3.2.1 Unloading by hand Unloading by hand with two men is only allowed for small diameter pipes, not exceeding 40 kg. 3.2.2 Mechanical unloading Mechanical unloading is required for pipes heavier than 40 kg. Flexible slings or straps should be used combined with a mobile crane. When unloading is done with a mobile crane, care must be taken that the pipes not to slide off the slings. Therefore, it is recommended to use two slings or nylon lifting straps to hold and lift the pipes. Steel cables must not be used for lifting or handling Glass Reinforced Plastic pipes. Glass Reinforced Plastic pipe can also be lifted with one sling or strap balanced in the middle with the aid of a guide rope.

Figure-1

Figure-2 Lifting Single Pipe.

Figure-3 Lifting Unitized Package.

INSTALLATION GUIDELINE UNDERGROUND PIPE SYSTEM | FPI-KSA-FSV-IG-UG

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Caution: Hooks must not be used at the pipe ends to lift the pipes, nor should the pipe be lifted by passing a rope or sling through the pipe. 3.3 Unloading couplings Couplings shall be unloaded with care and at any circumstances must not be thrown off the truck on the ground. In general, couplings are strapped and bundled in the factory and can be off loaded like the pipes. 3.4 Storing rubber gaskets, lubricant and raw materials on site Rubber gaskets are delivered in closed bags from the factory and must be stored in the shaded area in their original packing, protected from direct sunlight, until they are ready for use. Also, the gaskets must be protected from exposure to greases, oils, solvents and other harmful substances. Gasket lubricant should be carefully stored to prevent damage. Partially used buckets should be sealed again to prevent contamination of the lubricant. Project specific handling and storage procedure shall be referred for the complete information on the storage conditions of various raw materials and components. 3.5 Storing pipe on site 3.5.1 Distributing along the trench It is preferable to unload Glass Reinforced Plastic pipes alongside the trench directly from the truck. If the trench is opened, string out the pipes on the opposite side to the excavated earth. Allow sufficient space between pipes and the trench for excavator, cranes, etc. Avoid placing the pipes where they can be damaged by traffic or blasting operations. If possible, Store pipes on soft level ground (e.g. sand), timber bearers or sand bags. It is generally advantageous to store pipe on flat timber to facilitate placement and removal of lifting slings around the pipe. 3.5.2 Storing in stock piles Care must be taken that the storage surface is levelled, firm and clear of rocks or solid objects that might damage the pipes. Store the pipes in separate stock piles as per their class and nominal diameter. If it is necessary to stack pipes, it is best to stack on flat timber supports at maximum 6 meters spacing (3 meters for small diameters). The maximum stack height is 1.5m without supports and approximately 3 meters with side supports those are placed at a distance maximum 4.0m. Stacking of pipes larger than 1400 mm diameter is not recommended. This height is limited for safety purpose and to avoid excessive loads on the pipe during storage. Wooden wedges, which are used to prevent the pipe stack from sliding should be placed on both sides of the stack on the timber bearer, as shown in figure 4.

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Figure-4 3.6 Lowering the pipes into the trench Manual lowering of small diameter pipes into the trench can be executed by at least two men. It is recommended that the weight carried by one man do not exceed 20 kg. Pipes weighing up to 120 kg can be lowered by means of two ropes. The ropes must be anchored to stakes as indicated in figure 5

Figure-5 Mechanical lowering is used for larger diameter pipes, especially when combined with pipe assembly in the trench. Two straps or slings can be used from an excavator boom if no separate lifting equipment is available, as shown in Figure 6.

Figure-6

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Note:- project specific handling and storage method statement shall be referred for more details of handling and storage techniques.

4. TRENCH SPECIFICATIONS 4.1 The Trench Excavate trenches to ensure that sides will be stable under all working conditions. Slope trench walls or provide supports in conformance with safety standards. Open only enough trench that can be safely maintained by available equipment. Place and compact backfill in trenches as soon as practicable, preferably no later than the end of each working day. Place excavated material away from the edge of the trench to minimize the risk of trench wall collapse. The trench excavations should not be too far ahead of the pipe-laying team to ensure a better control of the trench and for safety reasons. The excavated soil should be placed on one side of the trench leaving the other side clear for equipment and pipe handling. If the trench consists of various layers of soils, these should be placed separately to use the stonefree granular material for backfilling. 4.2 Trench Width The trench width must be maintained within certain limits. A very wide trench will increase the volume of backfilling material required and compaction labour and effort. A very narrow trench will render laying, handling, joining of pipes and compacting side backfill difficult. The minimum trench width(W) at the bottom of the trench for a single pipe shall be: W=1.25XOD+300mm Note :- Project specific AWWA-M45 calculation shall be referred for each project. The space between the pipe and the trench wall or between adjacent pipe must be 150mm wider than the used compaction equipment. In poor native soil conditions and depending on pipe stiffness and burial depth, a wider trench (up to 4 x ND) might be required. 4.3 Parallel pipes installed in the same trench Where two, or more, Glass Reinforced Plastic pipes are installed parallel in the same trench, the following minimum distance ’X’ as shown in figure 8 should be maintained to allow for sufficient room to place and compact the backfill material under the pipe haunches, for all the pipes in the trench. The minimum spacing ‘X’ must be two third of the average radii of adjacent pipes for a cover depth less than 3.5m and average of the radii of adjacent pipes for cover depth greater than 3.5m. However, in all the cases the spacing shall not be smaller than 300 mm. If mechanical compacting equipment is used, the minimum space between the pipes and trench wall or adjacent pipe shall not be less than width of the widest piece of equipment plus 150mm.

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Figure 7 4.4 Pipes Crossing Where two Glass Reinforced Plastic pipes are crossing each other as shown in figure 8, the minimum vertical distance between the two pipes shall be at least the average of the radius of the two pipes, in any case this distance should notbe less than 300 mm.

Figure 8 4.5 Trench depth 4.5.1

Minimum cover depth

To Preclude damage to the pipe and disturbance to pipe embedment, a minimum depth of backfill above the pipe should be maintained before allowing vehicles or heavy construction equipment to traverse the pipe trench. The minimum depth of cover should be established based on an evaluation of specific project conditions, such as pipe diameter and stiffness, soil type and stiffness, and live load type and magnitude. In the absence of an engineering evaluation, the following minimum cover requirements should be used. In general for embedment materials installed to the minimum densities given in Table-3 and live loads similar to AASHTO H-20, provide cover (i.e., depth of backfill above top of pipe) of at least 0.6 m for Class I embedment and cover of at least 0.9 m for Class II, Class III, or Class INSTALLATION GUIDELINE UNDERGROUND PIPE SYSTEM | FPI-KSA-FSV-IG-UG

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IV embedment before allowing vehicles or construction equipment to traverse the trench surface; provide at least 1.2 m of cover before using a hydro hammer for compaction. Where construction loads may be excessive (e.g., cranes, earthmoving equipment, or other vehicles with wheel loads that exceed the AASHTO H-20 loading), minimum cover should be increased or special structures, such as relief slabs at grade, may be installed to reduce the load transferred to the pipe. Project specific AWWA-M45 calculation shall be referred and installation parameters to be strictly adhered for each project. Table 2: - Minimum Compaction density Soil Classes

Class I

Class II

Class III

Class IV

Embedment Compaction Minimum Recommended density, SPD

Minimum density typically achieved by dumped placement

85%

90%

95%

If a risk of pipe flotation occurs, the minimum cover should be 1 pipe diameter. If a specific analysis is made of the buoyant force of an empty pipe compared to the submerged weight of soil over the pipe, this minimum cover may be reduced. In the presence of permanent traffic loads, a minimum cover above pipes shall always be maintained. A detailed engineering should be carried out and installation parameters as per AWWA-M45 calculation shall be strictly followed. Higher pressures ( more than 10 bar) require consideration of the possible uplift forces at joints both during operation and field hydrotesting. For operating pressures 16 bar and above the minimum burial depth should be 1.2 m for pipes DN 300 mm and larger and 0.8 meters for pipes less than DN 300 mm. During hydrotesting at pressures below 16 bar the couplings should be backfilled at least to the crown, with pipes backfilled to the minimum cover depth and pressures 16 bar and above: f or pipes and couplers in straight alignment backfill to the minimum cover depth before performing the hydrotest. For pipes installed with angular deflection both the pipe and the coupling must be covered to the final grade before the field pressure test. In case of high ground water table, a minimum cover depth equal to 0.8 times the pipe diameter of granular soil (minimum dry density of 1300 Kg/m3) must be provided to prevent Glass Reinforced Plastic pipes from floating. Always insure that this minimum cover is available before turning off dewatering systems. 4.5.2 Maximum cover depth The maximum cover height depends on the type of installation, backfill material and its compaction, pipe stiffness class as well as the native soil conditions.

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5. SPECIAL UNDERGROUND REQUIREMENTS 5.1 Road Crossing Road crossings require special attention and requirements. Precautions shall be taken to protect the pipes, which cross underneath roads against the possible consequences of traffic loads. The influence of the wheel load of traffic passing a buried pipe reduces with increased burial depth. A minimum cover depth above the pipes (Detailed in Table 2) shall always be maintained for all stiffness classes. Minimum cover depth can be reduced with special installation such as: i.

Sleeve pipe.

ii. Concrete Protection Slabs. iii. Concrete encasement of the pipe. The below details are considered as a guideline, prior to apply these methods, site team to align with FPI Engineering team to collect the relevant details of the protection slabs. i. Sleeve Pipe. The Glass Reinforced Plastic pipe is nested inside a sleeve pipe. To avoid direct contact between both pipes, spacers are used to centre the GRP pipe inside the sleeve pipe (Figure9). The annular space between the two pipes is grouted. The sleeve pipe should be longer than the width of the road.

Figure-9 ii. Concrete Protection Slabs. Two types of concrete protection slabs exist: a) Concrete Relief Plate. b) Protection slab at grade level a) Concrete Relief Plate:

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This protection slab is specially designed and dimensioned to minimise the transfer of wheel load on the pipe and divert the load away from the pipe (Figure-10). The plate has a rebate which must be kept free from soil during installation (for example by means of synthetic foam). The distance between the relief plate and crown of the pipe shall be 50% of pipe diameter as a maximum. The plate must not be installed too high because the spread of the load will cause increased load on the pipe. The plate shall be positioned at the recommended distance to provide the required protection to the pipe.

Figure-10 Concrete Relief Plate b) Concrete Protection Slab at Grade Level This concrete slab (Figure-11) dissipates the effect of traffic loading and minimise the transfer of wheel load on the pipe by increasing the contact surface between the vehicle wheel and the soil. The concrete slab must be with appropriate length to ensure that the slab is rested on undisturbed walls of the trench.

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Figure 11: Concrete Protection Slab iii. Concrete encasement of the pipe. Encasing the pipes in concrete is an alternative to protect the pipe from excessive traffic load. Precautions to be taken while encasing the concrete are explained below. Pouring concrete around the pipe results in uplifting forces that can damage the pipe and /or joint. To avoid such movement, the pipe should be anchored downward by straps hooked to a rigid base as shown in figure 12. The straps should be of flat material of minimum 25 mm width and strong enough to withstand flotation uplift forces. The distance between straps should not exceed 4 meters, with a minimum of two strap per section length. The straps should be tightened to prevent pipe uplift, but should not be over-tightened to avoid additional pipe deflection.

Figure 12 - Pipe anchored by straps INSTALLATION GUIDELINE UNDERGROUND PIPE SYSTEM | FPI-KSA-FSV-IG-UG

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The pipe should be supported in such a way that the concrete can easily flow completely around and fully underneath the pipe. Also, the supports should result in an acceptable pipe shape (less than 3% deflection and no bulges or flat areas). The concrete must be placed in stages allowing sufficient time between layers for the cement to set and no longer exert buoyant forces

6. BACKFILL AND INSTALLATION SELECTION The installation type and choice of Pipe Embedment Zone material is normally specified by the design engineer, based on the specified pipe stiffness class, maximum burial depths, depth of water table, wheel load, and native soil conditions. 6.1

Foundation, Bedding and Backfill materials.

Most coarse-grained soils are generally acceptable as backfill material for the foundation and pipe embedment zone. The following materials may be used (Table-05) if compacted to the required degree. Table 4: - Standard classification of soils-ASTM D2487

Table 5 - Acceptable Backfill Material Soil Category

Symbol (as per ASTM 2487)

Crushed Rock / Gravel

GW, GP, GW-GC, GW-GM, GP-GC, GP-GM, GM, GC

Sand

SW, SP, SW-SC, SW-SM, SP-SC, SP-SM, SM, SC

The maximum particle size is as follows; Table 6 - Maximum Particle Size

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DN ≤ 450 mm 450 mm < DN ≤ 600 mm 600 mm < DN ≤ 900 mm 900 mm < DN ≤ 1200 mm DN > 1200 mm

13 mm 19 mm 25 mm 32 mm 38 mm

If the native soil meets the specifications in tables 5 and 6 above, the same soil may be used in the Pipe Embedment Zone. 6.2 Migration When backfill materials such as gravels and crushed rocks are placed in a trench adjacent to a finer native material, the finer material may migrate into the coarser material under the flow pressure force of the ground water table. Migration can also occur when selected sand is used as backfill in a trench where the native soil is coarser. Significant hydraulic gradients may arise in the pipeline trench during construction, when water levels are controlled by various pumping or well-pointing methods. Gradients may also arise after construction, when permeable underdrain or when the open graded embedment materials act as a “French” drain under high ground water levels. Migration can result in significant loss of pipe support and increasing pipe deflections that may eventually exceed the design limits of the Glass Reinforced Plastic pipe. The gradation and relative size of the embedment and adjacent native soils must be compatible to minimize migration. In general, where significant ground water table is above the foundation or bedding level and when the native soil is a finer than the backfill, avoid using open graded materials such as crushed rocks and gravel, unless a geotextile filter fabric is used to line the trench bottom and sides. The following gradation criteria may be used to restrict the migration of finer material into a coarser material under a hydraulic gradient. a. D 15 / d85 30

16 - 30

8 - 15

4-7

1-3

Hard

Very Stiff

Stiff

Medium

Very Soft

Blow counts, N (ASTM D 1586) Cohesive Soils

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Granular Soils

6.5

Dense

Compact

Slightly Compact

Loose

Very Loose

Alternative Installations

If the burial depth requirement for the selected pipe stiffness, installation type and native soil group exceeds the limits given tables 6A and 6B, three alternative installation methods may be considered:

6.5.1

•

Wider Trench

•

Permanent Sheeting

•

Cement Stabilized Backfill

Wider Trench

Increasing the trench width allows a deeper installation. 6.5.2

Permanent Sheeting

Permanent sheeting can be used to distribute the pipe’s lateral loads appropriately. The sheeting should be at least 300 mm higher than the pipe crown level and driven below the foundation level. The sheeting system is to be designed by a specialist and the material to be of quality to last the lifetime of the pipe. 6.5.3

Cement Stabilized Sand Backfill

Cement stabilized sand is a mixture of one sack of cement (50 kg) and one ton of clean sand. This backfill material provides excellent support for Glass Reinforced Plastic pipe where native soil conditions are poor. The mixture should be placed in the foundation, bedding, haunches and Pipe Embedment Zone in layers of 15-20 cm. each layer should be wetted with clean water and compacted with plate vibrators before the cement sets. 6.6

Pipe bedding and foundation

To ensure a firm support for Glass Reinforced Plastic pipe, a proper bedding must be provided under the pipe. During trench excavation, a pipe bedding thickness of at least 150 mm must be provided. In case of very poor native soils (silt, clay or mud) an additional 150 mm thick foundation layer must be provided below the bedding. Selected backfill material should be placed at the foundation and bedding layers and thoroughly compacted by plate vibrators or by hand tamping. Wetting of sand bedding/foundation material prior to compaction will improve and facilitate the achievement of the degree of compaction required. Reference shall be made to the soil investigation report to determine the foundation thickness for the specific site conditions. Pipe laying should always take place in dry trenches. It is not acceptable to lay pipes in flooded trenches. The installation Contractor should provide the necessary dewatering equipment to enable installation to proceed in a dry trench. Dewatering equipment should be removed and pumps turned off only after completion of backfilling the Pipe Embedment INSTALLATION GUIDELINE UNDERGROUND PIPE SYSTEM | FPI-KSA-FSV-IG-UG

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Zone, and sufficient backfill has been provided to prevent pipes from floating, if the normal ground water level is above the pipe invert. Prior to lowering of the pipe into the trench small holes should be dug under each joint location (Figure-13) so the pipe does not rest of the joints. The bedding material should provide firm and continuous support over the entire length of the pipe excluding the joint areas.

Figure-13- Proper bedding and support for joints.

Figure-14- Improper bedding and lack of support for the joints Pipes shall be lowered into position after checking the proper levels and alignment of the pipeline. Pipes shall be laid perfectly horizontal and avoid resting the pipe ends on sand piles to avoid any steps between the pipes that will result the joint assembly difficult. 6.7 Pipe Embedment Zone The selected backfill material should be evenly placed and properly compacted on both sides of the pipes. Appropriate hand or mechanical tamping shall be carried out by the Contractor to achieve the specified degree of compaction required by the selected installation type. During the first one or two lifts (lift height shall not exceed 250mm), special care should be taken to place and compact the backfill material under the pipe haunches (Figure-15). The best way to achieve this compaction is to do it manually with the help of a wooden board. This is one of the most important installation steps and should be executed with care. Failure to place and to compact the backfill material under the pipe haunches may cause deformation, localized loads and over deflection of the pipes (Figure-16).

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Figure-15-Pipes laid with haunches properly compacted.

Figure-16-Pipes laid with improper compaction at the haunches Notes: 1. Trench wall inclined shall be as per the soil characteristics and angle of repose. 2. Foundation thickness must be in line with the geotechnical recommendations. 3. The first two lifts ate the pipe zone embedment shall not exceed 250mm. Pipes joined in the trenches should not be left for long periods without backfilling as some joints may rupture due to daily expansion and contraction of the pipes due to ambient temperature fluctuation. However, if the pipes are sufficiently restrained to prevent movement, the joints may be left exposed for an easy visual inspection during the field hydrotest. These joints must be backfilled immediately after the test to avoid damages. INSTALLATION GUIDELINE UNDERGROUND PIPE SYSTEM | FPI-KSA-FSV-IG-UG

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The Contractor should note that the compaction of clean and mixed sands is best achieved when the material is at its optimum moisture content. While the wetting of sand is recommended prior to compaction, trench flooding should be avoided to prevent pipes from floating. Following the first two layers where the backfill has been sufficiently placed, compaction should proceed from the sides of the trench towards the pipe. The Pipe Embedment Zone backfill should proceed in 150 to 300 mm lifts depending on backfill type (see section 6.1). For Gravel backfill 300mm lifts are permitted. The Pipe Embedment Zone backfilling and compaction should continue until the backfill reaches at least 15 cm above the pipe crown. For pipes, larger than 1000 mm in diameter, backfilling the Pipe Embedment Zone should continue to 300 mm above the pipe crown. After completion of backfilling in the Pipe Embedment Zone, native material excavated from the trench may be used to complete backfilling to final grade. No compaction is required in these final backfilling layers except where specified by the Engineer, or in the case of traffic or other high external loads over the pipe where settlement of the native backfill is to be avoided. Caution: Sand layers of more than 300 mm cannot be compacted properly and may result in loss or reduced support for the pipes. The best compaction results are achieved with wet sand near its optimum moisture content. Flooding of the trench must be avoided as pipe floatation may occur. A minimum of 1 pipe diameter of granular backfill is normally required to prevent Glass Reinforced Plastic pipes from floating. For backfill material such as Gravel (Class I) and Sand (Class II) a 200kg plate vibrator is required to compact the backfill in 15cm layers, and a 500kg plate vibrator is required to compact the backfill in 30cm layers. For Class-III and Class-IV backfill materials a 500kg plate vibrator is required to compact the backfill for both lift cases. Before using plate vibrator directly above the pipe crown, insure that backfill reaches 25cm above pipe crown for 200kg vibrators and that backfill reaches 50cm above pipe crown for 500kg plate vibrators. 6.8 Temporary sheet piles and Shoring Special attention and care from the Contractor’s side is required when the Glass Reinforced Plastic pipes are backfilled in sheeted trenches. If sheeting or trench shoring is withdrawn after compaction, hollow spaces will be left and soil pipe support will be lost or reduced. Caution: Sheet piles must be withdrawn in stages as backfilling progresses in such a way that all hollow spaces left behind the sheeting are filled with compacted backfill material. 6.9 Offshore Pipelines This installation method is used for the offshore portion of Glass Reinforced Plastic pipes. The pipe joints are assembled under the water. Steel angle iron lugs will be provided on the two ends of pipe to allow divers to assemble the standard REKA coupling joints under water. It INSTALLATION GUIDELINE UNDERGROUND PIPE SYSTEM | FPI-KSA-FSV-IG-UG

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may be possible to assemble on the barge up to 3 lengths of pipe and to lower the assembled section (total length of 36 m) into the excavated sea bed trench. Spreader beam or sea horse shall be used for lifting the preassembled segments Caution: Standard Glass Reinforced Plastic pipe is not designed to be assembled on-shore in long lengths and then dragged out to the sea. Installing Glass Reinforced Plastic pipe under water requires a trench same as that of the onshore trench, except the fact that the trench width is larger. The typical underwater trench width is equal to 2 x ND, but is no case less than ND + 1 meter. Consult FPI Engineer for recommendation of the minimum burial depth over the pipe crown. The divers should make Backfilling with excavated granular seabed material in maximum 300 cm lifts, paying attention to the placing of the backfill under the pipe haunches. Backfilling should be made evenly on both sides of the pipe to avoid pipe displacement. Vibrators or seabed water jetting may be used for placing and spreading of backfill material. Sufficient counter weight by means of backfill material or sand bags shall be provided soon after the joint assembly to prevent misalignment due to uplift forces as well as turbulent under currents. Protection to be provided for the backfilled sea bed over the pipe trench. Large size stones or rocks (rip-rap) and concrete mattresses may be used for this purpose.

Figure-17-Typical off shore installation

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7. SYSTEM ASSEMBLY Glass Reinforced Plastic pipes are generally joined using Double Bell Couplings in buried installation. Other jointing system such as flanges (inside chambers), adhesive bonded joints, mechanical couplings, Rubber seal lock joints, REKA Seal Lock Joints and lamination joints may also be used for joining the Glass Reinforced Plastic pipes. Refer to the relevant method statements to perform the jointing activity. It is the installation contractor’s responsibility to make the necessary method statements available to the installation team members.

8. SPECIAL REQUIREMENTS 8.1 Standard short pipe lengths Standard short Glass Reinforced Plastic pipe lengths are required in various situations, such as: •

Outside rigid structures (i.e. water reservoirs, pumping station, thrust blocks, valve chambers, manholes etc.)

•

To connect the pipes to a line fitting such as bends or tees inside thrust blocks.

Standard short lengths of pipes shall be planned by the Contractor. Standard short pipe length can be 1.5XND with a minimum of 500mm and a maximum of 2000mm. The length (L) may follow in between a range as per the below on a case to case basis. L=Smaller of 2m or 2XND L= Smaller of 0.5m or 1XND

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Figure-18-Option-01

Figure-19-Option-02 Cautions:

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The expected settlement for massive concrete structure shall be calculated by the geotechnical engineer to determine the number of short pipes & couplers required to withstand the settlement without excessive loads onto the pipes. Backfilling around the concrete structures shall be thoroughly compacted with the same selected backfilling material. 8.2 Wall Penetration Recommended wall penetration protection is as shown in the figure below.

Figure-20

Figure-21

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Figure 22 - Rubber Wrapping 8.3 Pipeline Closures or Make up pieces For a closure in a line it is required to order a special short pipe from the factory with double spigot calibration. The Contractor should clearly indicate in his order that a short pipe closure/make up piece is required. In closure pipes, the length of the machining is equal at least to the width of the REKA coupling plus 30 mm. In case of export jobs or where the site is very far from the factory, cutting and machining of closure pipes must be carried out on site. Glass Reinforced Plastic manufacturer will provide supplementary instructions for export projects during the execution phase. Before ordering a closure pipe, the Contractor should measure accurately the gap between the two ends of the line. The length of the pipe to be fitted must be 32 mm (for ND300 and below 20mm) less than the measured length to allow a gap of 16 mm (10mm for ND300mm and below) between the jointed ends in both couplings. Mark the home line on the machined ends and lubricate them abundantly. The assembly of the short length pipe is made as indicated in the figure-23 below.

Figure-23- Pipe line closure/Make up piece assembly INSTALLATION GUIDELINE UNDERGROUND PIPE SYSTEM | FPI-KSA-FSV-IG-UG

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Caution: When pulling the couplings over the closure pipe it is necessary to pull the second rubber ring smoothly over the chamfered end of the pipe to avoid damaging it. For that purpose, apply a continuous layer of approved lubricant. 8.4 Thrust blocks and anchoring Thrust blocks must be used in pipeline systems wherever thrust loads are expected, such as at: f.

Changes of direction (bends, Tees, Wyes)

g. Cross section changes (reducers) h. Valves and hydrants i.

Dead ends.

The thrust blocks can be dimensioned and designed as per the expected thrust load as well as native soil properties. Thrust block spaces must be foreseen in the design and trench excavations. At vertical bends, the line or the bend must be anchored by thrust blocks or other means to resist outward thrusts. Thrust blocks must be cast against undisturbed trench walls (native soil) and must completely encase the Glass Reinforced Plastic fitting (except at the joint area). The maximum allowable displacement of fittings is 0.5% of the diameter, or 6 mm; whichever is less. The outlet part of the encased Glass Reinforced Plastic fitting in the concrete block shall be rubber wrapped as shown above in figure 22. See appendix II for additional information about thrust blocks. Note: Gravity lines up to 1 bar design pressure do not require thrust blocks. Caution: Always provide a standard short pipe outside thrust blocks (see section 6.1) to protect the pipeline from differential settlement. Nozzle connections should not necessarily be concrete encased. Nozzles are tee branches meeting all the following criteria: 1. Nozzle diameter ≤ 300 mm 2. Header diameter ≥ 3 times nozzle diameter 3. If the nozzle is not concentric and /or not perpendicular to the header pipe axis, the nozzle diameter shall have considered to be the longest cord distance on the header pipe wall at the nozzle/pipe intersection. Caution: Exposed length of fitting shall be considered while designing the thrust volume (minimum distance as shown into figure 18 – options 1) shall be considered. 8.5 Hybrid system

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Hybrid system is a technique in which a combination of restrained and non-restrained piping system is being employed to eliminate the use of thrust blocks. It is an ideal system where dimension constrain exists due to limited space availability such as in plant piping. It is recommended to carry out a detailed engineering to determine the minimum required restrained lengths to be used at the locations of direction changes, Tees, Reducers, End caps, etc. 8.6 Fittings for valve chambers One of the advantages of Glass Reinforced Plastic pipe systems is customized fittings. Using a Glass Reinforced Plastic pipe system greatly simplifies the valve chamber design. Valves must be sufficiently anchored or supported to take the thrust force.

Figure-24

9. PIPE DEFLECTION The deflection of Glass Reinforced Plastic pipe depends on the pipe diameter, stiffness, embedment zone backfill, and native soil classification. Pipe deflection is defined as the percentage reduction in vertical diameter after installation, as shown in figure 25.

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Figure 25-Pipe Deflection % Deflection = 100 x (Actual un-deflected pipe ID - Installed vertical ID) Actual un-deflected pipe ID To ensure that the long-term deflection does not exceed the maximum allowable limit, the preliminary & initial deflection of the pipe must be monitored and controlled on site by the Contractor. Maintaining the deflection within the allowable limit is achieved by proper selection of pipe stiffness, installation method related to the native soil conditions, and maximum burial depth. Measuring pipe deflections is easy and is the best way for the contractor to check if the installation was executed properly. Glass Reinforced Plastic pipes deflection is measured in the following manner: For pipe sizes 800 mm and larger, where human entry inside the pipes is possible, the installed vertical pipe ID can be measured by means of a manual Micrometre at 3 to 4 m intervals. An electronic deflectometer can be used to measure the deflection of pipes of diameter within the range of 150 to 800 mm. A probe with sensor arms is pulled through the line to record the pipe ID on a data logger kept outside the line. The results are then presented on a computer-generated report. Note: It is important that pipe deflection measurements are done at the same time of pipe laying operations and not after. This will allow for early detection of any installation deficiencies and allow corrective action to be taken quickly to reduce the time and expenses necessary to rectify defective installations. 9.1 Preliminary Deflection This measurement should be taken when backfill reaches 30 cm above pipe crown. At this stage the measured deflection should be slightly negative, but not exceeding -2%. A

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negative deflection means the pipe vertical ID has increased because of the compaction forces/stresses coming from the side backfill. A positive deflection (ID < un-deflected ID) at this stage indicates inadequate compaction in the Pipe Embedment Zone, hence improvement in the quality of installation and compaction is required. In such case, it is advisable to remove the backfill to about 1/3 of the pipe ID from the pipe invert level and to re-compact the backfill in stages up to the top of the pipe embedment zone, with special care to the compaction of the pipe haunches backfill area. After this rectification, the preliminary deflection should be measured again. 9.2 Initial Deflection This measurement should be done immediately after backfilling reaches the final grade and after all temporary sheeting has been withdrawn and all de-watering systems have been turned off for two days. The initial deflection limits are set to account for creep and soil consolidation with time (determined by the deflection lag factor). If the initial deflection exceeds the allowable limits as per the AWWA-M45 calculation, and up to 9% of the pipe diameter, the Contractor should re-excavate the trench (by hand from 0.3 m above pipe crown), remove the pipe embedment zone backfill and start re-backfilling the pipe, paying attention to the pipe haunches and backfilling in appropriate lifts to reach the required compaction. If the deflection slightly exceeds the allowable limits, the deflection may be monitored over the following 6 months’ period with monthly deflection measurements. If deflections at the end of the 6 months do not exceed the allowable longterm deflection limit, the pipeline section may be considered as accepted. Any recently installed pipe exhibiting deflections equal or greater than 9% (7% for pipes SN 10,000) must be replaced. Such pipe must not be re-installed nor incorporated in any permanent works on site. 9.3 Final Deflection This measurement should be done at least 6 months after the initial test is done. The maximum deflection at this stage should not exceed the limits specified in table 8.

Table 8 - Maximum allowable deflection Deflection (% of Pipe Diameter) Native soil group* 1 2 3 4 Large Diameter Pipes, DN ≥ 300 - Water and Sewer Initial 4.0 3.5 3.0 2.5 Long Term 5.0 5.0 5.0 5.0 Small Diameter Pipes, DN < 300 - Water Initial 3.0 3.0 2.5 2.0 Long Term 5.0 5.0 5.0 5.0 Small Diameter Pipes, DN < 300 - Sewer Initial 2.5 2.5 2.0 1.5 Long Term 4.0 4.0 4.0 4.0 *Native soil group is based on the soil stiffness classes INSTALLATION GUIDELINE UNDERGROUND PIPE SYSTEM | FPI-KSA-FSV-IG-UG

5 2.0 5.0 2.0 5.0 1.5 4.0

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10. FIELD HYDROSTATIC TESTING Field hydrostatic testing shall be carried out based on separate specific method statement for hydrostatic testing. Contractor shall make sure that the relevant approved document is available at site during this activity. 10.1 Joint Hydrostatic Testing Joint testing is applicable only for diameters of 1200 mm and above. This method is recommended in the case of: •

Non-availability of a sufficient water supply source.

•

Unstable soils, which is a potential problem in the case of section testing

•

Large diameter pipelines where traditional pipe section pressure test is not feasible.

Refer to the user manual for the details of joint tester. Contact our engineers for more information about the joint tester. As laying proceeds, each coupling is tested for its water tightness by applying internal hydrostatic pressure by means of a mobile joint testing apparatus fitted internally and designed to seal internally the gap between the pipe ends. Through the pressure applied, a high thrust result hence the pipes must be solidly anchored with the help of backfilling. The last pipes laid must be at least 2 pipes ahead of those to be tested. Prior to the test, the pipe sections must have at least 1 x DN of cover above the pipe crown, with a minimum of 300 mm and maximum of 1 m. It is not essential to leave the joints exposed to ambient atmosphere in this test method. The test pressure shall not exceed 2 barg. The purpose of the joint test is to provide assurance to the contractor that the two rubber gaskets are installed properly and that the joint is water tight up to 2 barg. Which can allow the contractor to proceed with further installation and backfilling works. Caution: Pipe joint testing shall be performed in well ventilated pipelines. The safety of the operators inside must always be assured. For safety considerations, the operators must preferably work at the free end of the joint tester (near to the pipe access). All operators must be securely hooked to a guide rope with other workers terminating outside the pipeline to allow pulling them out from the pipes in case of an emergency. 10.2 Testing Gravity Lines Two methods are available for testing gravity (PN 1 bar) lines, a low head water test or a low-pressure air test. 10.2.1 Low head water test The Contractor should plug both ends of the pipeline section (between two manholes) with suitable plugs. The test section should not exceed 200 meters. The plugs should have connections for a standpipe (typically 50 or 75 mm in diameter) connected to the pipe plug with a 90degree elbow. At the upstream manhole, the standpipe shall extend 1.2 m above INSTALLATION GUIDELINE UNDERGROUND PIPE SYSTEM | FPI-KSA-FSV-IG-UG

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the crown of the gravity pipe, or 1.2 m above the existing ground water level. This level is called the test level. The test section shall be filled slowly from the upstream manhole while releasing the air out. Allow the water to stand for about 1 hour for stabilization, then add water until the test level is again reached in the standpipe at the upstream manhole. Start the test, and over the next 30 minutes, the amount of water necessary to maintain a constant test level water head shall be measured using graduated containers of water. The line shall pass the test if the exfiltration amount does not exceed 0.02L/mm of nominal bore per kilometre of pipeline per 24h per bar of test pressure applied. A typical test setup is shown in figure 26.

Figure-26 10.2.2 Air Test The Contractor should plug both ends of the pipeline section (between two manholes) with suitable plugs. The plugs should have connections for air and a manometer or air pressure gauge. Air shall be pumped into the line until a pressure of 25 KPa is indicated on the manometer or air pressure gauge. After a 5minute stabilization period, air may be added to INSTALLATION GUIDELINE UNDERGROUND PIPE SYSTEM | FPI-KSA-FSV-IG-UG

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restore the pressure up to 25 KPa. During the test period shown in table 11, if the pressure drop does not exceed 7 KPa, the line shall be considered as having passed the air test. Table 09 - Test time for low pressure air test

Note: In case where the pipes are laid below the ground water table, the test pressure shall be increased by 10 kPa for every 1 meter of ground water above the pipe crown. If the resulting air test pressure exceeds 35 kPa, the air test method should not be used and the infiltration method is recommended. Caution: Air test can be dangerous if the line is not prepared properly and safety precautions are not taken. It is very important to install the test plugs properly and brace them to prevent blowouts. Air pressure must always be relieved before attempting to remove the test plugs. The test equipment should include a pressure relief valve designed to release air and prevent pressure from exceeding 42 kPa.

11. AIR IN PIPELINES, AIR VALVES, AND SURGE CONTROL Air in pressure pipelines can cause major operational problems. Typical problems induced by the presence of such air are the reduction in flow capacity because of reduced crosssectional areas, and fluctuation in flow caused by expansion and contraction of the air pockets in the line. High surge pressures can result from the flow fluctuations, which cause sudden movements of the air from one location to another, followed by slugs of water. Also, surge (water hammer) can occur in pipelines from opening and closing valves and from the start-up and shutdown of pumps. Air can enter a pipeline from many locations: •

Line Drains

•

Negative surges (vacuum) causing air to enter at air valves in the pipeline

•

Intake Source

•

Release of dissolved air from the water by temperature and pressure variation

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•

Draining parts of the pipeline or the pipe system during normal shut-down. In the first instance, air shall be prevented from entering the line. This will reduce operational difficulties.

Suggested solutions for controlling entrapped air in pipelines are as follows: •

The intake point should be provided with low water level pump cut-off

•

Release of air: Air dissolved in the water at the intake and released due to temperature and pressure fluctuations cannot be prevented. However, the quantities of such air are not large and provisions for releasing the air can be made by the means of air valves. Proper selection of air valves is essential.

•

While draining the line, air cannot be prevented from entering the line. Large orifice air valves should be provided for exhausting the air during refilling. Long filling times will allow the complete release of air.

•

Negative surges (vacuum) - Large volumes of air may be involved here and can cause serious operational problems. The best way to prevent air from entering under these conditions is by proper design to eliminate the possibility of water column separation.

•

Studies have shown that suddenly released entrapped air under apparently static conditions creates a situation like a water hammer. Generated pressures can be of the order of several times the pipeline test pressure. Any pipeline material can be seriously affected by the quick increase in the magnitude of pressure loads.

Remedial actions against entrapped air and water hammer are as follows: •

Lay the pipe line essentially to grade wherever possible, avoiding major slopes. It may be advantageous to create artificial high points by providing a small slope of around 3-4 mm per 1000 m to facilitate air collection at high points. Also, for drainage, it is recommended to provide a slope of 1-2 m per 1000m.

•

Automatic continual acting air release valves should be used at all major high points. Almost all the air release valve manufacturers limit the maximum distance between air release valves to around 750 meters

•

Air should be sucked out from pipeline slowly.

•

Maximum filling velocity of the pipeline is 0.3 m/s.

•

Use d/D = 1/10 to 1/15. d = diameter of air release valve D = pipe diameter

•

Using motorized actuated valves is an effective means of limiting positive surges to an acceptable level by controlling the rate of opening and closing of the valves.

•

Flywheels on pump motors allow the pump to keep on running for a short period after any power shutdown, before it gradually stops.

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12. HSE REQUIREMENTS Entrapments, hits and run over by vehicles I.

Collective systems and organizational measures

•

Avoid workers staying inside machinery work zones

•

Have a clearly marked loading/unloading area

•

Coordinate and supervise vehicles displacements, especially reverse ones

II. PPE: Reflective safety vest, safety shoes and safety helmet Vehicle overturning I.

Collective systems and organizational measures

•

Avoid the circulation and staying of vehicles at a distance smaller than 4m from excavation borders

•

Coordinate and supervise vehicles displacements, especially reverse ones.

II. PPE: Reflective safety vest, safety shoes and safety helmet Falling from height I.

Collective systems and organizational measures

•

Close excavation with fences

•

Preparation of wide and moderate slope ramps as trenches access.

•

Do not climb trenches walls

II. PPE: Reflective safety vest, safety shoes and safety helmet Entrapments and burials by detachments I.

Collective systems and organizational measures

•

Daily inspection of trenches walls looking for cracks or unstable materials, especially during and after rainy conditions

•

Cleaning and removal of material in excavation borders in case of caves appearance

•

Avoid the circulation and staying of vehicles at a smaller distance than 4m from excavation borders

•

Avoid any material storage at a smaller distance than 4m from excavation borders

•

Not allow entrance of not accompanied workers in trenches

•

For stable soil, it is allowed a 90° slope between ground and walls. For rest of the types sloped trench walls should be arranged

II. PPE: Reflective safety vest, safety shoes and safety helmet

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Fire, explosions because of existing conductions (gas, etc.) I.

Collective systems and organizational measures

•

Obtain all available information about existing underground conductions

•

Stop all works in case of appearance of sand and/or coloured straps during excavations

•

In case of pipe breakage turn off all the machinery, stop all the works and avoid any source of flames or sparks. Leave the area and inform to supervisors.

II. PPE: Reflective safety vest, safety shoes and safety helmet Cuts, hits, abrasions I.

Collective systems and organizational measures

•

Cover rebar’s ends with plastic protections

II. PPE: Reflective safety vest, safety shoes and safety helmet Loads falling I.

Collective systems and organizational measures

•

Delimited loading/unloading area

•

Avoid under load zone

•

Respect crane safe loading chart

•

Inspect slings to detect damages

•

Use two lifting points being symmetrical to the pipe's centre of gravity.

II. PPE: Safety helmet

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