Method Statement For Tank Survey (mfl) And Repair

CONTRACT No: 560-S28 CORROSION REPAIR AND PROTECTION WORKS

METHOD STATEMENT FOR

TANKS SURVEY USING MFL, REPAIR AND INSIDE COATING

Rev.

Date

Description

Prepared By

Checked By

Approved By

0

21-05-2014

ISSUED FOR APPROVAL

SINOOF

RIZWAN

YASSER EL SAYYED

Engineer

QC Manager

Project Manager

Document No.:01-072-00  

CONTRACT 560-S28 CORROSION REPAIR AND PROTECTION WORKS

TABLE OF CONTENTS 1.0

PURPOSE

03

2.0

SCOPE OF WORK

03

3.0

REFERENCES

03

4.0

PLANTS, EQUIPMENT AND MATERIALS

03

4.1

PLANT AND EQUIPMENTS

03

4.2

MATERIALS

03

5.0.

SITE PLANNING AND PREPARATION

04

6.0

WORK PROCEDURE

04

6.1

PREPARATION

04

6.2

INSTALLATION

04

6.3

REMOVAL OF FORMS

05

6.4

SITE CLEAN-UP AND RESTORATION

06

6.5

SITE WELFARE

06

6.6

ORGANISATION, RESPONSIBILITY & SUPERVISION

06

6.7

WORK FORCE

07

7.0

8.0 9.0

HEALTH AND SAFETY

07

7.1.

RISK ASSESSMENT

07

7.2

ENVIRONMENTAL SAFETY & HEALTH CONTRACTOR REQUIREMENTS

07

7.3.

PROTECTIVE AND SAFETY EQUIPMENT

07

7.4.

CONTRACTUAL REQUIREMENT

07

7.5.

INFORMATION TO PERSONNEL

08

7.6.

EMERGENCY PROCEDURE

08

7.7.

PERMITS REQUIREMENT

08

ENVIRONMENTAL ISSUES

08

8.1.

08

ENVIRONMENTAL IMPACT ASSESSMENT

QUALITY CONTROL

09

9.1.

CONTRACTUAL REQUIREMENTS

09

9.2.

CRITICAL WORKS

09

9.3.

INSPECTION AND TESTING

09

9.4.

REQUEST FOR INSPECTION (RFI)

09

9.5.

FOLLOW UP AND EVALUATION

09

9.6

BEFORE CONCRETING

09

9.7

DURING AND AFTER CONCRETING

09

10.0

SAFETY ACTION PLAN

10

11.0

CONFIRMATION OF INSTRUCTIONS TO OPERATIVES

10

12.0

APPENDICES

10

Method Statement for Tank Survey using MFL, Repair and Inside Coating

Page 2 of 14

Rev. 0

CONTRACT 560-S28 CORROSION REPAIR AND PROTECTION WORKS

1.0

PURPOSE The intent of this document is to provide a complete Method Statement for the use of materials, equipment, tools and plants; it includes the manpower and construction methodology in compliance with RC requirements, drawings and technical specification with safety measures and quality control.

2.0

SCOPE OF WORK The Royal Commission has identified 22 irrigation water tanks under said contract for repair and coating which are located throughout the Jubail Industrial City. The Tanks are circular in section. Some of them are made of complete steel while some are constructed of reinforced concrete floor and steel shell. Due to aging, the internal surface of the tanks needs to be analyzed by magnetic flux leakage technique followed by ultrasound technique for plate thickness. The patch repair of floor plates after survey report is approved by RC and coating of internal surfaces of the tanks is also included in the scope of work. Refer Appendix-3 for the list of sites and Tanks details where the work is to be carried out.

3.0

REFERENCES The following documents has mainly been used as reference in the preparation of this Method Statement

4.0



CONTRACT DOCUMENT



APPROVED CONSTRUCTION EH&S PLAN (CODE-1)



METHOD STATEMENT FOR CONFINED SPACE (CODE-1)



RC IFC 560-801-20TY-CE-002



RC IFC 560-801-20TY-CE-029: LOCATION PLAN AND AS BUILD DETAILS OF STEEL TANKS



RC IFC 560-801-20TY-CE-030 : REPAIR DETAILS OF STEEL TANKS



RC GLS SEC. 09960 HIGH-PERFORMANCE COATINGS



RC GLS SEC 05120 STRUCTURAL STEEL



RC GLS SEC 05540 FLOOR PLATES

PLANT, EQUIPMENT AND MATERIALS 4.1 List of Equipment 1. MFL Instrument 2. Total Station 3. Level machine 4. Generator Set 5. Concrete Grinder 6. Air Blower 7. Welding Plant 8. Air Compressor 9. Exhaust Fans 10. Ventilation Fans and Shoots 11. SCBA 12. Fire Extinguishers 13. Potable Welding Machine Permits to be attained

Method Statement for Tank Survey using MFL, Repair and Inside Coating

Page 3 of 14

Rev. 0

CONTRACT 560-S28 CORROSION REPAIR AND PROTECTION WORKS 1. 2. 3. 4.

Encroachment Permit Work Permit Hot Works Confined Space Permit

4.2 MATERIALS Following materials will be used at the site 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.

Scaffolding pipes C-Clamps Joint clamp Levelling plump Hand Level Right angle Warning Tape U-Jacks 2”x2” Timbers 2”x4” Timbers Ladders Toe Boards Welding accessories RC approved coating Materials Approved epoxy filler for filling pits on steel surfaces

Material handling and delivery on site Materials will be delivered and received in the lay down area store room, in secured and controlled room, or temporary lay down area at site. For the ready mix concrete it will be deliver on site by transit mixer and it will be poured using a concrete pump. 5.0. SITE PLANNING AND PREPARATION Saudi Withcon shall define any precautions needed to carry out safety the main work filling of the main form work permit (hot or cold permit). In addition contractor shall to fill confined space entry permit reporting specific precautions are to follow to ensure that all workers involved in confined space work safely. Saudi Withcon has to ensure satisfactory preparation of the work area and verify that all precautions considered necessary for the safe completion of the work are installed. Preparation of a confined space, so that it can be entered safety may include depressurizing, draining, washing out, inserting, ventilating, shutting off, blanking, isolation or power, etc. The preparation may be carried out a previously issued Primary Work Permit (Cold or Hot). A marked up P&ID will be attached to the Permit showing isolation points-blinding, separation, etc. Following recommended work practices are reported 5.1 ELECTRICAL ISOLATION OF THE CONFINED SPACE Tanks / Vessels containing driven equipment must be effectively isolated by blinds and/or lock system from every source of motive power. For electrically driven equipment (e.g. agitators, fan), switchgear must be locked in isolated position, labelled and the key retained under control of the authorized person. In cases of other means of motive power, suitable positive means of isolation must be devised in each case. De-energization work permit must be issued.  More details are reported at the tag and lock-out procedure.

Method Statement for Tank Survey using MFL, Repair and Inside Coating

Page 4 of 14

Rev. 0

CONTRACT 560-S28 CORROSION REPAIR AND PROTECTION WORKS

5.2

PHYSICAL HAZARDS PRECAUTIONS. Temperature inside confined space should be reduced to near the ambient temperature as is practicable. Where it is not possible to reduce the temperature to less than 10˚C above ambient, it shall be defined the length of time that the operator can remain inside the confined space. In any case the temperature has not to be more than 45˚C. Mechanical or forced ventilation should be maintained while the operators are in the confined space to provide some cooling effect.

5.3

OXYGEN DEFICIENCY/ ENRICHMENT PRECAUTIONS. Conditions in surrounding areas must be checked including Oxygen test to ensure that neighbouring operators and maintenance will not bring any changes which could be detrimental to the persons inside the confine space. Saudi Withcon shall examine the prepared confined space and, if he considers the preparation sufficient, shall request a gas test to determine any concentration of harmful vapours and/or adequacy of the Oxygen content. The minimum level of oxygen required before entry is allowed, with or without breathing apparatus, is 19.5%. Only workers who are trained and qualified to use the monitoring equipment should carry out monitoring. Mechanical or forced ventilation should be carried out to purging the confine space.

5.4

FLAMMABILITY, FIRE AND EXPLOSION. Fires and explosions can result from accumulations of flammable vapours and/or dust in the presence of a source of ignition. Mixtures of flammable vapours and air can only be ignited if the hydrocarbon air ratio is within the flammable range. In general, if the oxygen content in hydrocarbon air mixtures can be maintained below 10% by volume, a fire/explosion cannot occur. Hot work must not be undertaken if the explosive meter reading exceeds 1% LEL (Low Explosive Limit) without breathing apparatus, is 19.5%. Monitoring alarm system shall not be set to activate about 20% LEL. Only workers who are trained and qualified to use the monitoring equipment should carry out monitoring.

5.5

CHEMICAL HAZARDS PRECAUTIONS. Chemical substances can be toxic. Toxic substances can cause injury, acute or long-latency illness, or death, depending on the concentration and duration of exposure and the characteristics of the substances. A toxic substance can cause harm by inhalation, ingestion, skin or eye contact. It can affect the tissue at the point of contact, or organs remote from the point of contact. Corrosives destroy the tissue and may leave permanent injury or scars. Hazard information of the substances has to be sought on the Material Safety Data Sheets. Hazard substance test has to be carried out before worker entries inside the confined space. It is recommended that a level of the chemical is not greater than 50% of the relevant published Occupational Exposure Limit (OEL). Only workers who are trained and qualified to use the monitoring equipments should carry out monitoring.

5.6

SAFETY EQUIPMENT FOR CONFINED SPACE WORK. A worker entering a confined space shall be equipped with all safety apparatus, testing and monitoring equipment relative to the hazard/risk assessment for that confined space. If ventilation is considered adequate Saudi Withcon must assure that the supplying cover all period; instead a supplied air breathing apparatus (self-contained or airline respirator) shall be wear if hazard/risk assessment recognizes need for use them. Canister type respirators are not suitable for confined space entry and must not be used. The priority of Saudi Withcon is to establish safe natural working atmosphere within the confined space; the use of breathing apparatus must be the last resort.

5.7

COMMUNICATION AND RESCUE TEAM. A qualified worker who is experienced and trained in all aspects of confined entry work shall be present to supervise workers who are in confirmed spaces and shall be responsible for all work and rescue procedures at all times. An appropriate number of standby workers trained in first aid (CPR)

Method Statement for Tank Survey using MFL, Repair and Inside Coating

Page 5 of 14

Rev. 0

CONTRACT 560-S28 CORROSION REPAIR AND PROTECTION WORKS and rescue procedures must be in attendance and continuously monitor the workers in the confined space. At all times, the standby worker must be prepared and be appropriately equipped to carry out rescue. Adequate provision should be made for the continuity of supervision at shift changeover or if work continues outside normal hours. A communication system must be provided:  From the worksite to outside rescue agencies.  In place between the worker in the confined space and the standby worker. This may be visual, twoway radios, or hard line communications. 5.8

OTHER PRECAUTIONS. Barricades shall be provided to keep vehicles and pedestrian traffic clear of the area, as required. Adequate fire-fighting equipment shall be readily available. Special non-sparking (non-ferrous) tools should be used where necessary. Lights and other electrical equipment must meet the requirements of the RC Guideline and Specification. Ground fault circuit interrupters may be used as an additional protection for operators of electrical equipment.

6.0

WORK PROCEDURE Following major activities / steps are involved for complete repair of the Tanks.

6.1 TANK SURVEY USING MFL AND ULTRASOUND TECHNIQUE INTRODUCTION TO MFLTECHNIQUE A ferromagnetic specimen is magnetised and depending upon the level of induced flux density, magnetic flux leakage due to both near- and far-surface flaws is detected by the voltage induced in a detector coil or a Hall effect element, which is traversed over the surface of the specimen. This method is not limited to surface-breaking or near-surface flaws, but actually becomes increasingly sensitive to far-surface flaws with increasing levels of magnetisation. Also, the output from the detector can be amplified, filtered, digitised, etc and stored to produce automated inspection systems. INTRODUCTION TO ULTRASONIC TECHNIQUE Ultrasonic methods of NDT use beams of mechanical waves (vibrations) of short wavelength and high-frequency, transmitted from a small probe and detected by the same or other probes. Such mechanical waves can travel large distances in fine-grain metal, in the form of a divergent wave with progressive attenuation. The frequency is in the range 0.1 to 20 MHz and the wavelength in the range 1 to 10 mm. The velocity depends on the material and is in the range 1000-6000 m/s. The technique detects internal, hidden discontinuities that may be deep below the surface. Transducers and coupling wedges are available to generate waves of several types, including longitudinal, shear and surface waves. This applications is very common for internal testing of thin plate thickness of steel tank PROCEDURE The bottom plate of steel tank will be inspected by this technique. The flaw models for pitting and local corrosion in tank floors may be a series of flat-bottomed cylindrical holes and rectangular grooves having various widths and depths. The magnetization characteristic curve for the steel plates will be examined and the value of saturated magnetic flux density (Bs) will be estimated (T) for the plain carbon steel. The experimental setup consisting of an electrically magnetizing yoke, a magnetic sensor, a controllable sensor positioned and test specimen is shown in Fig.1.

Method Statement for Tank Survey using MFL, Repair and Inside Coating

Page 6 of 14

Rev. 0

CONTRACT 560-S28 CORROSION REPAIR AND PROTECTION WORKS

The measurements of magnetic leakage flux density distribution will be done using a Gaussmeter and the sensor head for which consist of an axial type Hall probe which has an active area of 0.1 mm ´ 0.1 mm and a thickness of 0.1 mm. The specimens will be magnetized by direct current at a constant average magnetic flux density. This can be checked by using a search coil and a flux meter. The Hall probe scans across the center of flaws by taking small precise step using a computer controllable positioning motor. At each step, the horizontal (Bx) and vertical (By) components of magnetic leakage flux density in the upper spatial domain can be accurately measured. Then, the acquired data of Bx and By are stored into a personal computer, for the correction of background noise due to stray field arising immediately from the magnetizing yoke. In this experiment, the lift off value, which is defined as a distance from the uppersurface of test specimen to the central position of Hall probe, is set to be constant. This "lift off" is denoted by "y" mm in this paper. Measurements of the magnetic flux density (Bx and By) at the lift off value y=1.0 mm in the upper spatial domain can be done by scanning with the Hall probe across the center of flaws. After the corrections of background noise, the distribution profiles of Bx and By vs sensor's position were obtained. Some examples of the results on the horizontal component of magnetic leakage field (Bx) are shown in Fig.2 and Fig.3 for various sizes of flaws.

Method Statement for Tank Survey using MFL, Repair and Inside Coating

Page 7 of 14

Rev. 0

CONTRACT 560-S28 CORROSION REPAIR AND PROTECTION WORKS INVESTIGATION RESULTS The Coloured continuous scanning of the floor showing remaining the thickness corresponding to 20%, 40%, 60%m 80% thickness loss due to corrosion will be submitted to Royal Commission. The area of less than 4mm thickness remaining on the floor of the tank is recommended for patch repair.

6.2 PATCH REPAIR OF DAMAGED PLATES 6.2.1 Mark the areas of less than 4mm thickness on the floor of the tank 6.2.2 The marked areas as per survey report will be repaired only 6.2.3 The repair will be done by patching plates over the affected area 6.2.4 Verification will be done for the marked areas bu cutting plates as required 6.2.5 The minimum size of the plate to be patched is 300mm x 300mm 6.2.6 The patch plates size will be determined by extending at least 150mm beyond the edge of damaged area with less than 4mm thickness 6.2.7 Patching will be done by welding the new plate over the existing one 6.2.8 Grind the edges of patch plate to smooth at ends all around 6.3 REMOVAL OF EXISTING INTERNAL COATING 6.3.1 6.3.2 6.3.3

Remove the internal coating by light grit blasting.(SSPC-SP5, White metal blast cleaning) Grid blasting on concrete surface will be avoided Test the prepared surface to anchor profile which shall be in the range of 35-75 micron

6.4 COATING OF INTERNAL SURFACE OF THE TANK 6.4.1 6.4.2 6.4.3 6.4.4 6.4.5

Clean and clear the site Fill pits on the steel surface with epoxy filler Apply primer to steel surface Apply intermediate and top coat Test the coating for pinholes, blusters, DFT and Adhesion

6.5 SITE CLEAN-UP AND RESTORATION 6.5.1 Remove and transport debris and rubbish in a manner that will prevent spillage on existing canal adjacent to the working area. 6.5.2 Clean and clear the site 6.5.3 Remove all tools used, equipment and materials from the site upon completion of work. 6.5.4 Clean and repair damages caused by installation and construction activities used for temporary works. 6.5.5 Restore existing and permanent facilities used during construction to original or better condition. 7.0

SITE WELFARE Welfare facilities on site shall be provided like rest areas, toilet or washrooms, shaded area, chilled water dispensing area, smoking area, prayer area.

8.0

HEALTH AND SAFETY

8.1 RISK ASSESSMENT Detailed Risk assessment for all activities is provided in the Appendix-2

Method Statement for Tank Survey using MFL, Repair and Inside Coating

Page 8 of 14

Rev. 0

CONTRACT 560-S28 CORROSION REPAIR AND PROTECTION WORKS 8.2 ENVIRONMENTAL SAFETY & HEALTH CONTRACTOR REQUIREMENTS Section II series 15 (Personal Protective Equipment)     

Concrete wash pits will be provided at site for the disposal of concrete. Skips will be provided at site for garbage collection and will be disposed of properly. Spill tray will be provided for the genset or compressor in order to avoid oil spill. Chemical storage area will be set in accordance with RC requirement. Spill kit will be kept at site

8.3 PROTECTIVE AND SAFETY EQUIPMENT        

Hard hat, to be worn at all times Safety shoes, to be worn all times Safety gloves, to be worn all times Safety goggles, for workers around working equipment- (Tinted type for outdoors). Full Body Harness with Double Lanyard High visibility vest, especially for workers around machinery, to be worn all times Ear plugs & Ear Muff. Mask(N95 Dust Mask)

8.4 CONTRACTUAL REQUIREMENT 

SECTION II – 200 SERIES (15: Personal Protective Equipment):

15.1 Personal Protective Equipment shall be considered only as a “last resort of defence” against potential risks and hazards. Where so ever possible hazards and risk are to be addressed and reduced by other means. 15.2 based upon the findings of 3.1.3 Section 1 and 11 above the contractor shall ensure that adequate stock of Personal Protective Equipment are readily either available on site or issued to personnel. PPE shall be considered as consumable items. 15.3 All PPE utilised shall be manufactured to a recognized international acceptable standards

8.5. INFORMATION TO PERSONNEL All the manual workers that will be working in the site will be informed and reminded by conducting morning tool box meeting in order to continuously remind them of the existing safety risk and it will be handled by the designated site supervisor and sometimes with the presence of the safety personnel. 8.6. EMERGENCY PROCEDURE The following are the safety procedure that will be implemented in case of accident.  

In case of traffic accident or person hit by the equipment notify immediately the police and emergency crew do not engage in moving the person who are injured. Emergency contact numbers will be prominently posted on bulletin board. Police — 999 Ambulance — 997 Industrial security — (03) 341 7777 Fire brigade — 998

Method Statement for Tank Survey using MFL, Repair and Inside Coating

Page 9 of 14

Rev. 0

CONTRACT 560-S28 CORROSION REPAIR AND PROTECTION WORKS Waste water SCECO Potable water 

— — —

(03) 341 0109 (03) 341 7341 (03) 341 6095

First Aid box will be readily available on site.

8.7. PERMITS REQUIREMENT The following are the required permit before implementing the activity:    

Encroachment permit Work permit (Excavation permit & Hot work permit if any) Transport Permit Confined Space Entry Permits (Daily basis)

8.8 FURTHER PRECAUTIONS The SWCL-HSE Department will give advice of safety equipment, clothing and special precautions that may be required. 9.0

STARTING THE WORK Entry Site Supervisor verifies at site the full compliance with the precautions with the work permit and authorizes the work signing. Entry Site Supervisor shall watch that the work is carried out complying with all precautions stated on the work permit and that unexpected hazards appear during the work. He shall check the equipment/area several times during progress of work to ensure that safe conditions are maintained after work commencement. If the equipment or area becomes hazardous Entry Site Supervisor will and must stop the work, withdraw the permit and not issue it until the hazardous condition has been corrected. The work permit has to reissue just when the area or equipment is brought safely. Entry Site Supervisor may also seek counsel or assistance from SWCL-HSE Department for any argument concerning safety. Entry Site Supervisor signs the permit to signify that he accepts the job under prescriptions and that all workers assigned to perform the job are performed. As soon as the permit is been issued Entry Site Supervisor has to perform the work to ensure that all instruction and/or limitation reported on the permit followed. If changes during the activity that can affects to the safety occur, the permit has to be reissued. Entry Site Supervisor has the responsibility to cancel the permit and reissued a new one. Entry Site Supervisor and the SWCL-HSE Department have the authority to withdraw or to stop the hot work if hazard conditions occur. As soon as the work is finished confined spaces management will sign off the work permit. Refer Appendix—02 for Confined Space Entry permit sample and confined space entry management for issuing and closing the permit.

10.0

CONFINED SPACE ENTRY COMPLETION As soon as the work is finished confined spaces management will sign off the work permit. Refer Appendix—02 for Confined Space Entry permit sample and confined space entry management for issuing and closing the permit.

Method Statement for Tank Survey using MFL, Repair and Inside Coating

Page 10 of 14

Rev. 0

CONTRACT 560-S28 CORROSION REPAIR AND PROTECTION WORKS

11.0

PERMITS REQUIREMENT

The following are the required permit before implementing the activity:

12.0



Encroachment permit



Confined Space Entry permit



Work permit (Excavation permit & Hot work permit if any)

EMERGENCY PROCEDURE The following are the safety procedure that will be implemented in case of accident.  In case of any emergency, standby man will immediately inform the personnel inside the confined space by raising an alarm or horn to evacuate the area.  Standby man / work supervisor should be accountable for all entrants, prevent anybody from entering the workspace.  Standby man / work supervisor will summon external emergency team in case of any retrieval operation.

12.1

EMERGENCY NUMBERS 

In case of traffic accident or person hit by the equipment notify immediately the police and emergency crew do not engage in moving the person who are injured.



Emergency contact numbers will be prominently posted on bulletin board such as;

 12.2

Police

—

999

Ambulance

—

997

Industrial security

—

(03) 341 7777

Fire brigade

—

998

Waste water

—

(03) 341 0109

SCECO

—

(03) 341 7341

Potable water

—

(03) 341 6095

First Aid box will be readily available on site. THE STANDBY MAN The confined space standby man has a key role to play when a confined space emergency arises. Having established a system of communicating with the work party, he must be quick to respond when any emergency arises-either inside or outside the confined space. A key task is to raise the alarm if the work party gets into difficulties. This may be in the form of a klaxon/air horn or by the radio. The ASI completing the entry safety certificate will decide when radio is essential (e.g. when the work is in a remote area of the plant where an air horn is likely to be ineffective).

12.3

WORK PARTY SUPERVISOR Is the responsible for ensuring that all members of the work party understood the precautions lay down on the safety/clearance certificates and the standby man meets the criteria specified in safety program.

Method Statement for Tank Survey using MFL, Repair and Inside Coating

Page 11 of 14

Rev. 0

CONTRACT 560-S28 CORROSION REPAIR AND PROTECTION WORKS 12.4

AUTHORIZED SAFETY INSPECTOR (ASI)  In determining the need for a written emergency plan, the ASI will consider the site location and any special requirements of the confined space (e.g. presence of toxic gases; restricted movement; limited access/egress). If required as determined by the risk assessment. The ASI will, in conjunction with the work party supervisor, prepare the plan. The plan should consider the need for:  Specialist equipment (e.g. tripod winches, fall arrestors)  Additional rescue resources  Communication equipment (radio)  Resuscitation equipment  Prior to the entry, the ASI must convene a meeting with all personnel involved in the entry and inform them of the content and requirements of the emergency plan.

12.5

RULES FOR RESCUE OF PERSONNEL IN CONFINED SPACES 1. If an emergency occurs, the standby man should call/radio for help before rescue is attempted. 2. It must be treated as if it resulted from an abnormal atmosphere and SELF-CONTAINED BREATHING APPARATUS must be worn. A 10-minute rescue set must be available in case it is needed to assist victims breathing. 3. If the victim is unconscious remove him from the confined space immediately. In doing so, be as gentle as possible so as not to aggravate any injuries the victim may already have sustained. 4. If the victim is conscious and no apparent abnormal atmosphere is present, check the injuries, apply first aid if appropriate, prepare victim for removal soonest. 5. Once outside the confined space, render whatever first aid you are qualified to give until medical help arrives.

12.6

DUTIES OF STANDBY MAN FOR WORK INVOLVING BA IN CONFINED SPACE 6. He must position himself in a safe area where he can observe the men working and have with him a radio. 7. He must remain in visual and/or audible contact with personnel inside the confined space. He must also remain in visual contact with the back-up team. 8. The standby man must be equipped with an audible alarm which he must use to warn personnel to leave the confined space. 9. He must remain in visual contact with the Trolley man in order to advice the personnel within the confined space to leave, should the air supply reach a safe minimum level. 10. The signals to be used must be discussed and agreed between the Standby man and Trolley man before work starts.

12.7

DUTIES OF TROLLEY MAN 1. Ensure that all the equipment is suitable for the job and that it is in good working order. Must check that all visible/audible alarms are working. 2. Liaise with ASI as to the safe location of the trolley and air lines taking into consideration wind direction and equipment layout. 3. Ensure air supply to personnel is adequate and give timely warning of need to retire to change air bottles. 4. Ensure that personnel entering the restricted area are aware that BA masks must be worn when inside the restricted area.

Method Statement for Tank Survey using MFL, Repair and Inside Coating

Page 12 of 14

Rev. 0

CONTRACT 560-S28 CORROSION REPAIR AND PROTECTION WORKS 5. Read and understand the instructions attached to the air bottle trolley. 13.0.

VALIDITY OF HOT WORK PERMIT The period of validity of the permit must be stated by Entry Site Supervisor. If the work inside confined space cannot be completed in one shift the permit shall be endorsed for continuation of the job. This is to ensure that the job is properly handed over and that the new men understand work and precautions to be taken. The handing over has to be carry out in presence of Entry Site Supervisor and the SWCL-H SE Supervisor.

14.0

QUALITY CONTROL 14.1.

CONTRACTUAL REQUIREMENTS

 Prior to the construction activity RC Engineer shall inspect the area to verify the site conditions.  RC Engineer shall inspect the approved materials which will be incorporated into works.  RC engineers shall inspect hold point release (HPR) and witness points as per ITP. 14.2.

CRITICAL WORKS

The possible critical work for this activity is during the excavation & concrete pouring, could be the possible cave-in of excavated area due to softening of sub-soil or erosion due to water seepage and the presence of concrete pump & mixer during concrete pouring activities. 14.3.

INSPECTION AND TESTING

Inspection of Formwork shall be done as per the approved Inspection & Test Plan (ITP). Refer Appendix-1 for ITP. 14.4.

REQUEST FOR INSPECTION (RFI)

Request for Inspection of Work (RFI) shall be issued to RC Field Engineer 24 hours in advance. 14.5.

FOLLOW UP AND EVALUATION

We intend to follow up and evaluate our performance by constantly implementing strict quality control as this is the most critical activity that can affect our progress and constantly monitoring it and implement measures to expedite this activity. The crewing system shall be monitored constantly in order to meet the required volume installed and any delays shall be recorded and evaluated in order to implement measures and improvements to augment the productivity.

Method Statement for Tank Survey using MFL, Repair and Inside Coating

Page 13 of 14

Rev. 0

CONTRACT 560-S28 CORROSION REPAIR AND PROTECTION WORKS

12.0

CONFIRMATION OF INSTRUCTIONS TO OPERATIVES

Those names listed below confirm receipt of the method statement and have had the contents explained to them/understand it and are aware of the site ES&H requirements. Name

Position

Date

Signature

Note to contractor supervisor – Any significant change from this method statement requires it to be revised and resubmitted to OBI before work can commence.

13.0

APPENDICES APPENDIX-1

RISK ASSESSMENTS

APPENDIX-2

CONFINED SPACE ENTRY PERMIT

APPENDIX-4 CONFINED (MANHOLE/TANKS)

SPACE

ENTRY

LOG

APPENDIX-5

CONFINED SPACE MONITORING SHEET

APPENDIX-6

COLD WORK PERMIT

APPENDIX-7

HOT WORK PERMIT

APPENDIX-7

CONFINED SPACE AWARENESS TRAINING

Method Statement for Tank Survey using MFL, Repair and Inside Coating

Page 14 of 14

SHEET

Rev. 0