KOC Excavation Procedure

KOC.SA.026 - Excavation Procedure Page 1 of 11

Excavation Procedure Document Number: KOC.SA.026 Approver: (Technical)

Manager MP(I)

Author:

TL Safety

Manager HSE

Document Coordinator

TL Standard

Scope:

All KOC Directorates

Control Tier:

Tier 3

Issue Date:

26th August 2008

Issuing Group:

HSE Group

Revision / Review Date:

31st May 2011

Next Review Date:

30th May 2014

Approver: (Administrative)

1.0

Purpose / Scope The purpose of this procedure is to establish the precautions and conditions considered necessary for safety of the personnel involved in excavation work as well as integrity of above / underground services &/or facilities where such excavation work shall be carried out. The procedure is also aimed to define the roles & responsibilities of personnel associated with requesting, approving and carrying out excavation in areas under KOC jurisdiction. The procedure is applicable to all activities & facilities where excavation is carried out for maintenance, construction or inspection need. It is to note that requirement of work permit for excavation work shall be dealt in compliance with “Permit to Work Procedure”.

2.0

Definitions Excavation: Excavation is a man made cut, cavity, trench or depression in an earth surface formed by earth removal. Manual Excavation: The excavation without using any powered equipment or excavating machinery such as backhoe, loader, Jack Hammer etc. Mechanical Excavation: The excavation work using powered equipment or excavating machinery such backhoe, loader, Jack Hammer etc. Excavation Notification: Excavation Notification is a document to notify concerned authorities, who have responsibility and jurisdiction for safety & integrity of aboveground and / or underground services existing at the proposed site of excavation. Metal Detector: It is a device to screen the excavation area to mitigate the risk of damaging unknown pipelines, cables and utilities. Cave - ins: It is collapse of the trench side walls due to weight of the adjacent soil. A cave – in can drop several cubic meters of soils on trench worker. Sloping: Sloping is angling the sides of an excavation to prevent cave – ins. Benching: It is also one of the measures to prevent cave – ins by cutting trench sidewalls to form one or more steps. Shoring: Shoring involves the use of engineering structures (such as cross braces, vertical & / or horizontal rail, polling boards etc) to support a trench side walls. Backfilling: It is an activity to fill-in (with soil) a trench that is no longer needed and returning the area around its original condition. Revision Date: 31st May 2011

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3.0

General Requirements 

KOC HSEMS Element HSE – 03 - 1

4.0

Key Responsibilities

4.1

Permit Applicant / Initiator of Excavation Notification:

4.2



Initiate Excavation Notification informing concerned authorities, who have responsibility and jurisdiction for safety & integrity of aboveground and / or underground services existing at the proposed site of excavation.



Enclose drawings & sketches (with the Excavation Notification) marking the proposed site of excavation.



Identify the above / under ground services (such as pipelines, cables, sewage, flume, tunnel etc) before excavating the area without damage to those services.



Ensure risk assessment and mitigation of potential hazards associated with proposed excavation work.



Conduct Job Safety Analysis prior to applying the appropriate work permit (Cold Work Permit for Manual Excavation and Hot Work Permit for Mechanical Excavation) for carrying out excavation work.

Asset Owners for Above / Underground Services 

4.3

Permit Issuer 

4.4

4.6

The respective asset owner for aboveground / underground services will indicate (in the Excavation Notification); the required precautionary measures to be taken preventing any damage to those services at the proposed site of excavation.

Ensure safety & integrity of the worksite prior to issuance of appropriate permits (Cold Work Permit for Manual Excavation and Hot Work Permit for Mechanical Excavation) for safe work execution.

Worksite Supervisor 

Must not excavate without a valid excavation notification & authorized work permit.



Ensure safety & suitability of the equipment & materials to be used for excavation.



Conduct Tool Box Talk briefing the workers on potential hazards and precautionary measures to be taken during excavation activities.



Verify the existence of above / underground services before excavating the area.



Barricade the site of excavation along with the warning notice, signs and flashing lights to alert the people approaching worksite.



Check the excavation safeguards (such as shoring, sloping & supporting system) daily before starting the job & after every rain storm or other hazardous occurrence.



Fill the excavation checklist (enclosed at Appendix - 1) ensuring safety & integrity of the worksite.

Asset / Directorate HSE Teams 

Conduct periodical inspection of excavation site to assure the procedural compliance.



Advise the Permit Applicant & Permit Issuer for corrective measures in case discrepancy is noticed at the site of excavation. Revision Date: 31st May 2011

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5.0

Safety in Excavation

5.1

Hazards of Excavation: The following hazards may be encountered while excavating or working inside a trench: 

Cave – ins or collapse of soil / earthwork



Buried alive under earthwork / collapsed soil



Underground obstruction or damage to buried pipelines & services



Accidental fall of personnel or equipment inside a trench



Struck / hit by excavating machinery



Flammable & / or toxic gas release



Fire & explosion



Electrical shock due to contact with energized electrical / telecom cable.



Drowning due to water seepage into trench



Soil vibration due to machinery / heavy vehicles operations in the vicinity.



Possible presence of explosive devices



Lack of Oxygen or asphyxiation



Damage to shallow underground services due to weight of heavy equipment such as mechanical excavator.



Observing wet soil (mixed with water) or reaching water table.



Observing contaminated soil

The above – mentioned list is not exhaustive and it is recommended to carry out a site specific risk evaluation to identify additional hazards as well as to incorporate mitigation accordingly.

5.2

Control of Excavation Hazard Excavation accident can only be prevented by identifying & controlling their inherent hazards by:  Evaluating the site before and after excavation 

Site Specific Risk Assessment & Job Safety Analysis



Approval and authorization through Excavation Notification & Work Permit

Based on the site specific risk evaluation; it is advisable to develop an excavation plan addressing the following aspects: 

Size and purpose of excavation



Proposed excavation method (i.e. manual or mechanical)



Nature of soil being excavated.



Nature of soil surrounding the excavation



Stability of adjacent structure.



Position of any underground services (such as pipelines, cables, utilities) Revision Date: 31st May 2011

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5.3



Sources of soil vibration



Traffic condition on the adjacent road.



Weather & soil moisture condition

Excavation Notification & Work Permit Excavation Notification & appropriate work permit(s) are essentially required for all excavation work regardless of its depth. The following considerations shall be taken into account in this regard: a) Prior to raising an Excavation Notification, the proposed site of excavation must be thoroughly inspected to assess any underground / aboveground obstructions such as pipelines, cables, manholes, fire hydrants etc. b) The excavation notification must accompany a clear drawing of the proposed excavation site to help specifying precautions prior to its endorsement. c) The excavation notification shall be endorsed by concerned authorities, who have responsibility and jurisdiction for safety & integrity of above / underground services existing at the proposed site of excavation. d) The excavation notification has to be endorsed by Fire Team / Area Fire Station prior to digging / excavating / cutting within the bunded area of the crude oil storage tank. e) In addition to excavation notification, a hot work permit shall be required for any excavation work involving mechanical excavator; whereas cold work permit is needed for manual excavation. f)

5.4

The excavation notification as well as work permit must be cross referenced with the other live permits & excavation activities in the vicinity of proposed excavation site.

Precautionary Measures for Excavation The following precautionary measures must be taken to ensure safety of the personnel as well as integrity of the worksite: a) No excavation work in KOC area shall be taken without ensuring EOD clearance for that location. b) No mechanical excavation shall take place closer than 5 meters to any hydrocarbon carrying pipeline. Such restriction will apply even for levelling (with the use of mechanical excavator) at a worksite near hydrocarbon carrying pipelines. c) Similarly no mechanical excavation shall take place closer than 3 meter to a nonhydrocarbon carrying pipeline, cables and services. However for any mechanical excavation closer than 3 meter to pipelines, cables or services, it is recommended to apply Management of Change, thorough risk assessment and control measures. d) In order to reduce the risk of striking the pipe or underground services, the excavation will start at the side of the pipeline or midway between parallel lines. Manual slit trench shall be done along the length of identified underground services at appropriate intervals in the area marked for excavation in order to expose and positively locate such known or suspected underground services before commencing the use of mechanical excavator at the work site. e) Ground conditions shall also be assessed to confirm additional protection for shallow buried services prior to deploying any mechanical excavator at site.

Revision Date: 31st May 2011

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KOC.SA.026 - Excavation Procedure Page 5 of 11

f)

Excavations adjacent to buildings or other obstructions may require temporary support, and accordingly the relevant safety instruction must be stated in the Excavation Notification before taking up excavation activity.

g) For any excavation deeper than 1m, suitable ladder must be positioned projecting a minimum of 1 metre above the edge of the excavations. Ladders shall be provided every 7.5 meters (25 feet) of lateral travel in the trench. Ladders shall be securely supported at the bottom as well as at the top. h) Any walkway across trench shall have scaffold type platform with handrails to protect personnel from falling into it. i)

All trenches shall have barrier (such as fixed guardrails) and warning notices clearly displayed. Flashing lights are mandatory during poor visibility.

j)

Excavated material shall be placed at a distance not less than 1m from the edge of the excavation for depth up to 1.2 meter. Accordingly placement of excavated material shall be increased proportion to the depth of excavation.

k) Heavy equipment, material or excavating machinery shall be kept clear from the excavation area by at least 3 metres away. l)

The access to plant, equipment and emergency services must not be obstructed by the trenches.

m) The trenches shall not be left uncovered in the plant area and must be backfilled immediately on completion of work. n) No mechanical excavation is allowed inside the existing KOC facilities (Gathering Center, Booster Station etc.)

o) Personnel carrying out excavation work must use PPE in line with the requirements of HSEMS procedure KOC.SA.010 “Protective Clothing & Equipment”. p) Employees exposed to public vehicular traffic shall be provided with, and shall wear; warning vests or other suitable garments marked with or made of reflectorized or highvisibility material. 5.5

Inspection of Trenches To identify and control hazards a competent person must inspect all parts of a trench and its safeguards everyday in consideration to following issues: a) All materials to be used in shoring & support must be inspected for its suitability b) The timbering and shoring must be checked for any strain or slackness before commencement of daily work. Moreover timbering and shoring must also be checked carefully after heavy rains and or exposure to high temperature. c) All excavations must be carefully inspected following heavy rains, collapse of trenches or fall of equipment or materials inside. d) If an unsafe condition is found or suspected, work in trenches must stop until the necessary precautions have been taken to control the hazards.

Revision Date: 31st May 2011

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5.6

Excavation Process:

5.6.1

Excavation in Good Soil a) For excavations in good soil, shoring is not usually required, provided the excavations depth does not exceed more than one metre b) If the surface area permits, greater depth can be made by sloping the side down to an angle of 45°. c) If surface area is limited and needed excavation depth is more than one metre, then polling boards must be placed approximately two metres apart with horizontal brace (support), whereas horizontal brace should not be more than one metre apart. d)

5.6.2

Where a long trench is being made, the mechanical digging must be limited to approximately two metres ahead of shoring to give a protected position.

Excavation in Medium Soil a) If the depth of the excavation exceeds one metre, shoring must be used. The polling boards should be placed not more than 750mm (30") apart facing the wall, whereas horizontal brace should not be more than one metre apart. b) Extra polling boards should be inserted across if the condition of the ground deteriorates.

5.6.3

Excavation in Loose Sand or Poor Soil Condition If excavations are to be made in loose sand or poor soil condition, then close sheeting or continued series of polling boards shall be used.

The polling board & walling shall have a minimum cross-section as mentioned hereunder: 

Polling board = 200mm x 50mm, (8" x 2")



Walling = 150mm x 50mm (6" x 2")



Walling = 150mm x 50mm (6" x 2") Revision Date: 31st May 2011

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5.6.4

Using Excavation Machinery The use of excavating machinery (such as backhoe, hack hammer, loader etc) near above / underground services will require a Hot Work Permit in addition to Excavation Notification. The following precautions are to be taken while using mechanical means of excavation: a) Extreme care shall be taken to prevent any damage to above / underground services or power lines while using mechanical excavators. b) A mechanical excavator shall not be used until all underground obstructions have been uncovered through manual excavation. Once underground services are exposed the area should be further excavated manually as per clause 5.4 b & c on either side of the exposed services before using mechanical excavator. c) The machinery operator shall take extra care and follow banksman instruction while reversing or turning the excavator to prevent any accidental strike to the workers or equipment at location. d) The bucket must always be lowered to the ground if the loader or backhoe is not in operation. e) The machinery operator shall take necessary care to prevent exhaust gases entering the nearby trench or pit, in case personnel are working inside it.

5.6.5

Prevention of Accidental Fall inside a Trench Adequate fencing, barriers and warning notices are to be provided around any excavated area to alert and prevent accidental fall into it. Posting flaggers and / or watchman will be required if the trench is in a heavy traffic area. It is also recommended to illuminate the excavated area in the night and provide flashing hazard light. Any person entering the barricaded area must follow safety procedures to eliminate fall from height hazard in line with requirements of “Working at Height Procedure” (KOC.SA.031). Where equipment, workers or public are required or permitted to cross over a trench; then it is essential to provide a close – planked bridge or walkway with standard guard rail.

5.6.6

Trench as Confined Space An excavation that exceed 1.2 meter shall be treated as Confined Space and shall be checked for toxic gas, flammable gas as well as lack of oxygen. In such situation the requirement as applicable to Confined Space Entry Permit will be adhered.

Revision Date: 31st May 2011

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5.6.7 Backfilling & Reinstatement: If a trench is no longer needed then it has to be backfilled returning the area around it to its original condition. The following precautionary measures to be considered while backfilling a trench: a) Backfilling and removal of trench support shall be taken from the bottom of the trench layer by layer. b) The trench will be backfilled up to the level that allows removal of lower brace. After removing lower brace, the trench will be backfilled further to remove next level of braces. This process will be repeated until the trench is completely backfilled. c) In case of soil being unstable; the removal of brace / trench support shall be made with ropes from outside the trench without worker entry it. d) Removal of trench support shall be done slowly preventing collapse of side wall. e) Any surplus excavated materials shall be removed from the site making it tidy and compact. No contaminated soil shall be used for backfilling, whereas contaminated soil shall be disposed complying KOC "Waste Management Procedure" (KOC.EV.008).

f)

g) On completion of backfilling; the area including walkways, access roads, drainage etc. shall be reinstated to a condition equivalent to that before the commencement of excavation work.

6.0

Key Documents / Tools / References  Permit to Work Procedure; Doc. No. KOC. SA. 004  Entry into Confined Space; Doc. No. KOC.SA.007  Temporary Mobile Plant Equipment; Doc. No. KOC.SA.013  Control & Use of Ladder & Step Ladder; Doc. No. KOC.SA.001  Job Safety Analysis Procedure; Doc. No. KOC.SA. 024  Standard Guideline for "Safe Roads" Doc. No. KOC.S.001 Appendix -1 Excavation Checklist Appendix -2 Excavation Flowchart

7.0

Abbreviations 

KOC – Kuwait Oil Company



HSE – Health Safety & Environment Revision Date: 31st May 2011

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8.0



HSEMS – Health Safety & Environment Management System



PPE- Personal Protective Equipment



SA-Safety

HSE Records (Retention Time) 

Excavation Checklist Records (5 Years)



Excavation Notification (Refer Permit to Work Procedure)

Review/Revision Log: Review/ Revision Date

Document Technical Approver

Document Author

Manager – MP(I)

TL-Safety

Drafted the procedure

st

Manager – MP(I)

TL-Safety

Draft circulated among HSEMS Implementation Committee for review

th

Manager – MP(I)

TL-Safety

Reviewed & approved. by HSEMS Implementation Committee

Manager – MP(I)

TL-Safety

Document approved by Technical & Administrative Approvers

TL-Safety

Clause1.0 Services added, Clause 4.4 rd 3 bullet rephrased, clause 4.6 retitled nd and 2 bullet rephrased, Clause 5.1 - 3 bullets points added, Clause 5.4 bullet c),d) &J) rephrased and new bullets (n), (o) & (p) added, Clause 5.6 sub clauses renumbered, Clause 5.6.4 Bullet b) & c) rephrased, Clause 5.6.5 Referred working at height procedure , Clause 6.0 new document added, Clause 7.0 & 8.0 added to aligning with Document Control Procedure & Added Not Applicable column on the Checklist

st

1 May 2008 21 May 2008 15 June 2008 th

25 August 2008

st

31 May 2011

Manager –MP(I)

Revision Details

Revision Date: 31st May 2011

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KOC.SA.026 - Excavation Procedure Page 10 of 11

Appendix -1 Excavation Checklist Location:………………………………………………………………………………………………………Permit No. ………….……………………. S. No 1 2 3 4 5 6 7 8 9 10

Description of Checks & Measures

Yes

19

Banksman / Signalman for excavating machinery operator is required.

20

Continuous onsite supervision required during excavation work.

21

Safe detour / by-pass alongwith warning signs are provided as per requirement.

22

Excavated area backfilled, compacted and made as original.

15 16 17

Remarks

Required & to be reviewed

Protection provided to control source of ignition for equipment to be used in hazardous area .

18

12 13 14

Not Applicable

The proposed area of excavation is EOD cleared and certificate obtained The proposed location checked with appropriate detectors for any underground services Slit trenching to locate any underground services Only manual excavation will be carried out Excavation to be carried out by mechanical means only Excavation to be carried out both utilizing manual & mechanical means. Earthmoving & other mechanical equipment are fixed with approved spark arrestor Electrical wiring, termination joints & battery terminals of excavating machinery are safe. Excavation area to be isolated partially / completely from other adjacent facilities. Temporary supports are required for existing underground services to protect from exposure due to excavation. Area of excavation requires continuous Gas (flammable & toxic) monitoring. Fire protection (portable or fixed) system required. Excavation area is provided with safe access Area of excavation properly barricaded and danger signs (e.g. warning tape, reflective cone, safe cross over with handrail, flashing light etc.) are provided. Area of excavation / trenches is to be protected against possible ingress of rainwater / spilled liquid from adjacent facilities. Excavation will not lead to water / liquid ingress through the trench into adjacent building. The site of disposal for excess excavated material is determined

11

No

Name of Worksite Supervisor: ……………………………………………….Designation: …………………………………..Id. No. …….……… Controlling Team: ………………………………………………… …………..Signature: ……………………………………..Date …………….. Control Tier: 3

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Appendix -2 Excavation Flowchart

Need for Excavation Work (The Initiator to raise the Excavation Notification)

Endorsement of Excavation Notification (By all concerned Teams / Groups)

Is endorsement complete?

No

Take remaining Endorsement

Yes Apply for Appropriate Work Permit (By Permit Applicant)

No

Are potential hazards identified & mitigated? (In association with Permit Applicant & Issuer)

Address the hazard

Yes Worksite Supervisor completes Excavation Checklist

Work Permit authorized by Issuer

Excavation work carried out safely.

Work is complete & trenches no more needed

Backfill the trenches safely & return the area to original condition

Site condition verified & Permit Closed

Revision Date: 31st May 2011

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