KOC Excavation Procedure
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Transcript of KOC Excavation Procedure
KOC.SA.026 - Excavation Procedure Page 1 of 11
Control Tier: 3 Revision Date: 31st May 2011
Uncontrolled Copy If Printed
Excavation Procedure
Document Number: KOC.SA.026
Approver: (Technical) Manager MP(I) Author: TL Safety
Approver: (Administrative)
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
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.
KOC.SA.026 - Excavation Procedure Page 2 of 11
Control Tier: 3 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:
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.
4.2 Asset Owners for Above / Underground Services
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.
4.3 Permit Issuer
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.
4.4 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.
4.6 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.
KOC.SA.026 - Excavation Procedure Page 3 of 11
Control Tier: 3 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)
KOC.SA.026 - Excavation Procedure Page 4 of 11
Control Tier: 3 Revision Date: 31st May 2011
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Sources of soil vibration
Traffic condition on the adjacent road.
Weather & soil moisture condition
5.3 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) 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.
5.4 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 non-
hydrocarbon 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.
KOC.SA.026 - Excavation Procedure Page 5 of 11
Control Tier: 3 Revision Date: 31st May 2011
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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 high-
visibility 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.
KOC.SA.026 - Excavation Procedure Page 6 of 11
Control Tier: 3 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) 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.
5.6.2 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")
KOC.SA.026 - Excavation Procedure Page 7 of 11
Control Tier: 3 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.
KOC.SA.026 - Excavation Procedure Page 8 of 11
Control Tier: 3 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.
f) No contaminated soil shall be used for backfilling, whereas contaminated soil shall
be disposed complying KOC "Waste Management Procedure" (KOC.EV.008).
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
KOC.SA.026 - Excavation Procedure Page 9 of 11
Control Tier: 3 Revision Date: 31st May 2011
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HSEMS – Health Safety & Environment Management System
PPE- Personal Protective Equipment
SA-Safety
8.0 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 Revision Details
1st May 2008 Manager – MP(I) TL-Safety Drafted the procedure
21st May 2008 Manager – MP(I) TL-Safety
Draft circulated among HSEMS
Implementation Committee for review
15th June 2008 Manager – MP(I) TL-Safety
Reviewed & approved. by HSEMS
Implementation Committee
25th August
2008 Manager – MP(I) TL-Safety
Document approved by Technical &
Administrative Approvers
31st May 2011 Manager –MP(I) TL-Safety
Clause1.0 Services added, Clause 4.4
3rd
bullet rephrased, clause 4.6 retitled
and 2nd
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
KOC.SA.026 - Excavation Procedure Page 10 of 11
Control Tier: 3 Revision Date: 31st May 2011
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Appendix -1 Excavation Checklist
Location:………………………………………………………………………………………………………Permit No. ………….…………………….
S. No
Description of Checks & Measures Yes No Not
Applicable Remarks Required & to be
reviewed 1 The proposed area of excavation is EOD cleared and certificate obtained
2 The proposed location checked with appropriate detectors for any underground services
3 Slit trenching to locate any underground services
4 Only manual excavation will be carried out
5 Excavation to be carried out by mechanical means only
6 Excavation to be carried out both utilizing manual & mechanical means.
7 Protection provided to control source of ignition for equipment to be used in hazardous area.
8 Earthmoving & other mechanical equipment are fixed with approved spark arrestor
9 Electrical wiring, termination joints & battery terminals of excavating machinery are safe.
10 Excavation area to be isolated partially / completely from other adjacent facilities.
11 Temporary supports are required for existing underground services to protect from exposure due to excavation.
12 Area of excavation requires continuous Gas (flammable & toxic) monitoring.
13 Fire protection (portable or fixed) system required.
14 Excavation area is provided with safe access
15 Area of excavation properly barricaded and danger signs (e.g. warning tape, reflective cone, safe cross over with handrail, flashing light etc.) are provided.
16 Area of excavation / trenches is to be protected against possible ingress of rainwater / spilled liquid from adjacent facilities.
17 Excavation will not lead to water / liquid ingress through the trench into adjacent building.
18 The site of disposal for excess excavated material is determined
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.
Name of Worksite Supervisor: ……………………………………………….Designation: …………………………………..Id. No. …….……… Controlling Team: ………………………………………………… …………..Signature: ……………………………………..Date ……………..
KOC.SA.026 - Excavation Procedure Page 11 of 11
Control Tier: 3 Revision Date: 31st May 2011
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Appendix -2 Excavation Flowchart
Yes
No
Need for Excavation Work (The Initiator to raise the Excavation Notification)
Are potential hazards identified & mitigated? (In association with Permit Applicant & Issuer)
Worksite Supervisor completes Excavation Checklist
Work Permit authorized by Issuer
Backfill the trenches safely & return the area to original condition
Site condition verified & Permit Closed
Endorsement of Excavation Notification (By all concerned Teams / Groups)
Take remaining
Endorsement
Excavation work carried out safely.
Apply for Appropriate Work Permit (By Permit Applicant)
Work is complete & trenches no more needed
Is endorsement complete?
Yes
Address the
hazard
No