3. 3
Critical to Life Activities
– Road transportation
– Personal Protective Equipment
– Rigging
– Lifting
– Working at Height
– Scaffolding
– Trenching and Excavation
– Confined space
– Health and welfare
– Electrical Safety
– NDE
– Hot Works
(Trenching and Excavation
)
One of the main potential
causes of injury at the Worksite
4. 4
Training Objectives
By the end of this session you will understand:
• Terms used in Excavation
• The Hazards associated with excavation
• PTW requirements for Excavation
• What Control measures are required to overcome these
hazards
• Soil & Soil classification
• How excavations should be constructed
• Earth Moving Equipment & Safety
• Types of Barricades
• Daily Excavation Inspection Checklist
5. 5
EXCAVATION -
– A man-made cut, cavity, trench,
or depression formed by earth
removal.
– Digging away or removing
ground cover to expose, verify,
remove, repair, modify or
construct facilities.
Definitions
TRENCH – a narrow excavation. The depth is greater than
the width, but not wider than 4.57 m (15 feet.)
Width
Depth
6. 6
Underground Services
Before your begin any excavation work, you
must always check for the location of any
underground services:
• High voltage electrical cables
• Telephone and communication cables
• Water pipes
• Gas pipes
• Sewerage pipes
• Underground fuel tanks and pipes
7. 7
Hazards associated with
Excavations
– Damage to Underground Services
– Access / Egress
– Vehicle / Equipment Movement
– Falling Personnel / Materials
– Atmospheric Hazards
– Water Accumulation / Flooding
– Excavation Collapse / Cave-In
– Entrapment with Moving Equipment
– Electrical / Electrocution
8. 5887-ON-RE-HM-006 8
Damage to Underground Services
Digging into underground
services can lead to:
- Loss of communication
- Loss to electric power
services
- Electrocution
- Fires and explosions from
ruptured gas pipe
- Flooding from ruptured
water and sewerage pipe
- Soil contamination from
burst fuel pipes
9. 5887-ON-RE-HM-006 9
Damage to Underground Services
Digging into underground
services can lead to:
- Loss of communication
- Loss to electric power
services
- Electrocution
- Fires and explosions from
ruptured gas pipe
- Flooding from ruptured
water and sewerage pipe
- Soil contamination from
burst fuel pipes
11. 5887-ON-RE-HM-006 11
Buckets of excavators, backhoes, etc. are not to be used
as a means of Access & Egress.
Excavation Access & Egress
12. 5887-ON-RE-HM-006 12
Use ladders, stairs or ramps to access & egress into
excavations.
Ladders should be:
- set at no more than 75 degrees angle from base;
- extended at least one metre above the excavation.
- Located at intervals of no more than 7.6m in
trenches, where practicable.
Ramps should be no steeper than one (vertical) in six
(horizontal) and fitted with cleats. SWL must be
checked.
Use walkways or bridges, with guardrails, for access
across the excavation. Do not jump into an
excavation or over.
Excavation Access & Egress - Controls
13. 13
• If the excavation is very wide and long, one access point every
7.6m must be provided , where practicable..
Excavation Access & Egress - Controls
Barricade 1m
from the edge
14. 5887-ON-RE-HM-006 14
Vehicle / Equipment Movement Hazards
•Vehicles being driven into the
excavation due to driving errors,
inadequate barriers, or the absence
of stop blocks.
16. 17
Vehicle / Equipment Movement Control Measures
• Ensure proper barricading, sign
boards and warning lights or
adequate illumination at work site.
• Keep safe distance to a minimum of
1m from the edge of excavation
,while placing any equipment or
barricade.
• Assign a trained banks man for
traffic control, with the equipment.
• Appropriate sloping, benching or
shoring shall be done.
Barricade 1 metre
from edge
18. 20
Preventing Injuries from Slips, Trips & Falling objects
• Keep tools and equipment away from the edges
• Keep the floor of the excavation free of tools, equipment
& timber
• Remove loose stones and large rocks from the floor
• Keep at least 2 metres away from other workers, when
using a pick or shovel
• All rebar must have rebar caps
• Never work alone in an excavation. Make sure there
is another person close by, who can help in an
emergency.
19. 21
Electric Cable Management
Protect all exposed electric cables from damage by:
• Cables >1m long must be supported with slings or props
• Cables lying in the bottom should be covered with
wooden planks or troughing
• Not tipping anything into the excavation, that could
damage the cable
Protect plastic pipes from heat damage, if welding or gas
cutting equipment nearby
20. 22
Hazards: Underground Electrical Cable
High Voltage-more than enough to fry a
person or group of persons when safety
procedure is ignored during excavation
works
Excavation PTW must pinpoint the exact
location of underground services before
doing the actual digging. Remember…
23. 25
Atmospheric Hazards
• Excavations must be kept free of
toxic and explosive gases and conditions.
• Don’t use portable petrol or diesel
equipment inside excavations.
• Store compressed gas cylinders outside
the excavation and safe distance.
Install artificial lighting where:
- daylight does not provide enough lighting; or
- work needs to be carried out at night.
24. 5887-ON-RE-HM-006 26
• Water accumulation in a trench is
hazardous. You must take measures to
ensure that water does not accumulate
in the trench.
• Diversion ditches and dike must be
used for natural drainage of streams
interrupted by the excavation or in
anticipation of heavy run-off from rains.
• Caution: The de-watering pump should
be placed at a safe distance from the
edge of excavation to prevent it from
falling into the trench or pit. Make sure
water doesn’t fill into another
excavation.
Water Accumulation & Flooding
Entrapment
Personnel Injury /
Death
Pre planning
(TSTI, JHA)
26. 5887-ON-RE-HM-006 28
Collapse
Excavation Collapse and Cave-in Hazards
Protection from Collapse and Cave-in requires a systematic approach
including:
•Soil Classification
•Protective System
•Inspection
•Employee Training
Cave-in
27. 29
Preventing Collapses of an Excavation
• Store excavated soil at least 1.5m from the edge
• Keep vehicles and heavy equipment away from the
edges
• Pump ground water out
• Use ditches or bunds to divert surface water away
• Do not throw any tools or materials out from inside
the excavation or vice versa .
• Use the daily checklist to check for any signs of
faces collapsing
28. 30
Battering (Sloping) & Benching
BATTERING(SLOPING)
Digging the faces so that
they are sloped, rather than
vertical. Suitable for up to
3m deep excavations.
BENCHING
Is applied for excavations
deeper than 1.5m,where the
sides of the excavation are
taken down in steps(3/4
horizontal to ¼ vertical).
battered
face
Bench (cutback)
29. 5887-ON-RE-HM-006 31
Shoring
SHORING
Applied when battering (sloping) or benching is impractical. Various types of timber and
steel sheeting systems are used with support frames and hydraulic arms, to stop faces
caving in.
30. 5887-ON-RE-HM-006 32
Battering (Sloping) ,Benching & Shoring Requirements
• All shoring & benching requirements must
be submitted in Excavation PTW by
Supervisor.
• Civil Engineer must have input for safety
or stability is required in the case of soft
soil.
• You must not work in excavations
deeper than 1.5 metres ,which have not
been battered, benched or shored.
31. 33
• Use only authorized, qualified and certified
operators.
• Provide trained & authorized Banks Man
with moving equipment.
– Banks Man always be positioned
within the eye span of the operator.
– He will always keep safe distance from
the equipment.
• Equipment must be inspected and certified
by JK equipment Safety Inspectors.
• Equipment must follow the Posted Speed
Limit at site.
• A Daily Inspection Checklist must be
completed.
• Entry to the area will be Restricted.
Entrapment with Moving Equipment
32. 34
• Provide Fundamental Site Rules and Training to all
Personnel at Risk.
• Coordinate Operations of Various Trades Working in
the Same Areas.
• PTD must be conducted.
• Employees must learn, follow, and obey established
rules.
• Ensure that you see, and be seen.
• Be Alert; Stay Clear; Listen for Warnings.
Entrapment with Moving Equipment
33. 35
Always maintain a safe distance in
between yourself and the
equipment.
YOU MUST SEE AND BE SEEN!!!
Entrapment with Moving Equipment
35. 37
Barricading and Signs
Set up barriers or barricades around the edges of excavation (>1.5m from edge).
Place warning signs to warn people of the excavation.
Divert traffic away from the excavation area
Install flashing amber lights for night-time warning.
36. 38
- Ensure the barricading perimeter extends
far enough out to prevent contact with the
hazard.
- Position the barricading at approx. 1
metre height so it is clearly visible.
- Tie off soft barricading to posts so it is
kept in position.
- Posts should be fitted with a heavy base.
- Rebars must be fixed with the rebar caps.
- Position safety signs around the
barricade perimeter.
- Position flashing warning lights around
barricaded areas, such as excavations,
during hours of darkness.
Using Barricading
38. 40
Supervisors Responsibility , Excavation Check List
• The Competent Person
for Excavation:
• Inspects the
excavation and signs
the daily inspection
sheet of the
Excavation PTW;
• Ensures that shoring
details are followed;
• Inspects and monitors
systems to prevent
undermining;
• Must be done EVERY
day.
39. 41
Backfilling Excavations
• Excavations should be backfilled as soon as possible,
after the required work has been completed.
When backfilling you should:
• Gas Pipes: properly compact the backfill to prevent any
settling and damage to the pipe
• Never tip anything into an open excavation that could
rupture a pipe or damage a cable
40. 42
Excavation Safety Brief Summary
Stay away from moving
Machinery
Obtain Excavation
Permit
Spoils piled 1.5m away from the
edge of excavation
Sloping, Shoring or Bench is
required to prevent collapse
Barricading, Guardrails &
Proper Access is required
