Excavation Safety – hazards and precautions
Today we will explain Excavation Safety hazards and control measures
Definition of Excavation:
Excavation is defined as ground breaking or making trench in ground is called as excavation.
Definition of Cave-in:
The separation of mass of soil or rock material from the side of excavation, or the loss of soil from under a trench shield.
- Damage to underground facilities.
- Personal, vehicle, equipment and materials falling inside excavation.
- Cave-in, Soil collapse due to loose soil and heavy equipment moment.
- Presence of toxic and flammable gases.
- Injuries due to employees working very close to each other.
- Expose of existing building foundation.
Excavation safety Precautions:
- Slit trench using shovel, Do not use pickaxe for slit trench.
- Detection of underground facilities using metal or cable detector.
- Trial excavation shall be carried out to ensure protection of underground facility before mechanical excavation.
- Adapting soil protection method like stepping, sloping, shoring and close sheeting.
- If excavation reached more than 3 meter, shoring or close sheeting shall be done.
- Adequate barricade and excavation sign board.
- Gas test inside excavation before job.
- Temporary support shall be provided for existing foundations.
- Adequate spacing between workers.
- Ladder shall be positioned at least 1 meter above the landing level and is excavation exceed 1.2 meter two access is required.
- There should be at least two means of access for person working inside excavation if walking distance is more than 7.5 meter.
- Walkways across excavations should be made by scaffolding and jumping across excavation is not allowed.
- Excavated soil, materials, equipment shall maintained distance of 0.5 meter away from the edge of excavation.
- If engine driven equipment is using inside excavation; confined space conditions shall be followed.
- Signal man shall always be present with heavy equipment like excavator, dump truck, and loader.
Types of Excavations:
- Manual excavation – By shovel only.
- Mechanical excavation – By excavator
Excavation Authorization is require to identify and safe guard underground facilities such as pipe lines and cable etc. it is required for excavation deep more than half meter. After checking the drawing, site conditions and the effect on existing underground facilities.
Excavation authorization sign by:
- Operations shift supervisor/asses custodian.
- Instrument engineer.
- Electrical engineer.
- Corrosion engineer.
- Telecommunication engineer.
- Chief fire officer.
- General work engineer.
- Civil engineer.
- Safety engineer.
Excavations more than 1.2 meters require confined space entry authorization and gas test shall be done prior to job.
*Excavation authorization need as per KNPC safe work practices
- Valid construction license is required for operator.
- A Hot Work Permit in addition to an Excavation Authorization is require for the use of excavators.
- Valid safety certificates.
- Excavator operator has to be aware of blind spots where they may not see ground personnel.
- Certified signal man / flag man with flags.
- Personnel should not be inside the excavation while excavator in operation
- Excavator operator shall be aware from blind spot.
- The bucket shall always be lower to ground when not in use.
- Two numbers of DCP fire extinguisher.
- No hydraulic leakage.
- Spark arrestor.
Excavation edge Protection System:
2 .Stepping or benching
4. Sheet Pilling