Topic : Construction Safety
|Excavation Safety |
Excavation is the act or process of digging, especially when something specific is being removed from the ground or for construction of structures. Archaeologists use excavation to find artifacts and fossils.
Roles and Responsibility
Project Head: Provision of adequate resources for the development, implementation and maintenance of the Safety Standard.
Line managers: Provision of support for & compliance with Safety Standard dictates.
Line Supervisors: Provision of support for & enforcement of Safety Standard dictates.
Work Site excavation process:
- No excavation works can commence unless the appropriate authorization & permits have been issued.
- In all instances a thorough risk assessment of all intended excavation activities must be conducted by the senior site engineer under the guidance of a suitably trained/qualified site safety officer prior to work commencing.
- All excavation risk assessments must be approved & signed off by an Safety or Concerned department.
- No excavation permits will be issued without an approved risk assessment attached.
- The Senior Site Engineer shall inspect the excavation integrity regularly (at least once every 4 hours) & arrange back-fill to maximize safety as required.
- All open excavations shall be effectively hard barricaded at all times.
- Where personnel &/or equipment access or egress is required, closable access points will be installed in the barricading.
- All excavation works where pedestrian personnel are required to work inside the excavation itself must have at least two (2) suitably constructed means of easily accessible entry & egress.
- No person is permitted to work in any excavation containing liquids of a depth greater than 0.5m. So effective de-watering methods must be maintained at all times as required to service this rule.
Strict compliance with the following basic excavation safety rules is mandatory
Wherever/whenever possible excavation walls must be cut at no greater an angle than 60 degrees to the horizontal to minimize the risk of slippages and/or collapses. If, for whatever reason it is impossible to cut walls at 60 degrees and walls are at or close to the vertical (especially in unstable soil /material structures) then;
- Stepping/benching method must be employed.
- If this is not possible then;
- Appropriate shoring will be utilized.
- If this is not possible then;
- Appropriate meshing & or revetments methodologies must be used.
Authorization to Work & Permit Requirements
- Any task involves excavation or penetration greater than 300 mm.
- Wherever there will be any disturbance to the ground.
- When cutting into any vertical wall, floors or ceiling or any concrete slab.
All Excavation permits and any other relevant permits e.g. Electrical Isolation &/or Hot Work shall be issued prior to any work commencing:
The area/site/contract Excavation officer will be the issuing authority for all excavation permits. An excavation permit will not be issued without reference to the following information:
- Mark the location of Pipes and/or Services and excavation boundaries on proposed excavation surface with paint, safety tape or similar marker.
- The site Safety Officer & the senior site engineer will inspect the area and ensure information supplied is sufficient and correct for the job to commence.
- Isolate all services as necessary.
- Only upon receipt of all relevant permits can excavation work be allowed to commence.
Possible Hazards in excavation
- ollapses while connecting joists or trusses
- Workers struck by objects during miscellaneous activities
- Workers struck by objects and then falling
- Improper use or failure of fall protection
- Unsecured or unstable decking
- Other falls during decking activities
- Plumbing, bolting, welding and
- Walking/standing on the beam/joist (i.e., moving point-to-point
Prevent workers and / or pedestrians from accidentally impaling themselves, the protruding ends of steel rebar are often bent over or covered with special steel-reinforced plastic "plate" caps. "Mushroom" caps may provide protection from scratches and other minor injuries, but provide little to no protection from impalement.
Safety and Environment Requirements
- Safety helmet.
- Long sleeved Shirt, long trousers.
- Safety goggles.
- Safety Shoes.
- Ear plugs (when operating or working near heavy earth moving equipment).
- Confined Space or Restricted Space Entry permit must be obtained if personnel are to enter an excavation of 4m depth or greater.
- Trenching or excavation over1500mm, a minimum of two persons at the work site at any one time.
- Mobile equipment hazards, i.e. backhoes & excavators etc.
Rupture of gas, oil, water and/or sewage lines – containment and disposal routines must be covered.
Proposed work and access areas to be kept free from tools, rubbish, etc at all stages of this task.
Tools and Equipment
- Hand tools as required.
- Excavation tools as required, i.e. shovels, etc.
- Barriers, signs & ladders, etc.
- Mobile earth moving equipment operated by competent persons.
This checklist provides builders and building trades contractors with a framework of safety precautions to consider in formwork and concreting operations.
Before Starting the job ask yourself these questions:
- Has the formwork system been properly designed?
- Has the formwork been properly constructed?
- Is the formwork deck being laid safely?
- Is steel fixing being done safely?
- Is the formwork structurally adequate?
- Are wall and column shutters safely lifted and properly secured?
- Are workers prevented from accessing the area underneath the concrete pour?
- Are concrete pumps being used safely?
- Are kibbles being used safely?
- Are concrete vibrators being used safely?
- Are the concreters working safely?
- Is formwork being dismantled safely?