10. Excavation Work

Being a major part of the site preparation, excavation can make or break the stability of your future building.

First things first. Do not commence any excavation work before you have a clear map of underground utilities: cables, pipes, etc. Mark the services and make sure everyone in the excavation team knows where the buried services are. Also, test the soil and conduct site evaluation.
Armed with this information, you will be able to choose methods and safety measures that fit specific excavation works.

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Hazard Category	Hazards	Controls
Collapse of Trench Walls	1. Can occur if the soil in the walls is unable to support its own weight, if soil is full of sand pockets, If soil is broken down by rain, frost, etc. and/or by vibration from machinery nearby.	1. Trenches shall be securely boarded in line with current acops (i.e. poling board, cross struts, and walings). 2. A site survey shall be carried out prior to excavating to establish possible weaknesses in the soil caused by previous excavations, etc.
Falls of Equipment/ Machinery and/or Plant into Excavation	1. Can occur if equipment/machinery and/or plant are located too close to the excavation or if operational plant (such as dumper diggers, etc.) drive or reverse into the excavation.	1. Supervisors shall ensure all equipment/ machinery and/or plant located a suitable distance away from the excavation “so far as is reasonably practicalble”. 2. Supervisors shall ensure personnel operating machinery. (i.e. dumper, diggers, etc.) are aware of the potential risks, remain vigilant at all times and are competent.
Spillage	1. Can occur if suitable means of crossing the excavations are not provided such as man made bridges or suitable barriers are not erected around the excavation to prevent personnel from straying too near the edge of the excavation.	1. Walkovers shall be provieded across the excavation at predetermined points with handrails (if reasonalbly practicable). 2. Barriers shall be erected along/around the whole length of the excavation and signs displayed advising personnel of the potential hazard.
Damage to Services – Electricity/ Water	1. Can occur during excavation due to lack of information, knowledge and/or detailed execution plan/method statement.	1. Surveys shall ve carried out prior to commencement of any excavation work to establish any electricity/ water services, which may be present. 2. Contractors shall establish suitable and detailed execution plans & method statements for the proposed works and ensure all personnel involved are aware of how the work is to be carried out.
Inadequate Access/ Egress	1. Serious hazards can be presented if adequate access/egress is not provided such as falls of personnel or delayed escape in the event of an emergency.	1. Supervisors shall ensure that suitable means of access/egress is provided at predetermined points to enable personnel to enter and exit the excavation safetly.
Emergency Procedures	1. Serious accidents can occur if suitable emergency procedures have not been established prior to work commencement such as fire (cause by waste materials) and/or drowning (cause by burst water mains), etc.	1. Supervisors shall ensure that emergency procedures have been established prior to work commencement such as fire fighting equipment, first aid facilities and trained first aiders, etc. 2. Supervisors shall ensure that all personnel are aware of all emergency procedures that are in place (use practice drills if necessary).