26/10/2022
EXCAVATIONS
General measures to be implemented on excavation works are:
• Any excavation or trenching work will be subjected to a Work Permit Procedure. The excavation permit will remain at the site of excavation during the entire time the excavation is being accomplished. A properly completed Confined Space Entry Permit shall be obtained to enter excavations deeper than 1,2 m is considered as a
confined space when:
- the depth is greater than the width or/and
- has limited or restricted means for entry or exit or/and
- contains or has the potential to contain a hazardous atmosphere.
• Excavations equal to or deeper than 1.2 m shall be protected from collapse cave-in by adequate means, as designed by a competent civil engineer, based upon soil surveys, and other relevant factors. This may include, but should not be limited to the following means, or a combination thereof:
- Purpose built shuttering or shoring,
- Sloping/battering/benching the excavation walls to a suitable angle;,
- Sheet piling,
- Installation of trench-boxes,
• All the perimeter of excavations shall be surrounded by barricade warning tape and/or
other barricade means such as portable barriers. Excavations between 0.5 and 1.2 m
in depth shall be protected at all times with Hard-barriers except where a safety distance of at least 1.5 m is maintained by visible safety chains or flexible mesh of 1.1m in height. Excavations equal to or deeper than 1.2 m shall be protected at all times with guardrails and toe-boards. Toe boards are not required where the
guardrails are positioned at least 1.5 m from the edge of the excavation. Pits, shafts, wells, manholes shall also be protected either covered or barricaded to avoid risks of
falling.
• Adequate signalling shall be placed to warn employees of any risk from falling, the signs shall be visible at night.
• Excavation slopes shall be stable, close to soil natural slopes, otherwise benching or shoring will be used. No load, equipment, material or removed earths shall be permitted within one and a half (1,5m) meter of excavation edge.
• All excavations shall be provided with safe access and egress. Ramps, steps and
staircases shall be preferred to ladders.
• Access to trenches shall be by using straight ladders surpassing at least 1 meter from the edge, at intervals not exceeding 15 meters. Passageways for personnel provided
with railing shall be installed above trench excavations and they shall be at least
0,60m wide.
• Excavations greater than 5 meters in depth must be provided with dedicated
staircases with guardrails, ladder are prohibited. An access point shall be available at
no more than 20 meters in any direction.
• Excavations by mechanical equipment are prohibited within 3 meter of underground utilities. • Excavations are not permitted under an existing foundation. Excavations are not
allowed to intersect a forty-five degree (45°) plane extending downward from the
bottom edge of an existing foundation, unless a properly engineered support system is installed prior to start of work or the excavation is in stable rock
• Excavations shall be inspected daily, prior to the start of work and as needed
throughout the shift using a checklist design for that purpose.
• Vehicle and plant movement that is not in direct relation with the works in the
excavation shall be kept a minimum of 3 m from the edge of any excavation.
• Vehicles / plant working in connection with the excavation works must have a
banksman controlling their movement to prevent them from going close to the edge of the excavation, in order to prevent the edge to break away under their weight. Wheel-
chocks must be used to prevent the equipment moving towards the excavation.
• All means must be employed to prevent ingress of water into the excavation, and on its sides. In addition, water must be removed regularly so that it does not accumulate in the excavation pit.
