Transcript
Petrofac Doc. No. Rev: OOA Date:Page: 4of12 1. PURPOSE The purpose of this Procedure is to give the Project guidance for protection of site employeesworking in and around excavations and trenches. 2. SCOPE This Procedure applies to all Project excavation and trenching activities.This procedure is for excavations from 1.2 meters to 6 meters deep. Follow this workinstruction for excavations that are less than 1.2 meters deep if the inspection by the Competent Person reveals the need. It is not the intention of this procedure to apply to excavations deeper than 6 meters. In theevent that an excavation deeper than 6 meters is required a specific risk assessment will be completed prior to work commencing. 3. REFERENCES: ã BS 8000-1 :1989 Workmanship on building sites. Code of practice for excavation and filling ã Petrofac's Excavations ft: Trenching Guide PEC-BMS-HS-GDE-X-0447 1 ã Petrofac's CMS for Installation of Underground Piping and Trenching Work PEC-BMS-CM WIN-X-0289 ã Petrofac's CMS for Site Preparation -Earthworks PEC-BMS-CM-WIN-X-0287 4. DEFINITIONS ã Excavation: Any man-made cavity or depression in the earth's surface formed by earthremoval which produces unsupported earth conditions by reason of the excavation work.ã Trench: A narrow excavation below the surface Level of the ground, withits width at the Lowest LeveL below ground surface not greater than 9 meters.ã Competent Person: One who has had specific training in and is knowledgeabLe about soilclassification and the use of protective systems for excavations and trenches.Documentation and data to establish this is required and must be on file at the project.The competent person must also be capable of identifying existing and predictablehazards in the surroundings or working conditions, which are hazardous, unsanitary or dangerous to empLoyees, and must have the authority to take prompt corrective measures to eliminate them. Petrofac Doc. No. Rev: OOA Date:Page: 50f12 ã Benching: This is a method of protecting employees from cave-ins by shaping the sides of an excavation to form one or a series of horizontal levels or steps, usually with near vertical surfaces between levels.ã Shoring: Use of timberor other structure material for the purpose of providing support for an exposed face of an excavation.ã PTW:permit to work 5. RESPONSIBILITIES ã It shall be the responsibility of the Project Manager to ensure that the requirements areadhered to. ã The HSE Manager I Supervisors will monitor and provide feedback to ensure that the requirements are adhered to.ã Project management shall appoint a Competent Authorized Person with the follOwingresponsibilities: );> To implement the Procedures established for the type of Excavation. );> To ensure that the route of cables, live lines, pipelines or other hazardous infrastructure are identified and marked. );> To confirm the location of underground and overhead infrastructure beforestarting work. );> To apply the specified Procedures for soil testing and classification. );> To inspect Excavations and Shoring, including areas adjacent to the Excavation, for signs of ground instability, before each shift and before resuming work after adverse weather conditions. );> To monitor compliance with the respective PTW. );> To refer to the CONTRACTOR civil discipline head in case of unforeseenconditions or problems with the planned work. 6. WORK INSTRUCTIONS 6.1. HIERARCHY OF CONTROLS Should be considered:ã First: Eliminating the need for Excavation by applying Trench less Technology Petrofac ® Doc.No. Rev: OOA Date:Page: 6 of12 ã Second: Applying Maximum Allowable Slopes or Benching.ã Third: The Use of Shoring or Trench Shields.ã Fourth: Controlling Excavations in line with CONTRACTOR or COMPANY Permit to Work,depending on the WORK location, inclusive of the permit and controls for Confined Space Work when working in a Confined Space. 6.2. GENERAL REQUIREMENTS ã Prior to commencing excavation or trenching, Client, Operator and utility companies shallbe advised of the proposed work to allow them to determine the location of all underground installations (Le. sewer, telephone, water, fuel, electric and gas lines).Overhead hazards are to be assessed and dealt with at this time also. ,.. Depending on the project contract, if Petrofac's PTW to be applied the Petrofac's excavation certificate shall be followed. See appendix 1ã Excavations, trenching and adjacent areas shall be inspected by a competent person, after every rainfall, as soil conditions change and as needed throughout the shift.ã If there is evidence of possible slides or cave-ins; indications of failure of protectivesystems; hazardous atmospheres; or other hazardous conditions; necessary safetyprecautions must be taken before any additional work in that section of the excavationbegins.ã Employees shall not work in excavations where water is accumulating unless adequateprecautions have been taken to protect employees against the hazard posed by the wateraccumulation. ,.. If water accumulation is controlled or prevented by water removal equipment, the competent person must monitor the removal activities to ensure properoperation.ã If the stability of buildings or waLLs is endangered by an excavation or trench shoring,bracing or underpinning must be provided.ã Excavations and trenching that are adjacent to backfilled excavation or trenching, orwhich are subject to vibrations from railroad traffic, highway traffic, or the operation of machinery (e.g., shovels, derricks, cranes, trucks) will be secured by support system,shield system or other protective systems; i.e., sheet piled shored, and braced. Petrofac (~ Doc.No. Rev: OOA Date:Page: 7of12 6.3. ACCESS ã In trenching 1.2 meters (4 feet) or more in depth, ladders, steps, ramps or other safemeans of access and egress shall be provided and located at intervals of 7.5 meters (25 feet)or less lateral travel. );> If a Ladder is used, the Ladder will extend 1 meter (3 feet) above the srcinalsurface of the ground and must be secured.ã Walkways, ramps or bridges with standard guardrails will be provided at all excavationsand trenching where empLoyees are required or permitted to cross over. The crossing will be made of tightly secured uniformly sized planking. 6.4. SET BACK ã EmpLoyees shall be protected from excavated or other materials or equipment that couLd pose a hazard by falling or rolling into the excavation. );> Protection shall be provided by placing and keeping such materials or equipment at least 1 meter (3 feet) from the edge of the excavation, );> Or by the use of retaining devices that are sufficient to prevent materials or equipment from falling or rolling into excavations or by combination of both. );> For excavations deeper than 1 meter the dimensions in [Figure 1 Figure 2Figure 31 apply:
