Excavation and trenching safety training

Excavation and trenching safety training

1. ARCHIRODON GROUP NV Health & Safety Training

2. Introduction of Trainer Evacuation of the Training Room Welfare Facilities Mobile Phones No Smoking / Breaks

3. Excavation

4. Excavation-Definition " Excavation / Trench " is any: Man-made cut, Cavity, Depression in an earth surface, formed by earth removal and producing unsupported earth conditions by reason of the excavation

5. Trench – a narrow excavation. The depth is greater than the width, but not wider than 5 meters (15 feet). Shield - a structure able to withstand a cave-in and protect employees Shoring - a structure that supports the sides of an excavation and protects against cave-ins Sloping - a technique that employs a specific angle of incline on the sides of the excavation. The angle varies based on assessment of impacting site factors. Other Definitions

6. Collapse of the sides of the excavation Contact with underground services   Falls of people or vehicles into excavation Equipment or materials falling onto people within excavations Inert, Toxic or flammable vapours in excavation Water inside the excavation People being struck by machines Access and egress to excavation Vibration or Traffic close to the excavation Collapse of adjacent structures Excavation Hazards

7. The likelihood of the sides of an excavation collapsing is dependent upon the characteristics of the soil or rock The following factors increase the risk of collapse of excavation sides:  Excavation Collapse

8. Spoil Pile Slide The Problem The Outcome Excavation Collapse

9. Belly Slough (Slip Circle Failure) Vibrations The Problem The Outcome Excavation Collapse

10. Lip Slide The Problem The Outcome Excavation Collapse

11. Loose, un-compacted, granular soils, i.e. sand or gravel, or mixtures containing them Excavations through different strata The presence of groundwater, and the effect on the excavation sides from surface water running into the excavation Made-up ground Proximity to earlier excavations Loose blocks of fractured rock Excavation Collapse Factors

12. Weathering Vibration from plant, equipment, road or rail traffic Surcharging by spoil, stored materials or plant including vehicles Proximity of loaded foundations Damage to the support system by personnel, or when materials are lowered into the excavation Excavation Collapse Factors

13. A well-planned excavation shall consider: the type of Soil any underground / above ground utilities any side protections needed the correct design of protections (sloping, benching, etc.) attention to correct installation and removal of the protection Excavation Planning

14. safe entrance / egress to the excavation pit appropriate handling of materials and equipment control of interferences with machine / vehicles / people / adjacent structures proper area signage and segregation (barricates) Excavation Planning

15. This excavation has inadequate support posts and egress access Inadequate protective system Cave-in Hazard

16. Protection of Employees Employees should be protected from cave-ins by using an adequately designed protective system Protective systems must be able to resist all expected loads to the system Excavation Protection

17. A well-designed protective system Correct design of sloping and benching systems Correct design of support systems, shield systems, and other protective systems Plus Appropriate handling of materials and equipment Attention to correct installation and removal Equals to Protection of employees at excavations Protective Systems

18. Inadequate Protective System with no protective system, that is not sloped or benched and, has no means of easy and immediate egress Protective Systems The worker in the picture is in a trench deeper than 1.5 meters

19. The construction department shall select and construct: slopes and configurations of sloping and benching systems support systems, shield systems, and other protective systems Shield - can be permanent or portable. Also known as trench box or trench shield. Shoring - such as metal hydraulic, mechanical or timber shoring system that supports the sides Sloping - form sides of an excavation that are inclined away from the excavation Design of Protective Systems

20. Some of the factors that should be taken into account when designing a protective system: Soil classification Depth of cut Water content of soil Changes due to weather and climate Other operations in the vicinity Design of Protective Systems

21. The most common protective system for excavations is the use of timber or metal sheeting braced by timber or steel struts Design of Protective Systems

22. Design of Protective Systems

23. h h h1 h1 h1 h1 h1 h1 < 1.0 m Stepping (Benching) Sloping 1 1 Excavated soil Alternative systems to support the sides of an excavation is the sloping or stepping of the sides of the excavation. It depends from several factors, as the depth and the dimension of the excavation Design of Protective Systems

24. Methods of support can be: Battering back sides of excavation to suitable angle. Timber framing. Trench box. Drag box. Slide Rail System. Vertical Shore. Waler Frames. Light Duty Bracing. Heavy Duty Bracing. Hydraulic / Mechanical Struts. Design of Protective Systems

25. Underground Hazards Underground services may include Pipelines (water, natural gas, fuel oil, etc.) sewers, drains cables (electrical, telecommunication, etc.)

26. Power Cable damaged during mechanical excavation Underground Hazards

27. Underground Hazards An operator was using a post hole digger to excavate without calling the local authorities to locate the underground utilities and obtain the necessary permit . While excavating h e hit an underground, high-pressure cross country gas pipe, causing an explosion. Incident

28. Excavation area Nearby houses

29. They never did find the operator… Took out 2 homes…

30. Before starting an excavation the following steps must be taken: identify ALL underground services based on valid and updated drawings service-locating devices should be used to assist for the exact identification of the position of the underground services identified underground services must be isolated and de-energized where reasonably practicable a Permit To Work must be prepared and issued for the specific excavation exploration trenching Underground Hazards

31. Aboveground Hazards Similar with the underground hazards, aboveground hazards should be identified and controlled (eliminated or minimized) Such hazards can be the aboveground power cables which are usually Medium and High Voltage (can reach up to 400,000 volts) These hazards and the precautions taken must be described in the Permit To Work , as well

32. People falling into excavations is the cause of many injuries. All excavations must be securely fenced with a guards, intermediate rails, toe boards, barricades, etc. Falling Hazards Proper warning signs must be placed around the excavation area to warn all pedestrians, vehicle driver’s and equipment operators

33. Crossing over a trench can be dangerous. Where necessary access-ways of at least 600 mm width, with edge protection, should be provided. Falling Hazards

34. Falling Hazards ×

35. 40 Falls of Equipment and Materials To prevent equipment and materials from falling into excavations, adequate systems and precautions should be taken: Traffic Control. Movement of equipment should be away from excavation areas Barricades properly lit during nights Hand/mechanical signals/Flags Grade soil away from excavation Falling Hazards

36. The weight and vibrations of the vehicles and equipment can seriously affect the excavation stability causing collapsing of the slops Falling Hazards

37. Where people have to enter excavations to carry out work consideration should be given to the potential presence, within excavations, of fumes, which can cause asphyxiation and/or poisoning . Work in excavations should be treated as work in a confined space and the precautions defined in confined space Safety Practice should be complied with, where applicable. Atmosphere Hazards

38. Oxygen deficiency High combustible gas concentration (i.e. HC, etc.) High levels of other hazardous substances (i.e. H 2 S, CO, etc.) Test excavations more than 1.2m before an employee enters the excavation for: Atmosphere Hazards If any of above elements is present, then proper precautions should be taken (that may include ventilation, etc.)

39. There are occasions when excavation plant (e.g. diggers /backhoes) and lifting equipment has to be used. Such equipment can create: additional risks from surcharging , damage to the supporting structure injuries to people within the excavation being struck by the excavating equipment or the load being lifted over the excavation area Struck-by Hazards

40. The planning of such work should identify where the plant is to be located to minimise: the risk of surcharging the risk of falling into the excavation especially if the sides of the excavation collapse under the weight of the plant and equipment Struck-by Hazards

41. Safe and proper-made means to enter and exit from excavations must always be provided before people enter the area and commence any activities. Supporting Structures for the excavation must never be used as means of entry and egress Access and Egress Consideration must also be given on how an injured person, who is unable to use the means of access, will be removed from the excavation in an emergency case

42. Access and Egress

43. Means of Access & Egress that can be provided: Cerified Ladders Ramps Stairs Certified scaffolding Some of the rules that must be followed when setting the means of access & egress height to base ratio of 4:1 be securely lashed maintain three-point contact means of getting tools and equipment into and out of the excavation Access and Egress

44. Access and Egress ×

45. Water = Cave-in Hazard These workers must be protected from cave-in. Note the water in the bottom of the trench. This is an hazardous condition! DO NOT ENTER !!! Water Accumulation Hazard

46. Whenever an excavation is to be carried out close to: services existing buildings structures and scaffolding, care should be taken to ensure that the services or foundations are not disturbed or undermined. Collapse of Adjacent Structures

47. Hazard assessment of the work site completed by competent person. A P ermit T o W ork must be issued before the commencement of any work All underground hazards, eg. pipelines, electric cables, etc. must be identified, isolated and protected. Lockout – Tagout process must be implemented. Special remark should be made in the PTW Safety Tips - Summary

48. A confined space PTW must be issued if the entry meets the definition Adequate precautions should be taken to ensure safety of the people working in and adjacent to the excavation Ground movement must be controlled and collapse prevented by systematically shoring, sloping, benching etc. as appropriate Adequate access and egress structures must be in place Safety Tips - Summary

49. Interference beetween workers and machines shall be minimised, as well the precense of workers inside the excavation Excavation shall be barricated, materials shall be stocked away from the edge, proper access/egress to be ensured Ground and environment conditions must be continuously monitored for change Protected sharp steel bar ends Safety Tips - Summary

50. FOLLOW ALL SAFETY RULES AND PRECAUTIONS IF YOU WANT TO AVOID…

51. RESTRICTED AREAS – DANGER DO NOT ENTER !!! REMIND THAT EXCAVATIONS ARE……

52. REMEMBER… We want YOU to return home SAFE !!!