1 / 41

Trench Awareness Training

Trench Awareness Training. For safety is not a gadget but a state of mind.  ~ Eleanor Everet. Objectives . Governing Standards Anatomy of a Trench Soil Physics First arriving units actions/ Scene management Equipment Familiarization Type of Trench Collapses and Recognize hazards.

stew
Download Presentation

Trench Awareness Training

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Trench Awareness Training For safety is not a gadget but a state of mind.  ~ Eleanor Everet

  2. Objectives • Governing Standards • Anatomy of a Trench • Soil Physics • First arriving units actions/ Scene management • Equipment Familiarization • Type of Trench Collapses and Recognize hazards

  3. Objectives cont. • Understand what is required to manage a Trench Rescue Incident • Provide tools to enable the student in making safe and effective decisions during a trench rescue incident • Implement the Incident Management / Accountability System

  4. NFPA 1670 • AWARENESS Level Functions • Size-up of existing and potential conditions • Ability to call for more resources • Development & implementation of procedures for carrying out an emergency response system • Site Control & Scene Management • Recognition of hazards and procedures to mitigate these hazards

  5. Definitions • A “trench”, means a narrow excavation (in relation to its length) made below the surface of the ground. In general, the depth is greater than the width, but the width measured at the bottom is not greater than 15 feet. WIDTH DEPTH

  6. ”Excavation”, includes a trench It means any man made cut, cavity, trench, or depression in an earth surface formed by the earths removal. Again, in practical terms, when a hole is more than 15 feet wide at its base, it is called specifically an excavation. Overall, an excavation is wider than it is deep.

  7. Anatomy

  8. How Heavy is Dirt? • Physical forces associated with collapse: • Dirt has volume that has mass and weight • One cubic foot of dirt weights between 85 and 125 pounds per cubic foot.

  9. Weight of one cubic yard of soil Weight of a Volkswagen 2,785 Pounds 2,700 Pounds

  10. Soil Physics • Compounding the effects of gravity is hydrostatic pressure • Add the weight of water and rock, a cubic foot of dirt can be as much as 125 pounds per cu/ft

  11. Trench Shield / Trench Box • Shields are manufactured by a number of companies and are designed to protect workers working within the confines of the shield. • Top of Trench shield / box must be at least 18 inches above trench lip. • Additionally, the shield must be designed by a Registered Professional Engineer, be in good condition, and used properly.

  12. Shoring • Shoring is one of the most common used methods of worker protection. It is light-weight, portable and easy to install. • The manufacturer provides tabulated data with the shoring that provides the limitations, precautions, required spacing and proper use. This photo shows an example of aluminum hydraulic shoring. Sheeting not required with use.

  13. Accidents without cave-ins • Most emergencies in trenches deal with something other than a collapse • Most of the work is done after the trench has been dug • In these cases don’t be lulled to sleep by a protected trench • Approach identically as an open trench

  14. What makes trenches hazardous?

  15. Hazards Present?

  16. Most deaths occur in trenches 5 ft. to 10 ft. in depth and 6 ft. wide. 90% of fatal accidents occurred in trenches less than 20’ deep

  17. First Arrival • Apparatus spotting • Spot at least 100 ft. from location • Create Exclusion Zones (on next slide) • Size-up – accurate address of location, length, width and depth of trench, number of victims, length of time from collapse • Call for help-Zone 3 • Secure RP, job foreman, or witness to accident • Safety 360 • Lockout excavator; may require Police assistance • When doing a recon approaching the trench from the short end • Use available ground pads (Plywood) to stand on when near the trench, to distribute weight near trench • Conduct Risk-to-benefit analysis • Assess potential hazards to rescuers and patient(s) (Atmospheric, Water, Trench etc.) • Secure the utilities and or call the appropriate utility company • Place a ladder in the trench for possible self-rescue of the victim

  18. Hot Zone 0 – 100 ft. Warm Zone 100 – 150 ft. Cold Zone 150 – 300 ft. All are 360 degrees around incident Trench Scene ManagementExclusion Zones

  19. Equipment Familiarization • Strongbacks,Uprights, sheeting = Shoring Panels • Airshore • Speedshore

  20. Shoring Panel

  21. Airshore SCBA air supply with attached regulator to a controller to operate tool.

  22. Speedshore Hydraulic tool: used most in industry and public works departments

  23. Shoring Concept Works by creating “double funnel effect” Strong enough to prevent soil from starting to moveset in four feet intervals vertically and horizontally as a general rule. Strut pressurizes trench wall in all directions

  24. Types of Collapses Spoil pile slide • Excavated earth too close to the lip • Heavy rain increasing wt of pile

  25. Slough In / Lip slide Slough failure • The loss of part of the trench wall

  26. Sheer Wall Shear wall collapse • section of soil that loses it’s ability to stand

  27. Rotational Failure Rotational failure • Scoop shaped collapse that starts at the lip and transmits itself to the trench walls

  28. Toe Failure Toe failure • Slough that occurs at the bottom • Found in location of fill dirt

  29. Bell Pier Condition Bell pier condition • Long term toe failure on both sides

  30. Wedge Failure Wedge failure • Occurs with intersecting trenches, T or L Trench • Angled section of earth falling from the corner of an intersecting trench

  31. TECHNIQUES FOR TRENCH PROTECTION

  32. Outside Waler

  33. Inside Waler • Inside walers are used to span a set of panels for the purpose of creating an open space

  34. The intersecting “T” trench is a very unstable trench because not only is one wall exposed, but a section has been cut that intersects the other wall.

  35. The “L” trench can be describe as two trenches that intersect at there ends

  36. Deep trenches are those trenches over 10 feet but not more than 20 feet

  37. Trench Environments

  38. Tacoma incident w/ fatality Trench accidents have a 112% higher fatality rate that other construction accidents

  39. Create a Hot, warm and cold zone Hot zone 0 – 100 ft. Warm zone 100 – 150 ft. Cold zone 150 – 300 ft. Size-up – accurate address of location, length, width and depth of trench, number of victims, length of time from collapse Initiate command & Call for a Zone 3 Trench Rescue response Secure RP, job foreman, or witness to accident Identify a staging location Control traffic movement Shut down all heavy equipment operating within 300 ft. of the collapse, including excavator. Lay ground pads near the trench Ladders for egress every 25 ft. for possible self-rescue of victims in the trench Take Home Points

More Related