This Presentation Developed ByDrew R. Smith This presentation may be modified or reproduced by individual fire departments or training organizations provided it is not used to generate revenue or in any commercial manner.
Scope • First-in companies • Identify hazards • Describe initial tasks • NOT “team member” training
Length • Confined Space - 4 hrs. • Trench Rescue - 4 hrs.
Requirements • Firefighter II • Course completion • End-of-Course Examination • State Written Examination
Objectives As presented in class: Describe the need for trench rescue awareness training Identify: • The content of the Rescue Awareness Course
Identify: • The Office of the State Fire Marshal certification requirements. • The OSHA definition of a trench. • Ten hidden hazards associated with trench rescue. • Four types of trench collapses. • Six environmental factors which adversely effect trench stability.
The requirements imposed by the Illinois Department of Labor for persons involved in rescue operations. • How the National Fire Protection Association, Illinois Department of Labor, Occupational Safety and Health Administration, ANSI and NIOSH all interface. • The requirements of OSHA 29 CFR Part 1926 Subpart P - Excavations as it applies to rescue operations.
The requirements imposed by Illinois Department of Labor for persons involved in rescue operations. • The three classes of soil. • The methods of victim and rescuer protection. • The principles of sloping a trench. • The principles of trench shields. • The principles of shoring. • Four types of shoring.
The components of a shoring system. • The personal protective equipment that is required for trench rescue. • Required entry and retrieval systems. • Air quality monitoring and control systems. • The initial command operations at the scene of a trench rescue. • The initial tasks of the first-in company at the scene of a trench rescue.
Phoenix Segment 1
Trenches are a familiar sight Commonly seen occupied & unprotected • Public works routinely works in trenches performing maintenance and repair • Private contractors routinely work in trenches installing new utilities such as water mains and electricity.
Danger associated with them • Once earth is disturbed, pressure begins to act on trench walls • Sooner or later trenches will cave-in • Impossible to predict • Unprotected occupants are relying on luck
Rescues are rare • Fortunately we don’t deal with incidents often • Dangerous due to lack of experience • Limited funding for training & equipment • False sense of security • Dangerous since most hazards are hidden
OSHA • Regulations covering trench operations when depth is 5 feet or more • Regulations apply to rescue scenes
Definition of a Trench An excavation which is deeper than it is wide and is less than 15 feet wide
Types of collapses • Slough-in • Sidewall-in • Shear-in • Spoil-in
Spoil-in To prevent a spoil-in the spoil pile is to be at least 2 feet from the lip and laid back less than 45 degrees
Vibration • Extremely dangerous • Typical sources • Roadways • Railroads • Digging operations • Nearby construction/industry
Superimposed loads • Add weight & stress to trench • Examples • Spoil pile • Heavy equipment • Work materials (cable, vaults, pipe) • People
Surface encumbrances • Other structures whose support relies on the soil at or near the trench • Examples • Roadways • Utility poles • Foundations
Wet soils/submerged soils • Added weight • Loss of friction • Movement of water carrying soil • Standing water undermining trench walls
Exposure to elements • Time - longer trench is open the more unstable it will be • Sun and wind • Freezing / Thawing
Previously disturbed soils are common due to trenches being located in easementsExcavation within last 25 years makes soil previously disturbed
Buried utilities • Must be located • Often requires time-consuming hand digging • Common problem since most trenches are located in easements • OSHA requires that all utilities or other structures exposed in trenches be properly supported.
Phoenix Segment 2
Human nature • Would-be rescuers jump in & start digging • Backhoe operators try to dig victim out
Secondary collapses • Walls are undermined from initial collapse • Walls are often left more unstable than before initial collapse • Often occur while “quick” rescue attempt is being made
Weight of dirt • 1 cubic foot of soil weights 90-145 pounds • Average collapse is 1.5 cubic yards (4,000 pounds..) • Average worker buried under 2 feet of soil • Total weight 3,000 pounds • 1,000 pounds on chest area • Worker suffocates due to inability to raise chest
Speed of collapsing dirt • Often less than 1/10 of a second • Normal escapes methods ineffective • Being pulled out with a rope • Running out
Rescues are usually long operations • Commonly last 4-10 hours • Victims must be completely uncovered before removed • Often frozen in position • Limbs commonly bent at odd angles • Fractures are common
Backhoes used for rescues • Equipment is too powerful - can’t tell a rock from a head • Bucket too large & inaccurate • Operator will likely be excited • Will have watched cave-in • Will typically know the victim • Vibration may cause additional collapses • Weight of the backhoe
CASE STUDIES Incident when back hoe was used to try and dig out worker with legs straddling pipe Incident when backhoe was used to try and dig out worker on top of charged water pipe Incident where back hoe was used to pull on chain wrapped around worked
Inadequate make-shift equipment • Normally requires large timbers (trench 12 foot by 4 foot by 10 foot) 12 - 4”x6”x4’ crossbraces 6 - 10”x10”x14’ walers 48 - 4”x6”x13’ uprights • Timbers may be replaced by metal rams
Contractors often ignore OSHA limits • OSHA only provides regulations for trenches up to 20’ deep; deeper requires special engineering • Contractors who have ignored safety requirements may have also ignored the 20’ limit
Fire Officers who do not follow procedures and allow personnel to enter unshored trench may be: • Fined for not providing protection • Receive major fines for injuries • Possibly face criminal charges for deaths • A party to a civil suit (be sued)