Trench for the First Responder

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Trench for the First Responder

• Chris Bednarek
• Chicago Heights Fire Department

2
Orientation

• Extension of the Trench Rescue material in the
  Technical Rescue Awareness class.
• You will learn additional information about
  working safely around a trench rescue scene prior
  to the arrival of qualified trench rescue
  personnel.

3
Orientation

• This class does not qualify you for OSFM
  certification, nor does is qualify you for entry
  at a trench rescue operation.
• This information is intended to give the first-in
  company an idea of what to do and how to go about
  it safely.

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Terms to Know

• Angle of Repose the greatest angle above the
  horizontal plane at which loose dirt will lie
  without sliding.
• Back Fill the refilling of a trench, or the
  material used to refill a trench, or to fill a
  void between two surfaces.
• Spoil Pile the material excavated from the
  trench.

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More Terms to Know

• Fin Form ¾, 14-ply, arctic white birch.
• Strong Back a 2 x 10 or 2 x 12 attached to fin
  form to create a panel for shoring the wall of a
  trench.
• Struts the horizontal bracing between the
  trench walls.
• Uprights vertical supports, usually 2 x 8s,
  the depth of the trench.
• Ground Pads 4x8 or 2x8 sheets of plywood used
  to disperse weight around the edge of the
  trench.

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Where do we see trenches?

• Commonly seen occupied and unprotected
• Public works routinely work in trenches.
• Pipeline cable installation.
• Areas of new construction (water, sewer)

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• Fin-form strong backs
• Air-Shore strut
• Paratech strut
• Back fill (wood dirt)
• Ground pads

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• Use of multiple types of shores
• Fin-form strong backs
• Ground pads
• Whalers
• Escape ladders

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OSHA

• Defines a trench as an excavation that is deeper
  than it is wide and is no more than 15 wide.
• Has regulations governing operations in trenches
  5 deep or deeper.
• Regulations apply to rescues.
• Provides guidelines for trenches up to 15 wide
  and 20 deep. Custom engineering is required by
  a Registered Professional Engineer beyond those
  limits.

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60 to 65 OF ALL FATALITIES ARE THE WOULD-BE
RESCUER

• Lack of knowledge
• Lack of training
• Compassion for the victim

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Trenches are Dangerous

• Once earth is disturbed, pressure begins to act
  on the trench walls.
• Sooner or later all trenches cave in.
• There is no way to predict when a trench will
  fail.

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Note the deterioration to the left corner
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Vibration Hazards

• All heavy equipment should be turned off and
  secured (take the keys and block the tires).
• All sources of vibration should be eliminated for
  300 in every direction. This includes roadways
  and railways.

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Backhoes

• Backhoe operators will insist they can dig the
  victim out.
• OSHA statistics are riddled with cases of
  disembowelment and decapitation.
• Backhoe operators cannot tell the difference
  between a rock and a body.
• Weight of the backhoe adds to instability of
  trench walls.
• Vibration likely to speed up secondary collapse

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Atmospheric Hazards

• The victim may be the result of bad air in the
  trench and have no actual trauma.
• Air should be monitored every 15 minutes for O2,
  CO, H2S and combustibles.
• Rescuers can fall victim to the same bad air if
  it is not checked regularly.
• O2 permissible exposure limits 19.5-23.5.
• Methane Gas Flammable Limits 5.0-15.0.

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Public Utilities as a Hazard

• Many trenches are dug for utility maintenance or
  installation.
• Utility cables and pipes can add to trench
  instability.
• Electrical utilities can pose a threat to both
  the victim and the rescuer.
• Broken sewer or water lines may fill the trench,
  causing a drowning potential for the victim.

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CONTACT WITH UTILITIES CAN BE DANGEROUS CAUSE
DISRUPTION TO SERVICE
ROADWAY UNDERMINING
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Heavy equipment can fall into the trench trapping
workers
Workers can be struck by operating heavy
equipment
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Digging their own grave
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Seattle, WA 8/8/2000 Worker killed Rescuers using
camera to locate victims body
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Lebanon, MO 1989 Hit 10 propane pipeline Killed
operator
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1996 - Operator burned after hitting 8 gasoline
pipeline
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St. Paul, MN - 1993 City crew working on sewer
line hit natural gas line Killed 3, injured 11
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1988 Hit propane line 3 Workers injured
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Dirt as a Hazard

• One cubic foot of dirt weighs 90-145 lbs.
• The average collapse is 1.5 cubic yards (4000
  lbs.).
• The average victim buried under 2 feet of dirt
  will be covered by 3000 lbs., about 1000 lbs. of
  that will be on his chest.
• The speed of collapsing dirt is often less than
  1/10th of a second.

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TimeTimeTime

• The average trench rescue takes between 4 and 10
  hours.
• Long rescue time allows for further deterioration
  of trench walls.
• Rotation of rescue crews necessary to keep people
  fresh.

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The First-In Company

• Apparatus should be located no closer than 50 to
  the trench and should be shut down.
• Locate the victim and try to find out what was
  being done at the time of the accident from
  someone else on the scene.
• Approach the trench from the end, never from the
  side and stay as far away as possible.

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The First-In Company

• If the victim is conscious, he may be able to
  rescue himself if a ladder and/or shovel is
  lowered to him.
• Call Orland Dispatch (708/403-5584) and activate
  a CART box for a trench rescue.
• Keep everyone back from the trench and shut down
  all machinery on the scene.
• Shut down all roads and railways for a 300
  radius from the scene.

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The First-In Company

• Identify any utilities that my be marked by JULIE
  at the scene.
• Orange Communications
• Red Electric
• White Excavation Boundaries
• Yellow Natural Gas
• Green Sewer
• Blue - Water

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The First-In Company

• The location of an unconscious or trapped victim
  can be marked with paint or dry-chem at the edge
  of the trench.
• Ground pads will need to be laid around the edge
  of the trench.
• The spoil pile must be moved a minimum of 2 away
  from the edge of the trench. This must be done
  while working off ground pads.

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Water, Water Everywhere

• Prior to the rescue team entering the trench, all
  water must be evacuated. This includes water
  from a main break, ground water and rain water.
• Small amounts of water can be removed with a sump
  pump in a 5 gallon bucket.
• Larger amounts of water or water which is flowing
  can be removed with a vac-truck.
• The truck must be set up 300 away and have a
  safety valve in line with the vacuum hose.

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Incident Command

• Establish a trench team command structure
• Rescue Officer (required) Officer in charge of
  the rescue and designates other rescue sectors.
• Rescue Safety (required ) May be in addition to
  the scene safety officer and trained to the
  level of the incident.
• Rescue Operations Officer who runs the rescue.

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Medical Care for the Trench Victim

• Establish medical care for the victim as soon as
  protection is established and victim is accessed.
• Prepare for open closed fractures, chest
  injuries, spinal injuries, crush syndrome,
  hypothermia, dehydration and hypoxia.
• Give the victim a head, eye and respiratory
  protection as soon as possible.

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Trench Rescue Hazards

• Hazards are not obvious
• Secondary collapses are common
• Dirt is heavy and moves fast
• Rescues are usually long-term operations
• Backhoes are not safe for victim rescue
• OSHA has trench limits and regulations
• Buried utilities can pose a threat to rescuers
• Impact or entrapment from falling debris or
  equipment
• Unprotected trenches are dangerous
• There may be inadequate equipment for shoring
• Possible legal liabilities for fire officers

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The End