# Shared Flashcard Set

## Details

Trench Rescue
Block III
21
Aerospace Engineering
Pre-School
08/16/2013

Term
 What is trench?
Definition
 Excavation in the ground that is deeper than it is wide, that is not 15ft wide.
Term
 What is excavation?
Definition
 whole thing is an excavation (including hole in the ground) think of archeologist.
Term
 State Regulations
Definition
 Cal/OSHA AND NFPA 1670
Term
 Factors affecting cave-ins
Definition
 Soil Strength (soil type, moisture, freezing, previosuly disturbed soil, vibration)/ Downward force (trench depth, soil weight)
Term
 Just for general purposes
Definition
 consider all Type C-60 Soil which is soil that will stand long enough to install shoring and have water level at or below the bottom of excavation.
Term
 Failures based on Soils
Definition
 #1 Clay or mud: 32 failures   #2 Wet dirt/ silt clay: 21   #3 Sand/Gravel/ clay: 10   #4 Rock: 8   #5 gravel: 7   #6 Sand/gravel: 4
Term
 Components of a trench
Definition
 Spoil (remove soil 2ft back can't be higher than 4ft), Lips, then trench.
Term
 Collapse
Definition
 Dead end or L-Trench, Simple intersection, 4 way intersection, T-Intersection pg. 4   *Possible collapsed in the corners (45 degrees)   *You put ladders at the end of the trench!   *or you can create a bridge!
Term
 Silt Trench
Definition
 [image]
Term
 Types of Trenches
Definition
 #1 L-Trench   #2 T- Trench   #3 X-Trench (cross)   *Shaped exactly how the letter is.
Term
 Soil Mechanics
Definition
 1 Cubic foot of soil weighs approximately 100-125 Ibs   18-24 Inches of soil on a victim chest or back weighs approximately 700-1000 Ibs   1 Block of One Cubic foot all around is 100Ibs   5 Blocks of one cubic foot all around is 500Ibs    pg. 5
Term
 Soil Mechanics #2
Definition
 Sliding, Toppling, Bulge, Heave, Boiling    *Surcharged loads: generated by weight of anything in proximity of the trench, will affect pressures in the shoring systems   *OSHA requires spoil min. of 2ft from the edge and ideally not higher than 3ft.    pg. 6
Term
 **Types of Collapses**
Definition
 #1 Spoil In   #2 Lip In (When the lip collapses)   #3 Shear In (Whole piece shear off, previous trench)   #4 Slough In (bottom of the lip collapses- gives you a cliff with no bottom effect)   *Can be both sides or one side!
Term
 Making the Trench Safe
Definition
 #1 Approach (Head in, allows you to see side walls)   #2 Safety (Assign safety officer, stop all machinery, and remove all personell from the trench.)   #3 Ladder (Ladder placement: greater than 4ft maximum lateral travel 25ft/ if the trench is 50ft wide put 2 ladders/ must extend 3 ft above the access)   #4 Edge Protection (Spoin pile side: 2 - 2x12 plywood)   #5 Ventilation (Monitor atm. first)   #6 Sidewall preparation (Side wall protection/ Uprights must be a minimum of 2" x 8"/ Rescues: 2" x 12"/ Douglas fir or Southern pine/ Top of the trench/ Middle of the panel)   #7 Sheeting (4" X 8" 45 DEGREES corners/ Plywood: 1 1/8 for hydraulic and 3/4" for others pg. 9/ slides from oppossite side)   #7 Strut placement (18-24" from top/ 48" to the next Strut/ 0 to 24" bottom to the next strut) pg. 10   or   1         Approach head in 2         Safety – Assign safety officer, stop machinery and vibrations, and remove all workers from Trench. 3         Place ladder only if trench is greater than 4 ft. deep and every 25 ft. and must extend at least 3 ft. above access. 4         Edge Protection – Place two (2) 2x12’s on the spoil pile side and plywood on the opposite side measured at 24” or 4x8. Also, the spoil pile to the side must be at least 2 ft. back and no more than 4 ft. high. 5         Ventilation – Use on trench that is up to 4 ft. wide, attach tape to exhaust side to ensure ventilation is working. 6         Side Wall Protection – Uprights must be minimum 2x8 (commonly used are 2x12), use Douglas Fur or Southern Pine so we can hear it when it’s pressurized. Sheeting (Plywood) must be at least 4x8 ft., no more than 2 ft. from the bottom and not intended as structural member.   Extras – If trench is less than 5 ft. than NO shoring is required. A trench is deeper than it is wide but no more than 15 ft. An excavation is defined by OSHA as any made-made cut, cavity, trench, or depression in the earth’s surface formed by earth removal. (
Term
 Strut Placement
Definition
 Strut placement (18"-24" = 1-2 ft from top/ 48" = 4ft to the next Strut/ 0 to 24" = 2ft bottom to the next strut) pg. 10   *Can't exceed the measurement.
Term
 Shoring
Definition
 Installed from Top to bottom
Term
 Shores
Definition
 #1 Timber Shore: 20 ft deep use a 4x4 (top strut: 18" to 24" bottom strut: 0 to 24"/ Add wedges to void/ Rescuer: waist deep to put the first strut, distance from the lip 18-24" pg. 12)   #2 Hogshead: pg. 13   #3 Timber shores (Walers): Single and double walers   #4 Screw Jacks (18" to 24" from the lip)   #5 Hydraulic Shore(have diff. measurements/ Don't do this)- Lowers into the trench and it spread there.)   #6 Pneumatic Shore: Best choice pg. 20    #7 Ladder shore: Last resort   #8 Trench Boxes: Must stay inside the box for you to be safe!!
Term
 Sloping Shore
Definition
 Can work without Shoring
Term
 The Rescue
Definition
 #1 Develop pre-plan for trench incident   #2 Enroute considerations   #3 PPE/Safety equipment    #4 LCES: Lookouts, Communications, Escape routes, Safe zones   #5 Pre-entry breifing (identift S.O., RIC team, Emergency signal, Communications, Escape locations- ladder, Proper PPE, Work time frames, Specific hazards -Stress cracks/ moistures.
Term
 The Rescue Cont.
Definition
 #1 Control Hazrds: Atmospheres, Vibrations, Utilities, Hazmat.    #2 Size up and stabalize the trench (avoid stress cracks, remove any rescuers from trench until shored)   #3 Shoring/Safet equipment: place first shore as close to the victim as possible/ Safe zone 4ft. either side of the shore, lighting ventilation, lifeline with attendant.)    #4 Victim considerations: Administer 02   #5 Extricate Victim: (OSHA wants helmets on them!!)   #6 Bride: 2 x 12   #7 Getting out work from bottom to the top.
Term
 Trench
Definition
 -If a timber is deeper than 15ft we cant use timber shores we must use pneumatic shores.    -Timber: use 4x8 Plywood  and 2x12 Upright    -Ladder in a trench must be 3-4ft above the ground    -Beyond 5 feet we need a shore   *Pre-built shores: assemble before getting the shore.   -4X8 plywood can be used in a 10ft trench because it can exceed 2 feet   -Lengths of struts: If the distance from the first to second strut is more than 48" you can draw a line in the middle   *If its exactly 48" you dont have to put another strut.
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