Trench Safety Summit - ColoradoPresented by the North American Excavation Shoring Association (NAXSA) and OSHA in partnership with:
Associated General Contractors (AGC) of Colorado
Colorado Contractors Association
HBA of Metro Denver (Colorado Association of Homebuilders)
Colorado Chapter of the National Utility Contractors Association (NUCA)
Colorado 811
Unsafe work in trenching and excavation
industry is becoming an epidemic.
• Trench Fatalities A total of 488 trench and
excavation deaths between 1992 and 2000,
an average of 54 fatalities each year.
• Trench Fatalities for each calendar year 2014
and 2015. 11-Nationwide.
• Trench Fatalities for calendar year 2016
23-Nationwide.
• 15-Nationwide in the first 7 months and
estimated to surpass 30 fatalities in 2017.
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Who’s dying in trench “accidents”?
• Sixty-eight percent of trench fatalities
occurred in companies with fewer
than 50 workers.
• Over 43% of fatalities where
construction laborers.
• Hispanic workers die with 1 in 3
deaths occurring in construction.
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Who’s dying in trench “accidents”?
Fatalities by age:
• 36% 29 years old or less
• 26% 30-40 years old
• 38% 40-years old or older
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What protective system used?
•76% nothing was used
•12% Sloping and
Benching
•8% Trench Shields
•4% Shoring6
BRIEF DESCRIPTION OF ACCIDENT
• February 6, 2015-Manhattan, KS.
• A 30-year old City of Manhattan employee was working in a 5’ deep trench fixing a water main break when a trench collapse occurred. The work was buried to his waist for 20-min. when he was rescued by two local fire departments.
• He was transported to a local hospital where he was pronounced dead after succumbing to his injuries.
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Key Elements of OSHA Excavation Std.
• Designate a competent person to conduct daily inspections of excavation, adjacent area, and protective systems, and take appropriate measures to protect workers.
• Use adequate protective systems-shoring, trench shields, sloping or benching.
• Develop, implement, and enforce a comprehensive written safety program for all workers that includes training in hazard recognition.
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Key Elements of OSHA Excavation Std.
• Ensure that spoil pile and heavy equipment are kept away from edge of the trench or excavation if workers must be present in the trench.
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Adequate means of egress from
trench excavations.
• Excavations 4’ or greater
• Ladder, stairway or ramp
• No more than 25’ of lateral travel
• Ladder must be three feet above top of excavation
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Exposure to vehicular traffic.
• Employees exposed to public
vehicular traffic shall be provided
with, and shall wear, warning
vests or other suitable garments
marked with or made of reflect
ionized or high-visibility material.
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Excavation Standard Fed. OSHA
1926.652 (a)
Employees shall be protected from cave-
ins by an appropriate protective system.
What is the exception to this?
Exception: If excavation are
made of entirely in stable rock
or are less than 5 ft. deep, and
a competent person has
determined that there is no
potential for a cave-in.
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Registered Professional Engineer….
• Means a person who is registered professional engineer in the state where the work is to be performed. However, a registered professional engineer, registered in any state is deemed to be a “registered professional engineer” within the meaning of this standard when approving designs for manufactured systems for “manufactured protective systems” or “tabulated data” to be used in interstate commerce.**
** Only 1 out of 49 states requires a 2nd engineer's stamp from an in state engineer on manufacture’s tabulated data.
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Answer: Manufacture’s Tabulated Data that
exceed the limitations of the various tables
found in tables found in Appendices B thru D
of the excavation standard (29 CFR
1926.650) may be developed and used in
the design and application of trench systems
provided the development and use are
approved by a registered engineer.
Source: OSHA Letter of Interpretation October 1, 1991 (Letter #1991_10_01)
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1926.652 Requirements of Protective
Systems
• Shields shall be installed in a
manner to restrict lateral or other
hazardous movement of the
shield in the event of a sudden
lateral load.
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OSHA does not give a distance
between the dirt walls and your
trench shield.
You would need to refer to the
manufacture’s tabulated data sheet
for this distance.
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Can I use Speed Shore Trench
shields in combination with a
sloping system when the total
depth of the trench is greater than
twenty (20) feet deep?
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Example: A trench total depth will be 36’
deep and the contractor is going to stack 3-
8’ high trench shields with a rated capacity
that meets the depth requirements for the
trench shields location in the trench based
on the Competent Persons soil
classification.
The top of the trench will be sloped 18”
below the top shield based on the OSHA
sloping and benching tables.
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Based on Speed Shores Technical
Data Sheet # SS-6899-2 Dated
06/08/99.
This is acceptable as long as all other
provisions of Speed Shore’s
Manufactures Data is applied.
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Simple Slope excavations 20 feet
or less in depth
shall have a
maximum allowable
slope of 1 : 1 or 45
degree in B soils.
B=Dx2+W
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Simple Slope
excavations 20
feet or less in
depth shall
have a
maximum
allowable slope
of 1 : 1 1/2 or
34 degree in C
soils.
C=D x C + W 25
Trick question!
Who’s engineering
are you using,
OSHA or the
Manufacture’s
Tabulated Data?
It’s not one!
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I-Beam with Wood Lagging, Sheet Pile,
Hydraulic Wales and Cross Bracing- Site
Specific Engineered System
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