Tool Box Session
GA Tech Safety and Health
Consultation Program
INTRODUCTION
This training information has been prepared by the Safety and Health Consultation
Program at Georgia Tech with the technical collaboration of Mr. Juán C. Rodriguez and
under the sponsorship of OSHA. Its content may be copied and distributed for free, and
the only request made to the user is that Georgia Tech’s Safety and Health Consultation
Program be acknowledged as the source. All information contained in this training is
believed to be correct by the authors, but it is important to point out that, this is not an
official OSHA publication and has not been revised or approved by OSHA. The user
should be aware that the recommendations provided in this training do not replace any
OSHA standard or regulation.
Georgia Tech Safety and Health Consultation Program
Georgia Tech Research Institute
260 14th Street, Fourth Floor
Atlanta, GA 30332-0837
Voice : (404) 407-7431
FAX : (404) 407-8275
Web http//www.oshainfo.gatech.edu
Email: art.wickman@gtri.gatech.edu
GA Tech Safety and Health Consultation Program
Definitions
 Cave-in: means the separation of a mass of soil or
rock material from the side of an excavation, or the
loss of soil from under a trench shield or support
system. During a cave-in this material moves suddenly
into the excavation, either by falling or sliding, in
sufficient quantity to entrap, bury, or otherwise injure
and immobilize a person
GA Tech Safety and Health
Consultation Program
GA Tech Safety and Health Consultation Program
Definitions
 Competent person: means a person who is capable
of identifying existing and predictable hazards in an
excavation, or in the work practices of employees. If
conditions are unsanitary, hazardous, or dangerous,
the competent person has the authority to take prompt
corrective measures to eliminate the hazards
GA Tech Safety and Health
Consultation Program
GA Tech Safety and Health Consultation Program
Definitions
 Excavation: means any man-made cut, cavity, trench,
or depression in an earth surface, formed by earth
removal
 Trench: means a long and narrow excavation made
below the surface of the ground. In general, the depth
of a trench is greater than the width
GA Tech Safety and Health
Consultation Program
GA Tech Safety and Health Consultation Program
Definitions
 Stable Rock: means natural solid mineral material
 Soil Types
 Type A: means cohesive soils; example: clay
 Type B: means soil with poor cohesion, example:
crushed rock / angular gravel/sandy soil
 Type C: means soil without cohesiveness, example:
gravel and sand
GA Tech Safety and Health
Consultation Program
GA Tech Safety and Health Consultation Program
Acceptable visual and manual tests for soil
classification
 Observe the area adjacent to the excavation and the
sides of the opened excavation for evidence of surface
water, water seeping, utility pipes, or any other
underground material such as tree roots
 Determine if the soil is cohesive or not
 Make use of a pocket penetrometer, thumb
penetration, plasticity tests, soil’s hardness property,
and any other strength test
GA Tech Safety and Health
Consultation Program
GA Tech Safety and Health Consultation Program
Maximum allowable slope of an excavation
vertical face
Slope requirements for excavations < 20 feet deep:
 Stable Rock ….
 Type A………..
 Type B………..
 Type C………
Vertical
3/4 : 1
1:1
1½:1
(90o)
(53o)
(45o)
(34o)
GA Tech Safety and Health
Consultation Program
GA Tech Safety and Health Consultation Program
Protective Metallic Trench Box
 The intended use of a metal trench box is to protect the
workers from a cave-in or a similar incident
 The designed purpose of timber shoring configurations
and other systems of support are to keep the trench’s
sides stable
 The space between the excavation and the trench box
must be as narrow as possible in order to avoid lateral
movement of the trench box
GA Tech Safety and Health
Consultation Program
GA Tech Safety and Health Consultation Program
The soil from the excavation
 Soil and any other excavated material shall be placed
and kept at least 2 feet from the edge of excavations.
 This is done to protect employees from materials (soil,
loose rocks) or equipment that could pose a hazard by
falling or rolling into the excavation, and also to keep
an accurate measurement of the depth of an
excavation
GA Tech Safety and Health
Consultation Program
GA Tech Safety and Health Consultation Program
Access
 Trenches more than 4 feet deep must have a ladder or
other means of of access
 The separation distance between ladders placed in an
excavation must not be more than 25 feet
 Ladders shall be secured and the upper ends of their
side rails must extend at least 36 inches above the
surface of the ground / edge of an excavation
GA Tech Safety and Health
Consultation Program
GA Tech Safety and Health Consultation Program
Location of Underground Utilities
 Keep in mind that there might be underground utility
installations to be encountered during excavation work,
such as sewer, telephone, fuel, electric, water lines, or any
other underground installations.
 In order to avoid damaging utility lines and as a personal
safety measure, the estimated location of such lines must
be determined prior to opening an excavation.
 “Call Before You Dig” State Laws
GA Tech Safety and Health
Consultation Program
GA Tech Safety and Health Consultation Program