Trenches and Excavations Training Guide
(Taken from the "Tailgate Meetings that Work : A Guide
to Effective Construction Safety Training" series)
Robin Baker, Robert
Downey, Mary Ruth Gross, Charles Reiter
Labor Occupational Health Program
(LOHP) School of Public Health,
University of California, Berkeley Ca.
talks were developed for use under California OSHA regulations. The
complete set is available from the Labor Occupational Health Program
at UC Berkeley. For ordering information, visit the website (www.lohp.org)
The American Conference of Government Industrial Hygienists (ACGIH)
has adapted these talks to apply to federal OSHA regulations. To contact
ACGIH, visit its web site (www.acgih.org).
Before you begin
- Does this topic
relate to the work the crew is doing? If not, choose another topic.
- Did you read
this Training Guide and fill in the blanks where the
appears? (To find the information you need, look over the Safety Walkaround
Checklist for this topic.)
meeting is about working safely around trenches and excavations. A lot
of people think if there's ever a cave-in, they'll just outrun it. But
that could be the biggest mistake you'll ever make. You can't outrun them.
Between 50 and 100 workers die each year in the U.S. from .cave-ins and
other trenching accidents. Never enter an unsafe trench or excavation!
You or a crew
member may want to add a personal story about trenches or excavations.
with the crew where you will be excavating at this particular job site:
THE CREW THESE QUESTIONS:
After each question,
give the crew time to suggest possible answers. Use the information following
each question to add points that no one mentions.
to Cal/OSHA, excavations over five feet deep require a permit if workers
will be entering them. We must have a competent person in charge.
What does that person do?
- Determines the
type of soil, and decides what kind of cave-in protection is needed.
- Inspects the
operation daily and after every rainstorm, snowstorm, or earthquake.
- Checks and corrects
- Determines if
there are hazardous fumes or vapors in the excavation, and if there
is enough oxygen.
- Can shut down
the operation until it is safe.
- Must always be
on the when anyone is working in or around the excavation.
"competent person" for this job is: ________________________________.
2. When does
a trench or excavation need shoring, sloping, benching, shielding, or
other protection from cave-ins?
- If five feet
deep or more.
- When less than
five feet deep, similar protection may be needed if the competent person
has not yet inspected the excavation and determined it is safe from
3. An excavation
can cave in if weakened by rain, snow, or other water. What precautions
do we have to take in wet conditions?
- As a general
rule, don't work in accumulated water.
- The competent
person must re-inspect after each rainstorm or snowstorm.
4. What do you
need to know about utility lines when excavating?
5. Where should spoil
go? How far back from the edge.
- The area should
be marked by the Underground Service Alert (USA) system to show location
of underground utility lines.
- Make sure you're
not interfering with any kind of utility--underground, overhead, or
on the surface. Watch out for electrical, gas, telephone, water, and
- Keep all equipment
at least six feet from any electric power line (more distance for very
high voltage). Remember that electricity can arc.
- Keep it at least
two feet from the edge. If you can't, use retaining devices adequate
to prevent it from falling into the excavation.
- The same applies
to all tools, equipment, and other materials. Keep them at least two
feet from the edge, or use retaining devices.
6. How do you
get in and out of a trench or excavation safely? How do you cross over
- If the excavation
is over four feet deep, there should be designated access points within
25 feet of any worker in the excavation.
- If equipment or
people cross over a trench deeper then 6 feet or wider than 30 inches,
there must be a walkway with standard guardrails.
- Trenches and excavations
in remote areas should be barricaded.
7. When do you
need a lookout standing by?
8. What precautions
should you take if a trench or excavation is classified as a "confined
- Don't go in until
the competent person checks out the air. There may be toxic vapors or
fumes, insufficient oxygen, or both.
- Follow directions
from the competent person. You'll be told what special precautions to
spaces on this site:____________________________________
Most of the safety measures we've talked about are required by Cal/OSHA.
We have to take these precautions -- it's the law. I have a Checklist
of the Cal/OSHA regulations on trenches and excavations. If you'd like
to know more, see me after the meeting.
(Only if applicable.)
Besides the Cal/OSHA regulations, we have some additional company rules
about trenches and excavations.
company rules: ___________________________________________
Do you have any other concerns about trenches or excavations? Do you see
any problems on our job? (Let the steward answer first, if there is
What about other
jobs you've worked on? Have you had any experience with trenches or excavations
that might help us work safer on this job?
OF THOSE WHO ATTENDED THIS SAFETY MEETING
Meetings That Work : Collection
Published in June, 1994 by: Labor Occupational Health Program, School
of Public Health, 2515 Channing Way, University of California, Berkeley,
CA 94720. Phone: (510) 642-5507.
Permission is granted to duplicate these materials for non-profit educational
purposes, provided that copies are not offered for sale.
This paper appears in the eLCOSH website with the permission of the author
and/or copyright holder and may not be reproduced without their consent.
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