CONNstruction - Winter 2018 - 15

edge of the trench, advises Mangiafico.
"Not many people realize that one cubic
yard of soil can weigh as much as a car,
which can cause the walls of the trench
to collapse." For the same reason, heavy
equipment must also be located away from
the edge, he adds.

A Competent Person
Drives Protection
The first step in an effective safety program for trenches is a competent person,
says Mangiafico. "Trenches should be
inspected daily or as conditions change
by a person who is capable of identifying
existing and predictable hazards, and who
is authorized to take steps to protect against
hazards," he explains. The competent person should be familiar with different soil
types and be able to determine the most
effective protective systems required for
the site.
Employees should not enter a trench until
it has been inspected by the competent
person and deemed safe, says Mangiafico.
"There must also be a safe way to enter
and leave the trench, such as a ladder," he
says. OSHA requires that steps, a ladder or
a ramp be used for trenches that are 4 feet
or deeper and that the access equipment
be within 25 feet of all workers.
"Trenches must also be free of standing
water because it causes soil to separate
easily, which can cause a cave-in," explains
Mangiafico. This is especially true for soil
type C - the most commonly found soil in
Connecticut, he says. "The soil types are
stable rock, type A, type B and type C, which
is the least cohesive soil. Examples of a
type C soil include gravel, sand, and sandy
loam," he adds. "One of the first tasks for
the competent person is determining the
soil classification, which can be determined
by a field test or by sending a sample to a
lab for testing."
The three types of trench protective systems are:
* Sloping - protects workers by cutting
back the trench wall at an angle inclined
away from the excavation

Resources for Additional Information
The U.S. Department of Labor
Occupational Safety and Health offers
free downloads of safety publications on
all topics, including several publications
and fact sheets on trench and excavation
safety. Go to www.osha.gov and select
"publications" to browse the list of available downloads.
The Connecticut OSHA offices in
Bridgeport and Hartford have compliance assistance officers on hand to
answer questions. The telephone number for Bridgeport is (203) 579-5581 and

the telephone number for Hartford is
(860) 240-3152.
Free consultation services are available from CONN-OSHA, the state agency.
Consultation includes site visits to identify
potential hazards throughout the construction site and development of recommendations to ensure compliance with standards.
The consultative service is non-punitive -
no citations or penalties are issued during
the process. The telephone number for the
consultation program, which is based in
Wethersfield is (860) 263-6925.

Trench Safety Tips
* Do not enter an unprotected trench
* Trenches 5 feet deep or greater require
a protective system
* Trenches 20 feet deep or greater require
that the protective system be designed
by a registered professional engineer
* Know where underground utilities are
located before digging
* Inspect trenches at the start of each
shift, following a rainstorm or after any
other hazardous event
* Test for low oxygen, hazardous fumes
and toxic gases before entering a trench

* Shoring - protects workers by installing
aluminum hydraulic or other types of supports to prevent soil movement
* Shielding - protects workers by using
trench boxes or other types of supports
to prevent soil cave-ins
Choosing the right trench protective
system requires consideration of soil type,
depth of trench, water content of soil,
changes that may occur due to weather
or climate, surcharge loads - excavated
earth and materials to be used in the trench
that add load to the trench wall support
system - and other construction operations
in the area.
"The type of protection must take into
account the entire construction area,"

* Keep heavy equipment and excavation
spoils at least two feet away from the
trench edge
* Provide stairways, ladders, ramps
or other safe means of access in all
trenches 4 feet or deeper
* Do not work under suspended or raised
loads and materials
* Ensure that personnel wear high visibility or other suitable clothing when
working near vehicular traffic
Excerpted from: Trenching and
Excavation Safety, OSHA Fact Sheet.

advises Mangiafico. The protective system
must consider any vibrations from other construction equipment or traffic that can loosen
soil on the sides of the trench. "It is also a
good idea to barricade the area around the
trench to minimize vibration close to the
excavation," he adds.

Evaluate Trench Atmosphere,
Utilities In Ground
Trenches can also trap dangerous gases,
so the competent person must determine
if the atmosphere must be monitored, says
Mangiafico. Trenches and excavations that
are located near operating machinery may
subject workers to carbon monoxide exposures, and trenches and excavations that
CONNstruction / WINTER 2018 / 15


http://www.osha.gov

CONNstruction - Winter 2018

Table of Contents for the Digital Edition of CONNstruction - Winter 2018

Fleet Tracking with Telematics
Don’t Let Vibration Damages Shake You
Trenching and Excavation Safety
Preventing Runovers and Backovers in Work Zones and Construction Sites
If OSHA Knocks, How Do You Respond?
Diggers Mixers Fixers Golf Outing
2018 AGC/CT Industry Recognition Dinner
Connecticut Road Builder Association Dinner
YCF Yard Goat Baseball/BBQ & Fall Membership Meeting
OSHA-CCIA-ConnOSHA Annual Safety Alliance Conference & Press Conference
A Blue Light for Safety
“If You See Something, Say Something” Applies to More Than Homeland Security
CONNstruction - Winter 2018 - Intro
CONNstruction - Winter 2018 - cover1
CONNstruction - Winter 2018 - cover2
CONNstruction - Winter 2018 - 3
CONNstruction - Winter 2018 - 4
CONNstruction - Winter 2018 - 5
CONNstruction - Winter 2018 - A Blue Light for Safety
CONNstruction - Winter 2018 - “If You See Something, Say Something” Applies to More Than Homeland Security
CONNstruction - Winter 2018 - Fleet Tracking with Telematics
CONNstruction - Winter 2018 - 9
CONNstruction - Winter 2018 - 10
CONNstruction - Winter 2018 - 11
CONNstruction - Winter 2018 - Don’t Let Vibration Damages Shake You
CONNstruction - Winter 2018 - 13
CONNstruction - Winter 2018 - Trenching and Excavation Safety
CONNstruction - Winter 2018 - 15
CONNstruction - Winter 2018 - 16
CONNstruction - Winter 2018 - 17
CONNstruction - Winter 2018 - Preventing Runovers and Backovers in Work Zones and Construction Sites
CONNstruction - Winter 2018 - 19
CONNstruction - Winter 2018 - 20
CONNstruction - Winter 2018 - 21
CONNstruction - Winter 2018 - If OSHA Knocks, How Do You Respond?
CONNstruction - Winter 2018 - 23
CONNstruction - Winter 2018 - 24
CONNstruction - Winter 2018 - 25
CONNstruction - Winter 2018 - Diggers Mixers Fixers Golf Outing
CONNstruction - Winter 2018 - 2018 AGC/CT Industry Recognition Dinner
CONNstruction - Winter 2018 - Connecticut Road Builder Association Dinner
CONNstruction - Winter 2018 - OSHA-CCIA-ConnOSHA Annual Safety Alliance Conference & Press Conference
CONNstruction - Winter 2018 - 30
CONNstruction - Winter 2018 - cover3
CONNstruction - Winter 2018 - cover4
CONNstruction - Winter 2018 - outsert1
CONNstruction - Winter 2018 - outsert2
CONNstruction - Winter 2018 - outsert3
CONNstruction - Winter 2018 - outsert4
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