Trenching

TRENCHING

Each year more than 40 construction workers are killed in trenches.  A trench is a confined space with many special problems.  The majority of deaths that occur in trenches are due to cave-ins.  Other risks that are present while working in a trench are falling objects, and bad air.

If a trench will be dug, the contactor must name a competent person.  This person must know that OSHA excavation standard, be trained in soil analysis and protective systems, can identify hazards, and has authority to stop them right away.

OSHA has special rules to follow when working in a trench.  You must follow these rules unless:

• The trench is a stable rock 
• The trench is less than 5 feet deep and a competent person find no reason to expect cave –in.

A competent person must inspect a trench:

• Before every shift 
• If bad air is expected –such as, the trench is in a sewer or near a dump or stored chemicals.
• After anything that can increase hazards, such as :
• Every rainstorm 
• Vibration 
• The trench wall moves, causing cracking, scaling, or bulging 
• A heavy load near the trench moves or gets heavier


BEFORE WORKING IN A TRENCH

• Get a competent person to OK it
• Make sure all equipment is in good condition including pumps and ventilators
• You must have a way to get out
• The contactor must have all utilities marked before digging (The contractor must call utility companies and shut off all electricity, gas, and water pipes in the trench)
• Do not use a boom near overhead power lines 
• If a boom must be used, ask the competent person to make sure power has been cut off and the lines have been grounded.

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