the major cause of injuries is slips and falls tools parts and other things should not be left

lying around grease droppings oil sludge and especially polymers should be cleaned up

as soon as possible warning signs railings and covers in place can protect against low

piping open tanks and open manholes or hatches the simple knowledge of proper lifting

techniques bending the knees and lifting with muscles of the legs can save many strained

or injured backs

for work in manholes in streets safety requires full protective measures from traffic

hazards as well as from the hazards of explosive gases hydrogen sulfide or the lack of

oxygen in the manhole or sewer warning signs and barricades should be set up at suitable

distances on each side of the manhole on busy streets it may be desirable to station

workers to flag down and detour fast-moving vehicles on wide multi-lane streets the

service truck can be stationed on the side of the manhole toward on-coming traffic it is

important that sufficient workers be provided for the job at hand there should be at least

two workers at the top when one goes below a cage or guard device around the

manhole adds protection and aids entering and leaving the ventilation hole or lifting notch

when lifting a manhole cover a pick-axe may slip and cause injury or if struck hard may

give off an igniting spark unless a cover is very heavy it is safer for one person to handle

it alone

before entering a manhole the confined atmosphere should always be tested for the

presence of explosive gases hydrogen sulfide and oxygen deficiency after determining

that the conditions are safe for entry positive forced air ventilation should be started and

operated continually whenever a worker is in the manhole or sewer there should also be

a continuous sampling of the atmosphere with a visual signal alarm device kept near the

worker

before descending into a manhole note should be taken of the width spacing and

arrangement of manhole rungs and if they are staggered particular care must be taken to

get started with the proper foot and to avoid falling steel rungs may lose their galvanizing

and become dangerously corroded each rung should be tested during descent while the

worker distributes weight evenly between feet and arms a safer means of entry would be

to use a manhole ladder which can be carried on the service truck the ladder should

extend about three feet above the street surface as the worker climbs down even with a

separate manhole ladder the worker should use caution as his or her boots may have oil

on the soles causing a fall

on small sewers no one should enter a manhole deeper than the height of the chin without

wearing an approved parachute-type safety harness with rope attached in an emergency

when a safety belt may not be at hand a stout rope tied snugly under the arms with a

bowline or other non-slip knot may be the means of saving a life in either case at least

two people should be a the top of a manhole at all times when a third worker is inside in

order to handle the life line and help the worker if necessary a safety harness should also

be worn when entering any enclosed spaces around a sewage treatment plant such as

pump suction wells empty digestion tanks sludge storage wells or any other space

where access is difficult and assistance may be needed to climb out.

Back to the lesson

Answer Key

Practice 2