POWER April 2012 - 24

3. Understanding the risks. Before a worker enters a confined space at a power generation
facility, the plant safety officer should measure and analyze gases present to determine
if the space has an explosive atmosphere or is otherwise a danger to human occupants. Courtesy:
New Standard Institute Inc.
Customizing Safety Programs for
Power Plants
Confined space work requires the
identification and removal of unsafe
conditions, controlling access where
conditions are inherently dangerous,
and training entrants to prevent unsafe
acts. This can be an especially difficult
task for power generation facilities. Besides
the usual confined spaces found in
many industrial settings, power plants
have additional challenges, including
high-voltage hazards, tunnels, tanks,
coolant lines, and dozens of other safety
threats. The U.S. Occupational Safety &
Health Administration's 1910.146 standard
sets out the requirements upon
which safety specialists and operational
managers should base safety programs
for their individual plants' operations.
-Contributed by Michael Konopka
(mknowpka@newstandardinstitute.com),
product development manager at the
New Standard Institute Inc. This article is
adapted from the New Standard Institute's
confined spaces computer-based training.
Note: LEL = lower explosive limit, PEL = permissible exposure level; TWA = time-weighted average exposure.
be working in a confined space. This
evaluation should also include measuring
the size of the space as well as access
and egress availability. Oxygen,
carbon monoxide, hydrogen sulfide
concentrations, and the percentage of
the lower explosive limit (LEL) in the
confined space must be measured and
analyzed. The atmosphere within the
confined space should be measured in
terms of its LEL; typical permissible exposure
level (PEL) and time-weighted
average exposure (TWA) for different
gases are illustrated in Figure 3.
Even the slightest potential for a
change in air quality or hazardous atmosphere
is cause for concern. A space
that has walls that converge inward or
floors that slope downward and taper
could trap or asphyxiate an entrant.
Area inspections must identify all of
these potential conditions so that efforts
can be made to mitigate or control
any and all hazards before work begins.
It should be considered likely that the
space will require a permit entry program,
though efforts to control the condition
will make entry far safer.
As important as what is evaluated is
who does the evaluation. Make sure the
group is properly trained and qualified
to perform evaluations. If a contractor
has his or her own designated safety
personnel performing evaluations, make
sure they are qualified as well as au24
dited.
Many power plants are stepping
up their safety programs and requiring
all outside contractors to comply
with internal programs and use certified
equipment. The fact of the matter
is that people may cut corners to save
time and money; however, there is no
acceptable compromise when it comes
to safety. Audits should be frequent and
unscheduled, and each work site should
have an internal person assigned to
that task.
Emergency communications should be
well defined and centralized. A phone
number or radio frequency needs to be
on every document and work order so
no one has to look far in the event of
an emergency. Attendants must be in
continuous communication with workers.
Special attention will be required if
the space or work performed will be creating
excessive noise and workers must
wear hearing protection.
Layout of the workspace can be critical
as well. If workers are not visible
from outside the confined space, alternate
means must be employed. Radios,
video monitors, or other methods
should be considered. Some systems of
communication, such as tugging on a
safety line or rapping on the barrier of
a space, are prone to error or misinterpretation
and should be considered a
backup method that is only suitable for
use in an emergency.
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Preventing Downtime by
Picking the Best Switch
Technology
Common fuel-handling problems in the
power industry often result in production
downtime, costing the owner perhaps
up to $200,000 per hour. There are
many areas within a coal-fired power
plant where mishaps can cause stoppage
of material flow. Here we discuss
how to select the best switch technology
to reduce the possibility of coal
flow stoppages.
Efficient Coal Handling
Coal-handling systems in a power generation
station are designed to process
coal from large pieces into powdered
form. Raw coal is delivered from the
yard to the boiler island's coal feed
silos, usually by a dispensing system
known as a tripper car. The tripper car
is filled by a conveyor from the fuel pile
and then moves from one silo to the
next dispensing coal. It is very important
for reliable plant operations that
a continuous and accurate coal level is
measured within these silos. When fuel
silos are kept fully stocked, the boiler's
appetite for coal can be satisfied and
the plant can operate reliably at rated
capacity.
A good operating practice is to have
some type of point detection devices
that will provide operators early notice
of silo levels in order to prevent either
POWER | April 2012

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POWER April 2012

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