che_february-2025 - 35

FIGURE 2. Dynamic alarming takes the process state into account to help
ensure alarms are delivered when they are needed
tion, but because once they finish,
they have so many changes to manually
enter into the control system
that they never complete the job.
First and foremost, it is difficult to
decide how to get the changes back
into the control system and who will
do it. Often, weeks or months go by
with some changes implemented
and others not, and the team never
truly knows what has changed. In
the meantime, processes change,
and new alarm edits are made on
top of previous changes. Ultimately,
the team can never catch up.
Even if the team does successfully
complete rationalization with
an offline software tool, maintaining
those changes becomes a herculean
task. In the coming months
or years, the plant will likely have
equipment changeouts, or necessary
process changes.
If all alarm rationalization is performed
offline, it becomes increasingly
difficult to keep up as more
and more changes are applied.
Each change must be recorded offline,
and then applied manually to
the control system. Moreover, if a
year later the team wants to know
if the alarm system is still valid, they
need to go through the process
of exporting data and comparing
again - a process that will likely
take weeks or months.
Integrated software
To avoid the complexity of transferring
offline changes to the control
system manually, many of today's
forward-thinking organizations are
leveraging alarm management software
that is integrated with their
control system by design. Seamlessly
integrated alarm-management
software dramatically
reduces
the time engineers
spend updating the
control system with
new alarm parameters.
Such solutions
empower teams to
perform rationalization
online while
connected to the
control system.
With an integrated
alarm management
solution, alarms can be
modified one by one, or in bulk. As
each change is made, the user can
see the control system configuration
and establish process boundaries
linked directly to assets, and
then easily record that change in the
documentation. If an asset or alarm
changes at a later date, the team
can see what assets were impacted
by that change, and it can audit the
change against the boundaries.
Most importantly, once the team
has made its changes in an integrated
alarm management solution,
they simply click a button
and all changes are applied to the
control system. The ability to apply
changes online saves significant
time and effort. For example, a
large integrated chemical site can
make about 30,000 parameter
changes per month to their control
system, many of which impact
or are related to alarms. It would
be nearly impossible for that process
manufacturer to keep up with
those changes without an integrated
software solution. But with
the right software, the team can
instantly see the last-read value
when a change was made, what
was approved, who approved it
and why, and the initial reason the
alarm was created. This type of
database allows the team to document
and audit those control system
changes quickly and easily.
Changes increase complexity
Historically, when engineers would
design alarms for a control system,
they would ask themselves three key
questions:
* What alarm does the plant need?
* What is the purpose of this alarm?
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
FEBRUARY 2025
* What priority should be given to
the alarm?
However, even after asking those
questions, many struggle with alarm
floods during transition periods like
startups, upsets and shutdowns.
Transitional alarm floods contribute
to incidents, and this issue is exacerbated
because incidents are more
likely to occur during transitions than
in periods of normal operation. With
just one additional question, it becomes
significantly easier to eliminate
these alarm floods:
* When does the plant need this
alarm?
Modern alarm management must
accommodate dynamic process
states. For example, consider a flow
alarm on a heater. When the heater
is operational, low pass flow through
a tube would be a serious concern.
Over time, the tube with the low
pass flow would warp and eventually
create a loss of process containment,
and material from the process
would pour directly into the heater.
Hypothetically, the process could be
shut down for weeks and cost the
organization millions of dollars. As
a result, when the heater is operational,
it is essential to receive low
pass flow alarms.
However, sometimes the heater
will be shut down, but if the process
unit does not have dynamic alarm
management, the alarm system will
not know the difference. If the heater
has 16 pass flows, the operator will
receive 16 alarms, even though this
is the expected state during shutdown.
Those alarms will
fill up a
page and push many alarms onto
another page. The low pass flow
may be a high priority alarm, but it is
meaningless in the shutdown operating
mode.
While during shutdown, such a
problem might be frustrating, during
startup it becomes dangerous.
During startup, operators are putting
mass and energy into the process
and hoping that this is occurring
within specification. However,
the low pass flow alarm that was
activated while the heater was shut
down (potentially several weeks
ago) is still a standing alarm and is
now valid because the operator has
moved the process into an opera35
http://WWW.CHEMENGONLINE.COM
che_february-2025

Table of Contents for the Digital Edition of che_february-2025
