Alarm management is the
most important yet overlooked aspect of industrial operations. Many companies
do not even perform extensive analysis on their alarm system to identify its
strengths and weaknesses, forget about investing time and resources. However,
it is feasible to quickly improve alarm system performance by paying attention to
some high benefit items.
Here are the top 5 focus areas:
Maximum Activation Rates by Priority
Here are the top 5 focus areas:
Alarm definition and design:
Are you alarming
anything and everything? A true alarm requires an operator response, without
that it is a false alarm or nuisance alarm. Ask yourself if all your alarms
require operator action. If not, you may have some kind of alarm management
problem. A good alarm is unique, easy to understand, and provides clear
instructions to the operator. Defining alarm criteria, alarm setpoints, different alarm
states and alarm deadbands can help create
first layer of defence. It can also help reduce alarm overload and allow
operators to respond to the most important alarms in a timely manner.
Alarm priority: Imagine a scenario when the majority of alarms at your facility are set at ‘critical’ level or ‘High’. There will be a chaos in the beginning. But, what will happen in the 'long run' if corrective measure are not taken? Operators will become desensitized to alarms and eventually start ignoring alarms, increasing
the chances of making a grave error. This happens often in facilities where alarms
are not prioritized properly. Therefore, alarm system should be optimized in
such a way that the number of high-priority alarms is significantly less than
the low-priority alarms.
Setting
the prioritization of alarms enhances the operator’s ability to take the right
action at the right time. He becomes aware of alarms that require immediate
attention and the ones that can wait. This can lead to better control over
operations, improved plant performance and reliability.
Here is the alarm prioritization matrix, based on EEMUA 191, which you can refer to get some ideas.
Priority
|
Target Maximum Rate
|
Critical
|
Very
infrequently
|
High
|
< 5/shift
period
|
Medium
|
<
2/hour
|
Low
|
<
10/hour
|
Maximum Activation Rates by Priority
Also see the table below to find out annunciated alarm priority distribution.
Alarm messages: Do your alarm
messages make sense to the operator? Are the messages consistent, crisp, clear
and concise? If not, identify what all is lacking and prepare an action plan to
improve the quality of your alarm messages. Find out if the messages can be
written in a better way; it is of no use if your operators are unable to understand and respond faster.
The content
of alarm messages should be uniform in structure, based on terms and abbreviations used by the plant engineers and control-room operators. Alarm messages are meant to inform operators about the problem areas within the plant and the actions that should be taken to
address those problems. Sometimes companies are so busy evaluating and
discussing features that they forget that something as simple as ‘message
quality’ can have significant impact on the operator’s efficiency. This is
completely in your control; you just have to pay little attention.
Alarm metrics: Tracking
alarm statistics is vital to any alarm management program because it allows greater
visibility into the plant’s current alarms levels. Alarm key performance
indicator such as total alarms, alarm rate, peak alarm rate, alarm severity
distribution, and Pareto charts of the most frequent, fleeting and standing alarms
provide deeper insight the system performance. Measure past few weeks
or months of data and compare it with standards alarm guidelines or industry
standards to see where you stand. The next step then will be discovering the areas of improvement.
There
are many alarm analysis software that can help you benchmark and assess your
current alarm system performance – Wonderware Alarm Adviser
is one such software. It helps identify frequent, standing, fleeting and
consequential alarms, and enables monitoring of key performance indicators. Alarm
Adviser gives users the intelligence to discover the problem areas of an alarm
system and the ability to eliminate nuisance alarms. See Alarm Adviser Demo and try it yourself. Keep in mind – “you can’t
improve what you don’t measure.”
EEMUA 191
|
ISA 18.2
|
Oil & Gas
|
Petrochem
|
Power
|
|
Average alarms per day
|
144
|
~150 (~300 max manageable)
|
1200
|
1500
|
2000
|
Average standing alarms
|
9
|
<5 per day
|
50
|
100
|
65
|
Peak alarms per 10 minutes
|
<10
|
≤10
|
220
|
180
|
350
|
Average alarms per 10-minute interval
|
1
|
1 (~2 will be manageable)
|
6
|
9
|
8
|
Distribution % (L/M/H)
|
80/15/5
|
80/15/5
|
25/40/35
|
25/40/35
|
25/40/35
|
Source: EEMUA 191 ‘Alarm systems: a guide to design, management and procurement’ and ANSI/ISA-18.2-2009 Management of Alarm Systems for the Process Industries.
Alarm Benchmarks: Industry
Standards vs. Actual Industry Scenario – modern control rooms receive more
than 1,000 alarms per day, which is much higher than what EEMUA 191 and
ISA-18.2 recommend – 150-300 alarms/day or 1-2 alarms/10 minutes.
Accountability: It is
important to know who will be responsible to take action when alarms enunciate and
what type of operator response will be needed for each alarm. Primary and
secondary ownership should be made crystal clear, so that if the primary owner
misses a critical alarm or is unable to respond, an SMS alert goes to the
secondary owner. You must ensure that the right individual has the right
access; this can be achieved with a system that allows different levels of
access to the operator, the engineer and the facility manager based on their job
requirements. However, every plant personnel should be allowed to view each other’s
data for greater transparency and collaboration.
Managing SCADA alarms within a plant is not the job of any one department alone. It is the shared responsibility of operations, controls, instrumentation or engineering, and all these departments are equally accountable. Responsibilities should be stated with clarity in the alarm philosophy document. Defining roles and responsibilities clearly ensures accountability; it helps avoid inter- or intra-team conflicts and confusion that arises during abnormal situations.
Managing SCADA alarms within a plant is not the job of any one department alone. It is the shared responsibility of operations, controls, instrumentation or engineering, and all these departments are equally accountable. Responsibilities should be stated with clarity in the alarm philosophy document. Defining roles and responsibilities clearly ensures accountability; it helps avoid inter- or intra-team conflicts and confusion that arises during abnormal situations.
Closing comments
A
well-functioning alarm system provides deep insight into the functioning of the
plant. It delivers actionable information to the operator, helping him make
correct decisions on time. And alarms can be your closest allies in improving plant
performance and profitability while reducing the risks of unplanned system
downtime. It all depends on how well you are managing your alarm system. By paying attention to the most important and easy
to implement aspects of alarm management, you can avoid common mistakes and make
your plant more productive and reliable. Remember, alarm management is the key to the smooth functioning of
your plant, so it deserves some serious attention and thought process. Manage your alarms or alarms will
start managing you.
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