People,
This subject was mentioned by Steven van Els in another thread. I believe it deserves a discussion on its own, so I am starting this thread.
May I request members to post their views on whether they believe they have in their facilities:
- too few alarm units and/or
- too few trip actuators, or
- too many alarm units and/or
- too many trip actuators or
- just about right alarms/trip edvices
Please also state if your facilities are a continuos process industry such as refineries or chemical plants, batch process units such as pharmaceutical plants or a manufacturing unit such as a white goods or automobile plant.

I believe we will have material for a lively discussion once we have some views. Thanks.

Sometimes it is not the amount (few/many) of alarma / trip actuators, rather than if the alarm/trip actuators are monitoring the correct conditions. Many times I don't get what the designers were thinking when they speficy alarms.

I think it's under the realm of operations & process to determine whether there is an alarm overload or not.

Anyway, can an IPF study determine this?

Josh,
After the Milford-Haven Refinery disaster in the UK, the Regulator initiated a study on this subject. Their survey findings were quite surprising, but I will talk about that after forum members have had a chance to post their positions.
Suffice to say that alarm overload is not merely an operations issue. It affects Technical Integrity of the facility quite strongly, and that is an issue for all of us, whether we are in ops, maint or finance.

Vee,

This is an interesting topic and a scary one, too. Alarms are designed as part of the system to protect Asset..People, Product, Equipment, and the Environment.
I've been in Offshore platforms, Petrochemical Plant and above ground Mining operations. It is always a question of too many or not enough Alarms, be it in the Control Room or a sub-Station.
In my opinion, it is mostly the question of, if the people assigned to monitor process parameters, adjust conditions and normalize on-stream operation, have the relevant training to recognize a state of alarm and respond in a timely manner. Then of course, comes the next question of decision makers upon evaluating a situation/alarm, deciding what needs to done, to prevent an incident/disaster.
I've seen alarms being ignored, which eventually led to process upset, Equipment failure, Or due lean manpower operations, insufficient alarms had resulted in equipment failure.
What am I trying to say...it is a tough act trying to rationalize if Alarms are too many or insufficient. Especially when most facilities these days are operating with reduced resources/manpower.

Cheers...Rajan

Rajan,
That is an interesting observation, thanks. I hope you dont mind if I defer comment on the subject till a few others also pitch in with their views.
But you are quite right, it is a truly alarming subject.

TMI - - - Ignoring alarms
Chernobyl - - - Overriding alarms (safety functions)

Nuke Utility here...we're just about right (Goldilocks Syndrome???)

There are situations where more would probably be better, and situations of overly monitored; but oversight is extremely high - at many levels throughout the organization, so overall = just about right.

Vee, interesting topic.
RajSha stated relevant training to recognize a state of alarm and respond in a timely manner.

In the Texas City incident, during the filling of a column a blocked outlet to tanks remained undetected for several hours.

If we talk about training, what about practice. How many operators have experienced the "luxury" to work in a total blackout condition.
For those who work in industrialized countries with "uninteruptable power supply" this may sound strange. But when all the lights go out, 3-o-clock in the morning during a storm, you will have alarm overload, the alarm printers will empty a box of continuous paper, while during a quite night you will have maybe 3 alarms to acknowledge per hour.

quote:

Eugene Many times I don't get what the designers were thinking when they speficy alarms.

Me neither, there should be a law stating that the designer should operate/maintain his own brewery after commisioning.

Vee,

A bit of a sensitive subject, particularly with the emphasis on safety and disasters, so I will change the names here to protect the innocent if thats no issue.

In two large scale industries within the UK I continually find that:

a) There are often too many alarms. Many utilities for example are going towards, (if they haven't already) centralised control rooms. I think the term for this is "alarm flood".

I have had operators tell me that when they made the switch they had sheets and sheets of alarms come up continually. To the point where they needed to throw their hands in the air as they physically could not manage all of the workload.


b) Too many high priority alarms. My estimation is that around 80% of many of the alarms that I see are "high priority". Often falsely!!

So operators become quite used to these alarms, and even though they are of a high priority, they get ingored because the operators do not believe they are so important.

Creating the obviously dangerous situation that when something truly high priority does occur, or when the right circumstances occur to make the existing alarm truly important, people have become complacent.

I went through an alarm rationalisation process recently where we reduced the alamrs significantly, added a significant number that people had overlooked, and still reduced the overall number by 25%. (As well as a dramatic effort in recategorising alarms systems)

What I personally have found is that safety alarms, which we trqaditionally used prior to mass computerisation, were added to significantly when things became computerised. leading to a "watering down" of alarms from safety related to :

- Changes in operating states
- event logging
- abnormal conditions and lant status

c) A personal observation is that many of the control booths I have visited are often condusive to human error. For example, sheets of alarms appearing on two different monitors that require continual monitoring. When combined with the points above this makes things even more dangerous and even more likely that alarms, when important, could easily be overlooked.

So in general, my personal experience has been that there are often too many alarms, they are poorly categorised, the way they are relayed to operators is often not efficient, and there are often generic responses and no forethought of the time required to take a response in designing alarms systems.

This message has been edited. Last edited by: <Ozgipsy>,

quote:

Originally posted by Ozgipsy:


a) There are often too many alarms. Many utilities for example are going towards centralized control rooms...

To the point where they needed to throw their hands in the air as they physically could not manage all of the workload.


What I personally have found is that safety alarms, which we traditionally used prior to mass computerisation, were added to significantly when things became computerised. leading to a "watering down" of alarms from safety related etc..

I will emphasize on the terms alarm flood and mass computerisation, I think that Daryl described the situation correctly.

We had the luxury that we started with a centralized control room, in an area were the power grid is not reliable.
The worst that can happen to a process plant is an unexpected blackout caused by external factors. If the engineers that designed the alarms had to run with us for a year, they would be nuts right now. Somehow we accustomed to these type of incidents.

Daryl, Steven, Darth and others,
Thank you for your posts.
Daryl has stated the level of 'overalarming' in the cases he has worked on; I am still seeking answers to my questions in the original post from as many forum members as possible before venturing forth.
From Daryl's post, I sense that he feels some designers think that when Safety is concerned, MORE is BETTER. If we dare to question this view, that will be heresy (will it?). Perhaps others can comment on that as well. Dont forget the original questions though.

Will deteriorating performance of trip & control loops contribute to unnecessary process alarms or even trips?

This message has been edited. Last edited by: Josh,

Will over-alarm or under-alarm situations be easily visible to all people?

quote:

Originally posted by Josh:
Will over-alarm or under-alarm situations be easily visible to all people?

* I think over-alarm situations are very visible, lot of paper flowing, lights blicking/ horns harrasing your senses, phones ringing, etc. And then just one action cancel out many alarms.

* Under alarms are not that visible, seems that everything is going OK. Then, a critical equipment goes down, a process condition increase over the limits, and the rush and firefightinhg starts. It will require to someone take a step back and see whats happening, do some brainstorming and reach to the conclusion: we need an alarm system to monitor X conditions and gives us an early warning.
Under alarm reminds me of one of our Maintenance Supervisors likes to answer to the greeting "How are you?" with the phrase "Spooky right!" He means by that: "everything is going so good today that I worry that something awful is just pending to ocurr at any moment".

Depending on how you look at it, I have been fortunate or unfortunate to live in four different arenas, controls engineering, maintenance, IT, and Operations. When programming the alarms, you fault on a conditional event, usually high or low. The real challenge gets to be determining what the real root cause for the alarm when you merge the events together. Not many programmers assemble a fault tree in the logic that distinguishes root causes. I agree that they should. When I did IT, I was trying to gather controls information for downtime causes and generate pareto charts. Old saying, "Garbage in gives garbage out". It forced the cleaning up of the alarms to determine the real root cause. It is neat when you can get the alarms accurate enough where you can generate a work order from the controls system into the CMMS/EAM for items that operations cannot fix alone. The problem most companies have is they have no real change managment process. You spend months cleaning up the alarms. Then, someone comes along with the best of intentions to add or trap new alarms and with a few keystrokes, you start getting bogus alarms. From there, it tends to compound itself again into a vicious cycle.

Jeff

Vee,

Just to clarify in a few words. In terms of Safety I do think that designers mistakenly think more is better, contributing to alarm flooding and other situations.

But, there are also a range of additional "alarms" that we now feed in to these systems that have nothing to do with safety. Further clouding the view of control room operators and leading even more to alarm flooding.

Best regards,