When it comes to choosing an enterprise-wide alarm system, companies need to consider the advantages and disadvantages of a third party alarm management tool in comparison to a DCS vendor’s product.
Most industries should consider their alarm system as an integral part of their production facility. The Health & Safety Executive clearly states “alarm management is an issue for any site where there is claimed reliance on human response to an alarm to control major accident hazards”.
Since the 90’s, EEMUA 191 has developed into the internationally accepted standard for best practice alarm management. To establish an alarm system based on these procedures or to determine if an existing system is operating efficiently and within the rules, alarm data needs to be collected and analysed on a permanent basis. The simple process of collecting this data can already be a challenge in itself. Converting this data into a usable format for CRO or Control Room Operators and reporting on this data to managers are 2 key functions.
There are several alarm systems available for us on the market – some from specific alarm management vendors, whilst other alarm systems are offered as modules by developers of integral DCS or Distributed Control Systems. Before committing to a specific vendor, we need to consider the benefits of selecting a third party alarm system over a Distributed Control Systems vendor’s product.
No computing load on the Distributed Control Systems
The primary function of a Distributed Control System is to control the plant. Thus, computing power has to always take priority for this function. However, a Distributed Control System with an integrated alarm management module can actually become heavily loaded by multiple users requesting alarm and event key performance indicators, thus utilising valuable computing power away from the primary function of the Distributed Control Systems.
Data easily accessible
In process plants, there are usually 3 network communications stages: the process control network; engineering network; and lastly business network. For security reasons, it is a good practice not to allow data access to more than one level up or down the networks. A Distributed Control System is usually located on the process control network and thus providing access at the business level becomes difficult at best. With a third party alarm system, security and access are less of a problem as the system is not installed on the Distributed Control System, but can remain at any network level, generally at the engineering level, providing us with access to the sequence of events and key performance indicator reports across the business and at the plant control level.
Storing more data
Some plants might require hundreds of alarms to be monitored on a weekly or even daily basis. The total reliability of a third party alarm system guarantees that data from all safety-critical plant is logged constantly, thus enabling engineers to identify the cause of a plant upset. A third party alarm system provides considerably more data than a Distributed Control System integrated alarm system.
The primary function of a Distributed Control System is plant control and storage as well as computing power are utilised for that purpose, with alarm management frequently bring a secondary thought. A third party alarm management tool can provide years of alarm or event data without impacting on the Distributed Control System at all.
Easy to maintain
Third-party alarm management systems are commonly easier to maintain. The developer is much more likely to keep the software bug-free and to provide more frequent updates than a Distributed Control System vendor. This is very important and guarantees that the remains at all times based on the best practice guidelines. With a Distributed Control System vendor’s alarm management module, a Distributed Control Systems software upgrade might be required for what should be a very simple alarm system update.
Usually, a third-party development vendor is much more likely to be committed to the product they offer, since it is their lifeblood. This will mean the product is more fully-featured compared to a Distributed Control System vendor offering that is usually an afterthought module that performs the bare minimum.
With a third party alarm system, classically the cost of the installation is less than a Distributed Control System vendor alternative. While the individual cost of the alarm system might be well hidden within the total cost of the Distributed Control System package, the costs of any support and maintenance for the alarm system should be carefully considered. Usually, a third-party developer can charge less than half that of a Distributed Control System vendor alternative.