My believe is that the entire issues are related to the security and the way by which it is implemented. However, specific specification can be gotten from www.kplokusa.com. All the companies that want to have a crucial role in flow control have incorporated the rules on the reliability of the components and they are perfect for flow controls which have incorporated the rules on the reliability of components and they can be used for performing the probability of failure calculations. So there are some essential steps which are to be taken but when the relevance of this issue is considered, it is crucial to implement this knowledge.
What is the consequence of an improperly implemented knowledge?
This depends majorly on the application but it can be very serious in some cases. You just need to think of the failure of an emergency valve or a high integrity pressure protection valve. These system are one of the last line of defense against any potential injury or fatalities to workers and environmental or community disaster.
Is there any occurrence of failures to date as regards safety instrumented systems?
When speaking about the hydraulic and pneumatic actuator applications, I know of many end users who have a bad failure on their plants. In a previous role I was asked to take a look at the failure of some actuators which were fitted to the emergency valves on an offshore platform. The fortunate thing was that there were no serious consequences because the facility was provided with redundant safety valves. I am also aware of the investigation about the pneumatic actuators which was degraded on the platform after an incident where there was a failure in the spring because of corrosion.
Can you identify the major causes of SVRP issues?
There are several ones which can be mentioned in my field which is pneumatic and hydraulic actuators:
The specifications which are provided by the engineers might not be well defined and sufficiently clear which might result to different kinds of interpretations that which do not give sufficient consideration to safety issues.
The reference standard for actuator qualification need to be issued in the previous ten to fifteen years but it has to be implemented so as to ensure a high level of product qualification. And any actuator which has an emergency function needs to have a dedicated reference standard due to their relevance.
The final test which is used for testing the complete system are not performed under an actual operating conditions and are not enough to detect any problem which may arise.
The aging factor as well as corrosion of the components which occurs under the actual operating conditions is not always considered properly. For instance an emergency actuator can remain stationary in the compressed spring position and this will be submitted to many ambient conditions for a long time before being called upon for the operation which is an heavy duty service. The method of qualification used is usually based on historical data but such figure may not be reliable, or the actual operating conditions may not be covered and such will not guarantee that the system is well proven. This is one of the major factors that result to failure.