Functional Safety 2016

ABB Limited

Please reply to:

Tel: +44(0)1642 372000

Website:

Registration no:

Registered Office:

Pavilion 9, Byland Way

3780764 England

Daresbury Park

Belasis Hall Business Park

Fax: +44(0)1642 372111

E-mail:

Daresbury, Warrington

Billingham TS23 4EB

VAT Reg No:

Cheshire WA4 4BT

United Kingdom

668 1364 13

United Kingdom

The requirement for the class VI shut-off, was specified 6 years earlier and passed to the functional

safety team. There was no subsequent review of the SIF design and impact on the operating or

maintenance teams – a classic case of silo working.

Benefits of breaking down silos:

The impact of the high annual maintenance costs had prompted a revalidation exercise. During this

re-validation it was highlighted that the existing safety system would not achieve the intended

function and improvements had to be made. The requirement for the tight shut-off was challenged

and process engineering effort was invested into the process model. The outcome from the modelling

exercise demonstrated that a larger valve leakage rate could be accommodated without the resultant

runaway reaction. In addition, all the results from the previous valve leakage tests had met the

revised acceptable leakage rate.

Using the new safety requirements, information on the actual reliability of the valves and other

improvements in the basis of Safety, it was possible to extend the time between the valve overhaul

and leak test from annually to every two years. Enabling significant maintenance cost saving and

increased production uptime.