Accurate protection of process plant and personnel is what every plant manager is looking for. Roger P Bours looks at solutions whether it comes down to providing the right pressure relief solutionrunaway reaction control or monitoring the status of signaling devices.
In a recent report of the International Labour Conference it was found that an unfortunate 3000 individuals per day die from the effects of accidents at work. On an average the global industry is suffering a total of 700000 accidents per yearregistering an estimate of around one million of victims.
The same report indicates an expected increase of work-related accidents; where by 2020 up to 2.2millions of injuries can result.
A substantial percentage of accidents at work is directly related to failure of equipment or machines due to undefined operating conditions.
Post-accident investigations often lead to the conclusion that the detected failure was foreseeable but safety measures applied have been ineffective or insufficient.
An unacceptably high internal pressure in process equipment is often determined as one of the ‘unplanned conditions’. Where such overpressures are not safely handled the consequences can be dramatic: process downtimehigh-cost/
long-duration repair and occasionally physical damage or injuries to personnel.
These dramatic effects of such accidents can be avoidedthrough the design and use of effective pressure relief devices/systems. One of the most reliable and tamper-proof pressure relief devices used by a wide range of industries are commonly known as bursting or rupture discs.
Since 1945 Fike has gathered experiences in the designmanufacture and use of such pressure relief devices. The extensive range of standard products allows for design specialists to determine best application solutions without jeopardising the safe working of the process.
Recently Fike has introduced a new design and manufacturing processreferred to as G2 technologywhere bursting or rupture discs can be offered with unparalleled service performances. This technology breakthrough allows for the manufacturer to offer pressure relief devices suitable for the highest demanding operational conditions without noticeable effect on the service life.
Combined with full vacuum resistancesuitability for liquid/vapour and even two-phase mediaand non-fragmenting opening throughout the product rangethe Axius bursting disc allows for process design engineers to specify an all round safety device for all applications.
Like all other Fike bursting disc devicesthe Axius has been designed to even reduce the leakage of process media to the immediate surroundings of the installed bursting disc device and render the installation safe after the pressure relief event.
Some industry sectors are facing the legislative challenge â“ Directive96/82/EC (SEVESOII) â“ to prevent major accidents involving dangerous substancesand the limit their consequences to men and environment.
Requirements for management policies and systems are contained in the SEVESOII Directivewhich sets out basic principles and requirements for policies and management systemssuitable for the preventioncontrol and mitigation of major accident hazards. When hazardous reactions are involvedspecial analysis and reporting are required by the safety authorities.
The Directive recognises two distinct types of hazardous reactions: planned reactions that during their operation become unstable and go out of controland unwanted (often decomposition) reactions. Especially the latter may be of high concernnot only due to unknown reaction physics but also for the fact that a clear reporting of all products resulting from such ‘loss of control’ processes are required to be identified and safety measures for safe handling taken.
Due to the consequences resulting from such runaway reactionsmost process designers or plant users will be looking for ways to differentiate such reactions from ‘normal’ process events and design into the process measures to avoid or mitigate the exothermic reaction.
Early warning detection systems can be used to recognise in a timely manner the off set of such unwanted reactionswhere designer-solution interventions (crash cooling systemsdilution or inhibitor injection systemsemergency evacuation systemsetc) can be triggered to avoid the further development into real uncontrolled reactions.
Given the demanding operating conditions related to the release devices used to initiate the selected intervention in the ensuing runawaybursting disc devices are again highly preferred. They offer a combination of:
- Compact designs.
- Long-term pressure integrity.
- Instantunrestricted opening.
- Wide range of corrosion resistant materials of construction.
- Easily adaptable to specific application requirements.
- Accurate activation (set pressuresactivation methodsetc).
Another challenge for plant users or process engineers often underestimated and possibly retracting focus from other safety issues is the need to monitor the wide array of signaling devices used in process plants.
Indeedthe established trend to design fully autonomous24/7 production plants with minimal need for personal has resulted in a big increase in the of use of simple signaling devices such as level switchesposition switchesburst indicatorsopen/close detectorsend-of-line switchesetc.
Coping with the task of monitoring is often quite demanding for plant personnel; affordable monitoring and signaling devices such as the Fike SIM can offer a simple solution. Designed as a true plug and play system the SIM (Status Indication and Monitoring) offers individual monitoring of switching devices (even in explosion hazardous areas) combined with a centralised annunciating system.
The use of these designated monitoring systems will free up time and resources for other process related taskswithout jeopardising safety levels of plant equipment.
Total concept solution can be offered to cover a wide range of process plant safety issueswhere tailored solutions are modularly built from industry recognised devices.
And so the required safety levels can be maintained without running a risk of reducing the effectiveness of process production plants.
Roger P Bours is with Fike EuropeHerentalsBelgium. www.fike.com"