Rupture or Bursting Discs, a nonreclosing, fail safe device. Probably the most misunderstood and least appreciated safety device used in systems where pressure or vacuum are present and where excess pressures or vacuum may need to be controlled and relieved when conditions exceed the safe design parameters.
The history of Rupture Discs goes back to the early days of the oil industry in the late 1800’s where the level of control in pressure systems was very unreliable and the potential for excess pressures occurred regularly leading to accidents, injury or death of the workers as the pressure burst tanks, vessels and other pressure containment units.
The first discs were very simple flat pieces of metal, weakened to open, sometimes with very little accuracy or predictability, at a supposedly fixed pressure. Over the years the technology employed in controlling pressures in the various types of oil, gas, petrochemical and other downstream industries has improved and developed to high levels of safety, mostly through the use of electronics and pneumatics to maintain a safe working pressure regime in the various plants.
In addition, the development of safety valves has also moved forward, again raising the safety level to one where many design and plant personnel lost sight of the most important safety device in the plant, the Rupture Disc.
Today operators and end users have been lulled into a false sense of security that the design engineers and system process/instrumentation designers have covered all the possibilities with sophisticated control and monitoring systems, nothing can go wrong so why do we need a Rupture Disc? There are many reasons why we need REMBE Rupture Discs these include:
- Fast opening times, typically < 2ms, reacts to sudden pressure rises far faster than any valve
- Full bore opening, unlike safety valves where the orifice restricts the flow
- 100% isolation of process fluids, no leaks until the disc opens
- Isolate safety valves from corrosive process media when installed upstream of the safety valve, can also be used downstream to protect the outlet
- Prevents rogue emissions, blockage of the safety valve and can be used to pop test the safety valve in-situ
The same false thinking and a lack of understanding of Rupture Discs has led over many years to the wrong belief that Rupture Discs are a problem because they open and then have to be changed. The whole point of a properly designed Rupture Disc is that it will ONLY open when the design pressure and temperature are reached or exceeded.
The best news I know of is the Disc opened; it did its job and saved someone from a possible and highly dangerous over pressure failure of a pressure containment system. The mistake most operators now make is to rush to change the Rupture Disc so they restart production without identifying the root cause of why it opened!
Unfortunately some designs of Rupture Discs have not changed much over the last 80 years and we still find the old and unreliable scored or indented discs being specified today. The lack of understanding in the advancement of laser technology in the manufacture of Rupture Discs leads to the wrong belief that only the older and less reliable designs are the only ones available. REMBE leads the way in advanced laser technology and produces Rupture Discs with advanced design features that increase the reliability and operational life of their Rupture Discs far beyond those of scored discs.
So why do so many of the design engineers get it wrong when they set out to do the FEED work? Mainly because they were never taught or had an explanation of what a Rupture Discs does and does not do. They think that if they understand safety valves then the same design and selection process can be applied to Rupture Discs, it does not work.
Rupture Discs selection is based on the information given in the datasheet of the RFQ or tender, sometimes this is minimal, where in reality the volume of information needed is much higher to ensure that the Rupture Disc is engineered and manufactured to meet the needs for that application. As many as 53 different points are needed to ensure that the disc is engineered to the full specification so it will operate correctly, on average only 8 points are given to make the design. There is more emphasis given to painting specs, packaging, how many copies of paperwork, the inspection etc. than to the specification of the Rupture Disc itself.
Would you go to the doctor and say “I’m ill” and expect the correct treatment? So why would you expect a Rupture Disc to operate correctly with the same lack of information?
In light of “disc failure”, the term normally applied in the industry to the disc opening, operators try to avoid them when in fact the disc opening means it is doing its job, protecting the plant. If you run the plant above its rated capacity, something that is done regularly, but you still use the same disc design characteristics for normal operations, why blame the disc for opening? If you have new pressures and temperatures then the disc needs to be designed for those parameters, not the old ones.
To recap, a Rupture disc and its holder are your most important safety device, as long as it has been specified correctly in the design stage. It is failsafe, whatever else goes wrong a properly designed and engineered disc opens at its set pressure. Electronics, pneumatic and mechanical devices can fail, human error can cause operational errors in the pressure system, the Rupture Disc still opens, your best device to protect your plant.
REMBE has invested in technology advances in Rupture Disc design using laser technology and advanced engineering to produce the most reliable and cost effective Rupture Discs available. It doesn’t stop there, REMBE is 100% German and from our headquarters and manufacturing plant in Brilon, Germany, REMBE continues with our in-house R&D to push the engineered Rupture Discs and associated technologies further forward.
REMBE® is the safety specialist for process safety, explosion protection and industrial measurement worldwide. The company offers customers across all branches of business, safety concepts for facilities and equipment. All products are made in Germany and meet the standards of national and international regulatory requirements. Purchasers of REMBE® products include market leaders of various industries; amongst these are also the food, wood, chemical and pharmaceutical industries.
The engineering and technical knowhow is based on more than 40 years of application and project experience. As an independent, owner-operated family company, REMBE combines inventive talent with the highest quality. Short communication routes enable fast reactions and customised solutions for all applications – from standard product to high-tech special construction.