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Marston – CS Composite Slotted Rupture Disc / Holder Assemblies

Marston Composite Slotted (CS) discs usually comprise of two parts. Firstly, a vent side metallic slotted disc with a process side seal membrane, usually of a fluorocarbon material for corrosion resistance. When the disc is subjected to excessive pressure, the disc bursts and opens along the slots without fragmentation, making it an ideal disc for the upstream protection of safety relief valves. Metal seal membranes can be used but may fragment on burst. When subjected to vacuum conditions, CS discs will always require a vacuum support.

The CS disc is suitable for all relieving phases and can generally be operated at up to 80% of minimum bursting pressure.



Fragmentation: None (With Fluorocarbon Seal)
Operating Ratio: Up to 80%
Vacuum Duty: Requires Vacuum Support
Pressure Cycling Duties: Satisfactory
Leak Tightness (To Vent): <1 x 10-4 mbar.l.sec-1
Leak Tightness (To Atmosphere): <1 x 10-5 mbar.l.sec-1
KR Value: KRGL 1.2 (With Vacuum Support)


Marston is fully committed to an ongoing Total Quality Improvement programme. This was recognised with Marston audited and approved to design and manufacture bursting discs with its Quality Control procedure registered to the highest standard required by BS EN ISO 9001 Certification.

Quality is an integral part of all processes to provide customer satisfaction and confidence.

CS bursting discs are manufactured and tested in accordance with the requirements of the relevant standard, including BS 2915, AD Merkblatt A1, ISPE SL, ASME VIII, ISO 6719, and EN ISO 4126.

All of the Marston standard disc designs have been approved for use in accordance with the requirements of the P.E.D., 97/23/EC.


Standard tolerance on all CS bursting discs over 1.0 Bar is ± 5%. Improved tolerances may be available, please contact us for further assistance.

Corrosion Resistance:

CS bursting discs can be manufactured from all commonly used disc materials, including Tantalum, Nickel alloys, and Stainless Steel. Fluorocarbon lining provides an excellent protection for corrosive duties.

The Effect of Temperature:

Changes in temperature affect all bursting disc materials. Typically, as the temperature rises, the material strength reduces and the bursting pressure falls.