The Benefits of using Zook Sanitary High Performance Bursting Discs versus competitors.

Sanitary Bursting Discs
Zook’s Sanitary application bursting discs are based on a pure dome profile with no indentations or scorelines on the vent or process side. This eliminates areas of potential product build up and stress concentration on the disc dome. Uniform stress distribution through the whole disc dome helps to ensure the most consistent and reliable performance for the disc.

Sanitary High-Performance Bursting Discs –provide over-pressure protection in sanitary piping systems.

The Zook RAUS Sanitary Disc is an extension of ZOOK’s Reverse Acting Metal Rupture Disk design. Applications include: food processing, dairy, breweries, pharmaceutical, distilling, baking, canning, cosmetics, biotechnology, and petrochemical industries.

Zook are unique as a rupture disc manufacturer, in that they do not score their reverse acting rupture discs covering the general ranges – Zook RA4, RA6, RA8 Series with Pre-Torqued RAH holders as standard. The same applies for the RLP and RAUS Series designed for standard Tri Clover / Tri Clamp or NA couplings used with sanitary ferrules.

Reverse acting rupture discs are based on compression rather than tension. Other disc manufacturers score their reverse acting rupture discs. The scoring is different depending upon whether the disc is for use with gas/vapour only or gas/vapour/liquid. The scoring required is much deeper for a liquid burst (you can almost see through the score line on the disc). In addition, extra testing is required (special liquid lot and dye pen test on the score line etc.), all adding to the cost for the end user.

Gas/Vapour only is scored more lightly, because of the different energy (gas is compressible V1 x T1 = P1 V2 x T2 = P2), a gas burst opens fully. There is a concern with a scored disc on liquid service, is it fully open? A tear across the score line is considered acceptable to be relieving even though not fully open.

Zook non-scored reverse acting discs are a pure dome with no stresses, indentations or raisers allowing for a wider range. In addition, they are inherently superior for liquid applications.

The non-scored design Zook bursting discs means that it is far superior in terms of cycling. Discs will fatigue over time and should be replaced as part of normal preventative maintenance. One of the unanswerable questions with rupture discs is when should they be changed out. No one can answer this question, unfortunately. Disc manufacturers who use the scored design seem obsessed with telling the marketplace how many millions of cycles they have tested their discs to, while on the same hand they can’t recommend to the customer when they should change out their discs. The only true answer to this is by proper preventative maintenance, after all rupture discs are safety devices.

Another benefit offered by Zook is that Pre-Torqued holders are offered as standard. This is of great benefit to the customer in the following ways. It is easier to damage a disc using a normal insert holder as the disc needs to be installed on the vessel or system where it is being used, however, with the Pre-Torqued Holder, the disc can be assembled on the bench which reduces the risks of accidental damage during handling and installation by the end user. The other great benefit of the Pre-Torqued holder is that it allows the customer to inspect the disc. With the insert holder, the customer must remove the disc from the holder for inspection, however, once a disc is removed from its holder it cannot be reused and must be replaced. However, with the Pre-Torqued holder, the customer can inspect the disc without the need of having to remove it from the holder. Thus, considerable savings can be achieved on an annual basis if the disc is deemed to be in good condition and does not need to be replaced.


  • Ideal for high purity and corrosion resistance service
  • Designed for Non-fragmentation
  • Rugged, scoreless design offers higher cycle life when compared to scored reverse acting disks
  • Excels in liquid, gas, or two-phase applications
  • 0% manufacturing range is standard
  • Standard operating ratio of 90% of the marked rating on the disk tag – may be extended to 95% of the minimum burst pressure. (Contact Flexachem for operating ratio on pressures below 40 psig)
  • Self-supporting under full vacuum
  • Resists product build-up. Only the smooth convex side of the disk is exposed to the process medium
  • Installs using industry standard Tri-clamp®/Tri-clover® fittings (NA-Connect mounting also available)
  • Standard gasket material: Black Buna-N (see chart on reverse page for alternate materials)
  • Sizes 1″ (25mm) through 4″ (100mm) G ASME UD, CE, and TUV compliance available
  • 4 –  6 week delivery time 

Flexachem delivers over-pressurisation protection solutions via Zook to the Irish market. We provide a  broad range of Sanitary Bursting Discs offering excellent reliability of performance and delivery for your operational or OEM needs.

Our range includes;

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Contact Michael on 086 0476178 or Email