A rupture disc that has burst warns no one. On a fermenter under a sterile nitrogen blanket, or on a reactor venting a toxic product, the operator discovers the opening on the next round. Continental Disc®’s B.D.I.® (Burst Disc Indicator) turns the burst into an electrical signal: a conductive strip crosses the disc seat, the petal cuts it on opening, the circuit opens, and the PLC knows. ATEX certified for explosive atmospheres, including zone 0.

B.D.I.® Alarm System datasheet (PDF)

B.D.I.® page on the ESI website

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B.D.I.®, burst detector for Continental Disc rupture discs

Alarm strip with copper conductors on KAPTON® film, normally closed circuit, 24 V DC, 50 mA, -40°C to +204°C, ATEX 2014/34/EU Ex ia, integrated and universal models from DN 25 to DN 900

The heart of the system is the B.D.I.® alarm strip: copper conductors bonded to a thin KAPTON® film, with tantalum conductors for certain applications. In the integrated version, the strip crosses the seat of the rupture disc. In the universal version, it crosses the gasket face of the flange. It ends in a moulded plug or bare wires. The strip has no effect on the service life or burst pressure of the disc: reliability validated on site and in Continental Disc’s ASME-accredited flow test laboratory.

The circuit is normally closed. A low current flows continuously between the strip and the monitor. On bursting, the petal cuts the strip, the circuit opens, the relay of the corresponding channel switches and sends the signal to the control room, an indicator light or a siren, or directly triggers a pump, a valve or a shutdown procedure. A cable break gives the same signal: the system is fail-safe.

What it is for

Six situations in which the B.D.I.® should be specified: when relief alerting is essential to site safety; when a signal must trigger an automatic action, a process change or a shutdown; when you need to know immediately that an overpressure or vacuum has occurred; when loss or contamination of the product is certain if the disc is not replaced immediately; when toxic products escape through the vent; when the disc is installed in a hard-to-reach location.

Typical applications: fermenters under a gas blanket, where an undetected opening causes the batch to lose sterility; chemical reactors; process tanks; valve isolation discs, where the B.D.I.® signals that the valve is once again exposed to the fluid; valve outlets on toxic or corrosive fluids; transport tankers; pumping stations; storage and silos; distillation equipment.

Compatible with the Continental Disc discs distributed by Tubes Technologies: SANITRX LPX and SANITRX HPX® in the integrated version, HPX®, HPX®-Ta and LOTRX® in the universal version between flanges.

Characteristics

Minimum relief pressure for the universal version

Below these values, the opening energy of the disc does not guarantee that the strip will be cut. The low-pressure universal version goes down to 0.07 barg from 1″ to 4″.

B.D.I.® alarm monitors

Each channel controls its own relay: one monitor watches several discs and identifies the one that has burst.

Options

Tantalum conductors for media where copper would be attacked. GYLON® 3500 gasket for the universal version. Shielded cable with bare wires in 2, 3 or 6 m, or standard plug with 1.8 to 91 m extension and strain relief. Junction box recommended beyond 4.5 m of unsupported cable between strip and monitor, with shielded cable downstream to avoid false alarms. Low-pressure universal version for 1″ to 4″ discs rated down to 0.07 barg. MTB-700 monitors with or without audible and visual alarm, BB-100A and BB-400A.

Frequently asked questions

Does the B.D.I.® change the burst pressure of the disc?

No. The strip is designed to give way with the disc without contributing to its mechanical strength. Continental Disc has verified this in service and in its ASME-accredited flow test laboratory: no effect on the service life or performance of the disc.

Integrated or universal version?

The disc decides. SANITRX® sanitary discs (LPX, HPX®) and certain special discs take the integrated version, housed in the seat. Flanged discs such as the HPX®, HPX®-Ta or LOTRX® take the universal version, fitted like a gasket between the holder outlet and the downstream flange.

Does the B.D.I.® work on a very low pressure disc?

The minimum relief pressure must be checked. In the standard universal version: 1.03 barg at 1″, 0.28 barg at 2″, 0.07 barg from 6″ upwards. For a 2″ LOTRX® rated at 0.15 barg, the low-pressure universal version is required, which goes down to 0.07 barg from 1″ to 4″.

Can it be installed in an ATEX zone?

Yes. The B.D.I.® strip is certified to Directive 2014/34/EU, category 1, group IIC, up to zone 0 for gas and zone 20 for dust, with Ex ia intrinsic safety. It must be connected to an intrinsic safety barrier, such as that of the MTB-700 monitor, which is itself ATEX, FM, CSA and IECEx certified. The temperature class is marked Tx: it is set by the process temperature, as the strip does not heat up.

Can the signal go directly to the PLC?

Yes. The B.D.I.® is a simple normally closed contact: any PLC input or suitable relay can monitor it, provided that 24 V DC and 50 mA maximum are respected, and that it is routed through an intrinsic safety barrier in an ATEX zone. The MTB-700 monitor provides the barrier and dry contacts ready for wiring.

Does the strip need replacing after a burst?

Yes, the strip is cut by the disc: it is replaced along with it. It is designed for quick replacement. Plan a spare strip with each spare disc.

A glass-lined flange is not tightened like a stainless steel flange.

Tighten it enough to compress a rupture disc, and you risk chipping the glass lining.

Tighten it just enough for the glass lining, and the disc leaks.

Continental Disc®’s HPX-PT® pre-torqued holder separates the two problems: the disc is tightened in the workshop, to the exact torque, by socket head cap screws built into the holder.

The assembly is then fitted between the process flanges, which only have to seal their own gaskets.

DN 25 to DN 300, ASME, DIN or JIS flanges.

HPX-PT® Pre-Torqued Holder datasheet (PDF)

HPX® Product Family brochure (PDF)

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HPX-PT®, workshop pre-torqued rupture disc holder

Holder for HPX® and HPX®-Ta discs, tightened by coated class 12.9 socket head cap screws, DN 25 to DN 300, ASME 150 to 600, DIN PN 10 to PN 40, JIS 10 to 40K flanges

Rupture disc holder whose inlet and outlet are assembled with high-strength steel hexagon socket head cap screws. The HPX® disc is fitted and tightened in the workshop to the torques recommended by Continental Disc, in a clean, controlled environment, before the assembly is installed between the flanges of the relief line.

The pre-torquing screws are coated against wear, galling and corrosion. The reference torque in the installation manual assumes a class 12.9 alloy steel screw with NEDOX® FM-5 polymer coating: a lower-strength screw or one without this coating may give insufficient assembly load or break. Standard materials: carbon steel, 316 stainless steel, Alloy 400 and Alloy C276. National Board certified KR coefficients with HPX® disc: KRG 0.29 and KRL 0.38.

What it is for

Four situations in which the HPX-PT® holder is required. Glass-lined, glass or fluoropolymer-lined flanges, which cannot provide the compression needed to seal the disc. Piping where access to the flange bolts prevents correct torque tightening. Severe processes that require the disc and its holder to be removed regularly for inspection. Applications that require a leak test of the disc and holder assembly before installation on the line.

A second, less visible benefit: disc tightening no longer depends on the flanges. Pipe misalignment or flange gasket creep no longer affect the load on the disc. The burst pressure remains that stated on the certificate.

Combined with an HPX®-Ta disc and a tantalum-lined inlet, the HPX-PT® is the reference configuration for glass-lined reactors and tanks in fine chemicals and pharmaceuticals: full tantalum protection on the process side and compression ensured in the workshop.

Characteristics

HPX-PT® holder dimensions and weights

Extract from the HPX® Product Family brochure. The model may vary depending on flange class and diameter.

Options

Special heights. Pressure gauge taps threaded into the outlet. J-Hook on the inlet. Flange studs and nuts in alloy steel or 316 stainless steel. Fluoropolymer coating or TANTALINE® treatment against corrosion. Tantalum lining of the inlet for HPX®-Ta assemblies. Universal B.D.I.® burst sensor. For installations without tightening constraints, see the HPX® Insert holder.

Frequently asked questions

HPX-PT® or HPX® Insert: which should I choose?

If the process flanges can compress the disc correctly and torque tightening is accessible: HPX® Insert, simpler and lighter. If the flanges are glass-lined or lined, if access to the bolts is difficult, or if the assembly must be tested in the workshop: HPX-PT®. At 2″, the weight difference is 2.7 kg versus 4.2 kg in ASME 150.

Why coated class 12.9 NEDOX® screws?

Because the pre-torquing torque in the manual is calculated for this strength and this friction coefficient. An 8.8 or uncoated screw does not achieve the same load on the disc for the same torque, or breaks. If a screw needs replacing, it must be replaced with an identical screw.

Can sealing be tested before installation on the line?

Yes, this is one of its intended uses. The disc and pre-torqued holder assembly forms a self-contained sub-assembly that can be tested on a bench before fitting. Useful during qualification, or when a line shutdown costs more than the holder.

Does the HPX-PT® really protect a glass-lined flange?

It removes the need to tighten hard on the glass lining. Glass-lined flanges only have to compress their flange gaskets, not the disc. The risk of chipping the glass lining during tightening disappears, and the load on the disc no longer depends on what the flange can withstand.

Can the disc be refitted after an inspection?

No. A removed rupture disc must not be reinstalled: risk of leakage and operation outside its burst pressure. The advantage of the HPX-PT® is that a new, pre-torqued spare assembly can be prepared in the workshop and swapped in a few minutes.

Is there a more compact version?

Yes, the reduced-height HPX-PT-RH, from 1″ to 8″. At 3″, it is 55.6 mm high instead of 81.5 mm, and weighs 6.8 kg instead of 10 kg. On the other hand, it cannot be coupled directly under a safety valve.

At 104 mbar, a conventional rupture disc no longer has enough metal to be leak-tight, stable and accurate all at once.

Continental Disc®’s LOTRX® gets around the physics with three mechanical features: an initiation indentation at the top of the dome, a notched outlet ring and a vacuum-support inlet ring.

The result: a reverse-acting disc with burst pressures from 0.104 to 2.07 barg, from DN 25 to DN 200, that withstands full vacuum and opens cleanly along its semi-circular score.

LOTRX® sheet (PDF)

LOTRX® installation guide (PDF)

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LOTRX®, reverse-acting rupture disc for very low pressures

Scored reverse-acting disc with initiation indentation, 0.104 to 2.07 barg, DN 25 to DN 200, ZERO, -5%, -10% ranges, 90% ratio, full vacuum from 0.345 barg, up to 538°C

Scored reverse-acting rupture disc, designed for very low pressures. The initiation indentation, located at or near the top of the dome, lowers the pressure at which the dome reverses. The notched outlet ring guides opening along the precision semi-circular score, even at the lowest reversal pressures. The back-pressure support inlet ring allows operation under full vacuum for burst pressures of 0.345 barg (5 psig) and above.

High-precision manufacturing method to achieve and control burst pressure within a tight tolerance. Clean, repeatable opening, non-fragmenting design. Static, cyclic or pulsating service conditions. Materials: 316 and 316L stainless steel, Hastelloy® C, nickel, Monel®, Inconel® and tantalum. Stainless steel encapsulation rings as standard, other materials on request. Three-dimensional stainless steel flow-direction tag on all diameters.

What it is for

Atmospheric storage tanks, nitrogen-blanketed tanks, gas holders, filters and vent lines have a maximum allowable pressure measured in hundreds of millibars. To protect them, you need a disc that opens at 0.1 or 0.2 barg, not 0.7. Below 0.689 barg, the HPX® range stops. The LOTRX® takes over, with a minimum burst pressure of 0.104 barg.

A second use: safety valve isolation. Mounted upstream of a valve, the LOTRX® eliminates fugitive emissions at the seat and protects the internals from the fluid. It is also used as primary or secondary protection on the same equipment.

For hygienic processes between clamp ferrules, the equivalent is the SANITRX LPX, a low-pressure sanitary rupture disc. The LOTRX® is the flanged solution, in a LOTRX® Insert holder, for the process industry.

Characteristics

Flange stud tightening torques, extract from the installation guide

Continental Disc values for tightening the flanges on either side of the holder, according to diameter and flange class. The full guide covers ASME classes 150 to 1500, DIN PN 10 to PN 250 and JIS 10 to 40K.

Options

Fluoropolymer protective cover on the vent side for the disc and holder (1″ above 0.276 barg, 1½″ to 8″ at all pressures). Fluoropolymer coating on the process and/or vent side. Cleaning for oxygen or chlorine service. Encapsulation rings in special materials. ASME (UD) stamp on request. Universal B.D.I.® burst sensor, or BDI-FLX™ above its minimum burst pressure.

Frequently asked questions

LOTRX® or SANITRX LPX: which should I choose?

The installation decides. Between ASME, DIN or JIS industrial flanges, in a holder: LOTRX®, from 0.104 to 2.07 barg, DN 25 to DN 200. Between clamp ferrules on a pharmaceutical or food process: SANITRX LPX, from 0.40 to 0.689 barg, DN 40 to DN 80, Ra 0.5 µm finish and USP Class VI gasket.

How can a disc reverse at 104 mbar?

Thanks to the initiation indentation. A perfect dome requires high pressure to buckle. The indentation creates a controlled geometric defect at the top, which sets the starting point of the reversal and lowers the pressure required. The notched outlet ring then ensures opening along the score, even with very little energy available.

Does the LOTRX® withstand vacuum?

Yes for burst pressures of 0.345 barg (5 psig) and above, thanks to the back-pressure support inlet ring. Below that, full vacuum is not guaranteed: this must be checked as soon as the equipment’s vacuum scenarios are analysed.

How is the allowable operating pressure calculated?

A 90% ratio applied to the burst pressure minus the tolerance: maximum operating pressure = 0.9 x (burst pressure – tolerance). A theoretical example: with a burst pressure of 0.345 barg and a tolerance of 0.035 barg, this gives 0.9 x 0.31 = 0.28 barg. It is this figure that goes into the tank design calculation, not the burst pressure. The actual tolerance depends on the diameter and burst pressure: it is stated on the quotation.

Can a LOTRX® isolate a safety valve?

Yes. Mounted upstream, it isolates the valve from the fluid, eliminates fugitive emissions at the seat and protects the internals from corrosion. To know whether the disc has burst between two inspections, a B.D.I.® sensor or a pressure gauge is installed in the space between the disc and the valve.

Why follow the tightening torques in the guide?

Because at very low pressure, the compression of the disc in its holder directly affects the burst pressure. Insufficient tightening creates a leak; excessive tightening deforms the ring and shifts the burst pressure. The torques in the Continental Disc guide assume studs of nominal strength: weaker studs may not be sufficient.

In dry chlorine, many materials hold up. In chlorine that has picked up moisture during evacuation, most disc materials give way. Tantalum holds.

Continental Disc®’s HPX®-Ta is an all-tantalum reverse-acting rupture disc, designed for bromine, chlorine, hydrochloric acid, nitric acid and sulphuric acid.

DN 25 to DN 300, 0.689 to 55.2 barg, up to 260°C, compatible with the entire range of HPX® holders.

HPX®-Ta datasheet (PDF)

HPX® Product Family brochure (PDF)

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HPX®-Ta, tantalum rupture disc for highly corrosive media

Scored semi-circular reverse-acting disc in tantalum, DN 25 to DN 300, 0.689 to 55.2 barg, 260°C max, 90% operating ratio, 1,000 vacuum/pressure cycles, non-fragmenting

Scored semi-circular reverse-acting rupture disc with a tantalum dome. For certain concentrations, temperatures and moisture contents, tantalum is often the only rupture disc material that resists. Outlet ring in 316 stainless steel as standard, in Alloy C276 or tantalum on request. Non-fragmenting. Safety ratio of 1 to 1 or less: a damaged disc opens at or below its burst pressure.

Cycling resistance of at least 1,000 cycles from full vacuum to maximum operating pressure. Burst pressures, manufacturing ranges, tolerances and operating ratio identical to the -90 version of the HPX®. National Board certified KR coefficients in HPX® Insert and HPX-PT® holders: KRG 0.29 and KRL 0.38. Tantalum sourced from certified conflict-free smelters, in accordance with the Dodd-Frank Act.

What it is for

The classic scenario: a dry chlorine line, a nickel alloy disc that holds for years, then an evacuation that draws in moist air. Wet chlorine attacks, the disc is perforated, and production stops for an unplanned intervention. The HPX®-Ta eliminates this failure mode at source.

A second use case: glass-lined or PTFE-lined reactors and tanks. Combined with an HPX-PT® pre-torqued holder with a tantalum-lined inlet, the HPX®-Ta provides full tantalum protection on the process side, and disc compression is ensured in the workshop, where the glass-lined flange cannot provide it.

Typical applications: reactors, storage, exchangers, discharge heads and valve isolation in petrochemicals and agrochemicals; distillation columns and separators in oil and gas; production tanks and exchangers in pharmaceuticals; industrial gas columns and tanks; specialty gas distribution and storage in semiconductor manufacturing.

Characteristics

Burst pressure ranges by diameter

Minimum and maximum pressures available at 22°C, at the limits of the manufacturing range.

Options

Fluoropolymer liner on the process side (1″ and 1½″ above 2.07 barg, 2″ to 12″ above 1.72 barg). Fluoropolymer protective cover on the vent side for the disc and holder. Cleaning for oxygen or chlorine service. Holder with tantalum-lined inlet, or TANTALINE® coating of the inlet and outlet: the tantalum is formed into the base metal, with no flaking or delamination. ASME (UD) stamp and CE marking per PED on request. B.D.I.®burst sensor, with tantalum conductors on request.

Frequently asked questions

Tantalum or Alloy C276: where is the boundary?

C276 covers a large proportion of mineral acids. Tantalum takes over when chlorine or bromine are wet, in hot concentrated HCl, in concentrated nitric acid, and in concentrated sulphuric acid up to about 150°C. On a rupture disc, metal thickness is measured in tenths of a millimetre: a few µm per year of corrosion are enough to shift the burst pressure. If the corrosion table leaves any doubt about C276, choose tantalum.

Why a 90% ratio and not 95% like the HPX®?

The HPX®-Ta uses the burst pressures, tolerances and manufacturing ranges of the HPX-90 version. For an operating pressure of 4.5 barg, a minimum burst pressure of 5 barg is therefore required. This must be taken into account when sizing the maximum allowable pressure of the equipment.

Does the HPX®-Ta withstand vacuum?

Yes, at least 1,000 cycles from full vacuum to maximum operating pressure. This is precisely the situation in which moisture enters a dry chlorine line: the disc must withstand the vacuum and resist the attack that follows.

How can the holder also be protected?

Three levels. Fluoropolymer coating on the inlet, intermediate flange or outlet. TANTALINE® coating: pure tantalum formed into the base metal, with no porosity. Tantalum lining of the inlet of a 316 holder. Combined with a tantalum outlet ring, the assembly is fully protected on the process side.

Is the HPX®-Ta used in microelectronics?

Yes, for specialty gas distribution and storage in semiconductor manufacturing: HCl, Cl2, BCl3, HBr, where residual moisture turns a mildly aggressive dry gas into an acid. Cleaning for oxygen or chlorine service is available as an option.

The datasheet mentions the Dodd-Frank Act: why?

Tantalum comes from coltan, an ore whose extraction partly finances armed conflicts in Central Africa. Continental Disc sources from certified conflict-free smelters. Useful for responsible purchasing policies and the due diligence obligations of contracting companies.

How do you fit a reverse-acting rupture disc directly between two clamp ferrules, without a holder, and keep 95% of burst pressure in service on a tank that goes from vacuum to SIP several times a day?

Continental Disc®’s SANITRX HPX® and SANITRX HPX® II answer this question for pharmaceuticals, biotech and food processing: DN 25 to DN 100, 0.689 to 34.5 barg, gas or liquid, integrated USP Class VI gasket, ASME BPE and 3-A compliant.

HPX® Product Family brochure (PDF)

SANITRX HPX® II data sheet

SANITRX HPX / HPX / LPX installation manual

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SANITRX HPX®, reverse-acting sanitary rupture disc between clamp ferrules

Scored semi-circular reverse-acting disc, SANITRX HPX® 1″ to 3″ up to 17.2 barg, SANITRX HPX® II 1½″ to 4″ up to 34.5 barg, 90% or 95% ratio, ASME BPE, 3-A, USP Class VI

Reverse-acting sanitary rupture disc, precision semi-circular score machined on the vent side: the process face remains smooth, with no groove to clean. Non-fragmenting, leak-tight, full vacuum resistant. It fits directly between two standard sanitary ferrules, between NovAseptic® NA-CONNECT® flanges or in dedicated SANITRX® fittings. A permanently attached three-dimensional flow-direction tag protrudes from the clamp: installation direction can be checked visually, without dismantling.

Two models. The SANITRX HPX® covers 1″ to 3″ from 0.689 to 17.2 barg. The SANITRX HPX® II covers 1½″ to 4″ and goes up to 34.5 barg at 1½″. Disc materials: 316 and 316L stainless steel, Alloy C276, Alloy C22. Integrated gasket certified USP Class VI, FDA compliant, free of animal or human derivatives, polishing compound and release agent. Delivered in sanitary packaging. National Board certified KR coefficients: KRG 1.13 and KRL 1.60 for the SANITRX HPX®, KRG 1.60 and KRL 1.88 for the SANITRX HPX® II.

What it is for

In a hygienic installation, every flanged holder adds an interface, retention zones and a dismantling point. The SANITRX HPX® eliminates the holder: the disc and its gasket take the place of a standard clamp gasket between two ASME BPE ferrules. Same clamp, same tapping, same installation procedure as the rest of the process piping.

The HPX® family is validated in testing over 5 million cycles from full vacuum to 95% of burst pressure. This is what matters on a bioreactor or fermenter: vacuum after draining, steam ramp-up to 121°C or 130°C, repressurisation with sterile air, and the disc does not drift.

Typical applications: autoclaves, bioreactors, fermenters, process tanks, storage and transport tanks, WFI tanks and loops, clean steam piping, heat exchangers, filters, freeze-dryers, mixing, drying and granulation equipment, CIP/SIP skids and piping.

For a burst pressure below 0.689 barg, this role is taken over by the SANITRX LPX, a low-pressure sanitary rupture disc. To also eliminate the integrated gasket and pass the ASME BPE Appendix M spray coverage test, see theIntegrX-HPX™.

Characteristics

Burst pressure ranges by diameter, 316 / 316L disc

Minimum and maximum pressures available at 22°C, at the limits of the manufacturing range.

Temperature limits of integrated gaskets

The allowable temperature of the assembly is set by the gasket, not by the disc.

Options

Electropolished finish. Fluoropolymer coating on the process and/or vent side against corrosion. ASME Section VIII Division 1 (UD) stamp and CE marking per PED on request. Split replacement gaskets in the same material and with the same seat type (SF or IS). Continental Disc 316L fittings compliant with ASME BPE and 3-A: spool, butt-weld ferrule, concentric reducer, spool with ¼″ NPT pressure gauge tap, from 1″ to 4″. MBC™ multi-bolt clamp in cast stainless steel, 4 bolts, from 1½″ to 4″. Burst detection by B.D.I.® integrated.

Frequently asked questions

SANITRX HPX® or SANITRX HPX® II?

The two ranges follow on from each other without overlapping. At 1½″, the SANITRX HPX® stops at 13.8 barg and the HPX® II starts at 13.8 barg. At 2″, the changeover is at 10.3 barg; at 3″, at 6.89 barg. At 1″, only the SANITRX HPX® exists, from 1.72 to 17.2 barg. At 4″, only the HPX® II, from 0.689 to 6.89 barg. For a given diameter, the HPX® II covers the higher pressures.

SANITRX HPX®, SANITRX LPX or IntegrX-HPX™?

Below 0.689 barg: SANITRX LPX, gas only. From 0.689 to 34.5 barg with an integrated gasket: SANITRX HPX® or HPX® II. If the audit requires elimination of the integrated gasket and the ASME BPE Appendix M spray coverage test, or if the process goes down to -196°C: IntegrX-HPX™.

What is the maximum SIP temperature?

The disc withstands steam sterilisation up to 130°C. The practical limit is that of the gasket: 177°C for platinum silicone, 135°C for white EPDM, 232°C for PTFE. For SIP at 121°C with caustic CIP, EPDM works; for a biotech process sensitive to extractables, platinum silicone is the usual choice.

Why specify gas or liquid?

Continental Disc manufactures and tests each batch for compressible or incompressible relief. A gas-qualified disc may not open correctly under a liquid surge. On a media tank or fermenter that may overflow, the liquid scenario must be included in the specification.

Can the SANITRX HPX® be mounted on an NA-CONNECT® flange?

Yes. The NovAseptic® NA-CONNECT® flange allows the disc to be mounted flush with the tank wall, with no dead leg, making cleaning and sterilisation easier. The tag is then horizontal instead of vertical.

Is a special clamp needed?

A standard sanitary clamp is sufficient in most cases. For high pressures and temperatures, Continental Disc offers the 4-bolt MBC™ clamp in cast stainless steel, from 1½″ to 4″: the clamping force is distributed, and the failure of one bolt does not release the assembly.

A rupture disc that holds 95% of its burst pressure in service and withstands 5 million vacuum/pressure cycles in testing, without changing the piping when the recipe changes: that is the specification of Continental Disc®’s HPX®.

Reverse-acting disc, semi-circular score, non-fragmenting, from DN 25 to DN 300 and from 0.689 to 138 barg depending on diameter and material.

It is mounted between ASME, DIN or JIS flanges in an HPX® Insert, HPX-PT® pre-torqued or double-disc holder.

HPX® Product Family brochure (PDF)

HPX® installation manual (PDF)

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HPX®, reverse-acting rupture disc for the process industry

Scored semi-circular reverse-acting disc, DN 25 to DN 300, 0.689 to 138 barg, 90% or 95% operating ratio, 5 million cycles in testing, PED, ASME Section VIII, ISO 4126-2

Reverse-acting rupture disc designed as a differential-pressure relief device: instantaneous and full opening of the flow area in the event of overpressure. The dome works in compression, convex side facing the process. Precision semi-circular score: the petal opens and remains attached, with no fragments in the vent line. Bubble-tight sealing on the conical seat of the holder. Safety ratio of 1 to 1 or less: a damaged disc opens at or below its burst pressure, never above.

Each batch is manufactured to order according to the relief point specification, qualified by burst testing, and each disc undergoes a proof pressure test before shipment. Materials: 316 and 316L stainless steel, nickel, Alloy 400, Alloy 600, Alloy C276, tantalum (see the HPX®-Tadata sheet). ZERO, -5% and -10% manufacturing ranges. Two operating ratio versions: HPX-90 and HPX-95.

What it is for

A conventional forward-acting rupture disc works in tension and fatigues as soon as it approaches 70 to 80% of its burst pressure. The HPX® reverses the logic: dome in compression, 95% of burst pressure allowable in service, full vacuum without additional support. As a result, the margin between operating pressure and burst pressure drops from 20 to 30% down to 5%, and the protected equipment can operate closer to its maximum allowable pressure PS.

The HPX® is designed for multi-product facilities: short campaigns, changing fluids, shifting operating conditions. Its wide range of burst pressures and materials allows the specification to evolve under change control without touching the piping. The holder stays; the disc changes.

Typical applications: reactors, heat exchangers, chillers, isolation upstream of safety valves in chemicals; industrial gas columns and tanks, transport tankers; distillation columns, separators and coking drums in oil and gas; production tanks, mixers and mills in pharmaceuticals. For hygienic processes between clamp ferrules, see the SANITRX HPX®.

Mounted upstream of a safety valve, the HPX® isolates the valve from corrosive or fouling fluids and eliminates fugitive emissions at the valve seat. HPX® holders from 1″ to 8″ can be coupled directly under the valve; at 10″ and 12″, an intermediate spool is required.

Characteristics

Burst pressure ranges by diameter, 316 / 316L / Alloy C276 disc

Minimum and maximum pressures available at 22°C, at the limits of the manufacturing range.

Options

Fluoropolymer liner on the process side (1″ and 1½″ above 2.07 barg, 2″ to 12″ above 1.72 barg). Fluoropolymer protective cover on the vent side. Fluoropolymer coating on the process and/or vent side. Cleaning for oxygen or chlorine service. ASME (UD) stamp and CE marking per PED on request. Universal B.D.I.® burst sensor. Holders in carbon steel, 316, Alloy 400 or Alloy C276, with TANTALINE® or fluoropolymer coating: see HPX® Insert holder and HPX-PT® pre-torqued holder.

Frequently asked questions

HPX-90 or HPX-95: which should I choose?

HPX-95 whenever the operating pressure is close to the maximum allowable pressure of the equipment: 95% of burst pressure in service, ZERO manufacturing range. HPX-90 when a 10% margin is sufficient and the -5% or -10% manufacturing ranges help optimise cost. A worked example: for an operating pressure of 9 barg, an HPX-95 rated at 9.5 barg is sufficient, whereas an HPX-90 requires 10 barg. Half a bar of PS gained on the protected equipment.

Are 5 million cycles realistic in service?

It is a Continental Disc laboratory test result on an HPX-95 in 316 SS, from full vacuum to maximum operating pressure. It validates resistance to pressure/vacuum cycling. In service, temperature, corrosion and pulsation reduce this life. Continental Disc recommends a risk analysis and annual replacement of the disc, more frequently in severe conditions.

What type of burst pressure rating for the PED and for ASME?

For ASME Section VIII Division 1, the RATED burst pressure type (marked pressure) is mandatory. For CE marking under PED 2014/68/EU and the ISO 4126-2 standard, a SPECIFIED or MIN/MAX burst pressure is required. The choice is made when ordering: a single disc does not carry both.

Why specify gas or liquid when ordering?

Because Continental Disc manufactures and tests each batch for compressible (gas, steam) or incompressible (liquid) relief. A gas-qualified disc may not open correctly under a liquid surge. If a liquid relief scenario exists, it must be included in the specification.

Can an HPX® disc be refitted after removal?

No. A removed disc must not be reinstalled: risk of leakage and operation outside its burst pressure. Removal for inspection should be planned with a spare disc from the same batch, or with an HPX-PT® holder, which allows the assembly to be inspected in the workshop.

Can a reverse-acting disc protect a safety valve?

Yes, this is one of its main uses. Mounted upstream, the HPX® isolates the valve from the fluid, eliminates seat leakage and protects the internals from corrosion. To detect a leak or burst of the disc between the two, the intermediate space is fitted with a pressure gauge (tell-tale) or a B.D.I.® sensor.

A rupture disc is only as good as its holder.

Poorly centred, it opens outside its burst pressure.

Poorly tightened, it leaks.

Poorly designed, it fragments.

Continental Disc®’s HPX® Insert holder addresses all three: three centring pins, a conical metal-to-metal sealing seat, and a rounded outlet that guides the petal.

From DN 25 to DN 300, between ASME, DIN or JIS flanges, with a National Board certified flow resistance coefficient KR of 0.29 for gas.

HPX® Product Family brochure (PDF)

HPX Holder data sheet

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HPX® Insert, rupture disc holder between ASME, DIN and JIS flanges

Holder for HPX® and HPX®-Ta discs, DN 25 to DN 300, bubble-tight metal-to-metal sealing, KRG 0.29 and KRL 0.38 National Board certified, direct mounting under a safety valve up to DN 200

A two-part holder, inlet and outlet, fitted between the pipe flanges. It performs four functions: orienting the disc, sealing, protecting the dome during installation and preventing fragmentation on opening. Three alignment pins in the inlet orient the HPX® rupture disc. A conical seat on the inlet creates, when correctly installed, a bubble-tight metal-to-metal seal (no bubbles detected with leak detection fluid). The outlet bore has a radius that acts as a hinge for the petal: it rolls back without detaching.

The inlet protects the dome during fitting between flanges. Flow-direction arrows on the holder and on the disc tag confirm the orientation. An optional J-Hook orients the holder within its flanges. Flange faces with spiral serrations to ASME B16.5 as standard, i.e. a roughness of 3.2 to 6.3 µm Ra (125 to 250 micro-inches). Standard materials: carbon steel, 316 stainless steel, Alloy C276 and Alloy 400, others on request.

What it is for

The KR coefficient is the figure most often missing from a vent line design calculation. For the HPX® Insert holder and HPX® disc assembly, it is National Board certified: KRG 0.29 for gas or steam, KRL 0.38 for liquid. In a double holder, KRGL 0.97. These are low values, which leave the vent line sized by the piping and not by the safety device.

The 1″ to 8″ HPX® Insert holder can be coupled directly under a safety valve: disc upstream to isolate the valve from the fluid, no intermediate spool. At 10″ and 12″, a spool is required. The reduced-height HPX-RH version saves from 8 mm at 1″ to 89 mm at 8″ in height, but cannot be coupled directly under a safety valve.

When the flanges cannot provide the necessary compression (glass-lined or PTFE-lined flanges), or when the disc must be inspected in the workshop before installation, the HPX-PT® pre-torqued holder takes over. For highly corrosive media, the holder is lined or coated with tantalum and fitted with an HPX®-Ta disc.

Characteristics

Holder height and weight, ASME 150 flanges

Extract from the HPX® brochure: the height determines the spacing required between flanges.

Options

J-Hook orientation hook. Fluoropolymer or TANTALINE® coating of the inlet, intermediate flange and/or outlet, tantalum lining of the inlet. Tell-tale assembly between disc and valve: ¼″, ⅜″ or ½″ pressure gauge tap threaded into the outlet, ¼″ or ½″ steel or stainless steel nipples and tees, 316 excess flow valve, pressure gauge. Studs and nuts in alloy steel (ASME SA-193-B7 / SA-194-2H) or stainless steel (SA-193-B8M Class 2 / SA-194-8M). Case-hardened steel jack screws (set of 3), lifting eyes. Cleaning for oxygen or chlorine service. Universal B.D.I.® burst sensor.

Frequently asked questions

Why a metal-to-metal seat rather than a gasket?

Because a gasket ages, creeps and must be chosen according to the fluid. A conical metal-to-metal seat depends neither on temperature nor on the chemical compatibility of an elastomer. It provides a bubble-tight seal as long as installation follows the torques in the installation manual. For a quantified leak rate requirement, Continental Disc carries out specific tests.

Standard Insert or reduced-height HPX-RH?

The HPX-RH saves height: 14 mm at 2″, 26 mm at 3″, 51 mm at 6″. Useful on existing piping where the spacing between flanges is restricted. On the other hand, it cannot be coupled directly under a safety valve and is not available in 10″ and 12″.

Can the holder be mounted directly under a safety valve?

Yes, from 1″ to 8″. The HPX® disc isolates the valve from the fluid, eliminates seat leakage and protects the internals. At 10″ and 12″, an intermediate spool is required to allow the petal to open without touching the valve.

How can you tell whether the disc is leaking or has burst under a safety valve?

With a tell-tale assembly: a pressure gauge and an excess flow valve in the space between the disc and the valve. A rise in pressure signals a leak or a burst. For an electrical signal to the PLC, the universal B.D.I.® sensor slides between the flanges.

What is the double-disc holder for?

Two HPX® discs in series in a single three-piece holder. Three uses: leak detection on toxic or expensive fluids (pressure gauge in the intermediate flange), a rapid-opening device actuated by depressurising the space between the discs in a few milliseconds, and elimination of the effect of back pressure on the first disc. KRGL 0.97.

Which studs should be used?

Studs of the correct length to take the inlet, holder and outlet, in ASME SA-193-B7 alloy steel with SA-194-2H nuts, or in SA-193-B8M Class 2 stainless steel with SA-194-8M nuts. Lower-strength studs may not achieve the clamping load required for sealing.

Continental Disc®’s SANITRX LPX disc covers exactly the range that the SANITRX HPX® does not reach:

burst pressure from 0.40 to 0.689 barg, DN 40 to DN 80, polished 316L stainless steel Ra 0.5 µm, direct mounting between sanitary clamp ferrules.

SANITRX LPX datasheet (PDF)

SANITRX LPX page on the Continental Disc Corporation website

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SANITRX LPX, reverse-acting low-pressure sanitary rupture disc

Scored semi-circular reverse-acting disc, burst pressure 0.40 to 0.689 barg, DN 40 to DN 80, gas service, SF1 finish Ra 0.5 µm, ASME BPE, USP Class VI, 3-A

Reverse-acting sanitary rupture disc designed for pharmaceutical, biotechnology and food processes whose protection pressure is below the SANITRX HPX® threshold (0.689 barg, 10 psig).

316 / 316L stainless steel dome, precision semi-circular score machined on the vent side: the process face remains smooth, with no groove to clean.

Non-fragmenting design.

Minimum service life of 1,000 cycles from full vacuum to maximum operating pressure.

Internal surfaces and ferrules with SF1 finish to ASME BPE, i.e. Ra ≤ 0.5 µm (20 micro-inches), electropolishing as an option.

Integrated gasket certified USP Class VI with full material traceability.

Components free of polishing compound, release agent and animal-derived ingredients. Gas service only.

Flow resistance coefficient KRG = 1.13, National Board certified.

What it is for

Below 0.7 bar, choosing a sanitary rupture disc becomes more complicated. A forward-acting disc set at 0.4 bar works under permanent tension at 90% of its burst pressure, and each return to vacuum after a SIP cycle flexes it in the wrong direction.

The known result: fatigue, burst pressure drift, premature bursting, batch shutdown.

The SANITRX LPX applies the reverse-acting principle to very low pressures: the dome works in compression, the process pressure acts on the convex face, and full vacuum does not damage it.

A tank that goes from vacuum to pressure several times a day keeps a stable disc for at least 1,000 cycles.

Typical applications: sterilising filters and vent filters, autoclaves, bioreactors and fermenters, process tanks, storage and transport tanks, WFI tanks, heat exchangers, clean steam piping, CIP/SIP skids, freeze-dryers, mixers, dryers and granulators.

Anywhere the design pressure of the protected equipment is low and the product-contact surface must remain ASME BPE compliant.

Diameters 1½″, 2″ and 3″ (DN 40, DN 50, DN 80). Burst pressure 0.40 to 0.689 barg (5.8 to 10 psig) at 22°C. A permanently attached three-dimensional flow-direction tag protrudes from the line: installation direction and burst data can be read without dismantling. Installing a reverse-acting disc upside down reduces its burst pressure unpredictably: the tag is there to make sure that does not happen.

The disc is mounted directly between two standard sanitary clamp ferrules, between NovAseptic® NA-CONNECT® flanges or in dedicated SANITRX® fittings. No disc holder to machine, no additional retention.

Characteristics

Options

Electropolished finish on process-exposed surfaces.

Fluoropolymer coating for corrosive environments.

ASME Section VIII Division 1 (UD) stamp on request, to be specified when ordering.

Choice of integrated gasket from six materials according to the fluid, the SIP temperature and the regulatory file.

B.D.I.® burst sensor for alarm reporting to the control room or PLC.

Frequently asked questions

SANITRX LPX or SANITRX HPX®: where is the boundary?

At 0.689 barg, i.e. 10 psig. The SANITRX HPX® starts at 0.689 barg and goes up to 17.2 barg, in DN 25 to DN 80, for gas and liquid alike. The SANITRX LPX takes over from 0.40 to 0.689 barg, in DN 40 to DN 80, for gas only. A burst pressure below 0.689 barg on a sanitary tank means an LPX. Above it, an HPX®. No grey area.

Why a ±25% tolerance below 0.552 barg?

Because at these pressures, the absolute tolerance becomes a physical limit. ±25% on a burst pressure of 0.40 barg represents ±0.10 barg, an order of magnitude comparable to the ±0.138 barg applied above 0.552 barg. The practical consequence for sizing: the maximum operating pressure is calculated at 90% of the burst pressure minus the tolerance. For a disc rated at 0.40 barg, this gives 0.90 x 0.30 = 0.27 barg maximum operating pressure. It is this figure that must appear in the design calculation, not the burst pressure.

Gas service only: is that a real limitation?

Yes. The SANITRX LPX protects gas headspaces: fermenters, vent filters, tanks under nitrogen or sterile air, autoclave chambers. If overpressure can come from the liquid, through uncontrolled filling or water hammer, a liquid-qualified disc is required, i.e. a SANITRX HPX® or an IntegrX-HPX™ with a suitable burst pressure.

Which gasket should be chosen for SIP at 121°C or 130°C?

Platinum silicone (up to 177°C) for most biotech processes, with its reduced extractables. EPDM (135 to 149°C) when chemical compatibility with alkaline CIP is the priority. PTFE or stainless-steel-reinforced PTFE (232°C) as soon as thermal cycling is intense or the fluid is aggressive. All materials offered are USP Class VI certified, with batch traceability.

Is the disc subject to the PED 2014/68/EU?

The PED only applies to equipment whose maximum allowable pressure PS exceeds 0.5 bar. Part of the SANITRX LPX range lies below this threshold. The regulatory status therefore depends on the burst pressure and the protected equipment: to be validated case by case with your notified body. Tubes Technologies will provide you with the manufacturer data required for the file.

How can you tell the disc has burst without opening the line?

With Continental Disc®’s B.D.I.® alarm system, compatible with the SANITRX LPX. The sensor detects the opening of the disc and sends a signal to the PLC. On a fermentation tank of several thousand litres, an undetected burst means an undetected loss of sterility. The sensor costs less than a batch.

IntegrX-HPX™ datasheet (LIT21042)

HPX® Product Family brochure (PDF)

Continental Disc Corporation website

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IntegrX-HPX™, sanitary rupture disc with crevice-free design

Reverse-acting disc welded to its ferrules, no integrated gasket, ASME BPE-2019 Appendix M, range -196°C to +260°C

Reverse-acting sanitary rupture disc designed for the biopharmaceutical industry.

Scored semi-circular design, welded directly to its 316/316L stainless steel clamp ferrules.

The gasket integrated into the disc is eliminated: downstream sealing is provided by a standard sanitary gasket on the customer side, whose material and source remain under the process owner’s control.

No cavity, no dead zone, no anchoring interface for biofilm.

Compliant with the spray device coverage test described in ASME BPE-2019 Appendix M.

Cleanability test by dye penetrant (Dye Penetrant per ASME BPVC Section V) carried out on 100% of discs before shipment.

95% operating ratio. Range -196°C to +260°C. ASME (UD), PED (CE), UKCA and CRN certifications.

What it is for

On a conventional sanitary disc, even one compliant with ASME BPE, the disc + integrated gasket assembly has a micro-cavity at the welded interface. In practice, with a CIP spray device, this area is difficult to cover. The IntegrX-HPX™ eliminates the problem at source: the disc is welded to the ferrules, there is no longer an interface and no longer an integrated gasket. The ASME BPE-2019 Appendix M spray coverage test is genuinely passed, not circumvented. Dye-penetrant inspection on 100% of parts confirms this batch by batch.

Typical applications: hybrid single-use bioreactors, media tanks, WFI and Purified Water lines with intensive steam cycling, biotech cryogenic processes, freeze-drying lines, high-throughput CIP/SIP skids, sterile processes where change control requires user-side control of the gasket (material, batch, replacement interval). Anywhere a quality audit identifies the disc/ferrule interface as a cleanability risk.

Diameters 1 to 4 inches (DN 25 to DN 100). Burst pressure 1.03 to 34.5 bar (15 to 500 psig). The tag is positioned outside the line: burst data can be read directly without dismantling, and it aids identification during installation.

The welded design brings an additional mechanical benefit: downstream piping loads (expansion, misalignment, clamping stresses) no longer reach the scored area of the disc. The actual burst pressure does not drift under external stress.

Characteristics

Options

Electropolished finish on process-exposed surfaces. ASME (UD), PED (CE), UKCA and CRN certifications on request, to be specified when ordering. Compatible with installation between industry-standard ferrules, NovAseptic® NA-CONNECT® flanges and other sanitary configurations. The downstream sealing gasket must be ordered separately according to the material selected by the process owner.

Frequently asked questions

Practical difference compared with a standard SANITRX HPX® II?

Three major operational differences. One: the IntegrX-HPX™ is welded to its ferrules, whereas the SANITRX HPX® II sits loose between two standard sanitary ferrules. Two: no integrated gasket on the disc side, which eliminates the micro-cavity and transfers the choice of sanitary gasket to the user. Three: the temperature range extends to -196°C on the cryogenic side and to 260°C on the steam side (compared with 232°C for the SANITRX HPX® II). For standard sanitary cycling without cryogenic requirements or enhanced spray coverage, the SANITRX HPX® II remains the proven solution. As soon as a BPE 2019 audit is decisive or a steam cycle exceeds 232°C, the IntegrX-HPX™ is the right answer.

No integrated gasket: how is sealing achieved?

With a standard sanitary gasket, chosen and qualified by the user: platinum silicone, EPDM, enveloped PTFE, reinforced PTFE depending on fluid, temperature and regulatory requirements. The IntegrX-HPX™ design makes the hygienic system as a whole independent of the disc: the gasket is a consumable whose replacement interval and source can be managed, with no impact on burst performance.

Why only a ZERO manufacturing range?

A ZERO manufacturing range means that the marked burst pressure is hit exactly, with no negative production margin. The -5% and -10% ranges of the industrial HPX® range are used to optimise manufacturing cost on large runs. On a precision sanitary disc intended for biopharma, the repeatability requirement takes priority over manufacturing cost optimisation: ZERO only.

Truly cryogenic-compatible at -196°C?

Yes, the range stated by Continental Disc® goes down to -320°F, i.e. -196°C. Typical applications: liquid nitrogen tanks, vaccine cold chain lines, cryogenic cell preservation systems. At the other extreme, 260°C covers superheated pure steam. This thermal span is the widest in the Continental Disc® sanitary range.

Is the 100% dye-penetrant test batch by batch or part by part?

Part by part. Each IntegrX-HPX™ disc undergoes dye-penetrant inspection on the process side (Dye Penetrant per ASME BPVC Section V) before shipment. Objective: to guarantee the absence of machining or welding defects in the area in contact with the fluid. Test traceability is available on request.

UKCA certification: why mention it explicitly?

Since Brexit, CE marking is no longer sufficient for placing products on the British market. The IntegrX-HPX™ is available with UKCA (UK Conformity Assessed) and CRN (Canadian Registration Number) certification for the Canadian provinces, in addition to the usual ASME (UD) and PED (CE). Useful in practice when a pharma process is delivered to multiple international sites from France.