Rupture & bursting discs : Optimum Safety & Performance

Explore API 520's guidance on selecting ruptured discs for petrochemical applications, including device types, sizing calculations, and consulting a specialist pressure safety engineer for safety and compliance.

A rupture disc protects pressurized vessels during overpressure by acting as a fast, non-reclosing safety device powered solely by the process fluid, and is temperature sensitive.

Rupture discs provide primary or backup pressure relief in single, parallel, or fire-condition setups, with burst pressures tied to mawp and requiring venting and non fragmenting design with relief valves.

Explore pressure relief terminology and ruptured discs, define pressure relief devices per ASME and API standards, and outline key terms such as burst pressure, back pressure, and flow testing.

Define flow capacity testing and key terms for ruptured discs, including burst pressure, operating ratio, and safe operating range, with notes on back pressure and purge before installation.

Explore the three rupture disc designs—forward acting, reverse acting, and flat discs—and how pressure direction, compression, and scoring patterns determine safe, controlled rupture with relief valves.

Ruptured disc holders provide an inlet and outlet with a seating surface for the ruptured disc, using a raised metal-to-metal seat to create a leak-tight seal.

Welded rupture disk assemblies use safety cartridges as alternatives to disc and holder style rupture discs, offering robust sealing, prevention of fugitive emissions, and easier installation.

Select a rupture disk by defining process parameters that affect relief performance, including pressure, temperature, and fluid state, and by specifying burst pressure, relieving temperature, and materials.

Clarify the manufacturing design range for rupture disks, distinguish it from burst tolerance, and review 0%, 5%, and 10% marking options, with a preference for 0% to prevent confusion.

Explore five ruptured disc selection criteria—phase application, operating ratio, vacuum resistance, fragmentation, and soft criteria—and understand proper sizing by trained personnel for safety and compliance.

Rupture discs' service life depends on pulsation, temperature, corrosion, and handling/orientation; select compatible materials and use reverse acting discs for pulsating systems, and replace discs periodically.

Identify causes of ruptured disc failure and consult the manufacturer when unknown, then use the troubleshooting table to resolve issues like disc not discharging, excess pressure, leaks, or improper installation.

Learn sizing rupture discs using API Recommended Practice 520 and ASME section eight, division one, with emphasis on trained personnel and considering environmental factors, installation, and maintenance.

Size pressure relief with ASME code by applying overpressure allowances for primary, secondary, external fire, and storage vessel protection: 10% (3 psig), 16% (4 psig), 21%, and 20% above MAWP.

Explore three sizing methodologies for ruptured disk devices—coefficient of discharge, resistance to flow, and combination capacity—using discharge coefficient KD and velocity head loss CR to size relief systems.

Apply the eight and five rule for rupture disk sizing, accounting for inlet and discharge piping and atmosphere discharge, and use the CD method to determine subcritical or critical flow.

Learn to size rupture disks using critical pressure criteria, calculate airflow as mass flow rate, and determine the effective discharge area for gas releases in a carbon steel vessel.

Size ruptured disks for gases and vapors using the coefficient of discharge, standard volumetric flow rates, corrections for back pressure, subcritical or critical flow, and molecular weight or specific gravity.

Calculate the required ruptured disc discharge area for carbon dioxide, using critical flow equations and 12,000 scfm, highlighting CO2 hazards and flare system safety.

Examine the coefficient of discharge method for sizing ruptured disks in steam systems, part iii, applying ASME and API equations with mass flow rate, steam quality, and superheat corrections.

Calculate the required discharge area for a ruptured disc in a superheated steam application using API sizing equation, and determine relieving pressure, k_n and k_sh factors to obtain 1.2 in².

Apply the coefficient of discharge method to size ruptured disks for liquid applications. Use ASME for water, API for non viscous liquids, and viscosity corrections with kV for viscous liquids.

Size ruptured discs for viscous liquids using the API equation with viscosity correction, showing viscosity increases the required effective discharge area.

Size rupture disks within a relief system using the resistance to flow method, with a K value and a 0.9 derating factor, noting CR values vary by media.

Shows how KR values determine the flow capacity of a pressure relief piping system by summing resistances and using the Darcy equation with sonic flow and a 0.9 derating factor.

Apply Bernoulli's energy balance to relate elevation, pressure, velocity heads, and frictional losses in piping, then compute exit velocity and flow with a 0.9 ASME derating to confirm 50 cfm.

Explore rupture and bursting discs and their role in optimum safety and performance. Discover applications and operational considerations.

Examine the relief valve and rupture disk combination and how the disk presence derates relief valve capacity. Apply the combination capacity factor (ccf) in sizing to account for ruptured disk.

Compute the combination capacity factor (CCF) from certified testing of the stand-alone valve and ruptured disc valve assembly; the ratio yields a certified value less than or equal to 1.

Learn how the CCF derates the certified flow capacity in API 520 relief valve sizing, converting the standalone valve area to the required area for rupture disk–valve combinations.

Explore sizing a gas relief system using a safety valve with a rupture disc, applying combination capacity factors from NB 18 to determine the required discharge area.

Recognize a ruptured disk device as a pressure relief that opens at set pressure to protect a system; locate away from people, brace piping, vent fumes, and post danger signs.

Master holder preparation forward acting flat seat ruptured disc assemblies: separate components, remove packing, inspect and clean seating surfaces with approved solvent; avoid damage that may cause leaks or failure.

Inspect the ruptured disc and remove any foreign materials. Clean the disc carefully with an approved solvent, noting that fingerprints and acids can cause premature corrosion in the system.

Match the vacuum support serial number to the ruptured disc, install the support under the disc between flanges with the crown downstream, and tighten bolts evenly to avoid bursting.

Install the ruptured disk device in the piping system, tighten studs and nuts to the manufacturer torque values, and ensure flange faces are parallel to prevent leakage and deformation.

Inspect ruptured disk devices at least every six months, checking for leakage, corrosion, and visible danger signs; tailor replacement intervals to operating conditions and experience with each application.

Demonstrates the UD ASME code stamp for ruptured discs, with flow testing at an ASME-accepted lab in the inspector’s presence; results appear as CR and MNFA on the tag.

The lecture defines the loss coefficient k as the pressure loss in velocity-head terms for elbows, tees, fittings, valves, and reducers, and notes the SME code assumes geometry-only dependence.

Explore how the loss coefficient defines piping performance by summing k entrance, rupture disk, k pipe, elbow, and k exit, and review ASME and API RP 521 guidance for CR.

Analyze how ruptured disk CR values affect pressure drop and flow in pressure-relief systems, from short runs to long runs with elbows.

Find CR for a ruptured disk on the disk tag or in manufacturers’ CR tables by model; National Board’s Red Book lists all ruptured disks by model, number, and manufacturer.

Conclude with key takeaways on rupture & bursting discs, emphasizing optimum safety & performance for industrial applications.

Examine rupture and bursting discs to achieve optimum safety and performance, and access bonus material.