FRS™ Reverse Buckling Rupture Disk

Performance Features

  • Designed for gas service (acceptable for liquid service with a compressible gas/vapor pocket)
  • Suitable for operating pressure to 90% of the marked burst pressure (95% of the minimum)
  • Designed for non-fragmentation, recommended for Relief Valve isolation
  • Damage safety ratio ≤ 1
  • Vacuum resistant
  • Optional fluoropolymer liner/coating
  • Available with ASME “UD” (select 0%, -5%, -10% Manufacturing Design Range)
  • Pressure Equipment Directive “CE” marking and/or other International Certifications
  • BS&B proprietary technology

Request a Quote


  • Sizes & Pressures
  • Burst Tolerance
  • Safety Heads & Sensors
  • Accessories
  • Documentation

Sizes & Pressures

FRS™ Disk Specifications Minimum/Maximum Pressure with Rating at 72° (22°C)

Disk Size Burst Pressure
psig barg
in mm min max min max
1 25 13.5 (36)* 150 0.93 (2.48)* 10.34
1.5 40 11.5 (16)* 70 0.79 (1.10)* 4.83
2 50 11.5 (14)* 50 0.79 (0.79)* 3.45

* Pressures in parenthesis are with fluoropolymer liners

Note: Hastelloy® is a trademark of Haynes International Inc. Monel® and Inconel® are registered trademarks of Special Metals Corporation and Its subsidiaries. Available materials: 316 Stainless Steel, Nickel (alloy 200), Inconel (alloy 600), and Monel (alloy 400). Other materials available upon request.

Burst Tolerance

Marked Burst Pressure Burst Tolerance
≤ 40 psig (2.76 barg) ± 2 psig (0.138 barg)
> 40 psig (2.76 barg) ± 5%


BS&B supplies many of the Accessories required to safely and conveniently install our overpressure relief devices and complementary products. Through our professional team and global network of sales engineers and procurement personnel, we are able to provide the highest quality accessory products to meet your installation requirements.

Saf-T-Change Quick Disk Replacement (QDR)

After activation, the replacement disk is quickly slid into place. Saving hours of lost production due to blown rupture disks.

Tell-Tale Assemblies & Excess Flow Valves/Gauges

A gauge tap in the outlet flange of the safety head may be considered when the safety head is installed in a vertical position.

Spare Safety Heads & Cap Screws


When activated, the jackscrews effectively separate the flanges, providing adequate clearance to remove or insert a safety head and external gaskets.

Lifting Lug Eye Bolts

Eye bolts are recommended when weight and/or accessibility is a factor in lifting safety heads.

Baffle Plate

When a safety head is free-vented to atmosphere, a baffle plate may be considered to disperse overpressure and absorb recoil.

Product Literature

Sta-Saf System
Burst Alert Sensors
Saf-T-Change™ QDR Rupture Disk Replacement System
Detec Saf Alarm System - Burst Disk Monitor


Sta-Saf™ System Installation Instructions


The FRS™ is a Precision Circular-Scored Reverse Buckling Rupture Disk (Bursting Disc). When over-pressurized, this domed, solid metal, reverse buckling disk reverses and opens along a pre-weakened circular score line on the down-stream side of the disk. A patented hinge welded to the disk facilitates relief opening along the score line and retains the disk’s central petal preventing fragmentation even at high burst pressures.

FRS™ Rupture Disk (Bursting Disc) Material Options

The FRS™ rupture disk (bursting disc) is available in a range of corrosion resistant materials. Standard disk materials are Nickel alloy 200, Stainless Steel grade 316, Inconel® (Nickel alloy 600), & Monel® (Nickel alloy 400). Fluoropolymer film liners are offered with the type FRS™ rupture disk (bursting disc) at all burst pressures. All standard disks are available with 0%, 5%, and 10% manufacturing ranges.


Burst Alert™ Sensors & SmartDisk™ System

Burst Alert Sensors are installed downstream of the rupture disk (bursting disc) device and provide a convenient means of generating an electrical signal when appropriately integrated into plant control systems, or connected to the BS&B Safety Systems Burst Disk Monitor. The Burst Alert Sensor is a “membrane switch” that changes from closed circuit to open circuit when the upstream rupture disk (bursting disc) (or relief valve) opens.


Installation in SRI-7RS™, SRB-7RS™, SRB-7FS™, S90-7R™, SPR-7R™, or SR-7R™ Safety Head

The Sta-Saf family of Rupture Disk (Bursting Disc) devices is designed for installation between pipe flanges. Compatibility with all international flange standards is available, including: ANSI, DIN, JIS, BS, ISO, AFNOR and UNI. Between the Safety Head and the pipe flanges an application compatible gasket is used for sealing purposes.