Cost-effective OEM solution

O4A is a screwed and bonded rupture disc and plug assembly based on conventional rupture discs. The rupture disc is clamped between an inlet and an outlet which are screwed and bonded together. The design combines a brass body as standard with a stainless steel or nickel disc dependent on burst pressure and process requirements.

Thread-lock or an equivalent material is typically used to prevent tampering and the whole assembly is discarded after burst.

The one time use unit is available as standard with various thread connections and combinations to best suit varying specifications.

04A offers superior operational performance for various safety critical applications

Typical applications for 04A rupture disc assemblies include preventing over pressurisation in gas handling and cryogenic applications, benefiting from a zero maintenance design offering a good degree of leak tightness.



O4A is available with the only OEM burst detection system on the market benefiting from:

– Fail-safe and reliable burst detection
– First ATEX-approved detection system for rupture disc plugs
– Not affected by downstream pressure fluctuations or corrosion
– Suitable for use in a wide range of process/temperature conditions

O4A offers a unique range of benefits

– Cost effective solution
– Capable of withstanding back pressure
– Maintenance free solution
– Full vacuum service
– Tamperproof
– 4-6 weeks lead time

To view technical specifications for standard product, see product downloads. Alternatively, refer to our customised products OEM page or contact your sales engineer for alternative configurations.

Contact Elfab about this product
Standard Part Code Disc Sizes* 15mm, 19mm, 25mm, 40mm
Standard Thread Sizes available* 1/8″, 1/4″, 3/8″, 1/2″, 3/4″, 1″
Standard Thread Types available* NPT, BSPT or BSPP (Male or Female) – Left or Right handed
Standard Burst Pressure Range 1barg – 70barg (14.5 psig – 1015 psig)
Standard Temperature Range -20C – +150C (-4F – +302F)
Maximum Operating Ratio 90% of minimum burst pressure (1barg – 200barg)

(Reverse Acting)

85% of minimum burst pressure (55barg – 200barg)

(Forward Acting)

Performance Tolerance +/- 5%
Leak Rate 1×10-5cc/sec
Vacuum Service Yes
Fluid Compatibility Gas, Vapour (Reverse Acting)

Gas, Vapour or Liquid (Forward Acting)

Tamper proof Yes
Disc Type Forward or Reverse Acting Disc
Disc Material* Nickel, Stainless Steel Disc, Brass Body
Fragmentation May Fragment depending on design
Disc Connection to Body Bonded between inlet & outlet (screwed together)
Maximum Torque Size dependent


(* Others available on request)