Burst Testing Services

Burst Testing vs Proof Testing

Burst testing and proof testing are often grouped together because both appear in UG-101, but they answer different questions. A proof test pressurizes the part to a defined multiple of the proposed working pressure and confirms it holds without permanent deformation or leakage; the part can sometimes survive and remain usable. A burst test deliberately continues past that point until the component fails, capturing the ultimate pressure the part can contain.

Proof testing based on yielding is restricted to materials with a ratio of minimum specified yield to minimum specified ultimate strength of 0.625 or less. When that ratio is exceeded, or when a manufacturer wants the largest possible rating from a single sacrificial sample, a burst pressure test is the route. The trade-off is straightforward: proof testing may preserve the part, while burst testing destroys it but yields a higher, experimentally proven MAWP.

For a deeper look at how these methods sit within the broader code framework, our guide to ASME pressure vessel testing explains how proof and burst results feed into vessel certification.

Burst Test Procedure

A controlled burst test follows a repeatable sequence so the result can survive review by a code survey engineer or authorized inspector:

1. Identify and document the sample by drawing and revision number, size, and complete material specification, traceable to the heat or lot number of the material.
2. Confirm material strength, either from tensile coupons pulled per ASTM E8 or, for parts too small to machine coupons from, the minimum tensile value on the mill test report.
3. Install the part in a fixture that applies internal pressure uniformly, using a calibrated gauge or NIST-traceable transducer with a current calibration certificate.
4. Ramp the pressure in a controlled manner, usually hydrostatically with an incompressible fluid, while recording pressure against time.
5. Continue to rupture, then record the burst pressure, the mode of failure, and the location, with the test witnessed by a manufacturer's representative and an authorized inspector.
6. Calculate the MAWP per the chosen code paragraph and assemble the signed report and drawings.

ASME UG-101 Requirements for Burst and Proof Testing

Paragraph UG-101 of ASME Section VIII, Division 1 is the governing rule for establishing the maximum allowable working pressure of components by test rather than by calculation. It permits two families of tests, those based on the yielding of the part and those based on the bursting of the part, and it sets out exactly how each must be run, witnessed, and documented.

UG-101 also defines the specific procedures a manufacturer may choose from. The bursting test procedure under UG-101(m) is the basis for a true burst test, while the brittle-coating, strain measurement, and displacement measurement procedures under UG-101(l), (n), and (o) support proof testing. A separate procedure under UG-101(p) covers vessels with chambers of special shape subject to collapse.

The practical takeaway is that the measured burst pressure does not become the rating directly. UG-101 applies a margin and corrects for the difference between the actual and minimum specified tensile strength of the sample, so the resulting MAWP carries a built-in factor of safety. Getting that arithmetic and the supporting traceability right is exactly where many CRN burst test reports succeed or get rejected, and why the pressure equipment such as boilers and pressure vessels being registered should be reviewed against the relevant code before any sample is destroyed.

When is Burst Testing Required?

Burst testing is required, or strongly preferred, in a handful of recurring situations:

• Unlisted fittings and components. When a pressure-retaining fitting has no published pressure rating in the applicable code, a burst or proof test under UG-101 is the accepted way to establish one for a CRN application.
• Materials with a high yield-to-tensile ratio. Where the ratio exceeds 0.625, yielding-based proof tests are not permitted and a burst test becomes the practical option.
• Novel geometries. Custom vessels, multi-chamber assemblies, and irregular shapes that calculation alone cannot rate confidently are good candidates for destructive pressure testing.
• New product validation. Manufacturers bringing a new design to market often burst test prototypes to confirm the real safety margin before committing to production.

Jurisdiction matters as well. Some provincial and territorial authorities apply a more stringent interpretation than others, so it is worth confirming the witnessing and reporting expectations with the safety authority before any sample is taken to burst.

Real-World Applications of Burst Testing by Industry

Burst testing services support a wide range of sectors that build or operate pressure equipment:

• Oil and gas. Wellhead fittings, manifolds, and high-pressure piping are burst tested to confirm they contain reservoir and process pressures with the required margin.
• Biogas. Digesters, gas-handling vessels, and custom fittings often fall outside listed ratings, making a burst pressure test the cleanest path to a defensible MAWP.
• Pharmaceutical and food. Sanitary vessels and tubing built to ASME BPE still need verified pressure ratings, and burst testing confirms capacity on non-standard components.
• Water and cryogenics. Storage tanks, cryogenic vessels, and distribution piping rely on burst and proof data to set safe operating limits across a wide temperature range.
• Power generation. Boiler components and power piping evaluated under ASME I and B31.1 use bursting procedures referenced back to Section I, A-22.