GLSC // Global Leak Sealing Code

Pipe Crushing

Isolating a pipe by pressing it flat. Simple, fast, valveless. And the only method in this series that buys the isolation with a deliberate, permanent damage to the pipe. That is exactly where the question sits.

Request consulting GLSC in the Veritas Library All methods

Definition

What pipe crushing is

In pipe crushing, a pipe is pressed flat with pinch jaws until the cross section closes and the flow is temporarily isolated. The method only works on ductile materials such as polyethylene or lead that deform without breaking.

On rigid materials such as steel the method is ruled out. The decisive difference to all other methods: the isolation is created by a deliberate plastic deformation. The pipe is intentionally damaged in order to isolate it.

The grey zone

Isolation through damage

Pipe crushing has no overarching procedure code. It is established mainly in the gas and water utility field on plastic pipe, with references to the respective material and pipe standards and to the operational procedure.

The real question comes after the crush, not before: is the pipe still sound after re rounding, and is the permanent deformation acceptable. That is the liability vacuum of this method. FRALEX makes the residual integrity assessment mandatory, not an assumption.

Decision logic

The six questions before the crush

Before the jaws close, six questions stand, and their answers are documented and owned.

1. Material suitability

Only ductile materials such as polyethylene or lead can be crushed safely. Rigid materials such as steel are excluded, they tear instead of deforming.

2. Wall stress and permanent deformation

Crushing creates a deliberate plastic deformation. The extent and distribution of that deformation must stay within the acceptable range of the material.

3. Re rounding and residual integrity

Can the pipe be re rounded sufficiently after the crush, and does it still carry load afterwards. That assessment decides admissibility.

4. Single or repeated crush

Repeated crushing at the same spot leads to material fatigue. Whether and how often a spot may be crushed belongs in the decision.

5. Position and tool geometry

Jaw radius, jaw width and position determine the stress distribution. Wrong geometry creates local overload and cracks.

6. Documentation of the damage

The permanent deformation is documented and the residual integrity released. A crushed pipe without a documented assessment is an open risk.

Normative frame

The relevant reference points

Material and pipe standardsPermissible deformation of ductile pipe, e.g. in the PE field

Utility practiceEstablished practices for gas and water on plastic pipe

Operational procedureRelease, tool choice, re rounding, reassessment

ASME B31.3 / EN 13480Design frame where applicable to the pipe

FRALEX GLSCThe decision layer. Residual integrity after the crush

No code guarantees that a crushed pipe is sound afterwards. That is exactly why the documented residual assessment is the real value. Integrity is a decision, not a material property.

FAQ

Common questions

Short, reliable answers on pipe crushing. The full logic is in the GLSC in the Veritas Library.

The temporary isolation of a line by pressing a ductile pipe flat with pinch jaws until the cross section closes. Valveless and without a tap.

Only ductile materials such as polyethylene or lead that deform plastically without breaking. Rigid materials are excluded.

No. Steel is too rigid and tears when crushed instead of deforming safely. For steel, other methods such as pipe freezing or line stopping are used.

Only if the permanent deformation stays within the acceptable range and re rounding restores integrity sufficiently. That must be assessed and documented, it is not automatic.

Pipe freezing isolates without deformation via an ice plug and suits freezable media in steel and other materials. Pipe crushing deforms the pipe plastically and only suits ductile pipe.

With rigid or brittle materials, with excessive permanent deformation, with missing re rounding, or when residual integrity cannot be evidenced. Then the justified no go is the deliverable.