Confirming pipe shape and integrity after backfilling
Deflection testing is a post-installation method used to verify that newly laid sewer or stormwater pipes have maintained their round shape and structural integrity. It helps ensure that no deformation has occurred due to concrete encasement or backfill pressure and is required for Section 73, Sydney Water, and council compliance.
The test involves pulling a metal prover—slightly smaller than the pipe’s internal diameter—through the full length of the pipe. If the prover passes cleanly, the pipe maintains acceptable ovality. Any blockages or resistance indicate narrowing, compression, or potential misalignment that could compromise pipe performance.
Deflection testing helps confirm that the installed pipe meets technical specifications and can support long-term service conditions without structural failure. For non-contact ovality checks, CCTV inspections may also be used to visually assess the pipe’s internal profile.
What Deflection Testing Identifies
- Squashed or compressed pipe sections caused by concrete or backfill
- Deformed areas that may weaken the sewer or stormwater network
- Blockages and misalignments requiring remediation
- Ovality compliance for Sydney Water and council approval
Suitable Applications
- Sewer and stormwater installations
- Projects with encased or backfilled pipes
- Sites requiring ovality certification before handover
- Systems undergoing CCTV ovality verification
Key Benefits
- Meets Sydney Water technical specifications and Section 73 requirements
- Provides NATA-certified assurance of pipeline quality [Click here to view our certification.]
- Avoids costly repairs or environmental damage post-installation
- Supports compliance with council and utility regulations
