IKT – Institute for Underground Infrastructure

Test Centre for CIPP liners

Three-point bending test on a CIPP-Liner

The IKT Test Centre is a supervisory body for CIPP liners and short-liners and is recognised by the German Institute for Construction Technology (DIBt). It is accredited to European Standards (DIN EN ISO/IEC 17025) for selected mechanical and technical tests on polymeric components of pipe and CIPP liner systems and samples of GRP laminate.

The IKT Test Centre thus fulfils the requirements for the performance of materials tests in accordance with ZTV Materials Testing (CIPP liner test standards), DWA-M 144-3 and DWA-A 143-3.

Sample data sheet

Sample data sheet
Materials testing of CIPP liners

Please enclose this form when you send us your samples. This ensures that your sample can be correctly identified.
Please complete a sample data sheet for each individual site sample you send us.

Sample data sheet for CIPP liners

Site sample

What must be the dimensions of a site sample?
What else is important?

Dimensions of site samples

Request for quotation CIPP liners

Request for quotation
Materials testing of CIPP liners

Do you require standard or expanded-scope tests?
We will provide a quotation tailored to your needs, to ensure that your QA requirements are met.

Request for quotation CIPP liners

Accredited Quality Assurance

Unlike factory-finished pipes, CIPP liners attain their ultimate geometrical and mechanical properties only after in-place curing at the installation site. The quality of the work performed on site is thus critical for the quality of the end product.

To address this issue, the tests explained in more detail below are required in ZTV Materials Testing (CIPP liner test standards) as well as DWA Code of Practice 144-3 and DWA Standard 143-3 for quality assurance purposes.

IKT is a DIBt-accredited test centre for building products

IKT is an accredited test and supervisory body recognised by the German Institute for Construction Technology (DIBt) for the performance of tests on CIPP liners and plastics.

IKT tests samples of CIPP liners taken on-site impartially and independently on behalf of project clients. The test report documents in detail whether the required quality criteria have been achieved.

The institute publishes its IKT LinerReport each year detailing the performance of both liner systems and contractors.

Overview of test and inspection criteria

Three-point bending test on a CIPP-Liner

Modulus of elasticity (short-term flexural modulus)

CIPP liners must be capable of withstanding loads such as those arising from groundwater, road traffic and soil pressure
The modulus of elasticity is an indicator of load-bearing capability
Stability may be endangered if the modulus of elasticity is too low
Test method: Three-point bending test as per DIN EN ISO 178 and DIN EN ISO 11296, Part 4

Crown pressure test on a CIPP liner

Flexural strength (flexural stress at rupture)

This indicates the point at which the liner fails due to excessively high stress
If flexural strength is too low, the liner may rupture before the permissible deformation is reached
Test method: Increase of load up to failure in the three-point bending test in accordance with DIN EN ISO 178 and DIN EN ISO 11296, Part 4 (short-term flexural strength)

Mean combined thickness of a liner is measured using a precision slide gauge

Wall thickness (mean combined thickness)

Minimum values are specified in the structural-analysis calculations for liners
Wall thickness and modulus of elasticity jointly determine the stiffness of the liners
Excessively low wall thickness can endanger stability
Test method: Mean combined thickness is measured in accordance with DIN EN ISO 11296, Part 4 using a precision slide gauge

Water tightness: checking if red dyed water penetrates through a CIPP-Liner

Water tightness

A cut is made into the inner film if the latter is not an integral component of the liner; the outer film (if any) is removed
Water containing a red dye is applied internally
A 0.5 bar partial vacuum is applied externally
The liner is “Not tight” if water penetrates through
Test period: 30 min.

DSC analysis of resin samples

Glass transition temperatures (DSC analysis)

This indicates the curing of epoxy resin, e.g. in sewer-lateral liners
If the glass transition temperature is too low, the resin is not cured completely
The temperature can be determined using a small sample of 20 mm cross-section
It is determined if it is not possible to take a sample for mechanical testing

Expanded-scope tests

24 hour creep test for CIPP liners

The minimum scope of testing for CIPP liners consists of the three-point bending test for determination of modulus of elasticity and bending stress, and the water tightness test.

Further tests are available, as defined in the ZTV Materials Testing for CIPP liners specification, which make it possible to determine the quality of CIPP liners even more precisely.

They include: