Type tested Pipes for complete reliability :
If you refer to EN:545/2002 and ISO:2531/1998 in all these specifications, Type tests have been introduced in push-on joints. Performance type tests on D.I. pipe and their joints are basically carried out under extreme conditions of :

High Internal Pressure of the pipe and the joint.
Shear force on joint.
Under declared deflection of the joint.
Under vacuum (negative pressure)
Abrasion of Cement lining of the pipe
Acid and Alkali attack on lining of the pipe
Bending deformation effect on lining of the pipe by external loading.

These tests have been successfully carried out in India at ECL factory in presence of the representatives of British Standard Institute, U.K. and DQA, Government of India on randomly selected pipes covering the range of 80mm dia to 1000 mm dia. On the strength of these tests Electrosteel has been issued BS "KITEMARK" license and the BS "KITEMARK" logo is incorporated on pipes as per requirement of international norms. The quality system followed in the plant resulted in accreditation of ISO 9002 by both IRQS (INDIA) and BSI (UK). The records of product and plant are audited by BSI UK and IRQS every year to verify consistency and conformance to ISO: 9002 and other product standards. No other pipe material is subjected to these stringent conditions of type test.
For all design purpose the design value of C=140 is taken which is sound and on the conservative side. Over the years, Ductile Iron Pipe Research Association USA has conducted flow tests on cement mortar lined Cast Iron and Ductile Iron pipes in operational pipelines, new pipelines as well as those that have been in service for extended periods of 40-50 years. These field tests have shown a ‘C’ value of 140 to be realistic, and one that is maintained over time even when transporting aggressive water. In AWWA Manual M41 all charts and tables are based on C=140 only.