The purpose of this European Standard is to provide the principles and guidance for the preparation of extended application documents for penetration sealing systems tested in accordance with EN 1366-3. The field of the extended application document is additional to the direct field of application given within EN 1366-3 and may be applied to or based on a single test, or a number of tests, which provide the relevant information for the formulation of an extended application. It should be noted that this European Standard provides general guidance on the likely effects of a change. It gives no guidance as to the magnitude, nor how this magnitude is evaluated. Composite pipes comprising both metallic and plastics components are not covered by this European Standard.