UNE-EN 751-3:2023

This document specifies requirements and test methods for unsintered polytetrafluorethylene (PTFE) tapes and polytetrafluorethylene (PTFE) strings (PTFE tapes or PTFE strings, for short) which are suitable for sealing threaded metallic joints as specified in EN 10226-1.

This document covers two classes of PTFE tapes and PTFE strings suitable for fine (F) and coarse (G) threads.

The PTFE tapes and PTFE strings are typically for use in installations for 1st family gases (town gas), 2nd family gases (natural gas) and 3rd family gases (liquefied petroleum gases (LPG)) up to 5 bar, up to 7 bar for hot water of heating systems, and up to 0,2 bar in gas appliances and their auxiliary equipment. The maximum working pressure covered in this document is 20 bar which is relevant to LPG storage. The temperature range is limited to "20 °C to 125 °C.

NOTE For applications outside the scope of this document (e.g. compressed gases), the purchaser needs to consult the manufacturer.

Anaerobic jointing compounds are covered by EN 751-1, non-hardening sealing materials (e.g. in the form of jointing compound paste) are covered by EN 751-2.