ÖNORM EN 751-3/AC

This European Standard specifies requirements and test methods for unsintered polytetrafluorethylene (PTFE) tapes (hereafter referred to as PTFE tapes) which are suitable for sealing threaded metallic joints as specified in ISO 7-1. This European Standard covers two classes of PTFE tapes suitable for fine (F) and coarse (G) t hreads. The PTFE tapes 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 and up to 7 bar for hot water of heating Systems as weil as up to 0,2 bar in gas appliances and their auxiliary equipment. The maximum working pressure covered in this European Standard 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 Standard (e.g. compressed gases) the purchaser should consult the rnanufacturer. Anaerobic jointing compounds are covered by EN 751-1, non-hardening sealing materials in form of - e.g. jointing compound paste - are covered by EN 751-2. 7.2.1.2 Soundness test Pressurise the test assemblies 0,s h to 1 h after preparation of the test assemblies with air or nitrogen to a pressure of (30 I 1 3 bar while immersing in a water bath at (20 I 5) "C. lnspect all R -arid R 1% threaded joints for leakage over a 5 min period. Gas leakage shall be determined by the appearance of bubbles during the immersion period, ignoring those noted during the first 15 s of immersion.