The technical regulation for gas installations (in short: TRGI) is a binding and at the same time important regulation for skilled trade. The TRGI governs how gas installations are to be planned, designed, serviced and maintained. This applies to all gas installations. This regulation is taken care of by the German Association for Gas and Water (DVGW). The TRGI 2018 is the current version. Amongst other things, this states that gas pipes are to be tested according to the construction phase (basic shell, completion, and repairs). The following inspections particularly play a role in the application stated here:

Load testing
During testing, the material is tested for stability and the connections for service life; this takes place prior to plastering over or concealment of the gas pipes. During load testing, the newly installed pipe, without fittings or gas appliances, is put under 1 bar pressure. The testing medium is air or inert gas. There must not be a drop in pressure during the test, which lasts at least 10 minutes.

Leak test
This test is for checking the pipe for leaks, without fittings and gas appliances. The measuring instrument must not register a drop in pressure during the minimum 10 minute testing period (depending on the system volume); the test pressure is 150 mbar (previously 110 mbar).

A gas installation set up according to the legal provisions of the German Association for Gas and Water (“DVGW”) and the TRGI 2018 is the prerequisite for proper, long-term operation. However, while in operation, operating conditions or other general conditions may affect the safety of the gas installation. Technical systems are subjected to wear and contamination in their daily use. Only an expert can identify, assess and repair these kinds of safety-related changes. The leak test (or more aptly, serviceability test, also known as leakage measurement) for the pipeline system is to be repeated every 12 years using a measuring instrument and recorded in a test results report. The operator thus has a technical expert report. Some buildings insurers include these inspections and certificates/reports in their general insurance terms. For the serviceability test or leakage measurement, the gas pipe is always tested in operating conditions/with operating pressure (no increased test pressure). During this test, a measuring instrument detects whether gas is leaking from the pipe and how much.