Source: Bulgartransgas EAD - DVGW

Maintenance of Gas Networks
The diagnostics is carried out through technical examination, tracking their route,
pressure measuring, mode modelling (computer monitoring), gas balance control,
in-pipe diagnostics with intelligent monitoring pigs (next slide).
Tracking the gas pipe line route
main pipelines with pressure ≤5,5 MPa
–
once in 2 months;
gas pipe line with pressure ≥0.4 MPa – twice a month at least;
gas pipe line with pressure ≤0.1 MPa and Main Branch Pipeline from an Automatic
Gas Regulation and Measuring Station outside a built-up area– once a month at
least.
Tracking the route of the distribution networks involves the following activities:
measuring of the safety potential of the cathode station for metal gas pipelines;
check-up of working pressure in Gas Regulation Station and Gas Regulation and
Measuring Installations;
reflecting any construction and assembly works under way in the proximity of the
gas pipelines;
check-up for the presence of natural gas in the shafts of other utilities
(communication, sewage) etc.
the minimum time span of the technical examination for steel gas pipelines is once
in 4 years;