asked the Minister for Energy the results of the most recent survey of the Dublin Gas network; and, in particular (1) the percentage of gas being lost from the system and (2) the number and classification of accidental leaks.
Written Answers. - Dublin Gas Network.
39.
Dublin Gas have carried out two complete surveys of the mains network, the first in late 1987 and the second in early 1988. A third survey is now in progress. The results of these surveys have shown a steady reduction in the total number of leaks from one per five kilometres in the first survey to one per eight kilometres in the third survey. In particular, Class 1 leaks, that is leaks requiring immediate repair, are now only one per 50 kilometres.
Since mid-1987 apartment blocks have been surveyed seven times. The eighth survey is in progress. Apartment block leaks have dropped steadily to one per 19 buildings surveyed, almost twice as good as the criterion of one per ten buildings laid down by the Task Force on Multi-Storey Buildings.
Surveys of public buildings, bridges and network valves have also been carried out. The frequency of these surveys is in excess of the requirements of any of the safety reports.
Gas lost from the Dublin Gas network is now less than 5 million therms per year, that is about 6 per cent of gas issued, and still improving. This means that the task force requirement of reducing lost gas to 2,000 therms per kilometre of main per year has already been comfortably achieved.
The number of publicly reported escapes in Dublin has continued to decline steadily, and now averages less than 400 per week, about half the early 1987 level. The current level of PREs is equivalent to eight PREs per kilometre of main per year, which is the task force target. During 1987, 70 per cent of all network leaks were Class 1. The corresponding figure in 1988 has dropped to 40 per cent. Class 2 leaks now account for about 40 per cent of network leaks and Class 3 leaks now account for about 18 per cent. This leak classification profile has shown steady improvement over the past year, and is now in line with international norms.