Page 223 - Handbook of Materials Failure Analysis

2 Material and Age Structure of Utility Networks 219

% Length of pipes
−60% −40% −20% 0% 20% 40% 60% 80% 100%
−34%
Steel
−40%
−20%
Gray cast iron
−12%
21%
Nodular cast iron
−33%
PVC −20%
79%
PE 53%
0.6%
−0.5%
Concrete
Lead

Water supply networks Wastewater disposal network
FIGURE 9.1
Percentage share of the length of water supply and wastewater disposal networks in 2005,
compared to 1992.

In towns, the share of such conduits is even higher, while in small towns, the diam-
eters of water supply conduits generally do not exceed the diameter of distribution
networks.
Conduits made of traditional materials—such as gray cast iron—still hold a
majority share in the construction materials of water supply networks both in Poland
and in other countries. Conduits made of nodular cast iron constitute a considerable
part of water supply networks in Austria (about 36% of the network length) and in the
French region (about 26%), while in Poland, they constitute on average about 3.3%
of the length of water supply networks, which is due to the fact that this material
started to be implemented only in the 1990s. A high share of conduits made of plastic
is found in Poland and France, while in Austria, they constitute barely 7% of the
length of the network (Figure 9.2). Occasionally, one can still find conduits made
of such materials as lead (already excluded from water supply conduit production)
or asbestos cement that are effectively replaced with materials most often presently
implemented by polyethylene (PE) or polyvinyl chloride (PVC).

2 MATERIAL AND AGE STRUCTURE OF UTILITY NETWORKS
The development of the water supply and wastewater disposal networks has been
accompanied for almost 30 years by a systematic technological progress in the domain
of manufacturing of products made of various materials and designed for these net-
works. Both modifications of traditional materials and completely new generations