In order to make reasonable estimates of the maximum number of temperature load cycles when designing prestressed and self-induced prestressed preinsulated piping systems, it was proposed that the temperature variations in a number of existing DH systems be monitored and analysed. The result of the project should be a recommendation concerning temperatire load cycles converted to "full temperature cycles during the presumed lifetime".

The following measurements are to be performed for each utility:

• Supply and return temperatures at production site
• Suply and return temperatures at house connections

Data is to be collected from systems with multiple supply possibilities, with waste incineration and on house connection to consumers who use night-time set-back.

The data is to be analysed statistically, reduced to a homogenous form and converted to "full temperature cycles".