So that cold water remains hygienically cool
The TECE Hygiene Box thermally decouples the warm water circulation line from the fitting connection, and reliably prevents heat from being transferred via the fittings to the cold water side. Made up of prefabricated components, it prevents the cold water from being inadmissible heated.
To develop the Hygiene Box, TECE looked at installation variants where the circulation lines run above the tap connection. The fitting is supplied by a short stub line running vertically downwards. After the tapping process, under appropriate conditions, thermal stratification takes place in the stub line, reducing heat exchange to the fittings. This depends on the length, diameter and material used for the stub line. If this is too short, heat is still transferred via the fitting to the cold water side. A long stub line will reduce heat exchange but bears the risk of stagnation.
Thermally decoupled cold water side
The ready-to-connect Hygiene Box produced by TECE as a result of optimising the process, provides a practical solution to the problem. It guides the warm water pipe above the warm water wall disk. In this short, vertical connection piece between the wall disk and the circulation line, stable thermal stratification is created, resulting in thermal decoupling of the warm water pipe and the tap connection. This prevents inadmissible heating of the cold water side, so the fitter is sure not to get any complaints.
The insulated, ready-to-connect TECE Hygiene Box is available by itself for the warm water connection, as an assembly unit with a double wall disk for the cold water connection, and as a sanitary module for the TECEprofil dry-wall system. Ready for supply as of April 2017.
Favourable connections for legionella bacteria
For better compliance with drinking water hygiene requirements, installation using double wall disks in a row or as a ring was introduced more frequently a few years ago, instead of the previously common tee connection with stub line. This effectively guaranteed regular water exchange, even in rarely used tap connections.
However, a different problem was encountered: With this type of installation, the circulation line, which contains water at a temperature of 60°C, runs in the direct vicinity of the tap connection, which means that the mounted fittings heat up. Due to the good thermal conductivity of the fittings materials, the cold water side also subsequently heats up to temperatures which are considerably higher than the required 25°C – i.e. to temperatures in which Legionella bacteria and germs feel welcome and quickly multiply.