Page 513 - The City and Guilds Textbook: Plumbing Book 1 for the Level 3 Apprenticeship (9189), Level 2 Technical Certificate (8202) and Level 2 Diploma (6035)

Chapter 7 Central heating systems

 Table 7.21 Key design and installation information: suspended floor

Maximum heat output Approx. 70 W/m 2
Recommended design flow temp. 60°C
Maximum circuit length 80 m (15 mm pipe)
Maximum coverage per circuit using a 17 m 2 @ 225 mm centres
double spreader plate
Material requirements:
Pipe 4.5 m/m 2 @ 100 mm centres
Heat spreader plates 2 plate/m 2

Floating floor
This system is designed for use where a solid floor installation is not suitable
due to structural limitations. It can be installed directly onto finished concrete
or timber floors.

Wall

Finished floor surface

Double heat spreader plates

Floating floor panels
Underfloor heating pipes
p Figure 7.71 Floating floor underfloor heating installation

The pipework is laid on top of 50 mm-thick polystyrene panels, each having a
thermal transmittance of 0.036 W/m K. The insulation has pre-formed grooves
2
that the pipe clips into after the heat spreader plates have been fitted. The
insulation is not fixed and ‘floats’ on the top of the sub-floor. The finished
flooring can then be laid directly onto the top of the pipework, completing the p Figure 7.72 Floating floor
underfloor heating installation
‘floating’ structure. method

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