BS EN 1264‑3:2021 pdf download.Water based surface embedded
heating and cooling systems.
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 1264-1:2021 apply.
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4.1.1.4 Limit curves
The limit curves in the field of characteristic curves describe in accordance with EN 1264-2 the
relationship between the specific thermal output q and the temperature difference Δϑ H between the heating water and the room in the case where the physiologically agreed limit values of surface temperatures ϑ F,max = 29 °C (occupied area) or ϑ F,max = 35 °C (peripheral area) are reached 1 . For bathrooms (ϑ I = 24 °C) the limit curve for (ϑ F,max − ϑ i ) = 9 K also applies. For design purposes, i.e. the determination of design values of the specific thermal output and the associated temperature difference between heating water and room, the limit curves are valid for the temperature drop σ of the heating water in a range of: 0 K < σ ≤ 5 K
The limit curves are used to specify the maximum permissible flow temperature (see 4.1.3.2 and
Figure A.2).
4.1.1.5 Thermal inertia The difference between the minimum and the maximum surface temperature of a floor heating system is low. This means for design purposes that no consideration of thermal inertia is required.
4.1.2 Boundary conditions
4.1.2.1 Flow pipes to adjacent rooms The heat output of service pipes, not serving rooms through which they pass, shall be limited by careful design, or by use of thermal insulation coverings, so that any room temperature should not be increased substantially. The heat output of service pipes passing through the room in question to adjacent rooms is taken into account if the same type of room usage can be assumed.
4.3.2.2 Thermal insulation To limit the heat flow through the wall to rooms adjacent or to the external environs, the required thermal resistance of the insulating layer R λ,ins (in principle see Figure A.3) shall be at least in accordance with EN 1264-4:2021, Table 1. As for the rest, the contents of
4.1.2.2 apply accordingly.
4.3.3 Design
4.3.3.1 Pressure loss The maximum pressure loss per heating circuit should not exceed 250 mbar in order to limit the electrical power consumption of the pump, e.g. by hydronic balancing (see EN 1264-4:2021, 4.1).
4.3.3.2 Design specific thermal output It is recommended to apply the procedure described in 4.1.3.2 accordingly.
4.3.3.3 Determination of water flow temperature It is recommended to apply the procedure described in 4.1.3.3 accordingly. In the case of operating with floor heating connected in parallel and using uniform flow temperature, the flow temperature of the floor heating system shall be used.BS EN 1264‑3 pdf download.