BS EN 1264-2:2021 pdf free download – Water based surface embedded heating and cooling systems Part 2: Floor heating: Methods for the determination of the thermal output using calculations and experimental tests.
9 Test procedure for the determination of the thermal output of systems that cannot be calculated in accordance with Clause 6
For constructions which do not correspond to the basic construction of the types A, B, C or D, or in case of dimensions or material data outside the scope of the calculation method, the specific thermal output shall be determined by testing (experimentally) as follows.
A test sample consisting of at least three heating pipes, with the pipe spacing to be tested, in accordance with the system design of the floor heating to be investigated is positioned in the testing equipment according to Figure A.6. The size of the test sample shall be approximate 1 m x 1 m in agreement with the test laboratory. It shall cover preferably three-pipe spacing. In Figure A.6 the cooling plates simulate the room above the floor heating system (see Figure A.6, key 1), i.e. the temperature of the heated room a9, and the room below (see Figure A.6, key 4). For the cooling plates the construction according to Figure A.7 is recommended consisting of panel radiators with flat tubes in which disconnecting points realize the appropriate cooling water flow. The cooling plate shall be at least of size 1 m x 1 m. The upper plate shall exert a weight force of (450 ± 50) N during measurements. The thermal transfer resistance 1/a at the floor surface is simulated by the heat transfer layer (see Figure A.6, key 2).The two lateral heating pipes serve as a protection field to enable the optimum undisturbed temperature field around the central pipe. The thermal transfer resistance 1/cr at the floor surface, given by the basic characteristic curve, is replaced by the thermal conduction resistance s/A of the heat transfer layer of equal magnitude (mean value):
In the case of not feasible values of the measured temperature field caused by inhomogeneity of the screed, another part of the surface shall be taken.
Because of the fact that the temperature drop of the sample — 19R is very little and the fact that the temperature measurements shall be carried out in the undisturbed area around the central pipe no variation is necessary depending on the laying system (spirally or meandering).
The explanations above refer to the most usual case that the floor heating system is characterized by the repetition of the pipe spacing. The test sample in Figure A.6 which is symmetrical with respect to the central pipe is based on this fact. If another dimension characterizes the system the procedure has to be adjusted.