ISO 11855-1 is the first part of multiple series that specifies the basic definitions, symbols, and comfort criteria for embedded radiant heating and cooling systems.
The ISO 11855 series is applicable to water-based embedded surface heating and cooling systems in residential, commercial and industrial buildings. The methods apply to systems integrated into the wall, floor or ceiling construction without any open-air gaps.
NOTE-
ISO 11855 does not apply to panel systems with open-air gaps which are not integrated into the building structure. ISO 11855 series also applies, as appropriate, to the use of fluids other than water as a heating or cooling medium. The ISO 11855 series is not applicable for the testing of systems. The methods do not apply to heated or chilled ceiling panels or beams.
ISO 11855-1 on embedded radiant heating and cooling systems is useful for:
Thermal comfort can be defined as the psychological condition that expresses satisfaction with the thermal environment. An occupant's thermal comfort would be the primary objective that any heating, ventilation and air conditioning (HVAC) system pursues. Radiant heating and cooling systems can be used as primary or hybrid systems which are combined with an air system. Radiant heating and cooling systems directly transfer heat in order to condition space to a specific temperature. Meanwhile, radiant heating and cooling systems can be used to directly provide heat to humans as well as to spaces.
The ISO 11855 series addresses an embedded system that is integrated with the building structure. Therefore, the panel system with open air gap, which is not integrated with the building structure, is not covered by this series.
The object of the ISO 11855 series is to provide criteria to effectively design embedded systems. To do this, it presents comfort criteria for the space served by embedded systems, heat output calculation, dimensioning, dynamic analysis, installation, control method of embedded systems, and input parameters for the energy calculations.
The radiant heating and cooling system consists of heat emitting/absorbing, heat supply, distribution, and control systems. The ISO 11855 series deals with the embedded surface heating and cooling system that directly controls heat exchange within space.
ISO 11855-1 helps you to predict how occupants want the building environment by the requirements for general thermal comfort by predicted mean vote (PMV), operative temperature, and local thermal comfort (surface temperature, vertical air temperature differences, radiant temperature asymmetry, draft, etc.) and keep that concept in mind while designing the structure to provide an acceptable thermal environment to the occupants.
ISO 11855-1 specifies the comfort criteria which you can consider while designing embedded radiant heating and cooling systems to satisfy the thermal comfort of the occupants. Therefore, thermal comfort would be evaluated by asking all the occupants if they are satisfied with their thermal environment. However, in order to design and control radiant heating and cooling systems, it is necessary to predict the thermal comfort in a room without resorting to a polling result.
What’s changed since the last update?
ISO 11855-1:2021 supersedes BS EN ISO 118551:2015, which is withdrawn.
Main changes compared to the previous edition are as follows:
ENISO 11855-1
EN ISO 11855-1
ISO 11855-1