ISO 18292:2011 pdf free download – Energy performance of fenestration systems for residential buildings 一 Calculation procedure.
8.2 Thermal transmittance, U-value
The thermal transmittance, U-value, is determined for the whole fenestration product. Calculate the U-value as specified in ISO 15099, ISO 10077-1, and ISO 10077-2. The U-value can also be determined by laboratory measurement in accordance with the procedures specified in ISO 12567-1 and ISO 12567-2.
8.3 Total solar energy transmittance or solar factor, g-value Total solar energy transmittance or solar factor, g, shall be calculated as follows:
a) whole fenestration system (frame + glazing) with or without shading devices: ISO 15099 or ISO 13790;
b) glazing: ISO 9050 and EN 410;
c) glazing with shading devices: EN 13363-1 and EN 13363-2. The effect of the following shall be defined at a national level:
— influence of incident angle on solar gain; influence of the frame component;
in the case where no agreed national guidance for defining the influence of incident angle on solar gain values is available, use the value defined in ISO 13790.
The tilt angle of the fenestration system may slightly affect its g-value. When no specific data for tilted fenestration systems is available, the g-values obtained in the vertical position can be used.
8.4 Daylight potential
The daylight potential of a fenestration system indicates its potential to supply a building with daylight and depends on the visible transmittance, the glazing to fenestration system area ratio and on the view factor from the glazing to the sky and the ground. The latter parameter is used to determine the effect of different fenestration system slope angles.
The visible transmittance, shall be calculated for the glazing as specified in ISO 15099, ISO 9050 or EN 410. For shading devices it can also be calculated using the procedures in EN 13363-1 and EN 13363-2.
Quantify daylight potential of the fenestration system and quote this figure with the energy rating. Daylight potential is an important parameter for fenestration system selection but is not used in the energy rating procedure.
In this International Standard, the daylight potential of the fenestration system as a building component is treated as independent of parameters such as the fenestration system height over floor, building overhangs and of the interior of the building. These all affect the daylight performance in practical situations.
8.5.2 Natural ventilation through deliberate opening of the fenestration system
Use the procedures given in ISO 13790 for calculating free cooling and night time ventilation during cooling mode.
9 Reference building
9.1 Introduction
This clause describes step 2 of Figure 1.
It describes the set of data needed on one (or a set of) nationally specified reference building(s) and reference occupancy, including reference services (heating, cooling and ventilation) and their control.
ISO 13790 shall be used as the basis for specifying the reference building.
The energy performance of the fenestration system shall be determined using one of the following options of mounting the fenestration system being evaluated into the reference building:
a) one fenestration system type in one specific orientation;
b) area weighted average results from one fenestration system type placed in each of the four cardinal orientations;
c) defined by national regulations.
NOTE Ensure that the ratio of fenestration system area to reference building floor area is as specified by national regulations or use a “typical” ratio.