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Gallery
The gallery acts as a transitional space between the semi-public area (restaurant and meeting rooms) and the of ce area.
In winter, the gallery’s minimum temperature is maintained at 14°C (heating mainly via thermal radiation).This temperature corresponds to a comfortable operative temperature for a Clothing Level Value of 1.0 clo (winter clothing) and for a Metabolic Equiva- lent ofTask (MET) level of 1.7 MET (light intensity activity).
In summer, the gallery is not air-conditioned.To prevent overheat- ing, other methods are used such as adequate solar protection, the use of the building’s thermal inertia or natural ventilation. Certain areas in the gallery (waiting areas, the bar, etc.) offer Level B comfort.
aIR quaLIty
Standard NBN EN 13779: 2007 (Ventilation for non-residential buildings – Performance requirements for ventilation and room- conditioning systems) de nes different categories of ambient air quality.
CO2 concentration is a good indicator of the level of human activity. here are the different air qualities which may be encountered in non-smoking rooms:
Outside air contains about 400 ppm of CO2.
Annex VI of the Energy Performance of Buildings (EPB) Regulation stipulates a minimum air quality equal to the ‘acceptable’ category de ned in standard NBN EN 13779.This requirement is only in force for new buildings and for existing premises where the window frames have been replaced.
Category
IDA 1
IDA 2
IDA 3
IDA 4
usual range
< 800
800 - 1000
1000 - 1400
> 1400
Standard value
750
900
1200
1600
The client has speci ed IDa 3 as the ambient air quality, i.e.,
a moderate air quality corresponding to an air change rate
of 30 m3/h/person.
hygienic ventilation operates during working hours (7:00-18:00) on working days, and otherwise when the free cooling has been activated. heat recovery from exhaust air is done using a heat exchanger wheel (thermal ef ciency of 75% with bypass and ‘purge sector’ management).
HumIDIty COmFORt
In most buildings, no (de-)humidi cation of ambient air is necessary.
In the case of such a system being foreseen, standard NBN EN 15251: 2007 de nes three quality levels, each corresponding to a minimum and maximum level of relative humidity:
Performance
Maximum concentration of CO2 permitted in addition to the outdoor concentration (ppm)
Level of ambient air quality
table 4. air quality levels
Level a High quality
350
IDA 1
Level B Good quality
500
IDA 2
Level C acceptable quality
800
IDA 3
table 3. Levels of CO2 concentration in rooms (ppm)