Page 43 - Hong Kong Green School Guide

3. Green School Guide - 3.1 Green School Sites
Hong Kong Green Building Council 41
3.1.4 Access of Daylight
Benefits
• Improved health and visual comfort of student and staff;
• Study has shown that daylight has direct influence on regulation of the
circadian system and the mood, hence increased student performance;
• Daylight can kill many types of viruses and bacteria, which is particularly
beneficial in the winter when there is a high incidence of respiratory infections;
and
• Reduce the need of artificial lighting, i.e. energy for lighting when there is
sufficient daylight.
Issues to Consider
a. Opportunities
• Measures can be implemented to improve the access of daylight.
b. Constraints
• Knowledge for evaluation of daylight;
• Shading from surrounding buildings;
• Building orientation and window direction;
• Lighting inexcess andhence solar heat gaindue toexcessivewindowopening.
A balance between access of daylight and heat gain (i.e. air conditioning
demand) must be evaluated by building professionals thoroughly in order to
achieve good daylight harvesting while preventing excessive heat gain.
c. Solutions
• Lighting level of 300 to 500 Lux in classroom and teachers’ room is considered
to be sufficient. Lighting level can be measured by lux meter;
• For new developments, the following measures can be implemented to
improve the access of daylight (sorted by priority):
- - Select site to avoid obstruction from neighbouring buildings if possible;
- - Orientate window to the east, the south and the west and expand window
size; window and shading device for the east and the west shall be
properly designed to minimise glare issue and solar heat gain. Please
refer to External Shading Device section in this Guide;
Applies to NS & ES12
12 ES = Existing Schools