Page 127 - Hong Kong Green School Guide

3. Green School Guide - 3.5 Indoor Environmental Quality
Hong Kong Green Building Council 125
3.5.3 Thermal Comfort
Benefits
• Acomfortable environment can enhance
student and staff performance;
• Climate positive design implemented in
new school developments can reduce
energy required for air conditioning; and
• Relaxed dress code and climate positive
design for existing schools can reduce
dependence on air conditioning.
Issues to Consider
a. Opportunities
• Schools can promote, monitor and implement ways to improve thermal
comfort.
b. Constraints
• Evaluation of thermal comfort; and
• Schools situated in air and/or noise polluted areas (e.g. busy vehicular
roads, shopping centres with exhaust generation) are prevented from taking
advantage of natural ventilation to achieve comfortable temperatures.
c. Solutions
• Thermal comfort can be evaluated in two ways:
- - Simple approach: temperature +/- 1.5 OC from the set temperature during
the period the building is occupied; and
- - Advanced approach: using the Predicted Mean Vote (PMV-index) and
Predicted Percentage of Dissatisfied (PPD-index) which are determined
by the occupant activity level, clothing factor and environmental variables
including air speed, air temperature, mean radiant temperature and
humidity. Under a PMV-index +/- 0.5 and +/-1, less than 10% and 26% of
people will feel uncomfortable.
• If an advanced approach is adopted, please refer to information in Useful
Reference (1) to evaluate occupant activity level, clothing factor, air
temperature, humidity, air speed, mean radiant temperature, PMV-index and
PPD-index.
Applies to NS & ES