Page 59 - Hong Kong Green School Guide

3. Green School Guide - 3.1 Green School Sites
Hong Kong Green Building Council 57
3.1.9 Pervious Paving on Grade Applies to NS & ES
Benefits
• Allow rainwater to infiltrate paved areas and reach underground soil thus
providing water to surrounding plants;
• Reduce surface runoff to drainage systems thus minimising impacts on fresh
water supplies and ground water systems during building use;
• Filter the pollutants and prevent them fromwashing down stormwater system;
and
• Reduce heat island effect by holding water for evaporation, which leads to
reduced surface temperature.
Issues to Consider
a. Opportunities
• Pervious paving can be laid to allow rainwater to infiltrate paved areas and
reach underground soil, thus water can be provided to surrounding plants.
b. Constraints
• In area for emergency vehicle access (EVA), paving material must withstand
the weight of fire appliances and fire trucks as per Code of Practice for Fire
Safety in Buildings 2011 by Buildings Department.
c. Solutions
• Some paving materials (eg. pervious ceramic paving bricks, glass bound
pavement) available in the markets and some concrete mixture (known
as pervious concrete pavement) have good permeability and reasonable
compressive strength that allow for both emergency vehicle access and
water to pass through;
• Loading requirement and compliance to Code of Practice for Fire Safety in
Buildings 2011 by Buildings Department must be evaluated by Authorised
Person (AP) and Registered Structural Engineer (RSE); and
• Some materials require frequent maintenance because the grit or gravel
blocks the open pores while, some require less frequent maintenance (e.g.
the glass bound pavement) because of more void space.
d. Professional Help
• Authorised Person (AP) – Appendix A (2)
• Registered Structural Engineer (RSE) – Appendix A (4)