Design Criteria for Healthy Building
3. Protection Against Moisture and Mold
- Design should be adapted to local conditions
- Choose a waterproof pitched roofs to flat roofs
- Use overhangs and flashing to protect external walls and windows from rain
- Well-functioning subdrainage is needed
- Roof spaces, crawl spaces and external wall structures should be ventilated. Avoid dead air spaces
- Good thermal insulation is needed
- Cold water pipes and storm drains should be insulated
- Use waterproof floor structures in bathrooms etc.
- Floors in bathrooms etc. should be tilted
- Avoid over pressurizing in cold climate regions
- Avoid installing pipes and drainage inside building structure
- Rain penetration of exterior sheathing materials requires drainage planes in the walls so that drying will occur
- High humidity situations should be avoided whenever possible

4. Heating Ventilating and Air Conditioning
- Design to established criteria for occupant's health and comfort
- Individual control of room termperture and other environmental controls is recommended
- Outdoor climate should be taken into account when room temperature is controlled
- Use radiant heating whenever possible
- Heating system should be divided into zones based on location and loads in rooms
- Radiators etc. should be locate under windows in cold climate,otherwise special windows should be used
- Avoid high temperature heaters
- High variations in room temperature should be avoided
- The thermal gradient in the room should promote warm feet and cool heads
- High humidity situations should be avoided whenever possible
- Adequate ventilation rate
- Individual control of ventilation rates is recommended
- Pollutants should be extracted near their source
- Air should move towards spaces where pollutants arise
- Control of ventilation should be based on demand
- Total exhaust air flow rate should be 10 to 20% greater than total supply air flow rate in cold climate
- Operation time of ventiation should be much longer than working time
- Outdoor air should enter a building from clean location
- Distance between central air inlets and exhausts should be adequate
- Effective air filtration is needed
- Heat exchangers should not allow cross contamination of air streams
- Ducts and ventilation components should be clean
- Avoid internal duct lining (insulation)
- Ducts in cold spaces should be avoided
- Air conditioning should be divided into zones based on loads in rooms
- Supply air ducts should be insulated
- Recirculated air should be minimized
- Attention should be paid when components for air handling units are selected
- Operation and maintenance of the HVAC system should be incorporated in the design
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PV Vacuum Engineering Pte Ltd
21 Marsiling, Industrial Estate Road 9, Singapore 739175
Tel : 6755 6169 Fax : 6755 2801