Please enable JavaScript.
Coggle requires JavaScript to display documents.
1.3 INDOOR AIR QUALITY - Coggle Diagram
1.3 INDOOR AIR QUALITY
1) FACTORS THAT AFFECT AIR QUALITY
RELATIVE HUMIDITY
Affects comfort and health
Can cause Mould growth
generally should be in the
30-50% range
AIRBORNE PARTICULATE MATTER
Health concerns as some particles can penetrate deep into the lunges.
3 APPROACHES TO REDUCE DUST
1)
House needs to be tightly constructed to reduce air infiltration
2)
Incoming fresh air should come from a single source so that filtration can take place
before it's distribution throughout the house.
3)
Occupants need to choose or optimize activities that minimize the generation of dust
Examples: Cooking/hobbies/smoking/burning candles/pets/fibers from clothing/drapes/ and furniture
Low temperature electrical systems such as hot-water radiant or fan coil heating has substantial air quality benefits compared with forced-air fuel fired, high- temperature electrical systems
CHEMICAL CONTAMINANTS
Volatile Organic Compounds (VOCS) appear in gaseous forms in room temperature.
Semi-Volatile Organic Compounds (SVOCs) attach to airborne and settles dust particles on surfaces
FORMALDEHYDE is a VOC emitted by many different sources in building materials like: Engineered wood products like Particle board, Medium density fibreboard (MDF)
MOULD
Are microscopic Fungi
Can be airborne
Need oxygen, water, organic nutrients, and suitable temperature( 0 and 38 degrees Celsius)
Mould grows very slowly and takes several days to become established
COMBUSTION GASES
When there is a negative pressure inside
Several by-products are
MAJOR CONCERNS: CARBON MONOXIDE, NITROGEN DIOXIDE, AND ORGANIC PYROLYSIS that happens from INCOMPLETE COMBUSTION
SOLID GAS (RADON)
Radon is a
colourless, odourless, radioactive gas that occurs naturally in the environment.
Comes from
a natural breakdown of URANIUM in soils and rocks
Confined spaces like basements where air exchange is is poor, radon can accumulate and it becomes a health hazard. Increased risk of Lung Cancer
Protection is achieved by providing continuous AIR/SOIL GAS BARRIER, a gas permeable layer between ground and the air barrier, sealed outlet pipes that can be connected to a power vented exhaust.
2) DESIGNING FOR AIR QUALITY
Common ways to provide good air quality:
1) Select low-emitting building materials.
2) Ventilate Sufficiently
3) Construct continuous AIR BARRIERS to prevent the infiltration of outdoor contaminant
3) EMISSIONS FROM MATERIALS
Select products that certified as having low VOC content (example: look for Evironmental Choice label)
Materials can be separated into 2 groups
WET MATERIALS:
Such as Paint and sealants. HIGH VOC
emissions to start but it drops sharply in the first few days.
DRY MATERIALS:
Such as Carpet. Have low emissions
but can emit for a long time
MATERIAL SELECTION:
Paint and varnish coatings.
VOC high emission release in short-term.
safest-------> "Zero VOC"
Solid wood products.
Smell of wood can cause an allergic reaction.
Wood is low in VOC, but the coating may be high in VOC.
Engineered Wood Products (structural)
Glulam, wood I-joists, engineered rim framing, laminated veneer limber, parallel strand lumbar, plywood, oriented strand board (OSB). Low on VOC
due to be made in chemical bond to ensure performance.
Composite wood products (non-structural and decorative)
Appearance plywood, particleboard, medium density fiberboard (MDF)
wood Flooring
Low VOC emitters if treated with low-emission strains or finishes. Pre-finished flooring reduces possible air quality problems.
Ceramic Tile and Terrazzo.
Low VOC emitters
. However
adhesives, and sealers should be chosen carefully.
Carpet and carpet cushion
Requires careful selection
Resilient flooring
Vinyl, tiles, linoleum and cork-------> LOW VOC
Plastics
Soft plastics like vinyl wall covering, sheet flooring----> sources of air pollutants.
SVOC---> Plastics based on poly vinyl clean up.
Concrete
Air Pollution is very low. Sealing exposed concrete basement floors with latex paint will reduce dust and facilitate clean-up.
Thermal Insulation
Rigid and spray on insulation---> sources of emissions.
Emissions can be reduced by installation of an interior Air Barrier like sealed PolyEthylene or drywall
Sealants
WET---> High VOC
Acrylic, silicone and siliconized acrylic sealants---> safe to handle and LOW VOC content
Drywall
Not a source of VOC. But the paint coating can be a source of VOC---> "sink" material
Adhesive
Standard construction adhesive,
ceramic tile cement---> SHOULD BE AVOIDED.
Acrylic latex products---> LOW VOC