Indoor Air Quality (IAQ)
1
Sick Building Syndrome
• Sick Building Syndrome - associated with
indoor air pollution. Symptoms include
headaches, sinus congestions, dizziness, itchy
and watery eyes, nausea, lethargy, and a
reduced capacity to concentrate.
• EPA studies reveal that levels of indoor air
pollutants may be 2 to 5 times, and occasionally
more than 100 times, higher than outdoor
levels.
• Most people spend over 90% of their time
indoors.
2
Steps in Controlling IAQ
• Eliminate the Source
– Choose non-polluting products
• Control the Source
– Isolate the source (such as radon and CO)
– Seal or enclose the source (such as asbestos)
– Control relative humidity
• Ventilation
• Air Cleaning and Filtration
• Or as John Bower (Author of the Healthy Home
Book) says, “Eliminate Separate Ventilate”
3
Indoor Air Quality and RH
Total Water Vapor Air Can Hold
4
Common IAQ Pollutants
•
•
•
•
•
•
•
Radon
Volatile Organic Compounds (VOCs)
Dust and Dust Mites
Allergens
Carbon Monoxide
Mold and Mildew
Household Chemicals
5
Tight Homes
Keep out:
• Pollen and dust
• Noise
• Crawl space molds and moisture
• Insulation particles
• Termiticides and other soil treatments
• Radon
• Humid air in summer/dry air in winter
6
Radon
• Radioactive gas formed by decay of uranium in
the soil
• Any type of home (leaky or sealed) may have a
radon problem
• 14,000 deaths per year in the United States;
could range from 7,000 to 30,000 deaths per
year
• More risky for smokers (synergistic effect)
7
EPA Map of Radon Zones
Zone 1 Highest Potential:
predicted average indoor
radon screening level
greater than 4 pCi/L
Zone 2 Moderate Potential:
radon screening level
between 2 and 4 pCi/L
pCi/L = picocuries per liter (4
pCi/L is the EPA maximum indoor
guideline)
Zone 3 Low Potential:
radon screening level less
than 2 pCi/L
8
EPA Maps of Radon Zones
9
Radon
• Maximum accepted level by EPA is 4 picocuries/liter
• Testing kits are widely available
• Resources
• www.radon.com
• National Environmental Health Association's
(NEHA) National Radon Proficiency Program
(NRPP) www.neha-nrpp.org
• National Radon Safety Board (NRSB) www.nrsb.org
10
Radon Testing
•
•
•
•
•
Use state or national-certified kits
Test radon levels in lowest habitable rooms
Follow directions on kit carefully
For levels near 4 picocuries/liter, get professional testing
If levels are well over 4 picocuries/liter, ventilate home
and consider relocation during remediation
11
Radon Sub-slab Mitigation
A.
B.
C.
D.
E.
Permeable gravel layer
Plastic
Seal air infiltration
Vent stack (labeled)
Junction boxes for
continuous fan
Test after occupancy;
install blower if needed
12
Sub-slab Radon Pipe
• 4” PVC – label it!
• Connect to horizontal run of perforated
pipe under slab
• Extend through roof
13
Radon Mitigation Blowers
• Test for radon after
occupancy
• If levels exceed 4
picocuries per liter,
install continuous
blower
14
Radon Mitigation with Blower
• Basement location – pipe
must be well sealed to roof
• Blue alcohol manometer
indicates if blower is working
15
Carbon Monoxide
• A colorless, odorless, poisonous gas that results from
incomplete combustion of fuels
• Household sources: furnaces, gas heaters, motor vehicles
• Most signs and symptoms of CO exposure are nonspecific
(headache or nausea); can be mistaken as viral illnesses
• Undetected or unsuspected CO exposure can result in
death
16
Carbon Monoxide
• Eliminate combustion appliances, especially vent-less
systems
• Use only direct vent isolated air combustion
appliances
• Use carbon monoxide monitor and alarm
• Test each combustion appliance (gas water heater,
gas furnace, gas range and oven, gas space heater)
17
Health Effects of CO Levels
Maximum level ASHRAE recommends in an occupied
building is 9 parts per million (ppm)
CO Level (ppm)
Symptom
100
Nothing proven
200
Headache, tiredness, dizziness
400
Headaches, life threatening after three
hours
800
Convulsions within 45 minutes, death
within 2-3 hours
1,600
Death within one hour
3,200
Death within one-half hour
18
Chemical Off-gassing and
Multiple Chemical Sensitivity
What is Off-gassing?
The event of emission of chemicals into the air
when wet and the continued emission of
chemicals into the air after a product is “dry”.
• Off-gassing is often odorless
– The level of off-gassing may be below the typical
human ability to detect
– Some chemicals are odorless (CO)
“Everyday” Chemicals
• World Health Organization says that some 100,000
chemicals are now on the market and 1,000 to 2,000
are added each year.
• Consumers are exposed to 60,000 to 70,000 different
chemicals each year.
• Only some chemicals are tested for their effect on
humans.
• NIOSH has only tested 576 out of 100,000.
What Produces Off-gas?
• Treated wood: arsenic, formaldehyde, aliphatic
hydrocarbons
• Insulating materials: vinyl chloride, formaldehyde
• Plastic piping: formaldehyde, vinyl chloride
• Vinyl or plastic interior coverings: ketones, esters, ethers
• Wood stains: hexane, heptanes
• Liquid floor wax: formaldehyde
• Carpets: a “soup of chemicals”
Impacts of Other Chemicals
•
•
•
•
MSG (food additive): retinal deterioration
Solvents: panic disorder
Formaldehyde: chronic fatigue
Pesticides: inability to concentrate, irritability,
depression, poor memory, schizophrenia
• Benzene(gas): leukemia, deteriorating IQ
• Chlorine and ammonia cleaners mixed together:
phosgene gas
23
Multiple Chemical Sensitivity
Became more widely know in 1970s after off-gassing from
urea foam formaldehyde insulation in homes.
What is known:
1) Chemical sensitivity can produce any symptom, in
any person, at any time, but the brain and central
nervous system are the most common targets
2) Vast range of individual susceptibility
3) Spreading phenomenon
Volatile Organic Compounds (VOC)
• Organic compounds (contain carbon and hydrogen)
that vaporize (become a gas) at room temperature
• Examples: adhesives, manufactured woods that
release formaldehyde, carpet, cleaning products
• Seal cabinets to prevent off-gassing
• In laminated wood, prefer exterior glues to interior
glues
• Can cause eye, nose, and throat irritations and some
types can cause cancer
25
VOC Examples
• Rhinitis (nasal membrane inflammation): laser printers,
diesel exhaust
• Headaches, panic attacks, and kidney problems: solvents
• Heart arrhythmias: aerosol propellants
• Balance and memory difficulties connected to
formaldehyde exposure; asthma to carbonless copy
paper, perfume, and tobacco smoke; and connective
tissue diseases to some fuels, vinyl chloride, and hair dye
26
Formaldehyde Impacts
•
•
•
•
Formula  CH2O
Irritation of eyes nose and throat
Respiratory problems, lungs
Menstrual disorders and
pregnancy problems
• Cancer (long term exposure)
27
Household Chemicals
• Cleaning products, degreasers,
solvents, paints and finishes
• Most made of petrochemicals
• Vapor is sometimes toxic
• Very dangerous if swallowed
• Keep locked up away from children
28
What can we do about it?
• Use natural building methods and materials
• Use organic cleaners or steam cleaners for
home and office
• Increase other people’s knowledge
• Look for products labeled (and certified) as
“no VOC or low VOC”
Paint and Sealant Options
• “Natural” paints and finishes made from
ingredients such as water, plant oils and
resins, plant dyes and essential oils, clay,
chalk, talcum, milk casein, natural latex, bees'
wax, earth and mineral dyes
• Low VOC
• Zero or No VOC
30
Low VOC Finishes
Low VOC paints, stains and varnishes use water as
a carrier instead of petroleum-based solvents.
• They have no, or very low levels of heavy
metals and formaldehyde. Lead – Mercury- Titanium
• To meet EPA standards:
– Paints and stains must not contain over 200 grams
of VOC per liter.
– Varnishes must not contain over 300 grams per liter
31
Low VOC Finishes
• As a general rule, low VOC paints, marketed
by reputable paint manufacturers, usually
meet a 50 g/L VOC threshold.
• Paints with the Green Seal Standard (GS-11)
mark are certified lower than 50 g/L (for flat
sheen) or 150 g/L (for non-flat sheen).
• Adding a color tint usually brings the VOC
level up to 10 grams/liter, still quite low.
32
Issues with Carpeting
• Regular carpet ingredients
– dyes
– pesticides
– biocides
– chemicals
– odors
33
Chemicals in Carpeting
•
•
•
•
•
Ethylbenzene - eye irritation
Acetonitrile - respiratory discomfort
Toluene - cough
Benzene - dizziness
Azulene - headaches
34
More Chemicals
• Indene - rash, itching
• Oxarium - muscular
aches
• Styrene - unusual
depression
• Tetradecene respiratory tract
irritation
• Dimethyl - sexual
dysfunction
• Methylnaphthalene hair loss, weight loss
or gain
• Polyacrylates abdominal pain
35
Health Problems
• Neurological and nervous system problems
• Respiratory problems – runny nose/eyes
• Depression - head aches
Sources
• Carpet adhesive - seam sealants
• Synthetic foam - latex - carpet dye
36
High Priority "worst in class" Chemicals
Persistent Bioaccumalitive Toxics (PBTs): pvc,
paints, finishes, etc.
Persistent Organic Pollutants (POPs): subset of
PBTs
– Dioxins, furans and PCBs are the prime POPs connected
with building materials.
Volatile Organic Compounds (VOCs):
formaldehyde
37
High Priority "worst in class" Chemicals cont.
1) Chlorinated building materials:
Polyvinyl chloride (PVC) often referred to as “vinyl"
• pipes and conduit
• water proofing
• siding
• roof membranes
• door and window frames
• resilient flooring
• carpet backing
• wall covering
• signage
• window treatments
• furniture
• wire
• cable sheathing
38
High Priority "worst in class" Chemicals cont.
Chlorinated polyethylene (CPE)
• Geomembranes
• wire and cable jacketing
Chlorinated polyvinyl chloride (CPVC)
• water pipes
Chlorosulfonated polyethylene (CSPE)
• roof membranes
• electrical connectors
• sheet membrane for pond liners
Polychloroprene (CR or chloroprene rubber, also brand name Neoprene)
• Geomembranes
• weather stripping
• expansion joint filler
• water seals
• other gaskets and adhesives
39
High Priority "worst in class" Chemicals cont.
2) PBT based material treatments
– Brominated Flame Retardants (BFRs), particularly
PBDE (polybrominated diphenyl ether)
• Furniture foam and fabrics
– Perfluorochemicals (PFCs) (most notably PFOA)
• Furniture & dividers - stain and non-stick
treatments, including Scotchguard®, Teflon®,
Stainmaster®, Scotchban®, and Zonyl®
40
High Priority "worst in class" Chemicals cont.
3) Heavy metal additives and components. Heavy
metals are inherently persistent and often bioaccumulative, including:
Mercury
• thermostats
• thermometers
• switches
• fluorescent lamps
41
High Priority "worst in class" Chemicals cont.
Lead
• flashing
• terne, copper and other roof products
• solder
• wire insulation jacketing (most PVC wiring
but apparently you can now buy even PVC
wire without lead)
Cadmium
• Paint (use GreenSeal paints to avoid)
• Some PVC products (as a stabilizer)
42
What Alternatives are Available?
• Untreated chemical-free wool carpets
– no pesticides
– no dyes
– no biocides
• Green Label carpeting
– Carpet and Rug Institute program
• Green Label Plus carpeting
43
Green Label Carpeting
• Carpets are tested by an independent, certified
laboratory and meet stringent criteria for low chemical
emissions.
• Green Label Plus is designed for architects, builders,
specifiers and facility managers who want assurances
that carpet and adhesive products meet the most
stringent criteria for low chemical emissions.
• Green Label Plus represents the fourth time the carpet
industry has voluntarily enhanced the IAQ standard for
its products.
http://www.carpet-rug.org/commercial-customers/green-building-and-the-environment/green-label-plus/index.cfm
44
Available Alternatives
Criteria for GreenSure Designation (Sherwin-Williams)
• Products that offer maximum performance and long-term
durability
• Have the highest indoor air quality ratings for low VOC and low
odor
• Meet or exceed the GS-11 criteria for coatings used in LEEDcertified buildings (LEED certification means that certain
"green building" standards are met, such as energy efficiency
and indoor environmental quality)
45
Third Party Verification Organizations
46
Green Building Material Resources
47
Green Building Material Resources
48
Fungi
•
•
•
•
•
•
•
Molds, yeasts and mushrooms
100,000 species
25% of earth’s biomass
Reproduce via spores
Digest organic material
Old building issue: rot
New building issue: sick
building
49
Dust, Dust Mites, and Allergens
Avoid Source
– Air leaks bring in dust (and dust mites)
and allergens
– Pets increase dust levels in homes
– Wall-to-wall carpeting is perfect
environment for dust mites
Control Source
– Frequent vacuuming helps;
central vacuums exhaust dust outside
– Japanese homes use controlled entry or dust removal zone
(take off shoes, put on slippers)
– HVAC filtration systems
50
Dust, Dust Mites, Allergens
Treatment of Source
•
•
•
•
•
Vacuum frequently
Control moisture
Control air filtration
Electrostatic precipitator as a filter
Eucalyptus oil
51
Building Mold
Two types
of outbreaks
– spot problem
– systemic
problem
• Is this a
spot problem
or systemic?
• What caused it?
52
Mold Issue: Driving Forces
• CDC study: 75% increase in reported
asthma cases from 1980 to 1994
• Cleveland study linked toxic mold to infant
pulmonary hemorrhaging cases
• Mold is often a leading suspect in “sick
building” syndrome
• Media attention and law suits
53
Mold = New Issue: Old Problem
If mold spreads in a house,
“It must be torn down, its stones, timbers, and all
plaster - and taken out of town to an unclean
place.”
Leviticus 14:45
54
Relative Humidity Levels
•
•
•
•
Building decay… 100% RH
Interior mold…… RH >70%
Dust mites……… RH >50%
Static electricity… RH <25%
55
Mold Remediation = Serious Business
56
Potential Health Effects
• Allergic reactions: allergies and asthma
• Infections
• Irritant: eye, skin, respiratory tract
• Toxic molds (mycotoxins)
57
Conditions for Mold Growth
• Food: organic materials
– Cellulose building materials (wood, paper faced
sheetrock)
• Temperature: 59°F to 122° F
• Excess moisture - the primary cause
– Water: flooding, roof and plumbing leaks
– Water vapor: mold grows above 70% RH
58
Locations for Mold Formation
•
•
•
•
•
•
•
•
Crawl spaces and basements
Attics
Inside damp/wet walls and on siding
Carpets on concrete slabs
Windows
Bathrooms
Behind vinyl wall coverings
Ductwork
59
Mold Formation after Flood
60
Poor Flashing = Mold Formation
61
Mold under Vinyl Wallpaper
62
Mildew Formation
Mildew Growth
63
Mold
Mold Growth
Build to Prevent Mold
Control Moisture
• Traditional methods: overhangs, gutters flashings, caulking,
drainage
• Air-sealed floors, walls and ceilings
• Simplified roof geometry
• Masonry capillary breaks
• Complete foundation moisture barrier; closed crawl spaces
• Dry out building materials before installing vapor barriers,
sheetrock, carpet
65
Build to Prevent Mold (cont.)
• Consider installing multiple foundation
drains – make sure they drain completely
away from home
• Relative humidity should be 30% to 50%
• Design cooling system for “latent load”
making sure cooling system dehumidifies
properly
66
Fixing Mold Problems
• Find the moisture source and fix the problem FAST
• Remove mold FAST
• Protect workers and occupants: respirators,
eye and hand protection, exhaust work areas
• Clean with soap and water, then chlorine bleach,
which should remain in place for several hours
• Final cleaning to remove dead mold spores
Mold sampling is best used
for litigation and research
67
Beware: Mold Lawyers
• www.toxic-mold-news.com
• www.toxicmoldinfocenter.com
• www.toxicmold-attorneys.com
• www.toxic-mold-stachybotrys.com
• www.atoxicmoldattorneyforyou.com
• www.moldlawyer.com
• www.nationaltoxicmoldattorneys.com
68
Ventilation Options
• Uncontrolled natural ventilation (air leaks)
• Controlled mechanical ventilation
• Heat recovery ventilation (HRV)
– without moisture removal
– with moisture removal (Enthalpy Recovery
Ventilation - ERV)
69
Ventilation Make-Up Air
• Incoming air leakage
• Independent air inlet vents
• Air inlet to HVAC return duct
70
Ventilation
• Why ventilate?
– Humidity control
• Reduce excessive moisture harmful to the building structure
• Reduce excessive moisture that is a source of mold and mildew
growth
– Help prevent pressure imbalances
– Dilute odors and pollutants harmful to human health
– Provide oxygen for fuel combustion
• Not a solution to high levels of indoor pollutants
71
Ventilation
• Ventilation required by code (IRC Section R303)
– Natural ventilation using windows, or
– Mechanical ventilation meeting ASHRAE 62
– Bathrooms
• Operable windows or 50 cfm/intermittent or 20 cfm continuous
72
ASHRAE 62
• American Society of Heating, Refrigeration, and Air
Conditioning Engineers (ASHRAE) sets standards for the
heating, cooling and refrigeration industry
• ASHRAE 62 states: a home must have the following
ventilation rate in cubic feet per minute:
(7.5 cfm x number of people) + (0.01 x house area in square feet)
Number of people = number of bedrooms + 1
73
ASHRAE 62 Example
2,400 square foot home with 4 bedrooms
• Number of occupants = 4 bedrooms + 1 = 5 persons
Minimum ventilation rate =
 (7.5 cfm/person x 5 persons) + (0.01 x 2,400 sq ft) =
 (37.5 cfm) + 24 = 61.5 cfm
74
Spot Ventilation
• Bathroom fans
• Range hoods
• Choose low sone fans
rated for continuous use
• Example – Panasonic
“WhisperGreen” allows
homeowner to set
ventilation rate
75
Installation is Critical
• Poor product
(vinyl duct)
• Potential for
condensation on
soffit board
• Exhaust air will
humidify attic
76
Simple Ventilation System
• Two approaches
– Low sone (db)
exhaust fans
– Central HVAC
blower
In the diagram, only
new feature is
dampered fresh air
to outside
77
Exhaust Fan Ventilation
Low sone kitchen
exhaust fan with
100 cfm at 0.3”
static P
-
Low sone bath
exhaust fan
with 50 cfm
at 0.3” static
P
Source of
fresh air
-
Dampered
inlet duct
78
Ventilation Using HVAC Blower
79
Make-up Air via Air Handler
When the air
handler runs,
assuming ducts
are tight,
outside air duct
results in slight
positive
pressure in
home.
80
Cycling the HVAC Blower
Products:
Air Cycler
April Aire Controller
HVAC Cyclers are low cost devices attached to the air handler
cabinet and connected to the low-voltage thermostat wiring block
inside the air handler. By periodically operating the central heating
and cooling system fan, they improve the effectiveness of the
temperature control, humidity and filtration system in a house.
81
Whole House Ventilation System
Example of central exhaust
fan: the “Octopus” – from
American Aldes
Central heating and cooling
system
Central
exhaust
fan
Dampered
outside air duct
82
Central Ventilation System
• “Pick-up” ducts
connected to
bedrooms and
bathrooms
• 3-speed blower is
typical
• Example supplier –
American Aldes
83
Heat Recovery Ventilation (HRV)
Stale room air return
ducts
Exhaust air
outlet
Fresh air inlet
Heat recovery ventilator
(not part of HVAC system)
84
Heat Recovery Ventilator
Heat Recovery Core
85
Ventilation and Air Quality Testing
•
•
•
•
Check for minimum natural ventilation
Check ventilation equipment
Test for backdrafting problems
Test pressure balance
86
EPA Mold Resources
• A Brief Guide to Mold Moisture and Your
Home
• Mold Remediation in Schools and Commercial
Buildings
www.epa.gov/iaq/molds/moldresources
87
Energy Myth
Never build a house “too tight!”
88
88
Typical Sources of Air Leakage in the Home
89
89
Which Subcontactors Are Key?
90
ASHRAE 62 (not revision): Minimum Ventilation
Requirements for Indoor Air Quality
• 0.35 air changes per hour, or at least 15 cfm per
occupant
• New ASHRAE 62 Residential
7.5 cfm per person + 0.01 x floor area
• Kitchen exhaust fans
– 100 cfm intermittent or 25 cfm of continuous fresh
air or operable window
• Bathroom exhaust fans
– 50 cfm intermittent or
– 20 cfm continuous fresh air or operable window
91
Estimating Natural ACH
1. Conduct blower door test - find ACH50 = CFM50 x 60/
volume
2. Find factor in table: Number
Degree of Protection
of
Floors
1
1.5
2
2.5
3
over 3
Exposed
18.9
17
15.1
14.2
13.2
12.3
Average
21
18.9
16.8
15.8
14.7
13.7
Good
25.2
22.7
20.2
18.9
17.6
16.4
3. ach = ACH50/ factor in table
92
Example - Natural ACH
• 2-story home with 4 bedrooms
– Area = 2,000 sq ft; Volume = 16,000 cubic feet
– Good protection from wind
– 10 ACH50 on blower door test
• Natural air changes per hour
– From table, ach Factor = 20.2
– ach = ACH50/ach Factor = 10 / 20.2 = 0.5
(often used in computer load sizing and energy
estimating calculations)
93
Example : ASHRAE 62 - cfm Requirement
• Required minimum cfm by ASHRAE 62 =
(# of bedrooms + 1) x 7.5 cfm + (0.01 x area) =
((4+1) x 7.5) + (0.01 x 2000) = 57.5 cfm
• Measured cfm for home = ach x volume / 60
= 0.5 x 16,000/ 60 = 133 cfm, which complies since it
exceeds required minimum of 57.5 cfm
94
Blower Door/ ASHRAE 62 Homework
• A home has a bottom floor measuring 24 feet x 48 feet and
has 10 foot ceilings. The second floor measures 18 feet x 48
feet, but has a sloped ceiling that is 8 feet high at its lowest
point and 16 feet high at its apex. The ceiling runs this way
along the entire 48-foot length.
• During a blower door test, you have a house pressure of 50
Pa, fan pressure of 225 Pa, and 4,500 cfm of air flow out the
blower.
• What is the CFM50 and the ACH50?
• Does the home comply with the old ASHRAE 62? (Assume
average shielding – factor from table is 18.9.)
95
Maximum Allowable Carbon Monoxide
Carbon monoxide poisoning affects people by cutting off the
supply of oxygen to muscles and the brain. The harmful
effects depend on both the concentration of CO in the air
and the length of exposure.
–
–
–
–
9 ppm ― ASHRAE
35 ppm ― 8 hour period
100 ppm in flues ― some duct repair programs
400 ppm in flues ― EPA
96
Carbon Monoxide Hazards
Concentration
200 ppm*
400 ppm
800 ppm
1,600 ppm
3,200 ppm
6,400 ppm
Inhalation time and toxic symptoms
developed
Slight headache, tiredness, dizziness, nausea
after 2-3
hours.
Frontal headaches
within
1-2 hours; life
threatening after 3 hours.
Dizziness, nausea and convulsions within 45
minutes; unconsciousness within 2 hours.
Death within 2-3 hours.
Headache, dizziness and nausea within 20
minutes. Death within 1 hour.
Headache, dizziness and nausea within 5-10
minutes. Death within 1/2 hour.
Headache, dizziness and nausea within 1-2
minutes. Death within 10-15 minutes.
12,800 ppm
Death within 1-3 minutes
*Maximum CO concentration for exposure at any time as
prescribed by OSHA. Effects can vary significantly based on age,
97
Summary
• Minimize pollutants in products – there are
alternatives available
• Install radon mitigation system
• Build as tightly as possible
• Control humidity levels
• Control moisture
• Provide effective controlled ventilation
98