indoor air quality
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Indoor Air Quality. WEATHERIZATION ENERGY AUDITOR SINGLE FAMILY. WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012. Learning Objectives. Indoor air quality. By attending this session, participants will be able to: Recognize about the factors affecting IAQ. - PowerPoint PPT PresentationTRANSCRIPT
1 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
Indoor Air QualityWEATHERIZATION ENERGY AUDITOR SINGLE FAMILY
WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012
2 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
By attending this session, participants will be able to:• Recognize about the factors affecting IAQ. • Describe the role moisture plays in IAQ. • Discuss moisture movement. • Formulate pollutant remediation techniques.• Examine the impact of occupant behavior on IAQ. • Describe the evolution of ventilation standards.• Describe the requirements of ASHRAE 62.2 2010.
Learning ObjectivesINDOOR AIR QUALITY
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• Moisture and Mold• Stored Toxic Materials• Carbon Monoxide (CO)• Radon• Sewer Gas• Other
IAQ and MoistureINDOOR AIR QUALITY
Photo courtesy of The PA WTC
4 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
Occupant Driven IAQ Sources
• Common household pollution sourceso Pet dander
o Volatile Organic Compounds (VOC’s) Improperly stored solvent, paints, cleaners
o General unhygienic conditions
o Rodent or Insect Infestations
• Making things worseo Tight house with a lack of ventilation
o Uninformed occupantsPhoto courtesy of The US Department of Energy
INDOOR AIR QUALITY
5 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
Sources of Water Vapor
Source Quarts per Day
Construction materials first year 40
Standing water in basement 30
Damp basement or crawlspace 25
Greenhouse connected to house 25
Humidifier - large 20
Drying 1 cord of firewood 16
Clothes dryer vented to inside 13
Respiration/perspiration – 4 people 4.7
Clothes washing 2.1
Unvented gas range 1.3
Cooking without lids 1.0
Houseplants – average number 0.5
Dish washing 0.5
Floor mopping 0.4
Showering/bathing 0.3
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Related to occupant behavior
Related to the building
6 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
Moisture Movement
Diffusion Through Surface Convection Through Holes
Air molecules are blocked.
Water vapor molecules are passed.
Air flow
Both water vapor and air molecules pass through.
INDOOR AIR QUALITY
7 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
Permeance of Building Materials
Permeance of Building MaterialsMaterial placed on the warm side of a building surface to retard diffusion of water vapor is called a vapor barrier. Material intended to retard convection is called an air barrier. Material which accomplishes both is termed an air/vapor barrier. A material qualifies as a vapor barrier if its permeance is 1.0 perm or less.
INDOOR AIR QUALITY
8 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
IAQ and Relative Humidity
Relative Humidity and Indoor Air Quality RelationshipsDecrease in bar width indicates decrease in effect
Bacteria
Viruses
Fungi
Dust Mites
Respiratory Infections
Allergic Rhinitis and Asthma
Clinical Interactions
Ozone Protection
Percent Relative Humidity 0% 10% 20% 30% 40% 50% 60% 70% 80% 90%
INDOOR AIR QUALITY
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What Determines IAQ?INDOOR AIR QUALITY
Photos courtesy of The US Department of Energy
10 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
Client Interview
Use the interview process to learn more about how the client uses their home as it relates to health and safety:
• How many people live in the home?• Are there cold rooms? Hot rooms?• Do they use the fireplace or unvented space heaters?• Does anyone in the home have asthma or other illnesses?• Are headaches a chronic problem in the heating season?• Do they use their kitchen and bathroom exhaust fans?• Do they dry clothes or wood in the house?• Are there any unpleasant odors or burning sensations?
INDOOR AIR QUALITY
11 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
• Properly size central AC units. • Talk people out of using unvented heaters.• Don’t overcool the house in summer.• Don’t hang wet clothes in the house.• Don’t dry wood indoors.• Use kitchen and bath exhaust fans.• Enhance room circulation with fans to avoid cold spots.
Client EducationINDOOR AIR QUALITY
12 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
• Testing and abatement is not an allowable expense. (WPN 11-6 H&S Guidance)
• Mold clean-up is not an allowable expense• Correcting moisture problems that may cause mold is
allowableo Controlling surface temperatures with good
insulation and air sealing practiceso Venting dryerso Installing mechanical ventilationo Fixing minor drainage issues
What WAP Can and Cannot DoINDOOR AIR QUALITY
13 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
Pollutant Action Tree
Source• Eliminate• Encapsulate• Dilute
Driving Force• Eliminate • Weaken
Path• Eliminate• Block
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Photo courtesy of The US Department of Energy
14 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
Outside Air and IAQ
How much outside air do we need for good IAQ?How do we get it?
Mechanical FansBuoyancyStack effect - warm air rising
Exhaust Fan
WIND DIRECTION
Wind
INDOOR AIR QUALITY
15 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
How has natural ventilation been calculated?
N-factor variables:
• Geographic location
• Building height
• Building exposure
The n-factor for the house illustrated at right would be different if it was one story taller, or less shielded. The map shown below is the LBL Climate Zone Map used to determine the geographic variable.
INDOOR AIR QUALITY
16 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
Why Isn’t the MVG Our Best Tool?
Photos courtesy of The US Department of Energy
The matched board ceiling above has many feet of linear cracks that expand and contract depending on relative humidity (RH).
The missing flue plug creates a stable-sized round hole with little air flow drag.
A single-point blower door test will see these holes as identical!
INDOOR AIR QUALITY
17 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
Neutral pressure plane
Random Size & Distribution?INDOOR AIR QUALITY
18 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
CFM50 = 4000
CFM50 = 2000
Desired ventilation = 75 CFM
CFM50 = 1000
CFM50 = 1000 + 75 CFM fan
050
100
150
200
250
Ventila
tion Rate, C
FM
0 20 40 60 80 100
Outdoor Temperature, degrees F
Based on single-story 1,500ft2 house
Chart courtesy of Paul Francisco
An Important Corollary!
INDOOR AIR QUALITY
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ASHRAE 62.2-2010
www.ashrae.org
What is the DOE Requirement Now?
A Wisconsin pilot study conducted in 2004 found that 78% of weatherized units required additional mechanical ventilation under 62.2, up from 47% using the previous ASHRAE standard, 62.1989.
Average installed cost, including controls: $525 (2004-2005 prices).
INDOOR AIR QUALITY
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ASHRAE 62.2-2010
Photos courtesy of The US Department of Energy
INDOOR AIR QUALITY
21 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
Floor Area (ft2)
BEDROOMS
0 - 1 2 - 3 4 - 5 6 - 7 >7
< 1500 30 45 60 75 90
1501 – 3000 45 60 75 90 105
3001 – 4500 60 75 90 105 120
4501 – 6000 75 90 105 120 135
6001 – 7500 90 105 120 135 150
> 7500 105 120 135 150 165
Table 4.1a: Minimum Ventilation Air Requirements, CFM, New Buildings1
1 ASHRAE 62.2-2010, p 4
ASHRAE 62.2-2010 Table
45
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22 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
· Assumes two occupants in master bedroom and one each in the other bedrooms. Over this density, increase ventilation by 7.5 cfm/person.
· Whole building, intermittently operating ventilation may be used under some conditions for compliance.
· Ventilation air must come directly from the outdoors.
· Credit is allowed for envelope air leakage in some cases, based on ASHRAE 62.2 and 136.
CFMfan = 0.01Afloor + 7.5(Numberbedroom + 1) + (alternative compliance supplement)
- (Infiltration credit)
A = conditioned floor area; “the part of the building that is capable of beingthermally conditioned for the comfort of occupants.” (ASHRAE 62.2, p.3)
2 Slide content from ASHRAE 62.2-2010
ASHRAE 62.2-2010 Formula
New or Existing Buildings2:
INDOOR AIR QUALITY
23 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
Beyond Fan CFM Requirements
ASHRAE 62.2 2010 includes:
• Spot ventilation requirements as mentioned.
• Attached garages must be adequately sealed from living space to prevent migration of contaminants.
• Clothes dryers must be vented to exterior.
• All duct joints outside conditioned space must be sealed.• Sone rating requirements must be met.
• Branch duct systems must have backdraft dampers.
• Whole-home fan flow must be verified.
• Continuous vs. intermittent fan specifications.Photo courtesy of The US Department of Energy
INDOOR AIR QUALITY
24 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012 eere.energy.gov
Summary
• IAQ depends on the pollutant source strength and the air change rate. Elimination at the source is preferable to confinement, which is preferable to dilution.
• Many pollutants are present in the average home: The air change rate is a function of inside to outside pressure difference, hole size, and hole location.
• A higher air change rate equals better IAQ, and usually higher space conditioning costs.
• ASHRAE 62.2 2010 guidelines are a required standard for new and existing buildings.
• Occupant behavior can have a major impact on IAQ.
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