1 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010 eere.energy.gov

Indoor Air QualityWEATHERIZATION ENERGY AUDITOR SINGLE FAMILY

WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010

2 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010 eere.energy.gov

By attending this session participants will:• Learn about the factors effecting IAQ.• Understand the role moisture plays in IAQ.• Learn about moisture movement.• Learn pollutant remediation techniques.• Understand the requirements of ASHRAE 62.1989

and ASHRAE 62.2 2007.

Learning ObjectivesINDOOR AIR QUALITY

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• Moisture• Stored Toxic Materials• Carbon Monoxide (CO)• Radon• Sewer Gas• Other

IAQ, Moisture and VentilationINDOOR AIR QUALITY

Photo courtesy of The US Department of Energy

4 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010 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

INDOOR AIR QUALITY

5 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010 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

6 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010 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 of less.

INDOOR AIR QUALITY

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What Determines IAQ?INDOOR AIR QUALITY

Photos courtesy of The US Department of Energy

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Pollutant Action Tree

Source• Eliminate• Encapsulate• Dilute

Driver• Eliminate • Weaken

Path• Eliminate• Block

INDOOR AIR QUALITY

Photo courtesy of The US Department of Energy

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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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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

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How is Natural Ventilation Calculated?

WIND DIRECTION

positive pressure

negative pressure negative pressure

positive pressure

INDOOR AIR QUALITY

12 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010 eere.energy.gov

Building Tightness Limit, Building Tightness Limit “a”, & Minimum Ventilation GuidelinesINDOOR AIR QUALITY

Photos courtesy of The US Department of Energy

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The amount of air leakage across any barrier is dependent on:

• Hole size

• Hole type

• The pressure differential

MVG Theory

Resulting in turbulent flow vs. linear flow vs. “drag”/friction

Long/narrow vs.big/round

Thick vs. thin surface

“Hairy” vs. smooth bore

INDOOR AIR QUALITY

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Random Hole Type?

INDOOR AIR QUALITY

Photos courtesy of The US Department of Energy

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Neutral pressure plane

Random Size & Distribution?INDOOR AIR QUALITY

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Tiny, deep bore, crack type holes through multiple layers located where wind and stack effect are minimal.

What’s Left?INDOOR AIR QUALITY

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ASHRAE 62.1989INDOOR AIR QUALITY

Photos courtesy of The US Department of Energy

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ASHRAE 62.2-2007INDOOR AIR QUALITY

Photos courtesy of The US Department of Energy

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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 R.J. Karg of R.J. Karg, Associates

ASHRAE 62.2-2007 Table

45

INDOOR AIR QUALITY

20 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010 eere.energy.gov

• Assumes two occupants in master bedroom and one 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.

Qfan = 0.01Afloor + 7.5(Nbedroom + 1)

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 R.J. Karg of R.J. Karg, Associates

ASHRAE 62.2-2007 Formula

New or Existing Buildings2:

INDOOR AIR QUALITY

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• Use ASHRAE 62.2-2007.• When using ASHRAE 62.1989:

– Install the MVG recommended fan capacity.

– Use client education on running fans for moisture control/mitigation to establish fan run time.

What are Auditor’s Choices?INDOOR AIR QUALITY

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Installing FansINDOOR AIR QUALITY

Photo courtesy of The US Department of Energy

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Upgrading ASHRAE 62.1 Installations to 62.2

Install Fan Control Measure fan flow

INDOOR AIR QUALITY

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Air-to-Air Heat ExchangerINDOOR AIR QUALITY

Photo courtesy of The US Department of Energy

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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 62.1 and 62.2-(2004 or 2007) guidelines are acceptable.

· Quality fans installed and used properly help ensure healthy IAQ.

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