Indoor Air Quality Diagnostic Tools for Tribal Professionals Building Science Review 1

Building Science? The practical purpose of building science is to help us understand and optimize the dynamic “Building Ecosystem” for occupant wellness and building performance. Interactions between: Building and systems (Structural & Mechanical), Environment, and Occupants. 2

Today’s Webinar Understand how the home responds as a “living system” Hone your detective skills; what to look for during assessment How to interpret what observations and measurements will tell you Will NOT provide a comprehensive understanding design and construction details Reviews Building Science principles important to healthy, comfortable, energy efficient homes. 3

Indoor Air Quality Diagnostic Tools for Tribal Professionals - Course Approach Assumes that you have a good understanding of IAQ basics – Sources – Health Effects – Actions to Improve IAQ Assumes you have a basic understanding of homes in your communities – IAQ and Health: What kinds of Concerns you are trying to address – Environmental: Climate, Weather, Site conditions – Structural: Typical Design & Construction for your area – Operation & Maintenance - Typical problems; potential solutions 4

Diagnosing a Home – What does the Assessment Consider? The Assessment examines 3 factors that determine a home’s “Healthy and Sustainable” status: – Environmental – Occupant related – Building/Structural 5

Environmental How the house interacts with the environment: Temperature Wind Precipitation Ambient Air Quality Soil Moisture Soil Gas Solar Gain 6

Occupant Related 7

Building/Structural How the house operates as a system: 8

Climate Driven Temperature Wind Precipitation 9 Humidity Solar Gain

Site Driven Geology & Soil Wind - Orientation & Protection Drainage Solar Gain Landscaping 10

Design Driven How the house is designed and built will determine how it interfaces and responds to the environment Foundation Type(s) Construction & Materials Size & Floor plan Mechanical Ventilation 11

Occupant Driven How we Operate and Maintain the House Heating and Cooling Exhaust Fans Water Usage Landscaping Pest Management Maintenance of House Envelope Sources brought into house Occupants as Sources 12

Building Science Principles Heat Flows from Warm to Cold Moisture Flows from Warm to Cold Moisture Flows from More to Less Air Flow from Higher Pressure to Lower Pressure Gravity Acts Down 13

Air Flows from Higher Pressure to Lower Pressure 14

Moisture Flows Downhill and from More to Less BulkCapillaryVapor Significantly more water moves through air leakage than by diffusion 15

Heat Moves from Warm to Cold 16

Heat Moves from Warm to Cold 17

Warm Air Rises Remember … heat moves from warm to cold 18

Equilibrium / Sources and Sinks House and interior spaces will attempt to equilibrate with the surrounding environment – driven by temperature, pressure, and concentration differential Energy, Water, and Pollutants move from Sources to Sinks (e.g. air, building materials, furnishings) We employ structural, mechanical, and passive approaches to manage temperature, pressure, moisture, and sources 19

Contaminant Transport Convective Transport: Movement of contaminants by air flow (pressure differences) Diffusion: Transport w/out air movement -- (diffusive movement is from higher to lower concentration) 20

Required for Air Movement & Ventilation Driving Mechanisms Need Holes and Pathways for Air & Contaminants to Move Openings or Leakage Paths + 21

Trapped air keeps water from entering the cup inverted into a tub of water 22

Water pressure (Driving Force) moves air through the Opening (Air Leak) in the cup 23

Infiltration Exfiltration Air Flow 24 Controlled Air Flow Uncontrolled Air Flow

Driving Mechanism Air movement is a result of pressure differences – from higher to lower pressure Pressure differences are a result of natural and/or mechanical forces Pressure differences interact with leakage to force air between: – Indoor Zones – Indoor / Outdoor Air – Indoor / Soil 25

Pressure: Driving Force for Airflow Sources of Pressure Differentials ( P ) Wind Heat – Neutral pressure plane Fans – Exhaust fans – HVAC Fans – Radon Control System Duct leakage to outside Air flow Imbalance – Imbalanced Supply and return – Door Closure 26

Natural Driving Forces Stack Effect Temperature difference causes warmer, indoor air to be less dense – more buoyant – creating pressure difference 27

Natural Driving Forces Wind Effects 28

Mechanical Driving Forces 29

Neutral Pressure Plane 30

Ventilation A system or means of providing fresh air The process of "changing" or replacing air in any space to provide good Indoor Air Quality Used to: – Introduce outside air / replenish oxygen / reduce carbon dioxide – Control temperature – Circulate air and prevent stagnation – Remove excessive moisture – Remove unpleasant odors – Remove smoke and particles Natural Ventilation is the ventilation of a building with outside air without the use of a fan or other mechanical system Mechanical - Controlled - ventilation is used to control indoor air via dilution or replacement with outside air. The V in HVAC 31

Climate Zones 32

Ventilation “Devices” How do the following impact ventilation? – Windows & Doors – Unplanned leaks – Passive Vents – Heat Recovery Ventilator – Energy Recovery Ventilator – Exhaust Fans – Radon Mitigation System – Filters – Ceiling Fans 33

Examples of Mechanical Driving Forces HVAC fans and blowers, exhaust fans, clothes dryers Bathroom FansHVAC FansKitchen HoodsClothes Dryer 34

Holes and Pathways for Air Flow Designed Holes – Flues, vents, chimneys, fans, HVAC systems, Windows & Doors Undesigned Holes – Attic, Ceilings, Walls, Floors – Should be air-sealed and blocked to control spread of draft, smoke and fire (Weatherization) 35

Air Leakage 36

What goes out Must come in Insert people here 37

Examples of Openings (usually intentional) Open Windows & Doors Ducts Chimneys/flues Passive Vents Transoms Transfer Grilles Door Undercut 38

Examples of Openings (usually unintentional) Plumbing Outlets & Switches Recessed Lights Ceiling Penetrations Electrical 39

More Unintended Leakage Construction joints (windows/doors, walls, floors) Construction openings (bypasses, plumbing block-outs, wall/floor/ceiling cavities, utility chases) Ducts Wall/floor air leak Leaky /disconnected ductsWall/Attic leak 40

Air Movement and Pressure Differences Chemical SmokeDigital Micromanometer 41

Pathways Unplanned air flows 42

Our homes are full of holes “unplanned pathways” 43

Unplanned air flows 44

Disconnected Duct In Crawl Space 45

Think... bathrooms, kitchens, utility crawlspaces, hobby/workshop areas, attached garages “Clean” “Dirty” Outside Do we want air from these areas in living and sleeping space? 46

Backdrafting Spillage of flue gases from combustion equipment into the home Caused by Depressurization – Mechanical – Environmental Can be Deadly 47 Carbon Monoxide (CO) is odorless, colorless, and tasteless

Heat Transfer Conduction – Transfer of heat by direct contact Convection – Transfer of heat energy through a moving fluid Radiation – Transfer of heat energy through empty space 48

Heat Related Factors U Factor – How quickly heat flows through a material – Higher the U Factor, Faster the heat flows R value – Ability of a material to resist heat flow – Inverse of the U factor Heat loss – Heat Loss = [(Area) x (∆T)]/R Value 49 Heat will transfer without airflow, Insulation will reduce heat transfer of airflow

Insulation Faults Gaps – cavities not adequately filled Voids – Areas without insulation Compression – should be at recommended density Insulation/Air barrier Misalignment- allows heated air to bypass the insulation Pressure imbalances (+ and -) cause air to cross the insulation. 50

51 Moisture Dynamics

Moisture Flow Bulk Moisture by Gravity – Rain, Snow, Groundwater – Direct away from the home – Close holes Capillary Action by Material Wicking – Provide capillary “breaks” Air Transported Moisture – Keep moist air out of the building – Exhaust moist air – Prevent cold spots Vapor diffusion by Vapor pressure – Use of vapor Retarders, Correct placement (FL vs.. MN) 52

53 Condensation /Dew Point The amount of moisture that air can hold increases directly with temperature Air that is cooled to the limit of its moisture carrying capacity releases the vapor as droplets. Condensation can occur when warmer/humid air contacts cooler surfaces The temperature where condensation occurs is the Dew Point Temperature

54 Climate and Humidity

55 Moisture Dynamics Vapor Transport via DiffusionVapor Transport via Bulk Transport (Airflow) Bulk Transport of water vapor accounts for the majority of moisture movement

Indoor Humidity 56

Permeability of Building Materials Vapor Impermeable – Glass, Poly, Foil Semi Impermeable – Kraft Paper, Oil-based Paint, Vinyl Wallpaper, Extruded Polystyrene >1” Vapor Semi Permeable – Plywood, OSB, Latex Paint, Polystyrene <1” Vapor Permeable – Fiberglass/Cellulose insulation, Unpainted Gypsum Board, Masonry, House Wrap Building America Best Practices Series: Volume 4 –…..Mixed-Humid Climate Version 1, 9/2005 Design-p13 57

Physical (Structural Barriers) Structure to Inside, Control layers to outside Rain (Water) Control Layer Air Control layer Vapor Control layer Thermal control layer Cladding – Aesthetics – Physical Protection – UV Protection Walls need to breathe - No vapor barrier on inside 58

Roof to Walls to Foundation – Water to Water to Water – Air to Air to Air – Vapor to Vapor to Vapor – Thermal to Thermal to Thermal Continuity at Penetrations (Windows, Doors, Vents) Continuity of Control layers 59

Contributors to a Wet House Wet foundation Structural Leaks Plumbing Leaks Capillary movement High Humidity Deficient Insulation (condensation) Combustion Resident Activities 60

Building Science Review Scenario 1 Temp °F% RH ∆ P Relative to LR Living Room 7280= Attic Basement Outdoor Ambient Soil

Building Science Review Scenario 2 Temp °F% RH ∆ P Relative to LR Living Room 7250= Attic Basement Outdoor Ambient 98 - Soil

Building Science Review Scenario 3 Temp °F% RH ∆ P Relative to LR Living Room 7015= Attic Basement Outdoor Ambient Soil