# Presentation: 127417

## 2001 National Workshop on State Building Energy Codes

***July 16-19******th******, 2001***
***Burlington, Vermont***

## A Systems Engineering Approachto the Design of  

**A Systems Engineering Approach****to the Design of  **
**Energy and Resource Efficient  Homes**

**Presented By:**
**Mark LaLiberte**

## Why is Moisture Important?

- Moisture damage contributes to over 90% of all building and building material failures (ASHRAE)
- Except for structural errors, moisture is the leading cause of building problems costing more than 9 billion dollar annually in the US. (ASTM)
- Moisture-related problems lead the list of top callbacks for most builders.
- Several consumer surveys list moisture problems as a primary concern

## Why is Indoor Air Quality Important?

- In 1994, EPA ranks health risks of 26 leading environmental hazards. The top concern was indoor pollution.
- Indoor air quality has been demonstrated to be many times worse than outdoor air quality
- We spend 90% of our day indoors and 65% of that is in our homes
- Asthma rates have increased dramatically in the last 12 years. Adults up 61%. Children up 72%.

## Trends in Building Technology

- Improved safety
- Healthier indoor environments
- Energy efficiency
- Increased building durability
- Affordability
- Resale value
- Improved comfort
- Intentional ventilation

## The Rules of Building

- Moisture moves from more to less
- Moisture move from warm to cold
- Heat flows from warm to cold
- CFM (air) out equals CFM (air) in
- Drain the rain
- Things always get wet - let them dry
- Heat, air & moisture are one
- It happens at the surface
- Keep clients out of harms way

## Characteristics of Many Older Buildings

- Leaky and drafty
- Poor insulation
- High energy use
- Uncomfortable
- Natural ventilation
- Materials get wet & can sometimes dry

## Characteristics of Many Newer Buildings

- Tighter construction
- Higher insulation levels
- Lower energy use
- More comfortable
- Poor ventilation
- Indoor air quality problems
- Moisture problems

## Characteristics of Improved Buildings

- Very tight construction
- Carefully insulated
- Low energy use
- High comfort level
- Mechanical ventilation
- Good indoor air quality
- Reduced moisture problems
- Durable and low maintenance

## Who Benefits from Improved Buildings?

- Building Owners & Occupants
- Improved comfort & energy savings
- Healthier indoor air
- Building Industry
- Reduced callbacks
- Reduced potential liability
- Society
- Improved building stock
- Better economy & environment

## How do Buildings Work?

- A building is a system of interactive parts.

## Basic Requirements of a Wall System

- Control heat flow
- Control air flow
- Control water & vapor flow
- Control rain penetration
- Control light & solar gain
- Control noise
- Be durable
- Provide strength & rigidity

## The Structure...

- What are the key components of the structure and envelope?

## Systems for Comfort & Security

- Heating equipment
- Cooling equipment
- Humidification & dehumidification equipment
- Other systems
- lights & appliances
- electronics
- security

## The Equipment...

- What are the key components of the buildings equipment and systems?

**Equipment **
**& Systems**

## The People...

- How do people affect performance?

## Common Callbacks in Residential Buildings - Various Climates

- High interior humidity level
- Wet crawl spaces & basements
- High cooling bills
- Uneven temperatures
- Drafts
- Indoor mold
- concentrations
- Insects

## Common Callbacks in Residential Buildings -  Various Climates

- Warped roof plywood
- Window performance - high solar gain
- Window performance - condensation
- Backdrafting of
-    combustion equipment
- Siding failures
- Stucco failures
- Poor air quality

## Problem: Ice Dams, Frost in Attics

- Solution:
- Continuous air/vapor barrier in ceiling
- Sealed fixtures
- All penetrations sealed
- Benefits:
- Reduces heat loss & moisture flow through the ceiling which helps reduce ice dams and frost.

## “You must learn from the mistakes of others. You can’t possibly live long enough to make them all yourself.”Sam Levenson

## Air & Energy Flow...

- Understanding Pathways & Pressures

## How does Air Flow?

- There must be a pathway and a pressure
- Pathways can be direct or indirect
- Through walls & ceilings
- Pressures can be natural or mechanical
- Through leaks, windows or systems

## Air Leakage Pathways

- Direct through walls
- Exterior outlet boxes
- Framing penetrations
- Plumbing penetrations
- Recessed lights
- Framing abnormalities
- Speakers

## Air Leakage Pathways

- Indirect through walls and ducts
- interior outlet boxes
- Framing penetrations
- Plumbing penetrations
- Recessed lights
- Attic duct runs

## Air Pressure in Buildings

- Natural forces
- Wind Effect
- Exterior penetrations allow air to infiltrate and reduce thermal insulation performance
- Wind in must be equaled by air flow out
- Stack Effect
- Temperature difference drives air flow
- Pressure planes establish directional flows (in/out)

## Slide 26

## Slide 27

## Working with Air Handlers

- Consider the system interactions!

## Leaky Ductwork andAir Handlers

## Leaky Supply Ductwork  in Vented Crawlspace

## Leaky Supply and Return Ducts

## Ductwork andAir Handlers in Vented Attics

## Leaky Ductwork andAir Handlers in Vented Attics

## Insufficient Return Air Paths

## Moisture...

***Moisture*****...**

- Understanding the sources & flows

## Forms of Moisture

- Solid
- Snow & ice
- Liquid
- Rain, soil moisture & condensed vapor
- Gas (vapor)
- Evaporated moisture

## Moisture Flows

- Gravity
- Rain & soil pressure
- Capillary
- Material wicking
- Diffusion
- Vapor pressure drive
- Air transport
- Pressure induced flows of moisture laden air

## Diffusion

- Migration of moisture by means of vapor pressure differential
- Occurs in either direction based on climate conditions and interior levels of humidity

## Air Transport of Water Vapor

- Air leakage
- Moisture flow
- 4X8 Drywall
- 70 F
- 40% RH
- 1square inch hole
- Flow quantity
- 30 Quarts of water!!

## Slide 40

## Slide 41

## Slide 42

## Moisture Sources

- External
- Above grade
- Below grade
- Internal
- Building materials
- Occupants
- Processes

## Strategies to Control Liquid Flow through the Building Envelope

- Flashing systems
- Weather barriers
- Rain screens
- Foundation drainage system
- Capillary breaks or non-porous materials

## Strategies to Control Vapor Flow through the Building Envelope

- Vapor retarders
- Air barriers
- Manage interior humidity levels
- Manage air pressures

## Strategies to Control Moisture inside the Building

- Source control
- Vent clothes dryers
- Vent bathroom moisture
- Moisture removal
- Dehumidification
- Ventilation

## Strategies to Control Condensation inside the Building

- Manage interior humidity levels
- Occupant education
- Ventilation
- Control surface temperatures
- Increase insulation
- Use warm edge windows
- Avoid thermal bridges

## Solutions to Common Problems

## AnnualRainfallMap

## Indoor Air Quality...

- Understanding sources and solutions

## The Nature of IAQ & Health

- Health Impacts
- Acute
- Chronic
- Occupant Sensitivities
- Age
- General health
- Duration of exposure
- Level of pollutant concentration

## Fact:

- 1 in 3 people have an allergy severe enough to seek medical attention on a routine basis.
- —American Lung Association

**Notes:**
Health

## Fact:

- Allergies and asthma cost Americans $10 billion/year in  medical visits, $51 million in prescriptions and $1.5 billion in over the counter relief.
- — American Demographics & American Lung Association

**Notes:**
Health

## Pollutant Sources

- External
- Outdoor air
- Attached garages
- Soil gasses
- Exterior applied insecticides

- Internal
- Building materials
- Combustion equipment
- Occupant
- Activities
- cooking
- cleaning
- hobbies
- Furnishings
- Mold & other biologicals

## Pollutant Removal Strategies

- Source Control
- Remove the pollutant
- Dilution
- Mixing
- Point source removal
- General ventilation
- Filtration
- Spot
- General

## Ventilation Strategies

- Consider the options and methods to source point and volume ventilate
- Use quiet, reliable systems

## Ventilation Strategies

## Ventilation Strategies

## Advantage to Homeowner

- Improve Health and Safety
- Provide ventilation & filtration strategies
- Exercise source control** **
- Increase Energy Efficiency
- Increase affordability
- Improve comfort
- Improved Durability
- Reduced maintenance

## System Improvements

-   Structural or Framing Systems
-   Building Enclosure (Air Flow Control)
-   Insulation Systems
-   Mechanical Systems
-   Airflow Distribution Systems

## For Additional Information...

- Journal of Light Construction
- Fine Homebuilding
- www.sheltersupply.com
- www.eeba.org
- www.healthhouse.org
- 888-Star Yes:  for Energy Star Homes Info.

## Thank You!