thermography and air barriers

Infrared Thermographys Use in Air Barrier Testing

Scott Wood

Scott Wood Associates, LLC

www.buildingsciencethermography.com

Large Building Air Leakage Training School Sept 2010Gig Harbor,

Washington

Consulting and Training

Excellence


Why Thermography?

Infrared Thermography technology allows

the observer to visualize air leakage.

Scott Wood Associates, LLCViewing Air leaks

Traditional smoke generators or

Infrared Thermography


Outline

What is Infrared - Electromagnetic Spectrum

Infrared Cameras - Minimum Specifications

Infrared Certifications/Training - Building Science

Thermography

What the cameras sees - Emission, Reflection, Transmission

Building Science and Thermography - Heat, Air, Moisture


Outline

The building barriers - HAMM

Heat: How is heat transfer - Radiation, Conduction,

Convection

Air: Air infiltration observation - Infrared thermography

Why use of Infrared thermography - Infrared

Thermography Testing

Moisture: How to detect moisture - Infrared thermography

and moisture meters

Discussion


Infrared Radiation

Electromagnetic Spectrum

13 m1 m0.4 0.7 2 m 5 m 10 m

Thermal Infrared

Visible light

1 km100 m10 m1m100mm10m1mm100m10m1m0.1m0.01m10 1 0.1

X-rayGammaMicro-wavesUV IR-Infrared Radiowaves

MW LWSW


Visible Spectrum

Infrared Spectrum


Infrared Cameras


Resolution and Thermal Sensitivity

Detector Resolution

Consider 380x240, Minimum 120x120The higher the numbers the better the image clarity

Detector Thermal Sensitivity

Consider 50mK (0.05C), Minimum 100mK. The lower the number the more patterns the camera can detect.

640x480380x240


Multiple Images

1040x240

790x240


Camera Considerations

Small, Light weight, Rugged

Easy to operate

Flexible Image Storage

many images

JPEG verse Proprietary that requires

special software


Condition Monitoring or Predictive Maintenance:

Level I, II or III

Most US training organizations use ASNT-SNT-TC-

1A recommended practice guidelines that are set by

the employers written practice. Employer Certified

In Europe The British Institute of Non-Destructive

Testing (BINDT) provides application specific training

and certification at the Level II (mechanical, electrical,

civil).

Third Party Certified

Training and Certification


Both the US ASNT-SNT-TC-1A recommended practice

guidelines and the BINDT Level II civil certifications fail to

provide significant training in building sciences or building

specific applications.

A Level I or II certification and

knowledge and training in building science, building

materials and testing procedures

is a requirement to properly interpret building thermograms



Some say ASNT Level II for large building application

BEST: A building application specific level I (and or II) based

course with building sciences

Especially the Certified Building Science Thermography

course by ITC / BSI

Good discussion: IEA Energy Process Assessment Protocol

Appendix G, Use of Thermography in Building Energy

Assessment



The Infrared Camera converts Invisible

Infrared radiation into Visible radiation


Emitted: radiation of the objects being observed

Reflected: radiation reflected off the surfaces

Transmitted: radiation passing through a non-opaque

object

78.8F

85.5F

80

82

84

Different Radiation Sources


78.8F

85.5F

80

82

84Transmitted

radiationEmitted radiation

Reflected radiation

The Camera sees all the infrared radiation

from the material.

Sometimes creating an

image that is difficult to

interpret


Reflection


The IR camera

can see through

some materials.

Transmittance


Emitted Energy

Emitted:

The IR camera must

see the radiation from

the surface of the

material to calculate a

temperature.

A higher temperature due to

ReflectionRemove Reflection

More accurate temperature

Gig Harbor,

Washington Scott Wood Associates, LLC

Building Science

Heat, Air & Moisture Flow

Through the Building

Heat

Air

Moisture


Building Science

Is the study of:

heat flow

air flow

moisture flow


Building Science & IR

Building Science & IR:

heat flow IR detects heat

air flow IR detects convection

moisture flow IR detects evaporation


Building Enclosures

The building enclosure has four functions.

In order of importance, they are:

1. Rain control

2. Air control

3. Vapor control

4. Thermal control


Why should we be concerned?

Typical American spends 65% Inside

68-76F and 30-60%RH

Comfort Zone


US Building Energy Use


Energy Consumption

Buildings use 71% of the US electricity and consume 40% of the total energy consumed annually in the US.

Our nations 81 million buildings consume more energy than any other sector of the U.S. economy, including transportation (29%) and industry

Buildings produce nearly half of all greenhouse gas emissions.


To have comfort and energy reduction,

Protect the Building from Environmental

Interactions

By blocking

Heat flow

Air flow

Moisture flow


HAMM is the acronym used for the barriers or retarders needed to protect a building against the environment and energy loss.

H Heat or Thermal Barrier

A Air Barrier

ML Water Barrier (Liquid Moisture)

MV Vapor Retarder (Gaseous Moisture)

HAMM

Gig Harbor,


blocks heat transfer, keeping

the heat in during cold days

and

out during hot days.

or Thermal

Barrier

Heat

Air

Water

Heat


Minimizes buildings exposure to degrading heat

Provides for better comfort

Reduces heat loss or gain, reducing energy consumption

A Heat Retarder or Thermal Barrier


Radiation

Conduction

Convection

A Heat Retarder or Thermal Barrier

Must block three modes of

heat transfer:


Radiation

The sun feels hot!


Conduction

The sand feels hot when touched!


Convection

The wind feels hot!


To block Radiation we shade the building surfaces or apply radiant barriers

Radiation

Scott Wood Associates, LLCRadiation

Shading


Radiant Barriers

Radiation


To block Conduction we use low

conducting materials.

Conduction

Scott Wood Associates, LLCConduction

Missing Insulation


Outside Looking In

Conduction

Metal Framing (Thermal Bridging)


Metal Framing (Thermal Bridging)

Inside Looking Out

Conduction

Scott Wood Associates, LLCConduction

Failed Double Pane Window

Scott Wood Associates, LLCWindows

Failed Double Pane Window


To block Convection we stop

Fluid (Air) movement.

Convection


An air barrier system on a building blocks convective heat transfer by blocking air (fluid) movement through the building.

Convection

Gig Harbor,


stops air flow through the

building enclosure

Barrier

Heat

Air

Water

Air

HeatConvection: heat movement due to

fluid (air) movement


An Air Retarder (Barrier)

Isolates the indoor environment

Reduces heat loss or gain (convection), reducing energy consumption

Minimizes the amount of air transported moisture

Improves indoor air quality

Improves acoustical isolation

Provides for better comfort

Sustainable, durable buildings


It is an excellent tool to locate air

leaks.

USACE Air Barrier Testing Protocol

Requires it

Why use Thermography for Air

Testing?


U.S. ARMY CORPS OF ENGINEERS

AIR LEAKAGE TEST PROTOCOL FOR

MEASURING AIR LEAKAGE IN

BUILDINGS

Test the completed building using Infrared Thermography testing.

in accordance with International Organization for Standardization (ISO) 6781:1983 and ASTM C1060-

90(1997).


Standard Practice for Thermographic Inspection of

Insulation Installations in Envelope Cavities of Frame

Buildings

Written in 1990 with reapproved in 2003

ASTM C1060


Minimum T-Minimum temperature difference (T) of 10C between interior and exterior surface 4 hours prior to survey

No direct solar radiation

Avoid wind for exterior surveys

Mottled looking (not uniform) or variation in the

temperature of the thermal patterns

Framing should be visible

ASTM C1060 Describes proper qualitative thermal

inspections of building walls


Insolation and shadowing

Shadow line

screws/s tud cool

screws/s tud warmer

19.1

34.1 C

20

22

24

26

28

30

32

34


Air Infiltration?

75%

Air

Scott Wood Associates, LLCLost Energy/Comfort

Thermal bridging

(Conduction)

Heat Patterns

Air Infiltration

(Convection)

(Radiation)


Warm Air Infiltration

Lost Energy/Comfort


Cold Air Infiltration


Warm or Cold, depends on the air


Cold & Warm Air Infiltration


Interior Room Pressure Difference


Windows

Good windows contributes 1 to 5 cfm per window


Exterior

Cladding

Windows

Joints

Gig Harbor,


Prevents water from reaching

the interior of the building

Barrier

bulk

Heat

Air

MoistureMoisture


Locating Moisture

Infrared thermography

Moisture Meter


Locating Moisture

Wet Wall Board


Locating Moisture

Wet Ceiling, Walls and Floor


Locating Moisture

Hard to Spot Leak

Scott Wood Associates, LLCDay verse Night

Night 8:54pm

Roof Moisture

Day 11:22am

Scott Wood Associates, LLCPerformance Testing

Scott Wood Associates, LLCFailed Test


Water testing


Water testing

Pre Water Test Post Water Test


Water testing

Infrared Thermographys Use in Air Barrier Testing

Scott Wood


www.buildingsciencethermography.com

Large Building Air Leakage Training School Sept 2010Gig Harbor,

Washington

Consulting and Training

Excellence

Questions -Discussion

thermography and air barriers

Documents

moisturescott wood associates

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building thermogramstraining

use of thermography

thermography heat

large building applicationbest

infrared thermographys

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