Thermography

Old buildings, New Technologies

Introduction

• Mr. Snippe• Physics teacher• Math teacher

Index• Introduction of thermography

• How does a Thermal Imager work?

• Problems to be aware of

• Applications

The Imager

FLIR E60bx

-320x240 pixels--20 to 120 °C

- Never touch the lens-Never aim at a spot warmer than 250 °C

Why thermography

• In physical processes heat is always an important factor.

• Sometimes cause, often the result of a process

What is Thermography

Thermography• makes temperature visible• translates temperature into

colours• gives a completely different

view of the environment

Examples

Spectrum• People can see visible light• People can’t see temperature

Elektromagnetic radiation• Every object emits elektromagnetic radiation

caused by its temperature• Sometimes this can be felt, but it can not be seen

Thermographic imaging

• A thermographic camera receives infra-red radiation and translates this into visible light.

Information on the screen

• Spot measuring

• Temperature scale/scope(automatic or set by hand)

• Emissionfactor – Paint = 0,95 – Aluminium = 0,05

• Reflected temperature

Setting the emission factor • One half aluminium

• Other half black paint

• Black part = 0.95Ɛ• Aluminium part = 0,07Ɛ

if the emission factor is not set correctly,the measured temperature is false!!

Reflection in a window

Reflections in other objects

Setting the emission factor

• A surface that does not reflect has = 1Ɛ• A surface that only reflects has = 0Ɛ

The more reflection there is, the more

unreliable the temperature image will be

Trick: Insulation tape has = 0,95Ɛ

Points of attention

• If you do not set the parameters correctly, the imager will not give you the correct results

• Always be aware of thermal reflections

Important• You just see differences in temperature

• Often the temperature difference is an effect from a cause

• Thermography is very useful for a quickscan of problem areas, further research is always necessary

Range of applications

• Making heat transmission visible• Checking wether insulation is effective• Searching for draught, especially in

combination with a blower door test• Searching for leakages• Checking of solar panels

Heat transmission

Checking of insulation

Searching draught spots

Blower door test

Leakages on a flat roof

Checking solar panels

Thermography

Old Buildings, New Technologies