Use of Infrared Thermography for Building Inspection

Transcription

1 Use of Infrared Thermography for Building Inspection Seminar on Building Diagnostic and Inspection Testing & Certification Association of Engineering Professionals in Society Ltd K.K. Lee, Kenneth

2 Introduction Theory Equipment Survey Conclusion

3 Definition Infrared thermography is a science of obtaining and analysis of thermal data or information by non-contact thermographic equipment.

4 Definition Real time Capture fast moving targets Capture fast changing thermal patterns Non-contact Remote sensing Keep out of danger Does not affect the target Two-dimension Comparison between areas Thermal patterns can be visualized for analysis

5 Spectrum

6 Emissivity

7 Kirchhoff s s Law Emissivity Reflectivity Transmissivity

8 Opaque

9 Reflective Object

10 Transmissive Object

11 Conduction Q = conductive heat transfer (J) t = time (s) A = area (m 2 ) L = thickness (m) T 1 T 2 = ΔT (K or C) hot cold k (or λ) = thermal conductivity (W m -1 K -1 ) Q/t = heat flow (W) Q/t = k x A x (T 1 T 2 ) / L

12 Conduction

13 Thermogram

14 Thermogram

15 Thermogram

16 Thermogram

17 Thermogram

18 Thermal Imager

19 Equipment System Compact and lightweight From shouldersupported to hand-held video camera Lenses Focus Detector Electrical signal Amplified Processed Displayed Eyepiece LCD viewer Memory card Digital photos

20 Basic Performance

21 Basic Performance

22 Basic Performance

23 Lenses Standard lens normally 25 (FOV) Telephoto Less than 25 Fewer things can be included High rise building inspection Wide-angle Greater than 25 More things can be included E&M inspection in limited space

24 Lenses

25 Operation Focus Range Span Auto-ranging Level Palettes Spot Area Isotherm Emissivity Distance Ambient temperature Reflected temperature

26 Software

27 Quantitative Analysis

28 Problems Workmanship Material Weather Application method Aging Regular checking Environment Usage Design Accident Maintenance record

29 Target Building External or internal Shape Size Distance Materials Texture Thickness of finishes Stains

30 Training In-house training Manufacturer tutorial Regional agent tutorial Infrared training organizations Academic background Oversea seminars

31 Equipment FOV and IFOV Thermal sensitivity Thermogram resolution LCD display and its resolution Detector Temperature range Spectral range Thermal fusion Lenses Picture in picture Accuracy Memory File format Weight and size Environmental data Battery Back up Accessory

32 Equipment Infrared camera Lenses Tripod Digital camera Distance measuring device Telescope Anemometer Thermocouple Thermo hydrometer Goniometer Hammer/tapper Range finder Personal protective equipment

33 Methodology International standards National standards Regional standards In-house method Governmental requirements

34 Environment Time Day time Evening Peak time Non-peak time Availability of access Weather Sunny After Raining Wind Cloudy Season Summer Winter

35 Environment Background noise Metallic panel Glass cladding Obstacles Advertisement Road sign Lighting pole Trees scaffolding Heat sources Air conditioner Fluorescent lighting

36 Environment Cold sources Leakage of conditioned air Moisture Activities Cold storage Restaurant Crematorium Hospital Structural

37 Limitation Surface texture Temperature Shape IR camera use Emissivity Viewing angle

38 Conclusion Application of infrared thermography is common in external wall inspection (qualitative). It is a good option to have a preliminary condition of building external wall. Assist with other tests is suggested such as tapping, pull-off tests (tile, mortar, coating), etc. Canopy Quantitative analysis

39 Thank You