User's Manual
Table Of Contents
- Table of contents
- 1 Warnings & Cautions
- 2 Notice to user
- 3 Customer help
- 4 Documentation updates
- 5 Important note about this manual
- 6 Parts lists
- 7 Quick Start Guide
- 8 Camera parts
- 9 Screen elements
- 10 Navigating the menu system
- 11 Connecting external devices and storage media
- 12 Pairing Bluetooth devices
- 13 Configuring Wi-Fi
- 14 Handling the camera
- 15 Working with images
- 16 Working with thermal fusion and picture-in-picture image modes
- 17 Working with measurement tools
- 18 Fetching data from external Extech meters
- 19 Working with isotherms
- 20 Annotating images
- 21 Recording video clips
- 22 Changing settings
- 23 Cleaning the camera
- 24 Technical data
- 25 Dimensional drawings
- 25.1 Camera dimensions, front view (1)
- 25.2 Camera dimensions, front view (2)
- 25.3 Camera dimensions, side view (1)
- 25.4 Camera dimensions, side view (2)
- 25.5 Camera dimensions, side view (3)
- 25.6 Infrared lens (30 mm/15°)
- 25.7 Infrared lens (10 mm/45°)
- 25.8 Battery (1)
- 25.9 Battery (2)
- 25.10 Battery (3)
- 25.11 Battery charger (1)
- 25.12 Battery charger (2)
- 25.13 Battery charger (3)
- 25.14 Battery charger (4)
- 26 Application examples
- 27 Introduction to building thermography
- 27.1 Disclaimer
- 27.2 Important note
- 27.3 Typical field investigations
- 27.3.1 Guidelines
- 27.3.2 About moisture detection
- 27.3.3 Moisture detection (1): Low-slope commercial roofs
- 27.3.4 Moisture detection (2): Commercial & residential façades
- 27.3.5 Moisture detection (3): Decks & balconies
- 27.3.6 Moisture detection (4): Plumbing breaks & leaks
- 27.3.7 Air infiltration
- 27.3.8 Insulation deficiencies
- 27.4 Theory of building science
- 27.4.1 General information
- 27.4.2 The effects of testing and checking
- 27.4.3 Sources of disruption in thermography
- 27.4.4 Surface temperature and air leaks
- 27.4.5 Measuring conditions & measuring season
- 27.4.6 Interpretation of infrared images
- 27.4.7 Humidity & dew point
- 27.4.8 Excerpt from Technical Note ‘Assessing thermal bridging and insulation continuity’ (UK example)
- 28 Introduction to thermographic inspections of electrical installations
- 28.1 Important note
- 28.2 General information
- 28.3 Measurement technique for thermographic inspection of electrical installations
- 28.4 Reporting
- 28.5 Different types of hot spots in electrical installations
- 28.6 Disturbance factors at thermographic inspection of electrical installations
- 28.7 Practical advice for the thermographer
- 29 About FLIR Systems
- 30 Glossary
- 31 Thermographic measurement techniques
- 32 History of infrared technology
- 33 Theory of thermography
- 34 The measurement formula
- 35 Emissivity tables
10399303;a1
Figure 33.7 Josef Stefan (1835–1893), and Ludwig Boltzmann (1844–1906)
Using the Stefan-Boltzmann formula to calculate the power radiated by the human
body, at a temperature of 300 K and an external surface area of approx. 2 m
2
, we
obtain 1 kW. This power loss could not be sustained if it were not for the compensating
absorption of radiation from surrounding surfaces, at room temperatures which do
not vary too drastically from the temperature of the body – or, of course, the addition
of clothing.
33.3.4 Non-blackbody emitters
So far, only blackbody radiators and blackbody radiation have been discussed.
However, real objects almost never comply with these laws over an extended wave-
length region – although they may approach the blackbody behavior in certain
spectral intervals. For example, a certain type of white paint may appear perfectly
white in the visible light spectrum, but becomes distinctly gray at about 2 μm, and
beyond 3 μm it is almost black.
There are three processes which can occur that prevent a real object from acting like
a blackbody: a fraction of the incident radiation α may be absorbed, a fraction ρ may
be reflected, and a fraction τ may be transmitted. Since all of these factors are more
or less wavelength dependent, the subscript λ is used to imply the spectral depen-
dence of their definitions. Thus:
■ The spectral absorptance α
λ
= the ratio of the spectral radiant power absorbed by
an object to that incident upon it.
■ The spectral reflectance ρ
λ
= the ratio of the spectral radiant power reflected by
an object to that incident upon it.
■ The spectral transmittance τ
λ
= the ratio of the spectral radiant power transmitted
through an object to that incident upon it.
The sum of these three factors must always add up to the whole at any wavelength,
so we have the relation:
Publ. No. T559597 Rev. a554 – ENGLISH (EN) – September 27, 2011 175
33 – Theory of thermography