Glossar

Terminology and Definitions

Accelerated Outdoor Weathering
Increasing one or more influencing parameters by sun as the source of irradiance.

Albedo
One part of radiation reflected by a surface.

Ambient Air Temperature
The existing temperature of the air or of an object in thermal equilibrium with the surrounding atmosphere.

Azimuth Angle
Angel of a plane to the horizon.

Blue Wool
Dyed-wool with eight grades, each step in the series representing a doubling of light fastness, used as a calibration and verification tool in test methods.

Black Box
Black painted aluminium box with an open top where the flat test specimens to be exposed constitute the top surface of the box. Test specimens are hold with mounting strips. The top surface of the box is completely filled all time. Any blank spaces on the top surface must be occupied by black “dummy” panels to maintain correct operating conditions.

Black Box Under Glass
Glass-covered enclosure or cabinet of any convenient size which is constructed of corrosion-resistant metal and is enclosed to prevent ambient air from circulating over the samples. Exterior non-glass surfaces are black painted and interior ones are not painted.

Black Panel Thermometer
A temperature measuring device consisting of a metal panel, having a black coating that absorbs all wavelengths uniformly, with a thermally sensitive element firmly attached to the center of the exposed surface. It is used to control a laboratory weathering device and to provide an estimate of the maximum temperature of samples exposed to a radiant energy source.

Black Standard Thermometer
Temperature measuring device which consists of an isolated black plastic to absorb all wavelengths of radiation uniformly, with a thermally sensitive element firmly attached on the center of the unexposed surface. It is used to control specimen temperature in air cooled xenon arc devices.

Climatological Types
Main parts to significant different recurring weather patterns. In weathering, several distinct climatological types are used to evaluate the atmospheric durability of materials within any single climatological variation, at a specific geographic location.

Corrosion
Chemical or electrochemical oxidation of a surface of metal which can result in loss of material or accumulation of deposits.

Dewpoint
Temperature where the water in the air starts to condense

Durability
In weathering, a measure of the retention of original condition and function of a material after exposure to a specified set of conditions.

Emissive Power or Radiant
Rate at which radiant energy leaves a surface per Self Exitance, W/m² unit area only by emission.

Exposure
The act of subjecting a test specimen to test conditions.

Exposure Angel
The tilt form horizontal of the test specimen or any other exposed material, or both.

Exposure Backed
A technique of weathering to mount exposed test specimens onto a solid backing material of sufficient strength to hold the specimen. If the specimen and the backing are contacted directly, the backing material mustn’t contaminate the specimen. When two materials are intimately joined to form one composite, the materials below the top surface are not considered as a backing.

Exposure, Open-Backed
A technique of weathering in which the test specimens are exposed such that the portion of the specimen being evaluated is open to the effects of the weather on all sides.

Fluorescent Ultraviolet Lamp
Low-pressure mercury arc irradiance lamp to transform higher wavelengths UV by a phosphor. The spectral power distribution of a fluorescent lamp is determined by the emission spectrum of the phosphor and the UV transmittance of the glass tube.

Fresnel-Reflector System
Flat mirrors in form of array to reflect onto a target, the illuminated area of which simulates the size and shape of the flat mirror. Such an array simulates the ray-tracing of a parabolic through of the same aperture angle.

Intensity
Luminous or radiant flux which is radiated by a. source

Irradiance
Incident radiant energy rate on a surface per unit area (W/m²).  

Irradiance, Infrared
Wavelengths of monochromatic components not visible and for that less than 1 mm.

Irradiance, Ultraviolet
Wavelengths of monochromatic components not shorter than there visible radiation.

Irradiance, Visible
Radiation causing a visual sensation. The limits very between 400 nm and 768 nm.

Laminate
A composite material made by adhering two or more layers of the same or different materials.

Light
Part of solar radiation which is visible for the human eye.  

Masked Area
A portion of an exposed specimen which is covered by the exposure rack or other means to have no contact with the light.

Metal Halide Lamps
lamps that emit radiation generated by a large number of different chemical components in the arc plasma. They offer a close match to sunlight and are an efficient light source with low infrared heating effects.

Nanometer
Unit of length equal to 10 -9 m.

Open Flame Sunshine Carbon Arc
Light Source which produces an arc across a pair of copper coated carbon rocks filled with rare earth elements intended to produce a specific spectral power distribution. The carbons are open to the atmosphere and is often surrounded by a glass lantern arrangement, which helps by the modification of spectral power distribution received by the specimens.

Photodegradation
Photochemically induced changes in the condition of the material.

Photodetectors
Devices for converting radiant or luminous flux into an electric current proportional to it.

Primary Standard
A standard whose calibration is determined by measurement of parameters usually different from the parameter for which it will be used as a standard.

Pyranometer
Instrument to measure hemispherical solar beam + diffuse radiation.

Pyrheliometer
Instrument to measure solar radiation by using a collimated detector.

Radiant Energy
Energy uses photons or electromagnetic waves with different length to travel through space.

Radiation, Actinic
The spectral region(s) of a light source responsible for the photo degradation of a particular material.

Radiation, Direct
Solar radiation which is not scattered by going from the sun through atmosphere.

Radiation, Diffuse
Solar radiation which has changed its way by scattering in the atmosphere. (Also as sky radiation or solar sky radiation)

Radiation, Long Wave
Radiation originating from sources at temperatures near ordinary ambient temperatures and for that wave lengths greater than 3 µm. The radiation is emitted by the atmosphere or by any other body at ordinary temperatures.

Radiant
Detection and measuring instrument for radiant energy

Radiosity or Radiant, Exitance, W/m²
The rate combining, emission, reflection and transmission to leave a surface, per unit area.

Reference Material
Known performance material.

Reference Specimen
Part of an exposed reference material.

Relative Humidity
The ratio of the actual pressure of existing water vapour to the maximum possible pressure of water vapor in the atmosphere at the same temperature, expressed as a percentage.

Sample
Parts of a larger unit or material quantity collection that servers to provide information that can be used as a basis for action on the lager quantity.

Secondary Standards
Everything else than primary standards.

Solarisation
Transmittance, reflectance or absorptance property material change as result of sunlight or other light exposure.  

Solar Radiant Exposure
The incident energy per unit area on a surface, found by integration of irradiance over s specified time period (J/m²).

Spectral Power Ditribution
Different energy kind due to the source over the wavelength span of the emitted radiation.

Spectrum
Spatial arrangement of electromagnetic energy in order of wavelength.

Standard Reference Material (SRM)
A weathering reference material having well documented weathering degradation properties that have been certified by a recognized standards agency or group and that are identical when exposed to identical test conditions.

Temperature, Dry-Bulb
Surrounding air temperature.

Temperature, Wet-Bulb
The equilibrium temperature of a liquid vaporizing into a gas.

Test Specimen
A special sample portion to be tested.

Tilt Angle
The angle between the horizontal and the plane of the test fixture, glass frame, or sensory instrumentation.

Time-of-Wetness
All the time in hours when the surface is wet.

Wavelength
Distance between two phases on adjacent waves points which are measured along the propagation’s line. Determined the colour of light, the visible light is between 400 – 800 nm.

Weathering Behind Glass
Weathering technique where the test specimen is exposed in a glass-covered frame constructed of wood, metal, or other satisfactory material that protects the specimen from the effects of rain und weather. If the Frame is open and at the back or sides surrounding air can circulate over the specimens.

Weathering, Direct
Test specimens are exposed to all prevailing elements of the atmosphere.

Weathering, Natural
Materials are outdoor exposed under concentrated sunlight to assess the effects of environmental factors on various functional and decorative parameters of interest.

Weathering Reference Material
A reference material whose weathering degradation properties are well-documented and repeatable when exposed to identical test conditions.

White Panel Temperature
Temperature measured on a metal panel with a with low-heat conduction coating and a thermal sensitive element firmly attached to the center of the exposed surface.

Whit Standard Thermometer
Measures its special temperature at the same plane and provides white low-heat conducting samples information during exposure.

Visual Evaluation
Visual interpretation of evaluated material made by an experienced observer.

Xenon Arc
A light source produced by a high-intensity electrical current through a tube containing low pressure xenon gas.

Zenith Angle
Φz The angle subtended by a vertical line to the zenith (i.e, the point directly overhead) and the line of sight to the sun.

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