UV light is responsible for almost all photodegradation of durable materials exposed outdoors. The QUV tester’s fluorescent lamps simulate the critical short-wave UV spectrum and reproduce the physical property caused by sunlight. Several different types of UV lamps are available for different applications, and optical filters are not required. The Q-SUN family of xenon-arc testers uses xenon-arc lamps to produce the most realistic reproduction of full spectrum sunlight including UV, visible light, and infrared radiation. For many materials, exposure to the full spectrum is necessary to provide an accurate simulation, especially when testing for color change and lightfastness. However, xenon light must be properly filtered to achieve the appropriate spectrum for each particular application. Differences in spectra may affect both the speed and type of degradation.
QUV Ultraviolet Fluorescent Lamps
All of the QUV accelerated weathering tester’s lamps emit mainly ultraviolet (UV) rather than visible or infrared (IR) light. All are electrically equivalent to an ordinary 40-watt fluorescent lamp. However, each lamp type differs in the total amount of UV energy emitted and in its wavelength spectrum. Fluorescent UV lamps are usually categorized as UV-A or UV-B lamps, depending on the region into which most of their light output falls.
UV-A lamps are especially useful for comparing different types of polymers. Because UV-A lamps do not have any UV output below the normal solar cutoff of 295 nm, they usually do not degrade materials as fast as UV-B lamps. However, they usually provide better correlation with actual outdoor weathering.
UV-B radiation includes some light with wavelengths shorter than sunlight that reaches the earth’s surface. Consequently, fluorescent UV-B lamps are widely used in Quality Control (QC) and Research and Development (R&D) for fast, cost-effective results. Because all UV-B lamps emit unnatural, short-wavelengths of UV that are below the solar cutoff of 295 nm, anomalous results can occur.
Q-SUN Full Spectrum Xenon Arc Lamps
Xenon arc lamps give the ultimate correlation to the full spectrum of natural sunlight. Unlike the QUV tester whose lamps directly determine the radiation that specimens see, the Q-SUN tester requires optical filters to accomplish the same. These optical filters are used to simulate a variety of service environments including direct sunlight and sunlight through window glass. Filter performance does not decline with age; therefore, filters do not need to be replaced unless the glass is broken.
The Q-SUN Xe-2 model’s optical filter lantern is designed to produce the spectra specified in ISO and AATCC test methods and is equivalent to sunlight coming through window glass. The lantern consists of an outer borosilicate cylinder and two sets of 7 inner filters, arranged in a two-tier heptagon.
There are three general categories of filters which can be used in the Q-SUN Xe-1 and Xe-3 xenon test chambers. The choice of filter depends upon the material tested and its end-use application. Within each general category, there may be several different types of filters. Each filter is a flat piece of specialty glass specifically designed to have a particular transmission.
Because the radiation from an unfiltered xenon arc contains too much short-wave UV to allow useful correlation to natural exposures on the earth’s surface, Q-SUN testers employ various types of filters to reduce unwanted radiation and achieve an appropriate spectrum. For most of the filter types used, the greatest effect is on the short wavelength portion of the spectrum. Because the damaging effects of UV are inversely proportional to wavelength (i.e., shorter wavelengths = more damaging), it is critical that the cut-on wavelength match the service environment.
Low Cost Replacement Lamps and Filters for Atlas Weather-Ometer® Testers
Q-Lab offers water-cooled replacement lamps and optical filters for use in Atlas Weather-Ometer® models Ci35, Ci35A, Ci65, Ci65A, Ci4000, Ci5000, and SUNTEST CPS and CPS+. These replacement lamps and filters are lower in cost and guaranteed to have a comparable spectral power distribution to those supplied by Atlas.
®Weather-Ometer is a registered trademark of Atlas Material Testing, LLC
Q-Lab supplies the highest quality UV fluorescent lamps available. The technology behind the lamps produces a spectrum that is inherently stable throughout their use. Each manufacturing lot is required to pass a stringent series of tests before it is approved for sale. The result is that the QUV tester provides a consistent, stable spectrum, year after year.
Several different types of UV lamps are available for different applications; part numbers are listed below. See the QUV Tester Page, Lamps Tab for more detailed information.
QUV Lamp Part Numbers (excluding QUV/basic)
UVA-340: The UVA-340 provides the best possible simulation of sunlight in the critical short wavelength region from 365 nm down to the solar cutoff of 295 nm. Its peak emission is at 340 nm
UVA-340+: The UVA-340+ lamp delivers the same light spectrum as the UVA-340 lamp, plus extended lifetime at high irradiance.
UVA-351: The UVA-351 simulates the UV portion of sunlight filtered through window glass
QFS-40: Also known as FS-40 or F40 UVB, the original QUV lamp. FS-40 lamps are still specified in some automotive test methods.
UVB-313EL: Substantially higher UV and, therefore, faster test results. Used in place of the QFS-40 in the QUV/se and QUV/spray.
UVB-313EL+: The UVB-313EL+ lamp delivers nearly the same light spectrum as the UVB-313EL lamp, plus extended lifetime at high irradiance.
Cool White Lamps: Cool white lamps are commonly used in commercial, retail, and office environments. The same cool white lamps can be used in the QUV/CW but at much higher intensities to test for indoor photostability of materials.
All lamps should be replaced after 8000 hours of operation at typical irradiance levels, or when irradiance set point can’t be reached.
UVA-340+ and UVB-313EL+ lamps should be replaced after 1500 hours of operation at high irradiance (1.55 W/m2/nm)
Q-SUN Xenon Arc Lamps
The Q-SUN Xe-1, Xe-2 and Xe-3 testers’ xenon arc lamps produce the most realistic reproduction of full spectrum sunlight including ultraviolet, visible light and infrared radiation. For many materials, exposure to the full spectrum is necessary to provide an accurate simulation, especially when testing for color change and lightfastness.
Air-cooling makes the Q-SUN xenon arc lamps economical, efficient and low maintenance. Lamps last for 1500 hours; the Q-SUN Xe-1 and the Xe-2 use a single 1800W lamp per machine, while the Q-SUN Xe-3 uses three. Common Q-SUN lamp part numbers are listed below. See the Q-SUN Tester Pages, Lamps Tabs for more detailed information.
Q-SUN Lamp Part Numbers
Low Cost Replacement Lamps for Atlas Weather-Ometer® Testers
Q-Lab offers water-cooled replacement lamps for use in Atlas Weather-Ometer® models Ci35, Ci35A, Ci65, Ci65A, Ci4000, Ci5000, and SUNTEST CPS and CPS+
These low cost water-cooled replacement lamps are guaranteed to have a comparable spectral power distribution to original lamps supplied by Atlas. The lamps meet a wide range of ISO, ASTM, SAE, and AATC requirements.
Atlas Weather-Ometer® Lamp Part Numbers
®Weather-Ometer is a registered trademark of Atlas Material Testing, LLC
QUV Optical Filters
Unlike xenon arc test chambers, the QUV tester does not require the use of any optical filters.
Q-SUN Optical Filters
Xenon light must be properly filtered to achieve the appropriate spectrum for each particular application. Differences in spectra may affect both the speed and the type of degradation. Three categories of filters are available to simulate a variety of service environments. The application or test method dictates which filters should be used. Below are some useful part numbers. See the Q-SUN Tester Page, Optical Filter Tabs for more detailed information.
Q-SUN Optical Filter Part Numbers
Low Cost Replacement Filters for Atlas Weather-Ometer® Testers
Q-Lab offers replacement optical filters for use in Atlas Weather-Ometer® models Ci35, Ci35A, Ci65, Ci65A, Ci4000, and Ci5000.
These low cost replacement filters are guaranteed to have a comparable spectral power distribution to original filters supplied by Atlas. The filters meet a wide range of ISO, ASTM, SAE, and AATC requirements.
Atlas Weather-Ometer® Filter Part Numbers
®Weather-Ometer is aregistered trademark of Atlas Material Testing, LLC