UV RESISTANCE / PROTECTION UPF- Ultraviolet protection factor rating. Ultraviolet Protection (UPF) 15 – 50+ Test Methods – AATCC AATCC Transmittance or Blocking of Erythemally Weighted Ultraviolet Radiation through Fabrics. standard by American Association of Textile. work, e.g. AATCC with ASTM D and. ASTM D in the United States and EN in. Europe. The Australian Radiation Protection and.
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Purpose and Scope 1. Principle ance transmitted and calculated through air to the average effective UV-R irradiance transmitted and calculated through fabric. The limits of the spectral range of ultraviolet radiation are not well defined and may vary according to the user. Filter, Schott Glass UG11 see Instrument Verification and Calibration aatvc.
Uses and Limitations 3. However, the techniques for stretching the specimens are not part of this method and are addressed in a separate test procedure. It must be noted that stretching the specimens could change the UPF properties. Apparatus and Materials 8. Avoid distorting the specimen during preparation and handling. These safety precautions are for information purposes only.
American standards for UV-protective textiles.
The precautions are ancillary to the testing procedures and are not intended to be all inclusive. All OSHA standards and rules must also be consulted and followed. Wear prescribed safety glasses in all laboratory areas. Calibrate the spectrophotometer or spectroradiometer according to manufacturer instructions. The use of physical standards are recommended for validating the measurement of spectral transmittance.
Calibrate the wavelength scale of the spectrophotometer or spectroradiometer using the spectral emission lines of an electrical discharge in mercury vapor. The wavelength calibration of a spectrophotometer can be performed using the absorption spectra of a holmium oxide glass filter. Validate the linearity of the transmittance scale by means of either calibrated neutral density filters or calibrated perforated screens supplied by the instrument manufacturer or standardizing laboratories.
Record the individual measurements. Thoroughly wet out the specimen in distilled water by placing it flat in the bottom of a beaker and then pour distilled water into the beaker until the specimen is covered. Allow the specimen to remain submerged for 30 minutes.
Press and move the specimen from time to time to ensure a good and uniform penetration. Prepare only one specimen at a time. If the fabric has low moisture absorption, repeat the soaking and wringing steps. Note, some samples may not be capable of achieving the specified wet pick-up such as tightly woven synthetic fabrics. Avoid evaporative reduction of the moisture content below the specified level before the actual UV transmission measurements are made.
The intervals in Table II are in 2 nm.
The intervals in Table I are in 2 nm. Although integration is indicated from nm to the stated wavelengths, little or no contribution will occur in the nm region. The average UPF was Between-laboratory precision has not been established for this test method. Until such precision information is available, users of the method should use standard statistical techniques in making any comparison of test results for betweenlaboratory averages.
Transmittance or blocking of erythemally weighted ultraviolet radiation through fabrics can be defined only in terms of a test method.
There is no independent method for determining the true value. As a means of estimating this property, the method has no known bias. Precision and Bias Appendix A Spectrophotometer or Spectroradiometer Specifications In Marchan ul- A1.
The integrating sphere surface is internally coated or constructed using a material that is both diffuse and highly reflecting in the ultraviolet region. Illumination and viewing geometries. In this geometry the specimen is illuminated with an unidirectional beam whose axis is not greater than 0.
Any ray of this beam shall not exceed 0. The cross-sectional area of the illuminating beam shall be at least 10 times the dimension of the largest hole in the test material.
The total flux transmitted by the specimen is collected by the integrating sphere. In this geometry the specimen is illuminated by an internally illuminated integrating sphere. The specimen is viewed unidirectionally with an axis not greater than 0. The cross-sectional area of the viewing beam shall be at least 10 times the dimension of the largest hole in the test material.
The error can be eliminated in either geometry by use of a separate reference beam that traverses its own port opening in the sphere. The reference beam impinges on either a portion of the sphere wall or a reference material mounted at a diametrically opposed port opening.
The spectrophotometer or spectroradiometer shall have a spectral bandpass of 5 nm or less over the spectral range of nm or less to nm or more. The measured wavelength interval aacc this spectral range should not be greater than 5 nm. The contribution of stray radiation within the instrument, including that due to sample fluorescence, shall produce an error of less than 0.
The contribution of sample fluorescence on spectral transmittance 813 on certain dyes and whitening agents present in fabrics that may fluoresce could result in artificially high astcc of spectral transmittance.
This includes nearly all wavelengths in the UVR spectral region. The error due to the fluorescence can be removed by placing a UV transmitting, visible blocking filter after the sample.
A Schott Glass UG11 filter has been found to be satisfactory.
However, the decrease in transmission of the filter with increasing wavelength may reduce the usefulness of the long wavelength UVA measurement. In spectrophotometers and spectroradiometers where the illumination is polychromatic and the monochromator follows the specimen in the optical path, the artificially high values of transmittance appear aatcx the emission wavelengths of the fluorescing agent.
The effects of fluorescence are, therefore, eliminated at most UVR wavelengths. The use of an zatcc light source that conforms to the spectral distribution requirements for solar simulators will most accurately include the contribution of sample fluorescence to the long wavelength UVA measurement. However, because the fluorescent component does not contribute to the UPF, the spectral distribution of the source is irrelevant, so long as it provides sufficient energy to cover the spectral range of interest to acceptable signal to noise ratios in the spectral data.