AATCC 183 pdf free download

AATCC 183 pdf free download.Transmittance or Blocking of Erythemally Weighted Ultraviolet Radiation through Fabrics.
1. Purpose and Scope
1.1 This standard test method is used to determine the ultraviolet radiation blocked or transmitted by textile fabrics intended to be used for UV protection.
1.2 This method provides procedures for measuring this fabric property with specimens in either the dry or wet states.
2. Principle
2. 1 The transmission of ultraviolet radiation (UV-R) through a specimen is measured on a spectrophotorneter or spectroradiometer at known wavelength intervals.
2.1.1 The ultraviolet protection factor (UPF) is computed as the ratio of the erythemal ly weighted ultraviolet radiation (UV-R) irradiance at the detector with no specimen to the erythemally weighted UV-R irradiance at the detector with a specimen present.
2.1.2 The erythemally weighted UV-R irradiance at the detector with no specimen present is equal to the summation between wavelength intervals of the measured spectral irradiance times the relative spectral effectiveness for the relevant erythemal action spectra times the UV-R weighting function of the appropriate solar radiation spectrum times the appropriate wavelength interval.
2.1.3 The crythemally weighted UV-R irradiance at the detector with a specimen present is equal to the summation between wavelength intervals of the Incasurcd spectral irradiance times the relative spectral effectiveness for the relevant erythernal action spectrum times the spectral transmittance for the specimen times the wavelength interval.
2.1.4 The percent blocking of UVA and UVB radiation is also calculated.
4. Safety Precautions
NOTE: These safety precautions are for information purposes only. The precautions are ancillary to the testing procedures and are not intended to be all inclusive. It is the user’s responsibility to use safe and proper techniques in handling materials in this test method. Manufacturers MUST be consulted on specific details such as material safety data sheets and other manufacturer’s recommendations. All OSHA standards and rules must also be consulted and followed.
4.1 Under any circumstances, do not look directly at the equipment and materials that may increase the light source intensity, such as mirrors.
4.2 Good laboratory practices should be followed. Wear prescribed safety glasses in all laboratory areas.
7. Instrument Verification and Calibration
7.1 Calibration. Calibrate the spectrophotometer or spcctroradiometer according to manufacturer instructions. The use of physical standards are recommended for validating the measurement of spectral transmittance.
7.1.1 When running a wet sample place the plastic wrap over the port and repeat calibration.
7.2 Wavelength scale. Calibrate the wavelength scale of the spcctrophotomcter 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. Reference wavelengths for both mercury arc emission and holmium oxide absorption are provided in ASTM Practice E 275, Standard Practice for Describing and Measuring Performance of Ultraviolet, Visible and Near-Infrared Spectrophotometers.
7.2.1 Transmittance scale. Set the transmittance scale to a 100% value by operating the instrument without a sample in the optical patfr therefore, referenced to air. The 00/0 value can be subsequently verified by fully obstructing the sample beam path with an opaque material. 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.AATCC 183 pdf download.