AWWA C671:2016 pdf download.Online Turbidimeter Operation and Maintenance
AWWA C671 can be referenced in documents for purchasing online turbi- dimeters, can be used as a guide for verifying the accuracy and precision of online turbidimeters, or can assist utilities in establishing online turbidimeter O&M pro- cedures. Te user should ensure the environmental conditions of the application match the manufacturer-specifed conditions and requirements for the analyzer. Te stipulations of this standard apply when this document has been referenced and then only to online turbidimeters used in the treatment and monitoring of potable water, reclaimed water, or wastewater efuent.
2. Calibration: A procedure that adjusts the accuracy of an instrument by comparison with a standard or reference. For the purposes of this method, calibrations often make an adjustment to an already established instrument algo- rithm that is part of the measurement software for a given instrument. Tis is sometimes referred to as a slope adjust.
13. Secondary standard: A material or device that is used to check the accuracy of an instrument. Examples include gel-based materials, glass devices, and optomechanical devices. It is often the case that a secondary standard is designed to check one type of instrument. Primary standards can also be used as secondary standards.
14. SSU (Surface scatter unit): Turbidity unit determined through light scatter from a defned volume beneath the surface of a sample. Applicable for reporting for USEPA compliance monitoring.
15. Verifcation: A procedure that checks the accuracy of an instrument by comparison with a standard or reference. Either primary or secondary standards can be used to check the accuracy of an instrument. An instrument should be veri- fed immediately following primary calibration. Tis is referred to as “calibration verifcation.”
6. Designs: Te primary diferences in nephelometric turbidimeter designs are based on the type of light sources used and whether or not the method uses a ratio technique. In a ratio turbidimeter, the output of the primary detector is in the numerator of the ratio algorithm, and also possibly in the denominator of a ratio algorithm, along with any other light scatter detector outputs.AWWA C671 pdf download.