tailieunhanh - Air Sampling and Industrial Hygiene Engineering - Chapter 3

Hiệu chuẩn kỹ thuật Chương này bao gồm các cuộc thảo luận lý thuyết và thực tế về những phức tạp của hiệu chuẩn. Nó đặc biệt nhấn mạnh đến tình huống mà các kiến thức về kỹ thuật hiệu chuẩn là một điều kiện tiên quyết cho an toàn lấy mẫu. Hiệu chuẩn là phương tiện được sử dụng để cung cấp bằng chứng rằng thiết bị đang làm việc chính xác và kết quả là đáng tin cậy và lặp lại trong phạm vi mức độ khoan dung quy định đối với các công cụ này. Hiệu chuẩn của. | CHAPTER 3 Calibration Techniques This chapter contains theoretical and real-world discussions about the intricacies of calibration. It gives special emphasis to situations where the knowledge of calibration techniques is a prerequisite for sampling adequacy. Calibration is the means used to provide evidence that instrumentation is working accurately and that results are reliable and repeatable within the tolerance levels prescribed for these instruments. The calibration of real-time instruments is very specific and manufacturer s instructions must be followed. Increasingly instrumentation is calibrated using electronic circuitry with empirical tests against standards in accordance with the manufacturer s requirements at prescribed intervals. Collection efficiency must also be taken into account when calibration curves are developed. As filters cartridges or sorbent tubes load air intake and calibrated airflow volumes across the media can be expected to change Figure . CALIBRATION REQUIREMENTS Instrument calibration records must be reviewed periodically by the users to assess accuracy of documentation and to evaluate instrument performance. Assessment is based on the instrument operating instructions and knowledge of the user. Users will check minimum calibration frequency requirements for the instrument and calibrate according to the applicable operating instruction manual. Calibrating the instrument at the worksite under actual field conditions is an important requirement. Air-sampling instrument readings for calibration will be corrected for temperature and barometric pressure. Record calibration and challenge results as follows in the field logbook and include the following information Instrument identification Date if not on page in logbook Precalibration readings as found or as set Readings after calibration and span settings if applicable 2001 CRC Press LLC Calibration gas challenge used and lot number Signature of person performing calibration