What is the acceptable deviation percentage for post-calibration flow rates in air sampling?

The acceptable deviation percentage for post-calibration flow rates in air sampling is 5%. This standard is critical for ensuring the accuracy and reliability of air sampling equipment. After calibration, the deviation percentage indicates the allowable difference between the measured flow rate and the standard flow rate. A 5% deviation is deemed acceptable because it balances the need for precise sampling with practical limits that recognize minor operational variances inherent in field conditions. Maintaining flow rates within this threshold helps to ensure that the collected samples accurately reflect the concentration of airborne substances, which is essential for effective occupational hygiene monitoring and risk assessments.