What is one requirement for TEM sampling regarding flow rate?

For Transmission Electron Microscopy (TEM) sampling, it is specifically required that the flow rate be less than 10 liters per minute when using a 25 mm cassette. This requirement is crucial because higher flow rates can affect the efficiency of airborne asbestos fiber capture and ultimately compromise the accuracy of the analysis. The delicate balance of flow rate is designed to ensure that a sufficient number of fibers are collected for reliable quantification while maintaining the integrity of the samples.

If the flow rate were to exceed this threshold, it could lead to a lower collection efficiency of the fibers, as the air movement might cause turbulence that prevents small asbestos fibers from being captured effectively. Therefore, adhering to this specific flow rate is fundamental in ensuring the reliability and validity of TEM sampling results in asbestos inspections and analyses.