Gas and Vapor Generating Systems For Laboratories.
DHHS (NIOSH) Publication Number 84-113
A report was provided which contained information about systems used in the laboratory to generate both static and dynamic concentrations of gases and vapors for industrial hygiene sampling and analytical method development or instrument evaluation. These generating systems were noted to be valuable tools for many applications, including the evaluation of the performance of sampling methods and sampling instruments. With the exception of some permeation tube and diffusion tube devices, preassembled generation systems have not been commercially available and had to be assembled by the user. The greatest single source of error in any generation system has been in the measurement and control of the air flow rate. It was observed that emphasis should be placed on this aspect by obtaining the best in air flow measurement and control devices that can be afforded and by becoming proficient in their operation and calibration. The basic components of dynamic generation systems included air supply, air control and measurement, mixing chamber and sampling chamber or manifold. Each has been used with vapor pressure, permeation tube, or syringe pump generation systems. By designing these with some flexibility it would be easier to install a different system if the needs of the laboratory changed.