Leak Testing

Leak testing is the bane of any instrument operator, but it's even more important for FILIF since not only will a leak dilute your sample flow, it will also contaminate the air due to indoor air containing levels of HCHO that are generally higher than outdoor levels.

Generally, spraying Swagelok fittings or any others joints with an acetone bottle will help detect most major leaks (for years, this has been the most common method the group has used for leak detection). If the PTRs are also present in the room, please check with their operator before spraying acetone since their instruments are highly sensitive to the molecule. Under no circumstance should you be spraying water on the instrument since it takes too long to dry (acetone evaporates almost immediately).

At a bare minimum, the leak rate should be less than 5 Torr/min and you should be able to achieve a pressure of 2 Torr or less when the vacuum pump is pulling on the instrument (needle valve and bypass MFC must be completely closed).