Medical Air Dew Point Alarm

Q: I have a compressor that delivers medical air for our patients and want to know what the requirements are for the alarm system for the air dryers. Where do the alarms have to sound and what is the range for the dew point for the dry air?

A: The requirements for medical air and related accessories are found in NFPA 99 (1999 edition), chapter 4. Section 4-3.1.1.9 describes multiple requirements for monitoring the air that is discharged from the medical air compressor. The point where the air quality must be monitored is downstream of the regulators, but upstream of the piping systems. Dewpoint as well as carbon monoxide must be monitored on a continuous basis and when these parameters are out of their normal range, they must actuate an alarm in the mechanical room where the medical air compressor is located and on the medical gas alarm mater alarm panels (mentioned in the above question).  The dew point monitor must active an alarm when the dew point exceeds 39%.