User Basics 
Part One 
 
 
User Basics 
 
This section provides a brief but thorough overview of the EverWatch product by 
maximizing information with minimal reading. These few pages explain the purpose (The 
Instrument), and the operation (Useful user information, Operator panel, Alarms) of the 
product. Technical product information is available in Part Two of the manual.  
 
 
The Instrument 
 
The EverWatch monitor measures and reports “face velocity” in fume hoods. Adequate 
face velocity is a key component needed to protect fume hood users. An adequate face 
velocity contains all the contaminants inside of the fume hood.  
 
The fume hood exhaust system produces a pressure differential between the hood 
interior and the laboratory, causing air to be drawn into the hood. In a properly designed 
and used fume hood the air drawn into the fume hood is the same everywhere in the 
sash plane (opening). The speed the air enters the fume hood is called the face velocity. 
The Model 8610 EverWatch Face Velocity Monitor continuously monitors fume hood face 
velocity by measuring the air velocity across a sensor mounted in the sidewall of the 
hood. The sensor and opening in the fume hood are driven by the same pressure 
differential so the velocity across each is related. 
 
The EverWatch device informs the hood user when the fume hood has an adequate face 
velocity by indicating the actual face velocity and turning on a green light. If the face 
velocity is inadequate, or too great, a red alarm light and audible alarm turn on. 
 
The EverWatch monitor consists of two pieces; a velocity sensor and monitor electronics. 
The velocity sensor is mounted in the sidewall of the fume hood usually near the top of 
the sash. The monitor electronics are typically mounted about eye level on the front of 
the fume hood cabinetry. The velocity sensor continuously measures the face velocity 
and provides the face velocity information to the monitor electronics. The monitor 
electronics continuously report the face velocity and activates the alarms when 
necessary.  
 
Useful User Information 
The monitor electronics has a green light (normal operation) and red alarm light (low and 
high alarms). The green light is on when the face velocity is adequate. The red low alarm 
light comes on when the face velocity drops below a safe level. The red high alarm light 
comes on when the face velocity exceeds a safe level. The display provides additional 
information by continuously indicating the actual face velocity