4-1 Professional advice
The most common type of fume hood sash is one which opens and closes vertically.
Tempered glass is often used for the front sash. Weights of the same mass are on the back side and are balanced by being connected with wires and belts.
The weights may be present on both sides, or it may be combined as one. (See figure for reference)
Repeated opening and closing of the sash causes deterioration of the wire, and wear of the pulley receiving the wire. The heavy opening and closing of the front sash mean that the resistance has increased for some reason.
If one side of the wire is broken, it may not be noticed immediately, and if it is used in the usual manner and the other side is cut, an accident in which the sash falls may occur.
Structural diagram
4-1 Advice for
Initial support/correspondence
Without continuing under those circumstances, consult with the lab manager or the facility administrator, and ask the manufacturer for an immediate inspection.
Put up a sign to remind people not to move the sash.
