1. Every boiler must have at least two independent means of indicating the water level. These indicators must be placed in a position where they can be easily and clearly seen by the operator.

2. A protective glass arrangement should be provided which partly surrounds the gauge glass to prevent injury to personnel in the event of gauge glass breakage under steam.

3. A steam restrictor orifice and water shut off ball valve are incorporated with the fitting to reduce the severity of breakage.

4. When any gauge glass fitting is in operation the cock handles should be vertical. If they were arranged horizontally and the gauge is in operation, vibration effects may cause the cock handle to gradually tend to take up a vertical position thereby closing the cock in the case of steam and water cocks, and opening in the case of the drain.

5. Plugs are fitted in the gun-metal bodies to allow for the renewal of the glass tube, and for cleaning the various passages.

6. Difficulty is often experienced with this type of glass in ascertaining whether it shows completely empty or completely full of water. It is good practice to place a board, painted with diagonal black and white stripes, behind the glass. If it is full of water, refraction will cause the stripes to appear bent to the opposite angle. If no board is fitted, a pencil, or similar object can be used to the same effect.

7. A drain cock fitted at the lower end allows for blowing through the glass to test it.

8. Extended controls for the cocks are fitted so that the gauge can be blown through from a
remote and safe position.