Sight Glass Failure

Sight glass is a transparent tube through which operators of tanks and boilers can see how much liquid is contained inside it. Failure of these devices can cause a number of major problems for the facility in question, including safety risks and an expensive clean up.

Compression vs. Tension

There are two main ways for a sight glass to fail -- through compression or through tension. While the type of glass used determines how likely it is for each of these scenarios to result, sight glasses almost always fail due to tension rather than compression.

Element Failure

Sometimes sight glass elements fail due to mechanical stress. This can be disastrous due to the fact that the glass will crack incredibly quickly -- up to 5 miles per second -- and will likely result in shards of glass being shot and scattered at supersonic speeds.

Contributing Factors

There are a number of factors that can contribute to sight glass failure. These include improper design, improper handling of materials during production and improper installation procedures.

References

• L.J. Star: Metaglas Sightglass Design
• Flow Control: Are You Gambling with Your Sightglass?