OK, sorry to drag this out - but what is a fuseable plug, where is it located on the boiler, and how does it work?

Thanks.

Wesley

A fuseable plug is a hollow plug with a tin alloy in the center, located on the crown sheet. When the fuseable plug is covered with water, the tin will not melt, but should it be uncovered, it will "drop" as the tin has a low low melting point and steam will issue from the plug. This is a sign that the boiler is in danger. It's not a sprinkler that puts out the fire as I was told. If you hear one go, it means that the crown sheet is too hot and a boiler explosion may be imminent.

Some interesting articles on fuseable plugs.

What is a Fusible Plug and How Does it Work?
http://www.steamtraction.com/archive/5424/

Fusible Plug Analysis
http://www.steamtraction.com/archive/5425/

The Medina plug
http://www.steamtraction.com/archive/5431/

A Short History of the Fusible Plug
http://www.steamtraction.com/archive/5509/

How Much Do You Know About Your Fusible Plug?
http://www.steamtraction.com/archive/5510/

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Kelly, you are right about everyone reading the articles above but I would like to add one more and it goes into detail about the condition of the boiler and a better understanding of why this boiler failed. The soft plug was not the only issue with this boiler. http://www.doli.state.mn.us/boilerohio.html
This boiler had not been maintained properly for a long time nor had it been properly inspected. Take a look at the pictures of the stay bolts as well as the notes on the thickness of the crown sheet around the stays. Had this boiler received a good visual inspection as well as a UT Map it would have been condemed.
Soft plugs will fail if they are not changed out on a regular basis due to the build up of material on the surface of the tin. Soft Plugs are not the ultimate safety answer they are just one of the tools available for prevention of a accident. Improper use or poor maintainence will render it unuseable.