Low pressure steam won't empty a boiler in an explosion as there isn't
enough energy in the heat of the water to do that but higher pressure
boilers do contain enough energy to vaporize all of the water to steam.
One of the things that I have found amazing while dealing with steam stuff
is the number of idiots that are quite cavilier about the explosive
qualities of steam when combined with low water conditions in boilers. I've
shut boilers off (to the irritation of the owner of the boiler) because I
couldn't see any water in the waterglass. Every single one of those idiots
stated that the boiler crown sheet is well below the bottom of the glass and
you can run the boiler even tho there is no water in the glass.
With all of the knowledge of how boiler explosions happen form 200 years of
steam work today and having such an attitude, you can imagine what it was
like back then in the first few years with people that really had no real
idea of why boilers exploded.

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Why do penguins walk so far to get to their nesting grounds?