A boiler operating at 100 psig requires how many fusible plugs if over 50 square feet?

In the context of boiler safety, the installation of fusible plugs is an important aspect to ensure that if the water level drops, the plugs will melt at high temperatures, allowing the steam to escape and potentially preventing an explosion. For a boiler operating at 100 psig, specific guidelines dictate the number of fusible plugs required based on the surface area of the boiler.

When a boiler has a heating surface of over 50 square feet, it is required to have one fusible plug. This is standard practice to provide an additional safety measure in the event of low water conditions. The requirement is designed to ensure that there is at least one point of failure that can alert operators to potentially dangerous situations, thus enhancing overall operational safety.

The other options suggest having either no plugs or an excessive number for a boiler of this size and pressure, which does not align with the recognized safety regulations. The proper adherence to having one designated fusible plug meets the safety standards set forth for high-pressure boilers, ensuring both compliance and the protection of personnel and equipment.