What happens to the MAWP when a boiler is derated?

When a boiler is derated, the Maximum Allowable Working Pressure (MAWP) decreases, along with the boiler's BTU output. Derating refers to the process of reducing the maximum capacity or output of the boiler, which often happens due to changes in operating conditions, such as being located at a higher elevation where less atmospheric pressure is available.

As the MAWP decreases, it is indicative of a lower capacity to handle steam or water pressure safely and effectively. This reduction often correlates with the BTU output because the energy produced by the boiler is directly linked to the capacity of the system. Therefore, as the operational pressure decreases, the ability of the boiler to generate power or steam also diminishes, resulting in a decreased BTU output.

Understanding this relationship is crucial for maintenance and operational adjustments in high pressure boiler systems, ensuring safety and efficiency according to the new capacity limits.