What does 'R' denote in the formula (TS x t x E) / (R x FS)?

The 'R' in the formula (TS x t x E) / (R x FS) represents the inside radius of the weakest course of the shell or drum of a boiler. This is a critical measurement in the context of boiler design and safety standards because it directly affects the structural integrity and stress distribution within the boiler components. The inside radius is important for calculating wall thickness and determining the capacity of the boiler to withstand pressure without risking failure.

Understanding the inside radius is critical in ensuring that the boiler operates safely under high pressure, and it plays a role in the overall efficiency of heat transfer as well. This specific measurement helps engineers and technicians assess how close the design is to the limits of safe operation, thus influencing decisions on maintenance and operational parameters.