What factor does I=B=R use to rate hot water radiation?

The formula I=B=R, which stands for Input = Brochure = Radiation, utilizes an average supply temperature of 200 °F to evaluate hot water radiation systems. This is significant because the designated supply temperature directly impacts the heat output and efficiency of the heating system.

Using 200 °F as the standard means that calculations based on this temperature reflect typical operating conditions for many hot water heating applications. This temperature is optimal for effectively determining the heating capacity and ensuring that the radiation system works efficiently in delivering adequate heat to the spaces being served.

Other supply temperatures listed in the options may not be standard for everyday calculations in hot water system design. For instance, lower temperatures like 180 °F might not provide sufficient heating capacity for certain applications, while higher temperatures might represent operational extremes that are not commonly used or recommended in practice. Thus, 200 °F stands as a balanced choice that aligns with standard practices in steamfitting and heating system assessments.