Which of the following must hydronic pipe insulation's R-value mark be?

The requirement for the R-value mark on hydronic pipe insulation to be visible is crucial for ensuring compliance with building codes and for maintaining safety and efficiency in a mechanical system. The visible marking allows inspectors, contractors, and maintenance personnel to easily identify the insulation's R-value without having to remove or disturb the insulation itself. This is important because R-value is a measure of thermal resistance, and knowing this value helps in assessing whether the insulation meets the necessary standards for energy efficiency and performance.

By having the R-value clearly marked and visible on the exterior, it aids in verifying that the insulation is appropriate for the specific application, thus promoting proper installation practices. This helps in preventing issues related to inadequate insulation, such as energy loss or freezing of pipes, which can lead to system failures and costly repairs.

The visibility of the R-value marking supports transparency in the materials used in the construction and maintenance of hydronic systems, contributing to overall system effectiveness and building performance.