Which closure system marking indicates the use of pressure-sensitive tape according to UL 181A?

The marking that indicates the use of pressure-sensitive tape according to UL 181A is indeed 181A-P. This specification is particularly important because UL (Underwriters Laboratories) establishes standards for materials and products used in the HVAC industry, and the various designations help clarify their intended uses and performance characteristics.

In this context, the suffix "-P" specifically denotes that the tape is designed to adhere to surfaces under pressure and is suitable for sealing purposes in HVAC applications. Understanding this marking is crucial for professionals who need to select the appropriate type of closure system for ductwork and insulation to ensure that they maintain energy efficiency and proper airflow in heating, ventilation, and air conditioning systems.

The other markings, such as 181A-M, 181A-H, and 181A-FX, refer to different types of closure systems that use different materials or technologies, which may not be suitable for the same applications as pressure-sensitive tape. Therefore, recognizing the specificity of these designations helps ensure that the correct type of sealing method is employed in a given situation, contributing to the overall safety and performance of HVAC installations.