AZ SB1557

Amends Arizona Revised Statutes section 42-13355 to clarify the definition and classification of clean rooms used in semiconductor manufacturing, processing, fabrication, or research and development as tangible personal property for valuation and assessment purposes.

Defines "clean room" as all property that controls humidity, temperature, particulate matter, and contamination within specified parameters, regardless of whether property is contained within that environment or affixed to real property.

Specifies that clean rooms include integrated systems, fixtures, piping, movable partitions, lighting, and all property necessary to reduce contamination or control airflow, temperature, humidity, chemical purity, and other environmental conditions, plus production machinery and equipment operating in the clean room.

Excludes the building structure itself and permanent, nonremovable building components from classification as personal property clean room assets.