The document provides an overview of the mechanical ventilation and air conditioning systems used in PJ Trade Centre Block A in Malaysia. It describes the supply, extract, and pressurization ventilation systems which deliver fresh air and remove stale air using fans, ducts, and grilles. The supply system is also used to pressurize fire staircases for safety during a fire. The document also outlines the centralized chilled water air conditioning system used to cool the building via AHUs and a chiller plant, as well as localized split unit systems. Diagrams illustrate the components and airflow throughout the building.