HVAC and BEMS

A set of connectivity standards for industrial automation from the OPC Foundation.  OPC added extensions to Microsoft's COM and DCOM object technology in order to provide a set of common interfaces for process control.  OPC offers interoperability between gauges, databases, programmable logic controllers (PLCs), distributed control systems (DCSs) and remote terminal units (RTUs).

Chemicals that contain carbon.  Volatile organic compounds vaporise at room temperature and pressure.  They are found in many indoor sources, including many common household products and building materials.

Air taken from the external atmosphere and, therefore, not previously circulated through the system.

HVAC term for air brought into a building from the outdoors (often through the ventilation system) that has not been previously circulated through the system.  Also known as "Make-Up Air".