A modular exhaust gas header designed for use with a process tool having a plurality of exhaust gas points of connection. Embodiments of the modular exhaust gas header include a plurality of branch ducts, at least one for each point of connection in the process tool. Branch ducts, and primary ducts with which they are fluidly connected, may be made from materials designed to withstand exhaust gases that have a high temperature, are corrosive, and/or include volatile solvents. If desired, flow control devices and pressure monitoring instrumentation that selectively measures pressure may be used in each branch duct. The header local to the processing system may be incorporated in a method of designing a layout for a manufacturing process tool and associated exhaust gas handling systems.