If the existing chimney stack requires extensive refurbishment/rebuild or is recommended to be lowered by the structural engineer, the design team shall evaluate if it is more cost effective to repair the stack and modify the flues which could include a new chimney liner, etc verses replacing the breaching/flue with new individual flues per gas boiler, water heater and unit heater routed to an new location. Present recommendation to CPS for approval. Often the existing chimneys were designed when coal and oil was the equipment fuel and required a higher point of discharge. If the equipment is located in a boiler plant with a roof directly above it is often more cost effective to provide separate flues up thru the lower roof than to rebuild/refurbish the chimney. Maintain 25’ horizontally where possible, 15’ minimum from building openings / adjacent vertical walls. Flues to extend 6’ above roof surface. Do not locate flues directly below air intakes/louvers on adjacent walls. CPS prefers separate flues / combustion air ducts per piece of equipment over shared/common flues where possible. Coordinate boiler room lighting adjustments as required to accomodate flue/breaching changes. See additional information under Structural Projects.
As part of any chimney project, life safety items like boiler/water heater kill switches at each boiler room egress door, carbon monoxide detectors and combustion air louvers / dampers / actuators shall be brought up to code. See additional information under Exterior Envelope Projects.
If the existing Flue Stack is to be maintained, verify that the existing flue size is correct based on the new discharge height and modify as required. Reduction in flue height / modification to flues/breaching requires connected boilers to be tuned as part of the project. Where existing flues/breaching is reused and insulation is missing / damaged repair/replace insulation.