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- Piping: All hydronic piping shall be routed in accessible locations to allow for proper maintenance and quick repairs. Piping shall include proper supports throughout. If a piping loop is required for service to elements, a reverse-return design shall be utilized.
- Sizing: Pipe sizing shall be determined based on 100% flow throughout the system, with no diversity taken. Pipe sizing shall take any planned additions or potential for future systems into account. This shall be directed by the Design Manager during the project design. Pipe sizing shall be per ASHRAE Fundamentals (most current edition) chapter on Pipe Sizing.
- Valving: All system valving shall be accessible for use and calibration. Each branch pipe shall include an isolation valve at the point of takeoff from the main.
- Equipment Connections: All connection to equipment shall be made with a union for ease of disconnection. For any equipment that has an integral fan, compressor or other source of vibration, flexible connections shall be used to eliminate the carryover of vibration to the piping system.
- Dual Temperature: Dual temperature system shall be sized for the greater of the 2 possible flows. Confirm that heating only devices can be isolated during cooling mode with a minimum quantity of automatic control valves.
- Expansion: Expansion devices and loops may be required on straight runs of greater than 50 feet. It is the responsibility of the EOR to verify the need of these devices and provide them in the design as needed.
- Insulation: All hydronic piping shall be fully insulated per CPS Specification 23 07 19.
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- Piping: Steam piping shall be run outside of public spaces whenever possible. Pitch piping uniformly down in the direction of steam flow at 0.25 inches per 10 feet of pipe. Install drip legs at all low points and natural drainage points in the system. These include the end of all mains, bottom of risers, ahead of pressure regulators, controls valves, isolation valves, pipe bends and expansion joints. Take off all branch lines from the top of the main at a 45 degree angle.
- Condensate: Condensate shall flow by gravity from the traps to the return piping system. Pitch return piping uniformly down in the direction of steam flow at 0.5 inches per 10 feet of pipe.
- Sizing: Piping shall be sized in accordance to ASHRAE Fundamentals.
- Valving: Valving for all steam equipment and piping shall follow Standard CPS Details and CPS Specification Section 23 05 23.
- Equipment Connections: All connection to equipment shall be made with a union for ease of disconnection. For any equipment that has an integral fan, compressor or other source of vibration, flexible connections shall be used to eliminate the carryover of vibration to the piping system.
- Steam Traps: Steam traps shall be provided on the discharge of all steam coils. Traps shall be placed in an accessible location for proper maintenance. Traps shall also be placed at the low points/drip legs of all piping runs and risers.
- Expansion: Expansion devices and loops may be required on straight runs of greater than 50 feet. It is the responsibility of the EOR to verify the need of these devices and provide them in the design as required.
- Insulation: All steam and condensate piping shall be fully insulated per CPS Specification Section 23 07 19.
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Refrigerant piping design shall comply with the City of Chicago Building Code and ASHRAE 15. EOR shall confirm compliance and provide ASHRAE 15 calculation to CPS upon request.
- Piping: Provide insulated type K copper or ACR brazed. Flare fittings are not allowed. Air conditioning condensate shall be type M copper soldered. All piping shall be sloped (Hot Gas: uniform downward slope away from compressors, Suction Line: uniform downward slope to compressors, Liquid Lines: level). Provide traps and double risers as required to entrain oil in vertical runs. Underground piping not allowed. See 23 23 00 for additional requirements.
- Sizing: EOR shall provide preliminary pipe sizes and routing on design drawing. Documents shall require final pipe sizing, routing/layout by equipment manufacturer.
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- Materials: All ventilation airflow shall be distributed in metal ductwork. The use of any other material shall be approved by CPS and allowed per Code.
- Ductwork:
- Supply air: 1,500 feet per minute (fpm) maximum in exposed locations.
- Supply air: 2,500 fpm maximum in mechanical rooms, chases or corridors where no direct connection to classroom or sound sensitive areas exist.
- Classroom, Library, Music, Auditorium distribution: 800 fpm maximum for all systems.
- Constant volume low pressure systems: 1,500 fpm maximum.
- Outside air intakes: 500 fpm maximum at the louver, 1,000 fpm maximum from the louver to the inlet of the fan or air-handling unit.
- Return air: 2,000 fpm maximum- in mechanical rooms, chases or corridors where no direct connection to the classroom exists.
- Exhaust louver or relief: 800 fpm maximum.
- Kitchen hoods: 1,550 fpm minimum, 2,200 fpm maximum.
- Laboratory exhaust: see CPS Laboratory Standards.
- Door grilles or undercuts: 300 fpm across the free area.
- Transfer grilles: 300 fpm across the free area.
- Low Pressure Ductwork: (-2.0” w.c. to +2.0” w.c.) at every level, size for no more than 0.08”/100 feet of duct run with restrictions on the velocity within the duct as noted below. The ductwork shall first be sized for the pressure drop, then for sound consideration, then only when these considerations result in a velocity exceeding those listed, shall the duct be increased to compensate.
- Medium Pressure Ductwork: at every level, size for no more than 0.2”/100 feet of duct run with restrictions on the velocity within the duct as noted below. The ductwork shall first be sized for the pressure drop, then for sound consideration, then only when these considerations result in a velocity exceeding those listed, shall the duct be increased to compensate.
- Refer to ASHRAE Fundamentals for Duct Sizing. Use the equal friction method for maintaining the velocities as noted. Where noise is the governing factor, modify values as necessary after coordination with Acoustical Consultant.
- Supply Air: Room air distribution design (diffuser location and selection) shall follow the design approaches in the ASHRAE Fundamentals, Space Air Diffusion. Consideration shall be made for exterior wall loads and full distribution within each space.
- Return Air: Return air system may be fully ducted or utilize areas of plenum return. Return air plenums must be coordinated with all trades to confirm the use of plenum rated materials and fixtures. All plenums shall be hatched on drawings and hatching identified in the project legend.
- Exhaust Air: Exhaust air shall be directly discharged to outside and may not be transferred to any other space prior. Exhaust air shall be taken from all areas required per Code and any space where there is a potential for odor generation. All areas of exhaust shall be maintained under negative air pressure. Air shall be transferred into these spaces from adjacent positive pressure spaces.
- Exterior: The use of exterior ductwork shall be limited to ductwork required to meet Code compliance with regards to air intake and discharge/exhaust separation. No other application of exterior ductwork shall be acceptable on new construction. Exterior ductwork on renovation projects shall be avoided and only to be considered as a last resort. All applications of outdoor ductwork shall be individually approved by CPS prior to design. When approved, provide a clear pathway around ductwork to access equipment on the roof without climbing over or crawling under ductwork. Where exterior ductwork is approved, provide round ductwork where possible (typically results in tighter seals, is less likely to be walked on and lasts longer). Slope ductwork so that water/snow pooling does not occur on surfaces/flanges/seams. Factory fabricated double wall insulated ductwork prefered. Insulation on outdoor ductwork shall be phenolic type (fiberglass/ mineral wool is not allowed). Outer duct shall be painted galvanized steel, 304 stainless steel or aluminum. Bottom of duct shall be a minimum of 24” above finished roof surface for future roof repair/replacement.
- Insulation: All ductwork insulation shall comply with CPS Specification Section 23 07 13.
- Volume Dampers: Volume dampers shall be included for every air outlet and inlet in order to provide proper balancing of the systems.
- Fire Dampers: Fire Dampers shall be included at all penetrations through 2-hour or greater fire separations, including both walls and floors. Access doors shall be included at all Fire Dampers for reset and inspection. Note: City of Chicago requires two back to back 3HR dampers in all 4HR rated walls.
- Accessories: Ductwork Accessories shall comply with CPS Specification Section 23 33 00. These include Duct Silencers, Access Doors, Dampers and Flexible Connections.
- Cross-Contamination Prevention: Sufficiently exhaust each space where hazardous gases or chemicals may be present or used (e.g. Chemical Storage Rooms and Cabinets, housekeeping/janitors closets, laundry areas, copying and printing rooms), using exhaust rates determined by LEED Minimum Indoor Air Quality The greater of Performance, code and 0.50 cfm per square foot, to create negative pressure with respect to adjacent space when the doors to the room are closed. Provide a separate fan or fans for each of these type of spaces.