Materials
All above ground natural gas piping shall be steel. All below ground piping shall be plastic. All piping, valves and other specialties shall meet the requirements of Specification section 33 51 13.
Service
Gas service shall be coordinated with Peoples Gas early in the design process. Service pressure shall be at 2 PSI unless unavailable at the project site. Service capacity shall be calculated based on the connected load plus future projected load for the facility. This includes Mechanical equipment, water heaters, generators, Science Classrooms, Kitchen equipment, Laundry Dryers, Shop Area use, and any other needs. No diversity shall be taken with this load.
If the proper gas pressure cannot be achieved at all pieces of equipment, a Gas Booster Pump system may be needed. This shall be determined by a Pressure Loss calculation performed by the EOR. If this system is needed, a packaged, dual pump, constant speed system shall be used. This packaged system shall include a control panel that can be directly connected to the BAS to monitor status and alarms. Obtain approval from CPS prior to adding a Gas Booster. On renovation projects or where an existing booster has failed, determine if the gas booster can be eliminated based on connected equipment requirements or by changes to utility/equipment regulators, or if the utilities service can be upgraded. Review potential elimination of booster with CPS. Where possible and cost effective, CPS prefers to eliminate gas boosters
Sizing
All gas pipe sizing shall conform to local Codes and be based on downstream capacity, pressure loss and pipe materials.
Distribution
All gas piping shall route within the building, with roof and wall penetrations made as close to the units as possible. Each branch pipe shall include an easily accessible isolation valve with the ability to lock closed. All piping shall be clearly labeled. 2 PSI gas may be routed directly to boilers, water heaters, generators and RTUs. Provide a dedicated branch with isolation valve and PRV set at 7”WC to serve all other equipment. On renovation projects, gas piping may be routed horizontally on the roof with CPS approval. Wood/masonry blocks shall not be used for roof piping supports. All outdoor piping shall be painted with protective coating. Coordinate painting with division 9. All 2 PSI piping and 0.5”PSI piping greater than 2” shall be welded. All 0.5PSI or less piping 2” or smaller shall be threaded or welded.
Emergency Shutoff
In all areas of gas usage, including Mechanical/Boiler Rooms (boilers/water heaters with an input greater than 400MBH), Kitchens, Science Classrooms (see Science Classroom requirements below), natural gas Generator Rooms, and Shop Areas, an emergency shutoff button shall be provided either at the Teacher's Station or near each exit door of the space, as Code requires. This button shall include a lock to reset. Electrically actuated valves shall be normally closed and fail closed on power loss.
Carbon Monoxide Detector (CO)
In all areas of gas usage, including Mechanical/Boiler Rooms, Laundry Rooms with gas dryers, Kitchens, Automotive/Vehicle (truck/tractor/snow blower) Storage/Repair/Parking Spaces, Science Classrooms (Refer to Science Classroom requirements below), natural gas Generator Rooms, rooms heated with gas fired unit heaters, and Shop Areas, etc., a hardwired CO detector shall be provided and integrated into the building fire alarm system as Code requires. Provide additional detectors in the first space served by gas fired ventilation equipment as required by the City of Chicago Building Code. See Electrical Chapter 7.0 for additional requirements.
Equipment Connections
Connections to all equipment shall include a local isolation valve, unions, appliance regulator and a dirt leg prior to the final connection to the equipment. All Mechanical/Plumbing/generator gas fired equipment shall include an individual isolation valve, gas train with a pressure regulator vented to the outdoors, dirt leg, and a hard connection to the equipment. Kitchen/dryer/generator equipment shall be made with a Code compliant flexible connector. All piping within a Science Classroom shall be hard piped to the gas turrets. Shop Area piping may require flexible connectors to some equipment, but this shall be limited.
Projects seeking LEED certification shall include whole project gas service metering (LEED Prerequisite) and may require Submetering of specific systems. All shall connect and report to the BAS. Design to facilitate submetering where applicable.