Mechanical System Description

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Julie McCarthy
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1 1. Building Description: Mechanical System Description The building is a Type-1B construction, 9-levels, non-high rise building with 67 affordable family housing units. The first level of the structure includes retail, bathrooms, utility and trash rooms, entry lobby, yard, and offices. The Second level contains 8 dwelling units and the typical residential level contains 9 residential units. The first floor yard and a 9 th floor terrace/community garden will provide common open space with hard-scaped and landscaped areas. The project is located at the corner of Sixth Street and Howard Street and it replaces an existing building at the same location. The project will subscribe to the Multifamily GreenPoint rating system for demonstrating the building energy and water efficiency and other aspects of the Green Building design. The project will also comply with the SF Green Building Ordinance requirements including the Full Building Commissioning. 2. Mechanical System Description: A. Residential Units Heating and Ventilation System. 1. Space Heating: A central hot water heating plant shall be located in the Mechanical Penthouse on Low roof and shall consist of (2) high-efficiency condensing gas boilers, (2) circulation pumps, with automatic lead-lag operation, and VFD for variable flow control. A simple Building Automation System (BAS) will be provided to start-stop and control the boilers, pumps, hot water supply temperature reset based on outside air stat and hot water distribution piping to all heating terminals. b. Residential Units: Each bedroom and living room shall be provided with hot water baseboard convectors or flat steel tube radiators (Runtal or equal) with remote wall thermostats. c. Bathrooms: Provide mechanical ventilation with ceiling mounted exhaust grille connected to the scavenger exhaust fans located on roof. The exhaust duct will be connected to the common exhaust duct riser with 22-inch subduct. d. Kitchen: Recirculation type Kitchen range hood will be provided for each kitchen. Additionally, a kitchen general exhaust grille will be provided and ducted to the common exhaust riser with scavenger exhaust fan on roof. The exhaust duct will be connected to the common exhaust duct riser with 22-inch subduct. e. Ventilations: Due to the project site being located at a heavy traffic area, and to comply with the City Department of Public Health mandate Article 38, up to 3 rd floor the dwelling units will be positively supplied with fresh neutral temperature air from the roof and is exhaust through the common Bath and Kitchen exhaust system. For units with multiple rooms, either the supply air will be distributed. For dwelling unit on fourth floor and above Z-ducts will be provided to provide ventilation air to the units. The combination of positive supply and/or Z-ducts and the 24x7 common exhaust fans on roof, provides ventilation for each unit. B. Residential Common Areas: 1. Corridors: Provide mechanical ventilation with 100% tempered (gas heating) outside air and 100% exhaust / relief. Corridor exhaust system shall be sized to provide minimum ventilation per the T-24 Standards. Supply and exhaust fans shall be located on roof, with duct risers down shaft to serve Levels 1 thru 9. Fire Smoke Dampers shall be provided at all corridor supply and exhaust air outlets. Supply fan shall run continuously, 24 hours a day. Ajmani & Pamidi Inc. Page-1 May 20, 2013

2 2. Trash/Janitor Rooms: Provide mechanical ventilation exhaust with ceiling exhaust fans, discharge into exhaust shafts via branch ducts. The shaft penetrations shall be protected with FSD. 3. Central Laundry Rooms: The central laundry rooms are located on 3 rd and 9 th floors facing the Howard Street. Each room is provided with Hi & Low lovers to provide combustion air to the dryers and general ventilation to the room. The dryers are exhausted sideways to the street. The dryer exhaust vents shall be provided per 2010 CMC with smooth interiors. Where the exhaust duct length exceeds the code maximum, a booster exhaust fans will be provided and interlocked with the operation of the dryer. 4. Exhaust shafts: Shall be constructed of galvanized sheet metal ductwork, up to rooftop scavenger exhaust fans. The exhaust fans shall run continuously, 24 hours a day. C. Office & Multipurpose Room HVAC System: 1. Space Conditioning: Each of the office spaces and the 1 st and 2 nd floors and the multipurpose rooms on floors 4, 6 & 7 will be provide with a central split heat pump system which can serve multiple indoor fan coil units with wall or ceilingmounted cassettes. The air cooled outdoor heat pump unit shall be located on roof. D. Main Multi-Purpose (Community) Room HVAC: 1. The main Multipurpose room is located on the 1 st floor and in the Northwest corner. The room is provided with split system heat pump units. Outside air louvers are provided on the interior yard side and the on the Howard Street sides to draw fresh air and mix with the return air and conditioned and supplied to the space. Excess air is relieved to outdoors through relief louvers and barometric dampers. The indoor fan coils will be ceiling hung within the room in soffited areas. E. First Floor common areas and equipment room Ventilation: 1. Outside Air Supply and Exhaust: Provide mechanical air handling unit with hot water heating coil, ceiling hung, with tempered 100% outside air for supply and in-line exhaust fan for excess air, odor and miscellaneous exhaust air removal. G. First Floor Retail Kitchen Ventilation System: 1. Type-I Grease Hoods: Provide mechanical ventilation with welded metal ductwork with cleanouts and duct riser up to mechanical penthouse roof. Grease exhaust fans shall be located on roof. Provide one system for Retail A. 2. Type II Vapor Hoods: Provide mechanical ventilation with welded stainless steel ductwork and risers up to mechanical penthouse roof. Exhaust fans shall be located on roof. Provide one system for Retail A & B. 3. Make-Up Air System: Provide space on the roof for hood make-up air unit on the roof. H. Life Safety System: 1. Fire smoke dampers shall be provided at all corridor supply and exhaust air outlets. Interlock dampers with Life Safety Control System.\ Ajmani & Pamidi Inc. Page-2 May 20, 2013

3 2. Duct smoke detectors shall be provided at all Air Handling Units in First Floor and the HV-1 unit on Roof, for automatic shutdown. I. Retail Tenant Space Provisions: 1. There are two retail spaces located on the 1 st floor facing the 6 th street. The retail space at the corner of Howard and 6 th Street is dedicated for a restaurant tenant. Outside air and general exhaust will be provided through the exterior wall louvers on 6 th street side. Additional Type-I kitchen hood make-up air will be brought-in from the rooftop make-up air unit. The ductwork and the shaft will be provided for future connection by the tenant provided rooftop make-up air unit. Similarly, exhaust duct risers in dedicated shafts will be provided for Type-I and Type-II hoods from the tenant space to the roof. Space will be ear-marked for the future tenant exhaust fans and make-up air unit. 2. The non-restaurant tenants will be provided exterior wall louvers for outside air and general exhaust on the 6 th street side. The retail tenant will provide necessary heat pump units within his space and the condensing units on roof to provided heating, cooling and ventilation for the respective space. the tenant will be provided with duct risers for type-ii hood exhaust. J. PG&E Gas Meter Room Ventilation: The PG&E gas meter room will be ventilated in accordance with the PG&E Rule J-16 with explosion-proof supply fans and gas detection system. Plumbing System Description A. Residential Units Plumbing System: 1. Domestic Cold Water: a. One (1) house meter shall be provided. Water meter shall be located under sidewalk, with backflow preventer at incoming service located inside building. Water pressure booster pump shall be provided to provide adequate water pressure to fixtures on Floors 3 thru 9 and with hydro-pneumatic tank and expansion tanks located in the penthouse Boiler Room at low Roof. b. Dedicated water meters will be also provided one each for the retail tenant space. The meters will be located under the side walk. Water pipes will be extended to each of the retail spaces, valved and capped for future use. 2. Domestic Hot Water: a. A central hot water heating plant shall be provided to service the dwelling units and the common areas and located in penthouse Boiler Room on low roof and shall consist of (2) gas fired hi-efficiency condensing water heaters, a storage tank and (2) re-circulating pumps (one is standby). The system shall be a re-circulated system. Provision will be made for integration of Solar Hot Water System. b. Each of the three retail tenants will generate their own hot water based on their demand. 3. Natural Gas System: a. One house meter shall be provided to provide gas supply for the water heaters, hydronic boilers and the HV unit on the roof. Gas meter room shall be located adjacent to exterior wall facing 6 th street, with distribution piping to Ajmani & Pamidi Inc. Page-3 May 20, 2013

4 all gas appliances and mechanical equipment on roof and laundry dryers. b. Each of the two retail spaces will be provided with dedicated gas meters and located in the common PG&E gas meter room. Gas piping will be extended from the meter room to the respective tenant spaces, valved and capped for future use by the tenant. 4. Potable Water Booster Pump: A packaged skid mounted booster pump for the domestic water supply. The pump will be located in the 1 st floor pump room to boost the available City water supply pressure to serve the building. A hydropneumatic tank will be provided at the water heater room to maintain constant pressure in the system under low load condition without bringing on the booster pumps. 5. Reclaimed Water Booster Pump: A packaged skid mounted RW booster pump will be provided in the booster pump room at the 1 st floor level to boost the available City water supply pressure to serve the building. A hudropneumatic tank will be provided at the water heater room to maintain constant pressure in the system under low load condition without bringing on the booster pumps. 6. Backflow Preventers: City approved type Reduced Pressure Backflow Preventers (RPBP) will provided for each of the building potable water supply mains, the Reclaimed water supply main, the Irrigation water supply main and each of the restaurant tenant domestic water supply mains. All RPBPs will be located within the 1 st floor pump room. 7. Solar Thermal System: A Solar Thermal (ST) system will be installed on the roof consisting of solar panels, (1) 1,500 gallon solar thermal storage tank, heat exchanger, circulation pumps, closed loop solar panel loop utilizing food-grade ethylene glycol and the open loop domestic hot water loop. The ST system provider will be responsible for providing the system to achieve a solar fraction capacity of 0.3 to 0.7 based on the availability of the roof space for the panels. The ST system will be used to preheat the domestic cold water supply to the water heaters. The solar thermal system components will be located on the low roof near the Domestic water heater equipment room. The plumbing contractor will be specified to provide all the interconnection piping between the potable hot water system and the ST system. All piping will be labeled to identify the system and direction of flow. 8. Building Reclaimed Water (RW) System: As mandated by the City of San Francisco SF-PUC Ordinance, all the water closets, urinals, trap primers, ornamental fountains, mechanical system make-up water will be plumbed separately to utilize the Reclaimed Water (RW) to flush or supply to these fixtures. A rain water harvesting system consisting of 5,000 gallon underground storage cistern, filtration system and pumping system will be provided to reduce the run-off per the City ordinance. The reclaimed water from this system will be used to supply the flushing requirements for the dwelling unit & common area water closets. As the available water pressure will be low, a booster pumping system will be specified. The RW backflow preventer and the booster pump will be located in the domestic water pump room. The entire RW piping system will be specified to use the purple piping system per the California Plumbing Code to clearly distinguish it from the potable water system. Similar to the potable water system, the RW piping and fittings will be Type-L copper but wrapped with purple color tape and labeled to distinguish it from the potable water piping system. Domestic water supply will be connected to the RW system to replenish the system during non-rainy season. 9. Landscape Irrigation Water Supply: One water meter shall be located under sidewalk with backflow preventer located inside building with distribution piping to all planter areas and valve stations. Planter irrigation distribution piping shall be Ajmani & Pamidi Inc. Page-4 May 20, 2013

5 capped for future extension by landscape contractor. 10. Sanitary & Storm Drain: Complete gravity drainage and venting for all fixtures. Storm water drainage shall be directed through a Retention Holding System. 11. The Interior yard landscape drainage shall discharge through sand interceptor. B. Retail Tenant Spaces: 1. Domestic Cold Water: One meter per space shall be provided. Water meter shall be located under sidewalk, with backflow preventer at incoming service located inside building. Water system shall be served with street water pressure for Floors 1 and Domestic Hot Water: A central hot water heating plant shall be located in the Boiler Room and shall consist of (2) gas fired hi-efficiency condensing water heaters, a storage tank and (2) re-circulating pumps (one is standby). The system shall be a recirculated system. 3. Domestic Hot Water for Dishwasher: An integral electric heater shall be provided by dishwasher supplier with dishwasher to boost water temperature to 180 deg.f. 4. Natural Gas System: One meter per space shall be provided in the house gas meter room with distribution piping to all kitchen / dining facility gas appliances and equipment. 5. Sanitary Drainage: Each of the retail tenant spaces will be provided with a 4 sanitary waste and a 3 vent stub outs within the respective tenant spaces for future connection to the toilet rooms added by the respective tenants. Per the City FOG ordinance, the future restaurant tenants will be required to provide point-of-use grease extraction devices (GEDs) to collect and recycle grease waste from each restaurant tenant space. C. Plumbing Fixtures: All fixtures shall be low-flow fixtures with water saving flow restrictors. 1. Water Closets: 1.28 gpf 2. Urinals: None in the project 3. Showers: 1.5 gpm 4. Kitchen Sink: 2 gpm 5. Unit Bathroom Lavatory: 1.5 gpm 6. Public Restroom Lavatory: 0.5 gpm Fire Protection System Description A B General: The fire protection system will be provided for the full coverage of the building in accordance with requirements of California Fire Code, NFPA 13, 24, City & County of San Francisco fire department requirements. Fire Sprinkler Classification: A. Light Hazard The major portion of the main building including the office and public areas. The maximum spacing per head shall not exceed 225 sq. ft. The flow density shall be 0.1gpm/sq. ft. over 1,500 sq. ft. area of sprinkler operation or as per NFPA 13. B. Ordinary Hazard Mechanical rooms, Electrical rooms, and Equipment rooms and similar areas. The maximum spacing per head shall not exceed 130 sq. ft. The flow Ajmani & Pamidi Inc. Page-5 May 20, 2013

6 density for Group-I shall be 0.16gpm/sq. ft. (0.19gpm/sq. ft. for Group-II) over 1,500 sq. ft. area of sprinkler operation or as per NFPA 13. C D E F Fire protection water supply will be from the city. The building fire water line will be extended 5-0 beyond the building exterior wall for connection to the site fire main under civil/site work. At the point of connection between the building supported piping and the street utility piping, settlement joints will be provided to allow for ground settlement under the Civil scope of work. Fire Pump: A fire pump, a jockey pump and associated control system will be provided for the building and located in a dedicated room adjacent to the booster pump room at the basement level. The double check detector valve assembly (DCDVA) will be located within the fire pump room. The room will be equipped with appropriate floor drains to handle the discharge from the relief valves and test valves. Fire Department Pumper Connections: Fire Department Connections (FDC) will be provided and located as required by the local Fire department. A minimum of two (2) FDCs are anticipated for the project and located atleast 50 feet from a hydrant. FDCs shall be provided with polished chrome finish. These locations will be discussed with the local Fire Department and reflected on the architectural drawings. Sprinkler Drain and Test Risers: 2" sch. 40 galvanized drain risers will be located at each of the combination stand pipe in the stairwell for the sprinkler control valve flow test. The discharge from the drain riser shall be terminated indirectly into the building sanitary sewer system per the City of SF Plumbing requirements. The drain riser will be appropriately labeled per NFPA. - END - Ajmani & Pamidi Inc. Page-6 May 20, 2013

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