School of Human Ecology Building UW Madison, Wisconsin. By Arnold & O Sheridan, Inc. A&O Project No Draft Report 01/12/01 revised

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1 School of Human Ecology Building UW Madison, Wisconsin By Arnold & O Sheridan, Inc. A&O Project No Draft Report 01/12/01 revised HEATING, VENTILATING AND AIR CONDITIONING SYSTEM REPORT Introduction The heating, ventilating, and air conditioning (HVAC) system in the school was reviewed. The HVAC needs of the school have changed and the HVAC system is no longer capable of meeting the environmental needs of the facility and the proposed remodeling. This HVAC report will summarize an assessment of the existing systems, equipment, and utility services. This report will also provide a summary of recommendations for remodeling and the building addition HVAC system. The remodeling and addition will be designed to incorporate a phased construction approach. This will maintain critical functions in the building by constructing the addition first, relocating critical space uses, and then remodel the existing facility. HVAC SYSTEM ASSESSMENT SUMMARY General The existing HVAC systems, equipment arrangements, locations, age, operating conditions, service history, and control problems indicate the systems should be completely replaced in a remodel project. Many of the components are 30 years old and have outlived the normal life expectancy. The systems cannot provide the environmental control and zoning needed for the technology requirements and upgrading of the facility. The existing air handling units are located on each floor adjacent to occupied classrooms, offices, and lab space. This has caused significant noise problems. Several areas are left unoccupied due to high noise levels. Return air is restricted from returning to units and causes air balance problems. The systems are constant volume reheat design. Energy improvements can be made with variable air volume features and economizer cycles. The existing systems should be removed and replaced with new in remote isolated mechanical rooms for sound control. Centralizing the equipment also reduces maintenance and repair costs. Steam Service High pressure 175#), low pressure 15#), 2 pumped return and 1½ (80#) compressed air enter the 1912 and 1948 buildings. The services are routed from Linden Drive Page 1

2 around the building on the east and around the north side. These services also feed other buildings east and north. (Van Hise and Observatory sites.) Assessment of the existing services indicates they are not large enough to serve the building addition and remodeling. New utilities are required. Cap existing utilities in tunnels. The low pressure 15#) steam, 1½ pumped return and 1 (80#) compressed air services to Child/Family Study and Preschool Buildings shall be demolished and capped at the steam main in Linden Drive. Building systems removed by a demolition contractor. Chilled Water Service Chilled water (8 200#) enters the west side of the 1948 building. A building secondary pump system operates in summer weather to distribute chilled water to the building air handling units. Assessment of the existing service indicates the new addition will be located over the service and a new service should be provided due to age, size, and location. Natural Gas Service Natural gas enters the west side of the 1948 building. The new addition will be located over the service. A new natural gas service is not required for the facility since there are not any wet labs proposed. Heating System Low pressure steam and condensate return is distributed to air handling units, heat exchanges, and domestic water heaters. Hot water is distributed to reheat coils and perimeter wall fin radiation. Zoning and control is a problem. Windows were observed open in winter weather. Air Handling Equipment There are 12 constant volume air handling units scattered throughout the basement, attics, and occupied floors on all wings. The units are marginally accessible, do not mix air well, and contribute to ambient noise. Many of the units are 30 years old. There does not appear to be an economizer cycle for the units unless lab or room exhaust has a 100% outdoor air scheme currently. The textile museum is a controlled environment space with primary and back-up air handling systems. City water cooled condensing units are used. Temperature and humidity conditions to be maintained are 60 and 50% RH, but the existing systems cannot maintain these conditions. Page 2

3 Ductwork Systems Supply and return ductwork is galvanized steel with slip and drive joint and largely lined for sound control. Supply is ducted to room reheat coils for zoning. Return generally uses the corridor with common return. The return air path is blocked or does not exist in many areas since door transoms are mechanically secured. Ductwork appears dirty on the interior due to use of low efficiency roll filters in the air handling units. Exhaust ductwork consists of 12 exhaust fans serving lab hoods, kitchen hoods, general and toilet exhausts. Lab exhaust fans are located in unaccessible attic areas with positive ductwork in the building. Exhaust air discharge is through gravity ventilators that potentially recirculate the fumes to air intakes. Exhaust systems are very noisy in occupied lab areas. Temperature Control Systems The existing control systems are largely pneumatic with receiver controllers. Many of the systems and components function marginally and out of control. Areas overheat and windows are cracked open in winter. The systems are over 30 years old and cannot be cost effectively repaired. A Johnson Control Metasys system provides monitoring of low limit, start/stop features and limited temperature input for some of the systems. This appears to be a partial system with no primary control functions. Recommend this system be replaced with current technology air handling unit DDC controllers for complete DDC initiated control. The old controllers will be turned over to the UW. HVAC SYSTEM SCOPE DESIGN General The existing HVAC system shall be completely replaced in the remodeled building and new systems provided in the addition as defined. Work for addition and remodeling shall be done in a phased project approach. The HVAC system and equipment shall be designed to meet State of Wisconsin DOC design, energy efficiency, service, and comfort requirement for occupancy. The HVAC load calculations shall utilize ASHRAE 1% coincident dry bulb/wet bulb criteria for exterior. Interior deign shall be based on 70 F, 30% RH average winter and 75 F, 50% to 60% RH summer, except critical textile museum, textile work rooms, gallery and staging rooms will require 60 to 65 degrees and 50% (±5%) RH year around. Load calculations shall include infiltration, sensible and latent heat gains, equipment loads, lighting loads, people, solar and transmission heat gains. Typical personal computer heat gain load used is 150 watts. There will not be a diversity factor applied to internal loads. Page 3

4 The outdoor ventilation air design shall meet ASHRAE Standard Table 2 for design ventilation minimum outdoor air at any supply air flow, except equation 6-1 dynamic fraction outdoor air calculation not utilized. The HVAC design shall be integrated in the building design and will provide adequate space for installation, service, and maintenance. Locate service entrances and vibrating equipment on grade mechanical rooms. Locate air handling units in mechanical rooms on grade with vibration isolation. The roof of the facility shall not be used for mechanical equipment due to visibility from adjacent areas. Exhaust ventilation shall discharge through roof gravity ventilators. HVAC Equipment Selections HVAC systems and equipment shall be specified and designed utilizing DFD Engineering Specifications and Guidelines to maintain state building construction uniformity. All design schedules and details shall be provided on the construction drawings. Include performance data and ratings for an equivalent selection process and contractor s manufacturer selections. Mechanical equipment shall be isolated from occupied areas with minimum 12 concrete and acoustical treatment. Occupied area will have a NC of 32 to 35 for moderately quiet rating in office and classroom type occupancies. The HVAC systems and equipment shall be designed to satisfy heating, ventilating, and air conditioning loads for the building automatically as seasonal loads and occupancy changes. Campus steam heating plant shall be utilized as the only heating source for facility. Campus chilled water shall be used as the only air conditioning source for the facility, except the textile museum, gallery and textile work areas will have a stand alone HVAC and chiller system to maintain critical environmental needs. The HVAC air handling systems shall be designed as variable air volume system. Vertical tube steam preheat with internal face/bypass (VIFB) shall be used for units with turndown of 50%. Chilled water cooling coils shall be utilized. Zoning will be provided by VAV boxes with hot water booster coils. Each room shall be individually zoned. The air handling systems using variable air volume design shall maintain minimum outside air as the load and supply air quantity varies. Variable volume boxes shall provide 30% minimum air flow and outdoor air flow measurement. Site Utilities Existing high pressure steam and chilled water services shall be removed and safely capped at connections. Page 4

5 New high pressure steam 175#, 3 pumped condensate return and 2 (80#) compressed air shall be provided. Services shall be installed in 36 x 24 concrete box tunnel per DFD design criteria. Connect to the existing steam pit in Linden Drive and route service into a mechanical room in the existing building first floor southwest corner. Provide steam reducing station location. Modify and expand steam pit as required for service and piping work. Piping shall be welded black steel with expansion joints. New 12 chilled water supply and return (200# design) shall be provided from Linden Drive connections into mechanical room in the existing building first floor southwest corner. Provide for secondary pumping location. Install system per DFD design criteria. Piping shall be ductile iron class 250 AWWA C110 design for direct bury 6-0 minimum. The chilled water service needs to be completed before the addition can begin. New natural gas service not provided. Building HVAC Systems Existing mechanical rooms and system shall be completely demolished. Provide new mechanical rooms and systems for building addition and remodeling with remote systems on first floor or garage levels of the existing and new facility. Provide new chilled water service into the existing building prior to starting new addition. Connect to existing systems temporarily and maintain existing building operations. Mechanical System #1: Existing Building (East Half) Location: Southeast Corner Existing First Floor Size: 40 x 50 x 16 high space Unit: 50,000 cfm built-up vav custom unit with dual supply/return fans and vertical air shafts sized at 150 square feet to fourth floor per DFD standards. Louvers 16 x 10 intake and exhaust with 25-0 separations required. Mechanical System #2: Existing Building (West Half) Location: Northwest corner existing 16 basement (first floor). Remove first floor slab and create a 1½ story space combining the basement and first floor into one mechanical space. Size: 40 x 60 x 16 high space Unit: 60,000 cfm built-up vav custom unit with dual supply/return fans and vertical airshafts sized at 150 square feet to fourth floor per DFD standards. Louvers 16 x 10 intake and exhaust with 25-0 separation required. Campus steam, chilled water, and compressed air services with head end equipment in this mechanical room. Services are routed into first floor southwest corner and north in pipe corridor to north basement/first floor mechanical room. Page 5

6 Mechanical System #3: New Building Location: New Parking Garage North Side (basement level) Size: 50 x 120 x 16 6,000 s.f. high space Unit: 70,000 cfm built-up vav custom unit with dual supply/return fans and vertical airshafts sized at 200 square feet to third floor per DFD standards. Provide areawells for air intakes and exhaust and louvers 20 x 10 with 25-0 of separation. Mechanical System #4: Pre School Areas Location: Northwest Corner New First Floor Size: 30 x 50 x 12 high space Unit: 30,000 cfm built-up vav custom unit with single supply/return fans and air delivery to preschool zones. Provide louvers 12 x 8 intake and exhaust with 25-0 separation. Duct shaft 40 Square feet to first floor. Mechanical System #5: Textile Museum Areas Work Rooms and Gallery Location: New Construction Parking Garage Northside Basement Level combined with system #3 mechanical room Size: Combing in mechanical room with System #3 room. Unit: Provide two redundant constant volume reheat systems using packaged air handling units with VIFB steam preheat, glycol cooling, 85% filtration, hot water reheat and stem injection humidifiers for zoned control. Maintain space at 60 F to 65 F with 50% RH. Systems (2) size estimated at 10,000 cfm each. Provide outdoor intake and exhaust louvers 8 x 5 with 25-0 separation. Provide duct shaft sized at 40 square feet to floors required. Mechanical System #6: Chiller Room Location: New Construction Parking Garage Northside Basement Level Size: Combined with system #3 Mechanical Room Unit: (2) 50 ton water cooled chillers, glycol pumping, condenser pumping, remote sump and storage system. System serves air handling units for the textile museum, work rooms, gallery and related work areas. Provide new cooling towers on grade north of parking garage in excavated tower well 800 sq. ft. Electrical Vault / Switchgear / Generator Rooms: Location: New Construction Parking Garage Level Size: Per Electrical system design Unit: Provide two areawells with outdoor/exhaust ventilation air systems for each room need to locate diesel exhaust fumes away from any air intakes 100 minimum. Cooling Tower (Winter Cooling) Location: In excavated well north of new garage level mechanical room Size: Two towers at 10 x 16 each in well approximately 800 s.f. area. Towers flush with grade. Unit: Campus chilled water is not available year around. The textile museum, gallery, and associated work rooms require critical temperature and humidity control This Page 6

7 requires winterized cooling system. In the future, the campus chilled water system may be available as condenser heat rejection for chillers. This will be reviewed. Steam and Condensate Heating System High pressure steam and condensate building services from manhole in Linden Drive shall be provided. Steam pressure reducing valves shall be provided in parallel and reduce from 175 PSIG to 12 PSIG for distribution to building systems including steam preheat, domestic water heat exchanger, and building reheat heat exchanger system. Piping, fittings, valves, accessories, and cleaning for building steam heating shall be provided. Steam reducing station in mechanical service entrance room. Piping shall be insulated per DOC Chapter 63. Water Distribution System Piping, fitting, valves, pumps, accessories, cleaning and treatment for the building heating hot water, chilled water cooling, condensate drain and water cooled condensing unit piping shall be provided. Hot water reheat will be provided for all systems. Piping shall be insulated per DOC Chapter 63. HVAC System Insulation Insulate all HVAC piping, ductwork and equipment per DOC Chapter 63. Acoustical sound control for equipment is required. Water Chiller System Campus chilled water provided for building cooling for summer season only. Stand-by building chiller provide for textile museum, work rooms, gallery, and related areas. Textile museum, textile work rooms and gallery require cooling year around with separate 50 ton (estimate) water cooled glycol chiller providing 35 glycol for cooling. Provide back-up 100% standby chiller. Chiller located in parking garage basement mechanical room with remote sump and condenser/evaporator pumping stand-by pumps. Two redundant forced draft cooling towers installed in well north of mechanical room. Caution required in location to not mix exhaust with building air handling unit air intakes. Terminal Heat Transfer Units Terminal heat transfer equipment including hot water reheat, unit heaters, wall fin radiation, cabinet unit heater and convectors are included. Perimeter heating will be provided along Page 7

8 building exterior in all areas. The perimeter heat will be zones with the VAV boxes for similar use and exposures. Air Handling Units These areas apply to offices, classroom, lecture halls, public areas and daycare systems. Central station air handling units with centrifugal fans, double wall casings, steam VIFB preheat, with face and bypass and chilled water cooling coils, humidifier, drain pans, integral face/bypass sections, motors and filter box with refilters and 65% efficiency bag final filters shall be provided. Units over 40,000 cfm shall be custom design with redundant fans. The air handling units shall be designed as variable air volume (VAV). Variable air volume systems shall utilize variable frequency drives for supply and return fans, air flow measuring stations and fan tracking. Variable volume units shall have terminal booster coils with 30% minimum stops. Outdoor ventilation air shall be controlled to maintain minimum outdoor air as system supply air flow modulates in a VAV system. A cooling coil air drying feature will be provided for all air handling units. Textile Museum, Gallery, Work Rooms and Related Areas Air handling unit system shall include a (2) 100% redundant air handling systems. Each system shall consist of a packaged air handling unit with glycol cooling coil, 85% bag filters and zoned hot water reheat with steam humidifier. Units shall be 100% recirculated air with ventilation air provided by central building system for occupied hours. Each air handling unit system shall be capable of maintaining 60 to 65 at 50% RH in areas. Provide (2) redundant water cooled chiller system (2) at 50 ton to provide 35 degree glycol for temperature cooling of areas. Provide (2) redundant blow through winterized cooling towers with remote sump in mechanical room for heat rejection. Chemistry Lab Exhaust Systems Wet lab classrooms and fume hoods not provided in the facility. Humidification Steam jacket manifold type with rapidsorb grid for 100% entrainment in 24 will be provided in new central air handling units and each zone of the textile museum, gallery and work areas. Low pressure steam supply with manifold distribution will be utilized. Include temperature switch for condensation prevention. Size manifold and orifices for steam capacity required. Orifices shall be metallic. Page 8

9 Campus steam utilized for direct injection. There are not any chemical to contaminate the air streams. Fan Systems Centrifugal fans shall be provided. Fans shall be located inside the penthouse or on accessible flat roofs for service and maintenance. Wet lab fume hoods not provided. Fan systems shall be provided with vibration isolation, sound attenuation, motor, drive, and motorized dampers. Parking Garage Ventilation Provide exhaust ventilation for the parking garage with CO monitoring system and outdoor air intake louvers. Parking garage is not heated. Ductwork Distribution System Supply, return, outdoor and relief air ductwork shall be constructed of galvanized sheetmetal according to SMACNA standards for 4 pressure ratings required and construction with Seal Class A. Ductwork shall be installed with long radius elbows and fittings where room permits and square radius elbows with turning vanes for mechanical areas. Exhaust ductwork shall be galvanized sheetmetal except fume hood exhaust shall be spiral PCD clad ducts. Commercial food service ductwork shall be 18 gauge stainless steel. Thermal and acoustical protection shall be provided for all air distribution systems. Consider perforated dual wall ductwork downstream of air handling units and duct liner on return air systems. Insulate all other ductwork per DOC 63. Leak test all main ductwork in accordance with SMACNA leakage test manual. Direct Digital Control System The building HVAC system shall be connected to the UW Madison Campus Johnson Control Metasys DDC/EMS System via fiber direct link. Building areas can be occupied from 7 a.m. to 1 a.m. depending on area and use. Provide global communications trunk and BACNET compatible interface. Provide building PC work station in main mechanical room. The HVAC systems shall utilize DDC initiated sequences with pneumatic actuation. Provide DDC application specific controllers for each air handling system. The work in this section will be negotiated with Johnson Controls. A complete points list and sequence of operation shall be provided. Include status, monitoring, start/stop, control, sequencing, start-up and training complete. Page 9

10 Pneumatic and Electric Control System System shall utilize direct digital control logic and initiated controls with pneumatic actuation for air handling units. Pneumatic thermostats with pneumatic actuation for room temperature, and air flow controls. A refrigerated dryer will be provided in the building. Campus 80# air shall be extended for building temperature control use. Miscellaneous terminal unit controls shall utilize pneumatic control strategy. All cables, sensors, transducers, input/out devices, relays and interlock interface with DDC system shall terminate with tagged label in DDC interface panel. All pneumatic devices and tubing shall terminate with tagged label in DDC interface panel. Temperature Control Sequences This defines the control sequences for the direct digital controls with pneumatic actuation specified. Systems are variable volume heating cooling and ventilating air handling unit with chilled water cooling coil, floating dry bulb economizer steam VIFB preheat coil, humidifier, supply and return variable speed fan controls, air flow modulation control, building pressurization, fan tracking, minimum outdoor air, minimum OA controls and fan interlocks. The system serve multiple variable volume boxes with hot water heating coils, and perimeter radiation. For temperature/humidity controlled rooms provide constant volume systems with features similar to the VAV systems. Provide DDC initiated controls complete. Individual room by room zoning provided by vav box and hot water reheat. Testing Adjusting and Balancing Include all air and water testing, adjusting and balancing for the entire project. This work will be contracted separate from the HVAC contract and the cost is not to be included except for coordination work required. Work shall be performed by an AABC or NEBB certified testing and balancing contractor. Emergency Power Requirements The HVAC systems shall not be on emergency power except for control compressed air dryer, control heating panel, building hot water pumps and building condensate pump. Fire Mode Operation Air handling system shall shutdown in fire alarm mode. Systems shall automatically restart by fire alarm reset sing start-up sequencing. Page 10

11 Building Expansion Provisions have not been included for any future expansions. END OF HVAC SCOPE DESIGN Page 11