G07_Hill_AFB_IFS_Mechanical_Systems_Design_Requirements.pdf

Hill Air Force Base Installation Facilities Standards (IFS)

G07 Hill AFB IFS Mechanical Systems Design Requirements

Comply with Air Force Corporate Standards for Overview:

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Record of Changes

Change No. Date Location 1 7/21/2026 7.9.1 General Control System Operations (7.9.1.1 - 7.9.1.3) 2 7/21/2026 7.9.2 Control System Guided User Interface (GUI) Programs (7.9.2.1 –

7.9.2.1.2.1)

Summary of Sections in this Supplementary Document:

G07.0. General Requirements G07.1. Purpose and Scope G07.2. Energy Supply G07.3. Heat Generating Systems G07.4. Cooling Generating Systems G07.5 Distribution Systems G07.6 Kitchen HVAC System G07.7 Industrial Ventilation G07.8 Indoor Air Quality Standards G07.9 Controls and Instrumentation G07.10 Systems Testing and Balancing G07.11 Water Treatment G07.12 Other HVAC Systems and Equipment G07.13 Design Analysis and Design Documentation G07.14 Design Conditions G07.15 Basis of Design G07.16 Mechanical Calculations G07.17 Mechanical Drawings

G07.0. General Requirements

7.0.1 Note: This Supplementary Document is provided as a supplement to the Hill AFB IFS. If there are any discrepancies between this Supplementary Document and the requirements of the IFS, the IFS will govern.

7.0.2 This Supplementary Document supersedes the Hill Air Force Base Architectural Compatibility Guide dated 01 February 2019.

G07.1 Purpose and Scope The purpose of this part of the standard is to provide technical guidance and outline technical http://afcfs.wbdg.org/index.html requirements for the more typical aspects of the mechanical engineering design on Hill Air Force Base. The information provided shall be utilized by mechanical designers in the development of the plans, specifications and calculations, and shall serve as the minimum mechanical design requirements. Project conditions may at times dictate the need for designs that exceed these minimum requirements.

7.1.1 Refrigerant Management. When any work is conducted on a refrigerant containing appliance, whether moving, repairing, replacing, or installing new, the designer will include the following Refrigerant Management practices as part of the contract requirements:

7.1.1.1 Technicians performing any work must be EPA certified.

7.1.1.2 All refrigerants remain property of the Air Force and must be recovered.

7.1.1.3 Prior to removing or relocating existing equipment the remaining refrigerant must be evacuated from the equipment and all associated piping by a certified recovery or recycling machine. Reclaimed refrigerant will be returned to the government in containers supplied by the Air Force for that purpose.

7.1.1.4 Designers will list, on the project drawings and in the specifications, the type of refrigerant and the working charge of the equipment specified.

7.1.1.5 The plans and specifications shall require the installing contractor to update these drawings to show the actual size and type of equipment installed and the final total installed refrigerant charge.

7.1.1.6 The plans must state that the contractor is not permitted to purchase any refrigerant on behalf of the government. If additional refrigerant required beyond the pre-charge will be provided by the government.

7.1.1.7 The following regulatory and industrial bodies, U.S. Environmental Protection Agency (EPA), Air-Conditioning, Heating, and Refrigeration Institute (AHRI), American Society of Heating Refrigerating and Air Conditioning Engineers (ASHRAE), U.S. Department of Energy (DOE) shall dictate the utilization of new/used/refurbished equipment using refrigerant; where the more strict standard shall be applied when there is a conflict.

G07.2 Energy Supply

7.2.1 Fuel Source and HVAC System Selection. The use of electric resistance heating is not permitted without prior approval from base civil engineering office. Solar hot water shall be used in each design to furnish a minimum of 30 percent of the hot water demand if life cycle cost effective.

7.2.1.1 New facilities and facilities undergoing major and minor renovation as defined in UFC 3- 400-01, Energy Conservation, are required to be analyzed to determine the most cost effective and practical fuel source(s) and heating and cooling system types. Both recovered and renewable energy shall be used in each design to the maximum extent that is life cycle cost effective.

Provide energy analysis in accordance with UFC 3-400-01.

7.2.2 All new facilities and major renovations where the HVAC system is to be upgraded will consider the use of Ground Source Heat Pumps (GSHP) as the first choice. Provide mechanical system based on lowest life cycle cost. Provide completed compliance forms provided in ASHRAE 90.1 User’s Manual, any additional documentation to support compliance with this Standard, and applicable state government required forms.

7.2.3. Facility Energy Conservation. The Energy Policy Act of 2005 (EPACT05) and The Energy and Independence and Security Act of 2007 (EISA 2007) have increased the energy conservation requirements. New facilities shall be designed to achieve energy conservation levels that are at least 30%below the levels established by the most recently adopted ASHRAE Standard 90.1 or the International Energy Code (for residential buildings).

7.2.4 ENERGY STAR: All HVAC equipment, appliances, related electrical equipment, and water saving fixtures shall meet or exceed the minimum efficiencies listed by Energy Star and Federal

Energy Management Program (FEMP). The FEMP website lists all Energy Star and FEMP rated products and provides recommended efficiencies and life cycle data. The FEMP website is at http://www.eren.doe.gov/femp/. For product groups where Energy Star labels are not yet available, select products that are in the upper 25% of energy efficiency as designated by FEMP.

Contractors shall also utilize the Energy Star Portfolio Manager Tool, to compare to other like facilities/buildings.

7.2.5 Sustainable Design. Integrate sustainable development principles into the mechanical system selection and design. Utilize the U.S. Green Building Council’s LEED Green building Rating System as a tool to apply sustainable development principles and as a metric to measure the sustainability achieved through the planning, design, and construction processes.

7.2.6 Indoor Environmental Quality and Mold. Provide outside air ventilation as prescribed by the latest edition of ASHRAE Standard 62. Consider the factors of “Multiple Spaces”, “Ventilation Effectiveness”, and “Intermittent or Variable Occupancy” as specified in ASHRAE Standard 62.

The building and mechanical system must be designed and constructed to prevent the growth of mold. Comply with UFC 3-101-01.

7.2.7 Economizer Cycles. Economizer cycles should be considered even when not specifically required under ASHRAE 90.1. Air side economizers shall not be utilized in areas requiring humidification without being specifically designed for humidified spaces. Such systems will require special design approval. Other energy saving measures may be used in their stead.

Contact the Government Project Manager for direction.

7.2.8 Building Pressurization. Maintain the building under positive pressure in order to negate infiltration.

G07.3 Heat Generating Systems

7.3.1 Emissions. All new or modified fuel combustion burners must contain Low Oxides of Nitrogen Burner Technology as outlined in Utah Administrative Code R307-401. Hot Water Heaters and Hot Water Boilers require ultra-low NOx as the Best Available Control Technology (BACT). Hot water heaters are also subject to ultra-low NOx, specifically Utah State Construction and Fire Codes Act, Subsection 15A-6-102 Nitrogen Oxide emission limits for natural gas-fired water heaters. All combustion devices rated over 5MMBTU/HR must be permitted by the Base prior to installation and require ultra-low NOx burner technology, or be fitted with a controlled device designed to achieve ultra-low NOx equivalent emissions.

7.3.1.1 Boilers. Install boiler(s) and associated hot water pumps in a mechanical room inside the facility unless otherwise noted in the Project Program. Passageways around all sides of boilers shall have an unobstructed width of 1 meter (3 feet), or the clearances recommended by the boiler manufacturer, whichever is greater. Boilers must comply with regulatory requirements under the Clean Air Act regarding Title V and New Source Review permits programs as well as requirements under New Source Performance Standards and National Emissions Standards for Hazardous Air Pollutants (NESHAP). Contact Base Civil Engineering Branch for specific requirements.

7.3.1.2 Boiler Procurement. All boilers will be ASME certified as required by Dept. of Defense.

7.3.1.3 Multiple Boilers. In multiple boiler installations, the lead boiler should operate up to full capacity prior to starting the next boiler. During heating season, multiple boilers should be kept warm and ready should the lead boiler fail to operate.

7.3.1.4 Draft Hoods. Provide for each gas-fired piece of equipment, except power vented and condensing type equipment.

7.3.1.5 Barometric Dampers. Provide barometric dampers for all boilers requiring negative draft.

7.3.1.6 Steam Boilers. On boiler start-up, the condensate in a gravity system may not return quick enough to maintain the boiler water level. Contact the boiler manufacturer for boiler feed system tank size and location.

7.3.1.7 Condensing Boiler Systems. Provide hydronic systems with condensing gas-fired boilers with a water volume equal to five (5) minutes of water flow through the system pump (minimum), or as required by the boiler manufacturer. This insures there is sufficient water volume to prevent short cycling of the burner. If there is insufficient water volume, an inertia tank must be installed to attain the minimum system volume required. Non-condensing boilers do not require this minimum.

7.3.2 Combustion Air. Provide combustion air for gas and oil-fired equipment in accordance with International Mechanical Code (IMC) and NFPA requirements.

7.3.3 Steam Heating. Steam heat should not be used except on rehabilitation projects where budget constraints preclude conversion of an existing steam heating system to hot water.

7.3.4 Infra-Red Gas Radiant Heaters. Infra-Red heating system designs shall be reviewed and approved by the equipment manufacturer and submitted designs shall include a letter so certifying. When using non-condensing gas infrared heaters, the length of the exhaust flue should be minimized. To minimize condensation, run the flue horizontally with a slight pitch down from the heater to a sidewall exit. Heaters should be properly braced where excessive movement, such as by wind through an open hangar bay door, may cause separation of radiant pipe sections and rupture of gas connections. Consider condensing type IR heaters for larger applications. Provide sufficient overhead ventilation for condensing type IR heaters to carry water vapor out of the building.

G07.4 Cooling Generating Systems

7.4.1 Condensing Temperatures. The design condensing temperature for air-cooled condensers, chillers, etc. must be ambient (i.e. 1% or 0.4%) design temperature (from ASHRAE climate data) plus 2.8 degrees C (5 degrees F) dry bulb, or higher (dependent on users’ requirement(s))

7.4.2 Chilled Water Systems. Chiller manufacturers recommend minimum system volumes to prevent short-cycling of the chiller(s) to promote long chiller life and good chilled water temperature control, especially in smaller chilled water systems. In small systems it may be necessary to install an buffer/holding tank in the chilled water loop to achieve the required minimum system volume. Check the requirements of the chiller manufacturer and provide an insulated, inertia tank of sufficient volume when required. Install the chilled water storage tank downstream of the chiller and upstream of the cooling coils. Provide calculations to demonstrate compliance with this requirement. Volumes for components may be estimated where manufacturer's data is not available.

7.4.3 Chillers. When multiple chillers serve a common central chilled water system, install a flow control balancing valve on the leaving side of the chilled water and condenser water (where applicable) of each chiller. Flow orifices with butterfly valves should be provided for larger pipe sizes. On multiple chiller systems, design pumping and piping systems to prevent water flow through chillers that are not in operation. Avoid the use of reciprocating compressors when possible. Utilize roof mounted chillers only as a last resort. If located on the roof, mount the chiller on a steel skid with isolators supported from the structural roof framing.

7.4.3.1 Per AFCEC/CO’s Memorandum and Justification and Approval Documents dated 10 Sep 2019, Trane Inc shall be the sole manufacturer source used for the installation of all chillers at Hill AFB until 30 Sep 2024. Please contact 75 CEG/CENM for a copy of these documents upon request.

7.4.4 Cooling Towers. Provide a butterfly or 3-way diverting valve in the by-pass line for all cooling towers that are specified to have a condenser water by-pass for regulating the condenser water supply temperature. Provide automatic isolation valves on inlet and outlet of each cell for multi-cell or multitower applications. Size condenser water flow to chiller for the design flow rate, not the oversized tower flow rate. Cooling tower piping shall by-pass to the cooling tower’s sump.

7.4.5 Ground-Coupled Heat Pump (GCHP) System Design Guidance: The guidelines that follow are intended to complement the guidance and requirements of ASHRAE and recognized consortiums, such as the International Ground Source Heat Pump Association (IGSHPA).

Nonresidential, commercial scale ground source heat pump systems require the utilization of computer design software. Such software should consider the interaction with adjacent loops and long-term buildup of rejected heat in the soil.

7.4.5.1 Provide a bypass line around the condenser of each heat pump unit to facilitate flushing and purging the condenser loop without subjecting the condenser coil to residual construction debris.

7.4.5.2 Provide isolation valves and valved tee connections for flushing and purging of the well field independently from the building condenser water system.

7.4.5.3 Do not provide automatic water makeup in residential GCHP systems. Reserve the added complexity and cost to larger, non-residential systems of 10 tons or larger. Utilize cupronickel refrigerantto- water heat exchangers in open condenser loops only.

7.4.5.4 Provide test ports (sometimes referred to as “Pete’s plugs”) on the inlet and outlet to each heat pump unit, circulating pump and desuperheater, if incorporated.

7.4.5.5 Utilize reverse return headers in large well fields. For heat pumps with reduced flow requirements of 2 GPM/ton or less, consider series return in order to maintain fluid velocities necessary to foster good heat transfer. Base the decision to commit to reverse return on installed cost, pumping costs and the system flow requirements. Consult ASHRAE and IGSHPA Design documentation for additional information.

7.4.5.6 Regulatory requirements for vertical wells vary widely among States. Some regulations require partial or full grouting of the borehole. Confirm with the Government Project Manager and consult current state and federal regulations, as well as relevant building codes.

7.4.5.7 The thermal conductivity of grouting materials is typically low when compared to the conductivity of native soils. Grout acts as an insulator and will, thus, hinder heat transfer to the well field. When governing regulations permit, consider the following alternatives:

a. Reduce the quantity of grout to an absolute minimum. Fine sand may be used as backfill where permitted, but caution must be exercised to ensure the interstitial space between pipe and borehole is filled to enhance conductivity.

b. Utilize thermally enhanced grout. Consult ASHRAE, Commercial/Institutional Ground-Source Heat Pump Engineering Manual. Reduce the borehole diameter as much as possible to reduce the insulating effects of grout or backfill.

7.4.5.8 All outdoor equipment with hydronic piping shall be installed with glycol (propylene or ethylene). No less than 30% propylene (adjust % for ethylene) shall be mixed with the chilled water medium. All equipment utilizing glycol and refrigerant mixture shall be derated appropriately for % glycol and elevation. Deration shall be based on calculations found in

ASHRAE .

. Utilize condenser water circulating pumps with high efficiency motors. Design them to operate near their peak of maximum efficiency.7.4.6 Refrigerants. The use of Ozone Depleting Substances (ODS) as well as the qualifications and credentials of personnel servicing equipment that contains ODS is restricted. Refrigerant servicing equipment must meet the appropriate certification from the manufacturer (e.g. Underwriter’s Laboratory certification label attached to equipment).

7.4.7 Refrigerant Piping. Avoid refrigerant piping runs longer than 15 meters (50 feet) unless specifically allowed by the equipment manufacturer. Size refrigerant piping in accordance with the manufacturer’s recommendations.

G07.5 Distribution Systems

7.5.1 Air Distribution.

7.5.1.1 Locker Room/Restroom HVAC Systems. Draw conditioned air into locker rooms/Restroom from adjacent spaces and provide additional supply air as required. This uses the outside air required for human occupancy in the adjacent spaces for secondary air conditioning of the locker space and maintains locker spaces at a negative pressure with respect to adjacent spaces. No air shall be returned from the locker space to the building HVAC system.

7.5.1.2 Outside Air Ducts. Size outside air ducts for velocities a minimum of 4.1 m/s (800 fpm) for accurate flow measurement. Provide a straight duct of suitable length to facilitate an airflow measurement traverse. Provide an airflow measuring station for VAV systems to verify proper outside air quantities. Equipment layout shall allow for the straight duct length requirements of the airflow measuring station in accordance with the manufacturer’s recommendations. Provide an access door in airflow measuring stations to facilitate cleaning and repair.

7.5.1.3 Variable Speed Drives. Select system equipment following AFPAM 32-1192 Energy Efficient Motors and Adjustable Speed Drives. Select to deliver design flows so that maximum operational flexibility is maintained. Verify fan performance at minimum and maximum operating points.

7.5.1.4 Vibration and Noise Isolation. Where vibration and/or noise isolation is required, provide a vibration isolator schedule on the drawings indicating type of isolator, application, and deflection in mm (inches).

7.5.1.5 Access Panels. Provide access panels in floors, walls, and ceilings (except in lay-in tile applications) as required to access valves, smoke dampers, fire dampers, balancing dampers, balancing valves, air vents, drains, duct coils, filters, equipment, etc. Indicate location and size on drawings. Verify that the dimensions will yield reasonable accessibility.

7.5.1.6 Equipment Supports. Provide for vibration isolation where required and schedule the vibration isolation components on the drawings. Coordinate with and provide hardware required to meet Antiterrorism requirements in UFC 4-010-01 and seismic requirements in accordance with UFC 3-310-04, Seismic Design For Buildings. All equipment mounted on a roof must be fastened to the building as recommended by the structural engineer.

7.5.1.7 Space Noise Levels. Design and install systems to maintain noise levels below those recommended in the ASHRAE Handbooks.

7.5.1.8 Variable Air Volume (VAV) HVAC System Design Guidance The guidelines that follow are intended to complement the guidance and requirements of ASHRAE.

7.5.1.8.2 Utilize computerized load calculations based on the ASHRAE Transfer Function Method, the Heat Balance Method, or the Radiant Time Series method. Select all central air handling equipment and central plant equipment for “block” loads. Spread diversity through the supply ducts, taking full diversity at the air handling unit, and lessening diversity when moving away from the air handling unit toward the VAV terminal units, until no diversity is taken at the distant VAV terminal run outs.

7.5.1.8.3 Design for both peak and part load conditions (minimal wall transmission load, low occupancy, etc.). VAV Systems shall provide acceptable air circulation and proper outside air for all conditioned spaces regardless of the loading conditions.

7.5.1.8.4 Address the psychrometric performance of the cooling coils, with full consideration of the method of capacity control and its limitations, during part load conditions when the sensible heat ratio can be significantly reduced. Submit part load design calculations. Check the fan operating characteristics throughout the range from the minimum to the maximum flow conditions that will be experienced. Evaluate the off-peak turndown requirements for the main air handler VAV fan. Do not utilize discharge dampers or inlet vanes for air flow modulation.

Provide variable frequency drives for air volume modulation.

7.5.1.8.5 Design a positive means of maintaining ventilation rates during part load conditions.

Select the minimum primary air requirements of the VAV terminal units to maintain at least the minimum outside air ventilation requirements. The Direct Digital Control (DDC) system shall comply with the requirements of ASHRAE 62 for polling of boxes to maintain proper ventilation levels. Provide an air flow monitoring station in the outside air duct controlling the outside and return air dampers or a constant volume outside air fan to maintain the minimum outside air requirements. Constant volume fans are the most reliable method for maintaining steady flow for outdoor air. Utilize variable volume fans for systems where number of people/crowds will vary within a space. When using airflow measuring stations (AFMS) for monitoring and maintaining constant outside air ventilation rates, avoid placement of the AFMS in the outside air duct unless a minimum of 12 duct diameters of straight duct downstream of the outside air louver can be provided. Turbulence generated by the outside air intake louver will generate high turbulence and a highly unstable control loop. For large systems using a constant air volume (CAV) fan use a pressure independent velocity controller in the outdoor air intake to keep outdoor airflow constant as the VAV air handler fan modulates. Provide a low velocity filter module upstream of the air injection fan to prevent dust/dirt build up that may clog the pitot tubes associated with the volume regulator. Provide a duct access door at the inlet to the CAV terminal box for periodic inspection and cleaning.

7.5.1.8.6 Utilize the static regain method in design of the supply ductwork. Design return ductwork using the equal friction method.

7.5.1.8.7 Provide control for a constant cooling supply air temperature. Resetting the supply air temperature upwards increases the coil sensible heat ratio and results in elevated space relative humidity.

7.5.1.8.8 Provide electronic controls; pneumatic controls present problems with repeatability and maintenance.

7.5.1.8.9 Locate the static pressure sensor for modulating fan capacity two-thirds to three-quarters the distance from the supply fan to the end of the main trunk duct. Locate in straight run of ductwork. Provide static pressure reset in accordance with ASHRAE Standard 90.1. Provide protection against over pressurization of the supply duct system. Utilize pressure independent (PI) terminal units. Do not use light troffer return units. Light troffers reduce room sensible loads with undesirable effects on room air changes and outdoor ventilation distribution. Control the cooling coil capacity, especially in the more humid climates. VAV is inherently one of the best of the chilled water systems for air conditioning in tropical climates.

7.5.1.8.10 Do not utilize DX VAV systems without prior approval of the Government Project Manager. Direct expansion equipment shall be specifically designed and manufactured for VAV applications. The same manufacturer shall provide central air handling units, VAV boxes/zone dampers and zone controls. Airflow through the evaporator coils shall not be modulated. Provide duct mounted zone control damper units with integral control box, designed for use with DX VAV packaged systems. Self-modulating air diffusers will not be allowed.

7.5.1.8.11 Provide round or flat oval duct systems for primary air on all VAV supply systems.

Utilize round ducts wherever space availability permits.

7.5.1.8.12 Proper VAV box primary air entry conditions are critical for achieving stable, accurate airflow delivery. Every effort must be made to avoid high turbulence in the proximity of the VAV terminal flow sensor. Design the primary air duct branches to the VAV terminals with a straight duct section of at least 6 to 8 duct diameters (more if required by specific manufacturers).

Reducer and increaser duct fittings installed immediately upstream of the VAV terminal connection collars are prohibited. If the branch duct size is other than the VAV terminal connection collar size, install the reducer or increaser fitting upstream of the aforementioned straight duct section.

7.5.1.8.13 Primary air connections to VAV terminals should always be with a rigid duct. If a section of flexible duct, or a flexible connection, is required for vibration control, limit the length to no more than 305 mm (12 inches), and ensure that it is placed at least 6 to 8 duct diameters upstream of the VAV box collar connection/flow sensor.

7.5.1.8.14 VAV terminal boxes have minimum primary air velocity limitations imposed by the volume regulators utilized. Though many manufacturers claim their VAV boxes can deliver minimum primary air at flow rates resulting in inlet velocities of 189 L/s (400 fpm) and a velocity pressure of 2.48 Pa (0.01 inch w.g.), the lack of a certifying agency to test the manufacturer’s claims support a more conservative approach. Minimum primary airflow rates shall be established to attain minimum velocity pressures of no less than 7.45 Pa (0.03-inch w.g.). Do not utilize system-powered (also called "pressure dependent") terminal units.

7.5.1.8.15 Special consideration must be given when fan-powered VAV boxes are specified and when it is necessary to specify a VAV box fan CFM in excess of the specified maximum primary air CFM. When used with a dropped ceiling return plenum, the excess VAV box CFM will introduce secondary air into the conditioned space. This has the effect of transferring return side coil cooling loads to room-side sensible loads. Always make sure the transferred sensible heat is taken into account in the calculated room-side sensible heat. Failure to do so may result in inadequate primary airflow rates to satisfy the room sensible heat loads.

7.5.1.8.16 Discharge dampers shall be installed on all series fan-powered VAV boxes (SFPVAV), regardless of the type of fan speed control utilized (3-speed fan switch or solid state speed control).

7.5.1.8.17 When it is necessary to install VAV terminals at high elevations above finished floors, service and maintenance accessibility must be carefully analyzed. Where mounting heights are in excess of 3.6 m (12 feet) above finished floors, special accommodations are necessary:

a. Do not use fan-powered VAV boxes in such locations, since there are many serviceable components involved. Instead, consider using non fan-powered terminal boxes for use in high mounting height locations to eliminate the need for fan servicing and filter change access.

b. When DDC controls are installed, specify the installation of the DDC digital controller to facilitate ease of access.

c. If scaffolding, scissor lifts, ladders or other means is required to access VAV units, special considerations must be made. Be sure clear floor area is available below the VAV boxes to facilitate the means of access (i.e. scaffolding, etc.) and in an area that will be likely to remain clear of permanent or semi-permanent equipment or furnishings.

d. When DDC controls are provided for VAV boxes, specify the ability to monitor VAV box hot water control valve position (if provided with hot water coils), control damper position, primary airflow, flow sensor pressure differential, and box leaving supply air temperature. The means to monitor VAV box function will maximize the means to troubleshoot remotely, thus reducing the frequency for above ceiling access by maintenance personnel.

e. Utilize electronic controls for VAV boxes mounted in high areas.

f. Specify the integral mounting of communication ports for the VAV box digital controllers to the room zone temperature sensor. When occupied/unoccupied modes of control are required of the VAV system, specify remote momentary override switch mounted integral to the room zone temperature sensors to permit non-standard schedule operation during unoccupied modes.

7.5.1.8.18 Fan-powered VAV terminal boxes can be noisy. Perform an acoustic analysis to ensure designs are within acceptable NC criteria noise levels. Pay particular attention to noise attenuation in locations where the boxes are installed in spaces without dropped ceilings. Analyze potential for sound breakout from main supply air ducts. Provide attenuation as required. Do not provide acoustical duct liner for attenuation.

7.5.1.9 Duct Lining. Duct lining shall only be used for room to room transfer applications.

Increase the duct dimensions as required. Acoustical duct lining shall not serve as thermal insulation for duct.

7.5.1.10 Fire Dampers. Provide fire dampers and access panels in ductwork penetrating fire rated walls and floors in accordance with NFPA 90A.

7.5.1.11 Flexible Connections. Provide flexible connections in ductwork at equipment. Support duct at flexible connections to ensure proper alignment.

7.5.1.12 Flexible Duct. Flexible duct lengths shall not exceed 1829 mm (6 feet) in length and shall not be used to make right angle bends.

7.5.1.13 Louvers. Provide rain or storm proof louvers at wall intakes and exhausts. Indicate dimensions, airflow rate, and air pressure drop. Consider the potential for carry-over of wind driven rain.

7.5.1.14 Screens. Provide insect or bird screens, as applicable, at all building intakes and exhausts.

7.5.1.15 Door Louvers. Size for minimal pressure drop.

7.5.2 Water Distribution.

7.5.2.1 Variable Speed Drives. Select system equipment to deliver design flows so that maximum operational flexibility is maintained. Verify pump performance at minimum and maximum operating points.

7.5.2.2 Chilled Water Pumps. Provide a dedicated primary pump and condenser water pump for each chiller. Provide piping and valve configuration that allows each chiller to operate with any primary pump and with any condenser water pump. Provide back-up or standby pumps so that the total system capacity is available with any one pump out of service.

7.5.2.3 Hot Water Pumps. Provide back-up or standby pumps so that the total system capacity is available with any one pump out of service.

7.5.2.4 Piping systems. When terminal equipment loads are relatively equal in percentage of total load, design closed system piping using reverse return method.

7.5.2.5 Pressure and Temperature Taps. Provide pressure and temperature taps ("Pete's Plugs") on the inlets and outlets of all coils, pumps, chillers, heat exchangers, and other equipment.

7.5.2.6 Expansion and Compression Tanks. Utilize diaphragm type expansion tanks. Size the expansion tank according to the latest edition of the ASHRAE Systems Handbook. Indicate the acceptance volume, nominal dimensions, configuration (i.e. horizontal or vertical) and pre-charge air pressure.

7.5.2.7 Expansion Loops and Devices. Provide expansion loops and/or devices as required for proper piping protection. Detail and dimension loops and schedule joints indicating minimum total traverse and installed expansion traverse. Indicate guide spacing. Avoid the use of expansion joints where possible due to the high resultant thrust. Instead utilize geometry and ball joints where possible.

7.5.2.8 Cold Water Make-up. Provide for make-up to each water system. Provide pressure gauges up and downstream of the PRV. Provide bypass line with a globe valve for each PRV. Provide hose bibs in the make-up water line to cooling towers and evaporator condensers for wash down of equipment.

7.5.2.9 Drain Lines. Provide drain lines from air handling units, fan coil units, etc. Provide a water seal on drains as required. Terminate condensate drain lines in accordance with the IMC.

7.5.2.10 Backflow Preventers. Backflow preventers are required at all connections to the potable water system. Design shall comply with AFI 32-1066, Backflow Prevention Program. Note this document requires compliance with the backflow prevention portions of the Uniform Plumbing Code, not the International Plumbing Code. The State of Utah also has regulations regarding backflow prevention.

Where conflicts exist the more stringent shall apply.

7.5.2.11 Chemical Feeders. Fill openings should be no higher than 1.2 meters (4 feet) above the finish floor for ease of filling.

7.5.2.12 Air Vents. Provide in locations as required in the IMC. Provide manual type vents where possible. Use of automatic air vents is discouraged and should be minimized. Pipe the drains from automatic vents away from concealed areas for visual inspection and to prevent damage to ceilings, etc. Provide manual shut-off valves or stop-cocks for automatic air vents.

7.5.2.13 Drain Valves. Provide manual drain valves at all low points and at each strainer in piping systems. Ball valves and strainers shall be a combination type assembly. Plumb drain valves to floor drains where possible. Where not possible, provide hose connection with hose cap.

7.5.2.14 Check Valves. Provide check valves to prevent backflow and at the discharge of most pumps. When used in drain lines, verify sufficient head to open flap to regain flow. Provide non-slam type on high head applications. Provide damping type on air compressor discharges.

7.5.2.15 Strainers. Strainers will have shut off valves installed on either side of the strainer to facilitate cleaning and to minimize loss of water.

7.5.2.16 Freeze Protection. Design pipe temperature maintenance systems (i.e. heat trace) to the lowest recorded temperature in UFC 3-400-02, Engineering Weather Data.

7.5.2.17 Underground Piping Systems. Underground piping systems for steam, condensate and chilled and hot water must be factory-prefabricated, pre-insulated, and direct bury type. The Underground Heat Distribution System manufacturer is the company responsible for the design and manufacture of the pre-engineered system. The manufacturer directs the installation of their system and provides a representative on the job site.

7.5.2.18 Legionella Disease. Design waterside systems to avoid potential exposure to Legionella Disease.

7.5.3 Building Exhaust System.

Provide exhaust system for removal of heat, fumes, dust, and vapors in various spaces in accordance with ASHRAE. If natural ventilation is proposed, provide calculations to support its use as a reliable means of ventilation.

7.5.3.1 Equipment Room Ventilation. Provide mechanical and electrical equipment rooms with 10 air changes per hour or an exhaust rate to limit room temperature rise to 5.6 degrees C (10 degrees F) above the outdoor summer design dry bulb, whichever is greater. Ventilate equipment rooms with a thermostatically controlled exhaust fan and a weather tight inlet air louver or hood.

To ensure that equipment rooms containing combustion burners for boilers, water heaters, or furnaces do not operate as negative pressure areas, utilize supply fans rather than exhaust fans for ventilation. For design heating temperatures less than 4.4 degrees C (40 degrees F), provide motor operated, normally closed dampers at air inlet and exhaust openings. Equipment rooms containing refrigeration equipment shall be ventilated in accordance with IMC and ASHRAE Standard 15.

7.5.3.2 Exhaust/Intake Locations. Provide adequate separation between outside air intakes and exhaust outlets, waste vents and boiler stacks. Consider prevailing winds and force protection requirements. Outside air intakes must be 3.0 m (10 ft.) minimum above ground elevation to satisfy Anti-Terrorism (AT) requirements.

7.5.3.3 Roof Fans. Roof exhaust fans should be avoided due to maintenance access restrictions and roof leak potential. If provided and where feasible, utilize direct drive fan motors with speed controllers to reduce maintenance requirements.

7.5.4 Fire Station Diesel Exhaust. Provide an engineered fire apparatus exhaust removal system.

Refer to Interim Technical Guide (ITG) # FY00-06 for additional information. The system should include an overhead sliding track mechanism to permit a flexible exhaust hose to travel with the fire apparatus into and out of the apparatus bays. The fire apparatus exhaust hose shall automatically disconnect from the vehicle as it exits the bay.

7.5.5 Maintenance Bay Vehicle Exhaust.

Provide an engineered vehicle exhaust removal system. The system shall include an overhead or under floor system. Overhead ductwork system shall be provided with a retractable flexible exhaust hose to travel from the vehicle exhaust into and out of the ductwork. The exhaust fan for all systems shall be specifically designed and manufactured for vehicle exhaust.

7.5.6. Roof Top Hose Bibs for HVAC Maintenance Access.

For any roof top HVAC unit installation, ensure at least one frost proof hose bib per roof is provided for HVAC maintenance and wash down usage. Install a freeze less yard hydrant with accessible isolation valve. Ensure its equipped with backflow protection and the drain runs to closest floor drain. Only install a hose bib if the roof exceeds 10,000 SF or has at least 3 HVAC units on the roof.

G07.6 Kitchen HVAC Systems Check project documentation to determine if air conditioning of kitchens is allowed. No air shall be returned from the kitchen to the HVAC system. Design dining facilities in accordance with UFC 4-722- 01 Design: Dining Facilities, and so that air flows from dining areas to kitchen areas to provide make-up air for kitchen exhausts. Maximize the use of dining area make-up air to the kitchen as this will provide secondary cooling for the kitchen staff. If additional make-up air is required for kitchen exhausts, provide push-pull kitchen hoods with built-in heated make-up air supply. Design kitchen hoods in accordance with UFC 4-722-01. Kitchen hoods with built-in make-up air shall be of the horizontal face discharge type. "Short circuit" hoods are prohibited.

Provide control interlocks for supply and exhaust fans to ensure that the HVAC system balance is maintained, and that the proper direction of airflow is maintained during normal operations.

Utilize evaporative coolers on kitchen supply air where appropriate. Analyze application carefully to insure increased humidity of the ventilation air does not negate any cooling affect.

Provide fire suppression system for hoods in accordance with UFC 3-600-01, Fire Protection Engineering.

G07.7 Industrial Ventilation

7.7.1 General. Design industrial ventilation systems in accordance with the latest edition of Industrial Ventilation, A Manual of Recommended Practice, published by American Conference of Government Industrial Hygienists (ACGIH). Air Force projects shall comply with UFC 3-410- 04N, Industrial Ventilation. and AFMAN 48-155 Occupational and Environmental Health Exposure Controls.

7.7.2 Design Guidelines. Research the process or operation before design starts (i.e. find out contaminants, toxicity, process temperature, etc.).

7.7.3 Provide hoods designed for effective capture of contaminants while minimizing air flow for energy conservation. Do not specify or provide a canopy hood unless process is nontoxic.

7.7.4 Specify the appropriate fan for the application. When selecting a fan, consider noise generation, material handled through the fan (e.g., corrosives, flammables, etc.), and future expansion or flexibility of the system.

7.7.5 Provide tempered make-up air for all ventilation systems. Ensure that make-up air does not cause turbulence at the exhaust hood. Interlock make-up air fan to exhaust fan. Do not recirculate exhaust air.

7.7.6 Provide an offset discharge stack, with drain, for exhaust systems. Do not utilize a "conical cap" exhaust stack. Provide at least 7.5 m (25 feet) between exhaust outlets and outside air inlets to prevent circulating contaminated exhaust air back into the building.

7.7.7 Provide an air cleaning device when required by state and federal regulations. Obtain clear guidance and direction from the Government Project Manager. Select air cleaning devices that will maximize contaminant removal and ease of maintenance while minimizing cost.

7.7.8 Provide air flow and static pressure calculations with each design following the methods in the latest edition of the ACGIH Ventilation Manual.

G07.8 Indoor Air Quality Standards

7.8.3.1 Ventilation. In addition to meeting the requirements above, new facilities must employ separate, dedicated, central ventilation air constant-volume supply systems that supply dehumidified and tempered 100 percent outside air to all occupied spaces. The design intent of these systems is not to provide total space heating and cooling; systems must continuously condition and deliver ventilation air to each occupied space. The ventilation air must be tempered to within room comfort conditions. Ventilation air room supply conditions must not be at or below room dew point. Humidification of ventilation air during periods of low ambient humidity is not required. Facility central ventilation air supply systems must not be subject to intermediate season (no-heat/no-cool) shutdown. (Individual room heating/cooling equipment must have occupant control, but may be subject to intermediate season heating/cooling curtailment as directed by local command.) Systems must be designed to minimize the transmission of sound between quarters. The designer will perform a psychometric analysis documenting that the system is designed to maintain space humidity with ambient condition of ventilation air at the 1 percent humidity ratio design weather condition. The system must provide the capability to condition ventilation air and maintain space relative humidity less than 60 percent over the full range of cooling loads. Use only metal ductwork for the central ventilation systems. Duct insulation must be external, and duct board or internal duct liner is not allowed.

7.8.2 Design Analysis. The HVAC design analysis for new facilities or renovation of existing facilities must include a psychrometric analysis documenting that the system meets design criteria. The analysis ratios) of outside air, mixed air, supply air, and return air flow streams. The cooling load for this analysis must be based on the load conditions identified in section 6.13 Design conditions.

7.8.3 Dormitories and Visitors Quarters.

7.8.3.1 Ventilation. In addition to meeting the requirements above, new facilities must employ separate, dedicated, central ventilation air constant-volume supply systems that supply dehumidified and tempered 100 percent outside air to all occupied spaces. The design intent of these systems is not to provide total space heating and cooling; systems must continuously condition and deliver ventilation air to each occupied space. The ventilation air must be tempered to within room comfort conditions. Ventilation air room supply conditions must not be at or below room dew point. Humidification of ventilation air during periods of low ambient humidity is not required. Facility central ventilation air supply systems must not be subject to intermediate season (no-heat/no-cool) shutdown. (Individual room heating/cooling equipment must have occupant control, but may be subject to intermediate season heating/cooling curtailment as directed by local command.) Systems must be designed to minimize the transmission of sound between quarters. The designer will perform a psychometric analysis documenting that the system is designed to maintain space humidity with ambient condition of ventilation air at the 1 percent humidity ratio design weather condition. The system must provide the capability to condition ventilation air and maintain space relative humidity less than 60 percent over the full range of cooling loads. Use only metal ductwork for the central ventilation systems. Duct insulation must be external, and duct board or internal duct liner is not allowed.

7.8.3.2 Exhaust Systems. A central ducted bathroom exhaust system will be used instead of individual exhaust fans for each space. The exhaust system must run continuously and be interlocked with the building supply air system. The exhaust duct for each space must have a manual volume damper accessible from the space for proper balancing. Install an exhaust grille constructed of corrosion-resistant material just outside each shower stall and bathtub. Exhaust systems must be designed to minimize the transmission of sound between quarters. Exhaust from moisture-producing equipment (i.e., clothes dryers) must be vented to the exterior.

7.8.3.3 Heat Recovery. Use heat recovery from exhaust air to reduce the energy consumption necessary to condition ventilation air where savings from heat recovery results in a life cycle cost payback for the heat recovery equipment.

7.8.4 Filtering. Filter ventilation air before it enters an air handler, heat recovery equipment, or preconditioning equipment. Use extended media filters with a Minimum Efficiency Reporting Value (MERV) of 7 or greater, in accordance with ASHRAE 52.2-1999, Method of Testing General Ventilation Air-Cleaning Devices for Removal Efficiency by Particle Size.

7.8.5 System Selection Criteria. Do not utilize room fan coil units or packaged terminal units, such as individual through-wall heat pumps, for facilities such as office buildings and Bachelor Quarters or for any facility larger than 465 square meters (5000 square feet), unless conditioned make-up air is provided to each space through a central, continuously operating, dedicated make-up air system. Conditioned make-up air shall be ducted to each room or to the return side of each fan coil or terminal unit.

G07.9 Controls and Instrumentation

7.9.1 General Control System Operations.

7.9.1.1 The authorized Hill AFB method for Building Automation System (BAS) controls is through Direct–Digital Control (DDC) methodology. Installers of DDC equipment shall use government-provided information technology (IT) systems to program all field devices intended for use within the CE Industrial Control System (ICS). All programming shall be performed from the EMCS central office. If any programming or configuration requires the use of files external to the local ICS Information Systems (IS) network, those file shall be transferred through the use of government-provided media, secured through EMCS and virus-scanned through an air gap system before use on the VLAN. No other externally-sourced hardware or software shall be used in the configuration of EMCS ICS Field Devices.

7.9.1.1.1 Two EMCS GUI front ends are currently utilized at Hill AFB; AscentCompass by Alerton, and InfoScan by Dorsett Technologies, Inc. DDC installers incorporating control systems into the ICS shall use the existing Alerton or Dorsett front ends. Predominant controls shall be the rule for control systems expansion, e.g. any control systems expansion into a building shall use the predominant control system already extend within that building, etc. DDC installers must be certified as authorized installers by either Alerton or Dorsett in order to perform work on these systems at Hill AFB. Designers shall ensure either the control system producers and/or their certified/authorized installers review the system design iterations throughout the design process (i.e. 30%, 60%, 90% 100% designs) to ensure the system designs are optimized for field installation.

7.9.1.2 DDC installers shall provide the equipment, software, and services necessary to complete all installation and commissioning tasks for full control system operation. Installers shall coordinate all computer and network system access with EMCS to ensure all security protocols are followed. Installers shall provide only that equipment which is necessary to completely install a functional control system.

7.9.1.2.1 System and network security is to be maintained at all times. Unauthorized users will be disallowed from using the systems, and unauthorized equipment connected to the network will be removed. No unauthorized hardware or software is to be placed on the network at any time. Failure to adhere to these conditions may result in disciplinary action taken against companies or people, up to and including permanent bans from accessing the ICS network. Any attempt to circumvent or damage the integrity of the ICS network, either by willful negligence or deliberate malicious action, will be met with the same disciplinary actions.

7.9.1.3 All DDC field devices shall be connected to the CE ICS VLAN. The current nature of EMCS’s Authority To Operate (ATO) forbids the direct connection of any communications device to the VLAN itself. All equipment that is to be monitored or controlled through EMCS is to be connected with the EMCS field devices acting as an interposing agent between that equipment and the VLAN.

7.9.1.3.1 Vendor equipment intended for direct control and monitoring through EMCS shall have configuration software provided to the government for installation onto trades service laptops.