Eielson_AFB_HVAC_Standards_June_2015.pdf

Eielson AFB HVAC Standards

18 June 2015

EIELSON HEATING-VENTILATION-AIR

CONDITIONING-REFRIGERATION (HVAC) STANDARDS

Only 11% of a “40 year commercial building” is “first cost” – the other 89% of the cost of the building goes to maintenance, repair, etc. BUILD QUALITY into all facilities and save the government/tax payers tremendous amounts of money (install quality equipment with the highest quality workforce).

(ALL THE FOLLOWING ITEMS SHOULD BE OBVIOUS IN THE SPECIFICATIONS/DRAWINGS)

A. General

Design calculations are based on the mechanical design criteria compiled/furnished by Eielson 354 CES/CENM (Fairbanks weather, etc. is not appropriate – i. e. the design temperature is –60 degrees F for Eielson)

All specified equipment is in mid-range of cataloged performance to allow for adjustment. This includes, but is not limited to, all pumps and air moving equipment

All heating, cooling, and head loads shall be calculated with a 20% safety factor

Heating systems for remote facilities are direct-fired, forced air (not hydronic or steam) unless approved by 354 CES HVAC Shop for specific applications

Operation and Maintenance (O&M) training is provided by the contractor

Contractor provides 100% submittal of O&M Manuals (minimum of 6 each), and

95% submittal of corrected contract drawings indicating as-built conditions, 15 calendar days prior to scheduled O&M training

Deficiencies found during O&M training are corrected by the contractor and updated drawings are submitted within 15 days of training completion

O&M training is part of the Commissioning specifications

Separate “as-built” full sheet drawing of each mechanical room is laminated and provided for operations personnel. Drawings show layout of all equipment (especially numbered valves, etc.) and clearly indicate clearances between equipment

Separate piping diagram for each pipe system is provided showing location of all valves

Valves are numbered on drawings, are listed in the valve schedule, and match specified valve tags

A large scale floor plan is provided indicating all zone boundaries

All equipment is protected from corrosion. For products with protective coatings, specifications shall be written to require the products’ corrosion protection bond to pass one of the industry standard adhesion tests

Use heat recovery in applications where feasible. Evaluate all HVAC systems for use of heat recovery system to conserve energy (see heat recovery section for more details)

ASHRAE Type “0” commissioning shall be performed

All HVAC equipment shall be served by a full sized, lockable disconnect located in readily accessible location adjacent to equipment

Use ring gaskets, spiral wound with centering ring, with all flanges

B. Mechanical Rooms

Entrance is large enough to allow movement of large equipment into the mechanical room. (Prefer double doors with a separate access outside the facility)

Hot and cold water hose bib connections are provided, including in air handler rooms

(Ensure that back flow prevention devices are provided)

Minimum of one interior floor drain with floors sloped toward it

Electrical power outlets are provided (115/120 VAC)

Clearance is provided to remove/replace/maintain the following devices:

Air filters

Heat exchanger coils

Water heater coils

Water filters

Glycol

Ergonomic access is provided to all mechanical components (i.e. worker does not have to climb over ducts to access an air filter)

Catwalks and ladders or steps, as decided by HVAC Shop, are provided to allow access to all elevated units over four feet. All platforms, mezzanines, must have guard rails and kick plates

Mechanical room temperature is maintainable below 90F

Combustion and mechanical room ventilation air systems are designed so the gravity combustion air inlet prevents cold air from “dumping” into the room and the outside air ventilation fan includes motorized mixing dampers arranged to mix outside air and return air to 55 degrees F. Inlet openings shall have hoods and filters

Intake air openings for all facilities have hoods and wire mesh or screen with access to remove frost where they penetrate the exterior wall. Exhaust openings may have louvers or hoods. Ensure proper sizing to prevent air flow restriction.

Exhaust fan is provided with hand-off-auto (HOA) switch readily accessible

Adequate lighting is provided to all work areas

Frame walls are cement board or a water-resistant gypsum board instead of common gypsum board and all walls are finished with water-resistant paint.

Mechanical room is not used as a return air plenum

Mechanical equipment is not constructed/mounted on rooftops*

Copies of Control Sequences and O&M Manuals are non-fading, laminated and placed in a built-in cabinet in all Mechanical Rooms

Copies of the following drawings/documents are non-fading and laminated in clear plastic and placed in the cabinet in all Mechanical Rooms (all documents provided for

Mechanical Room use are laminated):

Duct work drawing(s)

Piping drawing(s)

Valve Schedules

Control Schematics

Description of Control Operations (separate Control Sequences--see above)

One-Line Electrical Drawing (Mechanical Room & Associated Panels, etc.)

C. Air Handling Units

Preheat and Reheat coils are installed with the preheat coil being installed in the outside airstream, before the mixed air section.

Air handling units are factory manufactured units with insulated double wall construction with the inner wall being sealed and integral drain pans in all sections to allow full washdown of interior. Drain lines are provided for all drain pans with individual isolation valves and are piped to an indirect waste line or floor drain (if to a floor drain, must not constitute a tripping hazard) with isolation valves for each AHU section. AHUs shall be Trane or equal as a minimum

Filters are installed before all coils (except where heating and cooling coils are adjacent to one another, in which case filters will be placed before the leading coil, and access is provided for cleaning both coils), frames are of a standard size, and filters are minimum 30% efficient (fiberglass filters are not used) Proper space is provided to remove all coils and filters for cleaning and replacement (access doors can open fully)

Air handlers located more than 4 feet above floor level or above suspended ceilings have a servicing platform with legal guard rails and kick plates, with “OSHA” ladder or steps, as is appropriate, to be decided by HVAC Shop, for access & maintenance.

Platform extends a minimum 36 inches from the edge of the equipment

A clear working space of at least 36 inches above the equipment is located on the control side

Grease (zerk) fittings are extended to a single, readily accessible point

A thermometer is installed in all discharge air ductwork

A thermometer is installed in all mixed air sections

Thermometers are installed on entering and leaving sides of fluid lines for all coils

(adjacent to coils for reading temperature differential over coil)

Catwalks and ladders/steps (See note for AHUs) are provided to allow access to all elevated equipment.

Unit is labeled using engraved metal or plastic name plates (not embossed plastic tape).

No plastic components are exposed to unheated outside air (i.e. damper brackets).

Rooftop units are not used.

Access openings are provided in fan guards for checking fan speed (expose end of shaft for tachometer use) and for cleaning all coils

Inside lights are provided in air handlers having 25 square feet of coil area or larger

(exterior mounted light switch with pilot light—indicator light).

Control valves are three-way and installed outside the units in a readily accessible location. Some two-way valves may be used in conjunction with variable speed pumping with approval

Variable Air Volume (VAV) systems use Variable Frequency Drive (VFD) motor speed control and are used only when system has mechanical cooling. Drives shall contain 100% by-pass capability

Full sized lockable disconnects shall be installed in readily accessible location adjacent to equipment

Minimum distance of 3 times the equivalent fan discharge duct diameter is provided between the return air fan and the return air and exhaust air dampers (6 times if outlet velocities are >6000 fpm)

Exhaust/return fans are equipped with VFD motor speed control if system uses economizer controls (do not rely on relief vents)

D. Louvers, Dampers, and Mixing Boxes

Pressure independent balancing dampers downstream of VAV terminals are installed

Full quadrant balancing dampers for all fresh air and return air ductwork to all air handling units are provided as well as dampers immediately after branches leave main duct.

Duct access doors are installed on both sides of all dampers, when possible

High efficiency dampers are used on all fresh air dampers and mixing boxes, TAMCO 9000 series or equal (linkage and construction being key factors)

Air intakes and exhausts shall be designed where the point of zero water penetration corresponds to the point on the air intake or exhaust curve where water penetration as defined by the Air Movement and Control Association (AMCA) Standard 500 begins

(intakes will be at this point or lower velocities, while exhaust louvers will be at this point or higher velocities). Hoods shall be color matched to building and extend to 90 degrees from vertical

E. Ductwork

Fiberglass ductwork is not used

Sheet metal ductwork is specified to be constructed IAW “Low Pressure Duct

Construction Standards” or “High Pressure Duct Construction Standards” of

SMACNA as applicable

Ductwork leakage limits are 2% for round…. 5% for rectangular…

Vapor barrier material is specified for all insulation around air conditioning ductwork

Access doors/panels are provided to both sides of areas needing periodic cleaning/servicing

Reheat coils

VAV terminals

Cooling coils

Branch ducts are offset from the main trunk duct (not opposite each other) to allow system to be easier to balance

Lighting is provided in all large ducts, plenums and duct chases, with switches available at the entry.

Design of supply/return ductwork prevents stratification (use baffles as needed)

Each branch duct take off immediately after leaving the main duct shall have a manually operated blade damper and each terminal device/diffuser shall have an opposed blade or quadrant damper

Manually operated, opposed blade damper

Manually operated, single blade damper

Quadrant-type volume damper

Extended edge turning vanes are installed in rectangular elbows

Manual volume dampers are installed at branch duct connections upstream of registers/diffusers and opposed blade at the registers/diffusers. (Diffuser/damper combinations are acceptable only in addition… not in lieu of) (Registers/diffuser dampers cannot reduce high volumes without creating high noise levels)

Volume dampers are located at least two diameters from a fitting and as far as possible from diffusers/outlets.

Straight duct sections of at least 3 duct diameters from fan discharge, elbows, or open duct ends are shown to insure accurate traverse reading (industry standard) – we prefer more when possible; for instance, 7 ½ duct diameters of straight sections would be preferred.

Duct drops to diffusers have a minimum of 2 duct diameters to assure uniform/even distribution from the outlet (where space permits)*

Diffuser registers and/or light troffers should not be located on the same branch duct

(causes unbalanced conditions)

Ductwork containing terminal units for VAV systems shall be installed as a header or manifold with units in line and serviceable via a work platform with adequate spacing for installation and servicing

Ducts shall not be constructed exterior to the building space.*

F. Terminal Devices

Pressure independent terminals are used

Reheat coils are used in all VAV boxes and adequate access for cleaning/servicing shall be provided

VAV or dual-duct terminals having distribution/orifice plates are not susceptible to dirt entrapment

All terminal devices are to be placed in accessible locations, no more than two feet above ceilings, which could mean lowering ductwork (without forming a trap area) or placing VAV devices in common location such as a header off the main ductwork with work platform access as required for all elevated equipment. The common location being the preference and placement of individual units shall be the exception and allowed only with approval

Include an "exclusion zone" around VAV devices to prevent the installation of light fixtures, piping, fire sprinklers, or other such material which would block access

G. Testing, Adjusting & Balancing (TAB)

TAB, General

Commissioning specifications are an integral part of the TAB procedures/specifications – Commissioning governs TAB.

All mechanical systems are balanced.

If only part of a system is installed/constructed in the immediate contract, the entire mechanical system(s) to which the new equipment connects shall be tested, adjusted and balanced.

The appropriate type and quantity of balancing devices (valves, dampers, etc.)

shall be incorporated in the design, in accordance with good industry standards.

Hydronic Balancing

All hydronic systems shall have adjustable “flow/circuit setter” type devices for balancing; and contractor has been made responsible to provide balancing equipment to the government upon completion of the contract. Preferred brands are B&G and T/A.

Balancing valves are not used as isolation valves.

Combination (multi-function) valves are not used and fixed flow control valves are not allowed.

Balance valves shall be installed downstream of all circulating pumps.

Air Balancing

Volume dampers in branch ducts and opposed blade dampers (OBD) are provided at all air terminal devices.

Terminal devices for all air supply are balanced with new balancing equipment and this equipment shall be provided to the government as part of the contract (for contracts exceeding $1 million).

H. Control Systems

Buildings selected by the HVAC maintenance shop will have Delta Controls Direct

Digital Control (DDC) systems, which communicate directly with the proprietary front end program located in the shop as part of an overall system. All major components and functions will be monitored and controlled by this system and contractor shall provide communications, programming, including connection to the

ORCAView front end program and graphics development consistent with existing appearance and function. Entering and leaving fluid and air temperatures on each coil and heat exchanger, occupied space, outside air, return air, mixed air, discharge air, equipment run status, associated alarms, and controller outputs are among the points to be covered by DDC systems. DDC controls shall be installed by qualified, licensed, Delta Controls dealer.

The following list of Standard Control Names shall be used:

Supply Air Temp: SAT

Supply Air Set point: SASP

Discharge Air Temp: Never used

Return Air Temp: RAT

Mixed Air Temp: MAT

Preheat Air Temp: PHT

Preheat Entering Water Temp: PHEWT

Preheat Leaving Water Temp: PHLWT

Reheat Entering Water Temp: RHEWT

Reheat Leaving Water Temp: RHLWT

Chilled Water Entering Water Temp

Chilled Water Leaving Water Temp

Mixed Air Damper: MAD

Exhaust Air Damper: EAD

Supply Fan Enable: SF_ENA

Supply Fan VFD/Speed

Supply Fan Amps

Supply Fan Fault

Filter Status

Duct Static Pressure

Duct Static Set Point

Low Limit/Freeze Stat

Cooling Valve

Heating Valve

Preheat Valve

Bldg Static Pressure

Bldg Static Set Point

Glycol/Hot Water Pump

Glycol/Hot Water Pump VFD Speed

Glycol/Hot Water Pump Status

Glycol/Hot Water Pump Fault

Glycol/Hot Water Pump Differential Pressure

Glycol/Hot Water Pump Differential Pressure Set Point

Glycol/Hot Water Supply Temp

Glycol/Hot Water Return Temp

1/3 Heat Exchanger Valve

2/3 Heat Exchanger Valve

Glycol/Hot Water Pressure

Chiller Enable

Chilled Water Pump Enable

Chilled Water Pump Status

Chilled Water Supply Temp

Chiller Water Return Temp

Exhaust Fan Enable

Exhaust Fan Status

Buildings which do not utilize DDC (determined by maintenance shop) will have electronic controls

All control valves (low pressure steam) for heat exchangers will be staged in 1/3, 2/3 configuration with the smaller valve opening first and closing last. Heating medium temperature will be reset by outside air temperature, from 70 deg F to 190 deg F.

Circulation pumps are to be cycled off at outside air temperature of 70 deg F and alternated for lead/lag operation

Control valves on heating and cooling coils in air-handling equipment are to be proportional, three-way valves. Some two-way valves may be used in conjunction with variable speed pumping with approval from HVAC Shop supervisor

Complete point to point control drawings with sequence of operation are required in

O&M manuals and laminated, displayed on mechanical room wall.

Room zone valves must have a manual bypass or override

System will not have any automatic reset low limit switches

20 hours of training on controls will be provided (includes startup/shutdown, maintenance/calibration)

Two sets of all specialized tools, instruments, and equipment needed to calibrate and maintain the controls and variable frequency drive units have been provided

Manual overrides will be installed for all actuators, preferably on the actuator itself

Components are labeled with engraved metal or plastic name plates (not embossed tape)

Stand-alone, equipment air conditioners (for computers, etc.) are Liebert (or equal) and have advance microprocessor controls. Units shall communicate with and control by DDC via Liebert communication system

Steel channel structural supports are provided for any actuators installed on less than

16 gauge sheet metal

Over-current protection is provided for requested input/output circuits of DDC

I. Heat Exchangers

Thermometers are to be installed at inlet/outlet of fluid side

Pressure gauge with isolation valve is installed on steam supply after control valves

Due to our extreme maintenance challenges, shell & tube (u-tube) heat exchangers are used

Control valves for heat exchangers are configured in a 1/3 – 2/3 arrangement with the smaller valve opening fully before the larger valve begins to open. Smaller valve is the first to open and last to close

Glycol heating fluid temperature is reset according to the outside air temperature

Glycol heating fluid temperature does not exceed 190F

Steam supplied to heat exchanger control valves is 15 PSIG or lower

Condensate must gravity drain from exchanger facilitated by a vacuum breaker installed on the exchanger.

Size heat exchanger for no more than 3 psi.

A structurally sound rail or multiple pick points shall be provided for removal of the tube bundle where tube bundle weight exceeds 100 pounds.

J. Heat Recovery Units

Heat Recovery units shall be utilized with ventilation where possible. Required brand is Innovent or equal.

Access is provided on both sides of coils for cleaning.

Manually activated internal wash-down shall be installed with water piped to unit.

Preheat coils are used before outside air enters unit and coils are normally operated at

0 deg F, except for defrost, when they go to at least 35 deg F. Heating coils are sized at full capacity without regard for heat recovery. Defrost requirement shall be decided by pressure differential over the recovery unit.

Defrost is accomplished by running preheat coil at sufficient temperature to melt frost while unit functions normally.

Outside air is filtered prior to entering heat recovery unit.

Exhaust air is filtered prior to entering heat recovery unit.

Fin density is 8 fins per inch (or less, if efficiency is not compromised)

(Demonstrated fin density range capable of being cleaned by HVAC personnel).

Control valves and damper linkages/actuators are installed outside the units in a readily accessible location.

No plastic components are exposed to unheated outside air (i.e. damper brackets).

Drains are piped to an indirect waste line or floor drain.

Unit is labeled using engraved metal or plastic name plates (not embossed plastic tape).

All requirements listed for air handling units are applicable for heat recovery units.

K. Condensate Stations

Condensate pumps are non-motorized steam pressure powered pumps – with motive steam of 25—35 psi. (Spirax/Sarco condensate pumps or equal). Motive steam shall be supplied through a vertical drop placed as close to station inlet as possible to minimize final horizontal run and drip leg trap shall discharge into flash tank

(Alternate) Condensate pumps are electric duplex units with high temperature seals and motors (must be approved by HVAC shop supervisor prior to procurement).

Proper filling head is provided to the condensate pumps by the condensing equipment feeding the pump and required reservoir

Pressure gauge with snubber is installed on the discharge line with full-flow gate valves located on both sides of the pressure gauge port

All stations are fitted with a sight glass and factory provided insulated cover

Station shall be installed with stainless check valves provided with unit

L. Flash Tanks

Flash tanks are installed on the discharge of all traps serving lines over 15 PSIG and are vented to atmosphere. Discharge of tank shall be served by F&T steam trap before entering reservoir

M. Coils

General

Sufficient space is provided with access between cooling and heating coils to allow cleaning

All coils shall be freeze-proof (steam) or burst-resistant (water or glycol mixture;

basis of design: Sentry-Guard by USA Coil & Air).

All coils can be easily drained and cleaned

All coils have only copper tubing

Coils are equipped with air bleed valves

Thermometers are installed on entering and leaving fluid lines

Cooling coils have a minimum 1” diameter condensate drain

Preheat coils are used with all ventilation/make-up air introduced into a heated space.

Reheat coils are to be sized for full capacity, disregarding heat recovery equipment

Steam Coils

Condensate drain piping is sloped a minimum of ¼” per foot in direction of the flow.

Steam distributing tube type steam coils – freeze-proof design.

Reduce steam pressure to 50 psig or less for all coils – coil wall thickness for 25 psig or less shall be a minimum of 0.035-in., and a minimum coil wall thickness of 0.049-in. for pressures up to 50 psig.

Accessories included in all steam coil/piping installations shall include at a minimum: Automatic air vent, vacuum breaker, float and thermostatic trap

(located 12” – 24” below the coil condensate outlet; sized to 3 or 4 times the required condensate lb/hr rate).

Coils shall be accessible for cleaning

Steam coils are not to be used where contact with outside air is possible

N. Filters

Magnehelic (Dwyer-type) differential pressure indicators are installed across all filters

Filters are to be of standard frame size and no less than 30% efficiency

O. Steam Traps

Traps are located in a readily accessible location for maintenance

Traps are mounted 12” to 24” below steam coil outlet to provide adequate condensate head on the trap

Minimum of 6” dirt leg is provided before the trap inlet

Traps are to be labeled with a 2” round/square numbered brass tag with stamped lettering which is connected by a brass chain

F&T traps are used for most applications (Bucket traps are not used)

Traps shall be installed as shown in diagram, with isolation valves, strainer, check valve, unions, and test tee

P. Strainers

Strainers are provided upstream of all of the following:

Steam traps

Control valves

Meters

Pumps

Strainer housings are equipped with drain valves

Strainers over two inch, used in steam piping must be covered with removable insulation blankets as are all other major components

Cast iron strainers shall not be installed in high pressure steam lines

Q. Valves

Ball valves should be considered in lieu of gate or butterfly valves, except for steam systems

Multi-duty valves are not used

Balancing valves do not serve as isolation valves and are not of the fixed, flow control type (B&G or Taco preferred)

Bronze or brass valves (including check valves) are not used in steam/condensate systems

Control valves for heating and cooling coils are to be three-way configuration except where approved by HVAC Shop supervisor

Valves over 7 ft to centerline shall be equipped with chain drives

R. Pressure Reducing Valves

Pressure gauges with “pigtails” (and isolation valves) are installed on high and low pressure sides

Pressure Reducing Valves are configured in a 1/3 – 2/3 arrangement with the smaller valve opening fully before the larger valve begins to open. Smaller valve is the first to open and last to close

Bypass piping with isolation and throttling capability must be installed

Moisture eliminating devices must be properly installed before pressure reducing valves with condensate trapped, piped to flash tank, and returned to system

S. Pumps

Water/Glycol Heating Medium/Fluid

System lubricated (Wet Rotor) pumps are preferred in most applications

B&G or equal pumps shall be used for any pumps having mechanical seals. The seals must be compatible for use with a very high percentage of glycol, standard seal materials and designs are not acceptable

On any pump replacement projects the new pumps shall meet the above requirement

Horizontal split case pumps are considered for large floor mounted pumps

Pumps are to be sized to operate in the mid-range of performance curve

Circulating pumps have piped-in back-up pumps

Manual switching is used to power backup circulating pumps

Isolation valves and pressure gauges are installed on suction/discharge sides of pumps and pressure gauge ports are in pump flanges where possible, suction side between pump and suction diffuser

Balancing valves are installed on discharge side of all pumps. B&G and T/A are preferred by balancing personnel due to the location of pressure taps, giving greater accuracy

Circulating pumps and piping are sized so as not to require booster pumps.

Auxiliary pumps on coils are not used

All pumps have readily accessible and lockable disconnect switches

Pumps shall be sized to operate in the mid range of the performance curve within maximum efficiency range

A 60/40 ethylene glycol/water mix with phosphate based inhibitors (matching those existing throughout the base), with no silicates (produced specifically for heating and cooling systems) is utilized as a heat transfer medium. Ensure pump sizing and selection take this into account

Steam

Pressure powered pumps shall be used for condensate return. (If it is impossible to use a pressure powered pump, then approval may be given for a dual electric condensate pump). (See H. Condensate Stations above.)

Steel moisture separators shall be installed in all systems, piped as described elsewhere in this document

Steam from CHPP ranges from 80-100 PSI entering buildings and is then reduced to 15 or less PSI

Sound piping practices as stated and shown in other places in this document shall be practiced

T. Motors

Motor starter contactors are rated for cyclic loading (prefer solid state starters)

Motors must be NEMA Premium Efficiency Motors

All motors 5 horsepower and larger are to be provided phase and over/under voltage protection

All pump and fan motors shall be sized as non-overloading

U. Water Heaters

Water heater is semi-instantaneous, helical self cleaning steam coils

Aerco units are specified with electric controls (not pneumatic)

Operate on low pressure steam (less than 15 PSIG)

Pipe blowdown with full size ball valve to indirect waste receptor with separator for solid debris, with valve controlled discharge

V. Piping

Standard color coded labels (ANSI A 13.1) are used for all piping at 10’ intervals

Air vents shall be installed at all high points and drains at all low points of all sections of heating and cooling piping systems

Colored pipe labels are printed to indicate the type of fluid carried in the pipe and direction of fluid flow indicated (arrows)

All hydronic heating systems are piped with type L copper, using lead-free solder, 95/5 or better

Fittings are used for offsets (pipes are not bent for offsets)

Pipes are not taped to prevent contact between dissimilar metals; use proper hangers and clearances

Piping for heat systems is a reverse return configuration (monoflow or any single pipe system shall not be allowed)

Dielectric nipples or flanges are used at all connections between dissimilar metals

(do not use dielectric unions)

Isolation valves are located in very close proximity to all mechanical units, to include control valves, served by piping

Steam piping is schedule 40 black steel or heavier (galvanized pipes/fittings not allowed)

Condensate piping is schedule 80 black steel or heavier with extra heavy fittings

Bronze or Brass fittings (including check valves) are not used in the steam/condensate system

Install moisture eliminating device (Sarco or equal) before pressure reducing valves in steam supplies

Cast iron fittings are not allowed in steam systems above 15 PSI

Heating system can be isolated between individual floors and wings of the facility

Air vents with isolation valves are provided at all the high points in the heating system

Adjustable balancing valves are installed for each heating unit, cooling unit, and pump (not fixed flow devices)

Balancing valves are installed on all bypass and return lines serving a 3-way control valve (preferred brands of balancing valves: Bell & Gossett or Taco)

Balancing valves are not serving as an isolation valve anywhere in the system

Condensate return lines are sloped in direction of flow

Vapor barrier material is installed on all chilled water piping insulation

All exterior piping will be protected from freezing. It will be located in utilidors, buried below the freeze zone, insulated with heat tape along the full length of pipe, or other method approved by the 354 CES Mechanical Engineer.

W. Air Conditioning

Air conditioning is used in support of critical equipment where the need is justified by technical order (TO), Air Force Instruction (AFI), or manufacturer’s specification.

The need must be verified. Comfort cooling is allowed only with approval of the

Energy Engineer. It is recognized there may be a few days in the summer when the

78 degree indoor design temperature may be exceeded.

Humidifiers are bottle or infrared type (not immersion type).

Equipment cooling units are Liebert (base standard). Utilize free cooling coils whenever feasible (piped as described below). Condensers are to be sized for 105 degrees Fahrenheit

R-134a, or R-404a are the refrigerants used

Roof-top units are not used

Phase and low/high voltage protection required on all units

Glycol cooled units with external “dry-cooler” located at ground level, are used (base standard). Water-cooled condensers (whereby the cooling water is wasted to a drain) are not acceptable for new installations on Eielson. Dual circulation pumps are to be installed inside, with 3-way tempering valve (located inside) to supply 42-54 deg F free cooling and not less than 60 deg F condensing water to the indoor cooling unit.

Size all units for 60% ethylene glycol usage

Large chilled water cooling systems utilize Trane Helical Rotary Chillers with dry coolers and free cooling. Condensing/cooling water shall be tempered in the same manner described earlier in this section. The chillers shall be fully independent circuits and provide 100% redundancy. Piping and pumping requirements are as stated elsewhere

X. Refrigeration Piping

Suction gas lines are sized for minimum gas velocities of 900 fpm (ASHRAE)

Discharge gas lines are sized for minimum gas velocities of 2000 fpm (ASHRAE)

P-traps are located at the bottom of all gas risers with more than 8 feet of vertical run

All horizontal refrigerant lines are sloped 0.5 inches per 100 feet in direction of flow

Isolation valves are located at the inlet/outlet of all major system components

Isolation valves are located at each end of all long refrigeration lines

Each component of the refrigeration system has provisions for localized evacuation

Bypass lines are provided around all filter dryers

Y. Water Cooled Condensers

Space is provided to inspect/clean condenser tubes

Flanges and isolation valves are provided/located to allow removal of piping and headers immediately in front of tubes

Taps, with hose bibs, are provided to allow chemical feeding for cleaning purposes and thermometers are mounted on fluid inlet and outlets

Water-cooled condensers whereby the cooling water is wasted to a drain are not acceptable on Eielson. Water cooled condensers are to used in conjunction with a dry-cooler (gly-cooler) as described in Air Conditioning section

Z. Air Cooled Condensers

Selected condenser has a maximum condensing temperature of 20F above design ambient.

Are used only for summer operation and must have ambient temperature lockouts for unit.

Unit is not located on the roof

Ensure adequate air flow for proper heat removal. Special consideration should be given if the unit is inside the building where ventilation must be provided to move heat outside, and with outside applications where adjacent walls may prevent adequate air flow.

AA. Refrigeration Compressor Equipment

Compressor is not located on the roof nor on top of boxes

R-134a, or R-404a are the refrigerants to be used

The following devices are located on the equipment room wall (not on equipment)

Suction discharge

Oil pressure gauges

Isolation valves

* Check with CES Project Engineer and/or Mechanical Systems/HVAC Supervisor before incorporating in design and/or construction.

See supplements for additional mechanical information and information pertaining to metering and insulation requirements.