Revised 4-17-21 SPEC 11 41 21 - Walk In Coolers and Freezers.docx

01-01-21

SECTION 11 41 21

WALK-IN COOLERS AND FREEZERS

GENERAL

DESCRIPTION

This section specifies walk-in site assembled refrigerators and freezers.

RELATED WORK

Section 09 30 13, CERAMIC TILING: Quarry tile floor.

Section 11 05 12, GENERAL MOTOR REQUIREMENTS FOR EQUIPMENT.

Section 23 05 11, COMMON WORK RESULTS FOR HVAC.

Section 23 23 00, REFRIGERANT PIPING: Piping, pipe insulation and refrigerant.

Section 23 09 23, DIRECT-DIGITAL CONTROL SYSTEM FOR HVAC.

Refer to the construction documents for the refrigeration equipment schedules and installation details.

Refer to the submittal documents for the fire suppression system.

Refer to Division 26, ELECTRICAL for lighting and power requirements.

WARRANTY

Construction Warranty: Comply with FAR clause 52.246-21, “Warranty of Construction”.

Refrigeration Compressor Warranty: Manufacturer agrees to repair or replace compressors that fail in materials or workmanship within ten (10) years from the date of final acceptance by the Government. Failure includes but is not limited to inability to maintain set temperature. Submit compressor warranty. Walk-in Panels to be warranted for ten (10) years.

SUBMITTALS

Submit in accordance with Section 01 33 23, SHOP DRAWINGS, PRODUCT DATA, AND SAMPLES.

Manufacturer's Literature and Data:

Walkin units, including assembly instructions.

Condensing units, with mounting rack where required.

Unit coolers.

Temperature controls and alarms.

Diagrams and details of piping, wiring and controls.

Operational test reports.

Final field test reports.

Maintenance and operating manuals in accordance with Section 01 00 00, GENERAL REQUIREMENTS.

Manufacturer’s compressor warranty.

APPLICABLE PUBLICATIONS

The publications listed below form a part of this specification to the extent referenced. The publications are referenced in the text by the basic designation only.

Air-Conditioning and Refrigeration Institute (ARI):

American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE):

15-10-16 Safety Standard for Refrigeration Systems ASTM International (ASTM):

National Sanitation Foundation/American National Standard (NSF/ANSI):

7-09 Commercial Refrigerators and Storage Freezers National Fire Protection Association (NFPA):

70-20 National Electric Code Underwriters Laboratories, Inc. (UL):

PRODUCTS

PERFORMANCE REQUIREMENTS

NSF Standards: Provide equipment that bears NSF Certification Mark certifying compliance with applicable standards.

UL Certification: Provide electric and fuel-burning equipment and components that are evaluated by UL for fire, electric shock, and casualty hazards according to applicable safety standards, and that are UL certified for compliance and labeled for intended use.

Regulatory Requirements: Install equipment to comply with the following:

ASHRAE 15, “Safety Code for Mechanical Refrigeration.”

NFPA 70, “National Electric Code.”

WALK-IN REFRIGERATOR/FREEZER CONSTRUCTION

General: Prefabricated, sectional, all-metal clad, modular, designed for easy accurate field assembly.

Provide walk-in units manufactured for food service use conforming to NSF/ANSI 7, UL 207, and UL 471. Floorless, with insulated floor screeds, installed over insulated floors. Floor panel walk-in refrigerators and freezers with appropriate insulated floor assembly and polished aluminum or galvanized skin finish floor.

Panel Construction:

General: Interchangeable, 1219 mm (48 inch) maximum width, 101 mm (4 inch) thick, filled with insulation. Double seal serrated neoprene rubber gaskets to assure air and vapor tight joints.

Corner panels: 90 degree angle, radiuses 15 mm (0.5 inch) inside and outside, with 305 mm (12inch) dimensions each side.

Panel edges: Foaminplace, tongueandgrooved urethane to assure tight joints. Provide double seal serrated neoprene rubber gaskets to assure air and vapor tight joints on the interior and exterior of each panel along every tongue.

Insulation: 101 mm (4 inch) minimum foamed-in-place polyurethane with manufacturer’s rated “K” factor of not more than 0.15, free rise design of not less than 27 kg per cubic meter (1.7 pounds per cubic foot), or in-place density of not less than 32 kg per cubic meter (2 pounds per cubic foot). Provide floor screeds with minimum of 63 mm (2-1/2 inches) of foamed insulation.

Door Panel and Door:

Provide channel thermal breaker type reinforcing steel frame around the entire perimeter of the door opening.

Door to be an infitting flushmounted type with dual flexible blade wiper gasket on the bottom, and a replaceable magnetic gasket on the top edge and along both sides.

Provide heated, double glass view windows in refrigerator doors.

Door to be equipped with a minimum of three (3) hinges, for rough usage including aluminum diamond plate on inside of door panel and frame to a height of 915 mm (36 inches).

Provide hydraulic exterior door closer to prevent slamming and assure secure closing.

Door hinges and latch and strike assembly: Manufacturer's standard, selfclosing camlift type hinges, for 1219 mm (48 inch) door, chrome plated or polished aluminum finish, made to provide for locking, but with an inside safety release mechanism to prevent anyone from being locked inside when door is locked from outside.

Concealed, energy use selective, antisweat heater wire circuit: Provide sufficient heat to prevent condensation and frost formation at the door jambs and exterior edges of the door on all sides.

Thermometer: Manufacturer's standard, 50 mm (2inch) minimum diameter, dial type, flush mounted in door panel.

Pressure relief port: Provide for all freezers operating at 18 degree C (0 degree F), or lower, twoway type ports, to allow for an increase or decrease of air pressure on the interior of the freezer to equalize with air pressure on the exterior. Provide ports with automatically controlled, UL approved antisweat heaters. Complete device to carry UL Label and be assembled ready for connection. Install port in a wall panel away from the direct air stream flowing from the coils.

Floor Panels:

Floor Panel Strength: Capable of withstanding 28.7 kPa (600 pounds per square foot) uniform load.

Provide prefabricated floor panels of the same construction as wall/ceiling except with 1.9 mm (0.78 inch; 14 gauge) galvanized skin, stainless steel or aluminum diamond treadplate, sealed watertight. Provide prefabricated floor panels which are laid on or recessed with, sloping interior floor ramps at exterior entrance doors, panels flush with surrounding building floor. Furnish two (2) sets of erection tools, compatible with fasteners, with each unit.

Floorless Refrigeration Floors:

Make floorless refrigerator floors flush with the surrounding building floor.

Wherever compartment dimension exceed clearspan ability of ceiling panels, provide Ibeam support on exterior of ceiling or spline-hangers. Install 13 mm (1/2 inch) diameter steel rods through beam/hangers and secure to structure above. Beams or posts within compartments are not acceptable.

Rub rail wall protectors: Manufacturer’s standard, at floor line of walls exposed to traffic.

Lights: Provide high-efficiency rated LED light fixtures with safety shields. Lighting must conform with UL IP-65. Provide with diffuser and be capable of operating in minus 23 degrees C (-40 degrees Fahrenheit) temperature. Lights must run length of walk-in starting 610 mm (24 inches) from front panel and extending within 610 mm (24 inches) of back panel. Run between shelf rows to obtain 323 lux (30 foot-candles) at floor level regardless of any interior furnishings.

CONDENSING UNITS

Comply with ARI Standard 520. Water cooled as shown in construction documents.

Provide motor driven integral compressor, motor starter, condenser, receiver, common base, and safety/operational controls.

Receiver capacity not to be less than 125 percent of system refrigerant charge.

Provide two (2) condensing units and unit coolers with independent refrigeration systems for each refrigerator and freezer as shown on construction documents.

Do not locate compressors on top of refrigerators, freezers, or other compressors.

Provide positive oil lubrication and oil level indicating device for each compressor. Provide water regulating valve for water cooled unit.

Pressure Switches: Automatic reset low pressure switch, and automatic or manual reset high pressure cutout.

UNIT COOLERS

Comply with ARI Standard 420. Units to be UL listed, forcedventilation type. Provide demand defrost controllers for defrosting, internal or external refrigerant distributor, single or multiple fans and motors, drippan, deflectors, aluminum or bakedenamel steel housing, hangers, and all accessories. Unit coolers for kitchen walkin units to be NSF approved.

Motors: Permanent split capacitor type in accordance with Section 11 05 12, GENERAL MOTOR REQUIREMENTS FOR EQUIPMENT. Provide motors with thermal overload protection and manual starting switch.

Drain Pans: Galvanized sheet steel. Provide additional drain pans under uncovered refrigerant connections, and interconnect them with main drain pan. For freezer units provide electrically heated drain pan with heated tape over condensate drain line.

Defrost Provision:

Refrigerators: Defrost with Demand defrost controllers and occur during compressor off cycle with evaporator fan running continuously.

Freezer defrost: Defrost to be by demand defrost with Evaporator Efficiency Controller.

MONITORING ALARM SYSTEM

Provide an electronic monitoring and alarm system for each section of each unit.

System Components: Detecting thermostat, master control panel, interconnecting wiring, remote audible alarm, and defrost compensator. Provide dials showing temperatures and pilot lights, warning lights, switches, transformer, and buzzer, all as a part of the master control panel. Locate master control panel and remote audible alarm as indicated on construction documents. Provide power fuse to protect system components.

System Operation: Set alarms at 5 degrees C (10 degrees F) above and below specified operating temperatures.

Personnel Alarm: For each unit, provide separate audible alarm system operable from inside unit, for use of personnel unable to exit unit. Locate remote audible alarm where indicated on construction documents.

EQUIPMENT IDENTIFICATION REQUIREMENTS

Refer to Section 23 05 11, COMMON WORK RESULTS FOR HVAC.

Identify all walkins, refrigeration equipment and alarm devices.

SPECIAL REQUIREMENTS FOR FREEZERS

Provide entrance to freezers through a refrigerator of a higher temperature. Locate thermometer serving frozen freezer outside of higher temperature refrigerator used as entrance vestibule.

REFRIGERATION Split SYSTEM Digital Split System Lead lag controller, the system will utilize a predictive control algorithm and staging delay timer to sequence the system’s compressors, matching the conditioned space’s load requirements. The staging control algorithms will equalize the system compressors’ operating hours. The control system will prevent unnecessary multiple compressors start/stop cycles, provide duty cycles and ensure the cycles required for proper oil management. The controller will prevent demand surges from multiple compressors starting at the same time.

The unit shall be pre-wired for a single point electrical connection with a main fused disconnect. The unit shall include individual dedicated water-cooled condensers. Condensers shall be aluminum fin/copper tube designed to operate at 15 degrees T.D, easy access to service. Lifting points shall be integrated in the feet at each corner to facilitate installation.

All compressors shall be digital scroll type and factory assembled to operate with the refrigerant specified.

Systems to have a back-up compressor for 100% compressor redundancy. All stand-by compressors shall be scroll type and factory assembled to operate with specified refrigerant blend.

Compressors and refrigeration piping will be installed in such a manner as to eliminate noise with vibration eliminators in refrigeration lines, as needed. Each compressor unit shall be equipped with; oversized receiver, dual pressure control for cut-in cut-out, a ball-bearing fan motor, fixed head pressure control, suction filter, liquid line sight glass, liquid line drier, crankcase heaters, headmaster controls and/or fan cycling, liquid line inlet and outlet valves, defrost cycle and armored super hose connections (in lieu of capillary tubes).

All digital systems to include digital rack sequencer controller, oil separators. Low temp compressors supplying refrigeration wrapped rail cold pans or blast chillers shall be equipped with suction accumulator. Stand-by compressor system is manual change over, isolation valves to be supplied on suction and discharge line at the compressor inlet and outlet.

All systems with automatic change over compressor system shall be equipped with oil separator, oil reservoir, oil filter, and compressor oil management system.

All refrigerant lines shall be extended to one side of the package in a neat and orderly manner. All tubing shall be securely supported and anchored with non-corrosive coated clamps. All joints must be brazed, not soldered. All piping and controls shall be factory pressure-tested with nitrogen at 175 PSI.

Stand-by/redundant compressor shall be equipped with an independent evaporator. All evaporator coils shall be a direct expansion type. Evaporators used will be all "Underwriters Laboratory Listed" supplied from factory with an electric expansion valve, solenoid valve, suction transducer, and Eco-Smart on-demand defrost controller, pre-wired and pre-piped under nitrogen pressure and designed for use with the refrigerant specified. Isolation ball valves are to be installed on the liquid and suction lines at each evaporator coil. Isolation disconnect switch shall be installed in each unit.

All field piping installed as per factory standards and the sizing of the piping shall meet proper velocities as per factory standards. Insulation will be foam type 25/50 smoke and fire type. Medium temperature will use 3/4" thick wall, low temperature will use 1" thick wall and sub-cooled liquid lines will use 1/2'' thick wall insulation. All insulation shall be jacketed with Aluminum (complying with division 15000,) 1-1/2” overlap and secured with bundling ties. All jacket elbows to be roll formed. All field piping installed with plastic bushing wherever steel to copper tubing comes together. Include all labor, material, equipment, tools, refrigerant, oil, and other required accessories for the complete installation of the systems as shown and specified. Interconnection of all accessories accomplished for ease of servicing.

After installation and before charging, evacuate all piping systems to a 500-micron evacuation. After evacuation, charge system with nitrogen and maintain pressure of 150% working pressure for 6 hours. Cap off, install pressure gauge and hold for 24 hours minimum. Re-evacuate, hold for 6 hours, charge and make electronic detector test all joints.

Final wiring of connections, conduit and/or pull boxes, provided under applicable electrical and plumbing contracts. See R-1 drawing for wiring schematic for field wiring.

Included shall be a full one (1) year warranty for all parts by factory, full one (1) year compressor warranty by compressor manufacture and a 90-day warranty on labor on the entire refrigeration package only from the day of final acceptance of the installation as previously specified. Factory labor warranty does not cover installation. See section 1.3.B for additional warranty requirements.

EXECUTION

INSTALLATION

Assemble walkin units and install refrigeration equipment as described in the respective manufacturer's instructions. Make panel joints tight and seal all panel penetrations to prevent condensation or frosting.

Unit cooler: NSF approval requires that the unit be suspended at 90 mm (3-1/2 inches) minimum distance below the ceiling to allow cleaning the top of the unit cooler.

Mount pipe, conduit, and instrumentation on the exterior and pass thru neatly drilled penetrations to the lights or other devices.

Piping, Pipe Insulation and Refrigerant: Provide in accordance with Section 23 23 00, REFRIGERANT PIPING.

Controls Installation: As specified in Section 23 09 23, DIRECTDIGITAL CONTROL SYSTEM FOR HVAC.

REFRIGERATOR/FREEZER STARTUP, AND PERFORMANCE TESTS AND INSTRUCTIONS

Initial Startup and Operational Test:

Provide all lubricants and accessories before initial start-up. Start and operate all equipment.

Follow the manufacturer’s procedures and place the systems under all modes of operation.

Supplement initial charges of lubricating oil to assure maximum operating capacity.

Adjust all safety and automatic control instruments. Record manufacturer’s recommended readings hourly.

Operational tests must cover a period of not less than three (3) days. Submit operational test report.

Test Reports: Submit the final field test reports for each system tested, describing test apparatus, instrumentation calculations, and equipment data based on industry standard forms. Include in data:

Compressor and air moving device ampere readings.

Power supply characteristics, including phase imbalance, with 1/2 percent accuracy.

Thermostatic expansion valve superheat-value as determined by field test.

Sub-cooling.

High and low refrigerant temperature switch set-points.

Monitoring alarm system.

Low oil pressure switch set-point.

Defrost system timer and thermostat set-points.

Moisture content.

Ambient, condensing and coolant temperatures.

Capacity control set-points.

Field data and adjustments which affect unit performance and energy consumption.

Where final adjustments and settings cannot be permanently marked or drilled and pinned as an integral part of device, include adjustment and setting data in test report.

By arrangement with the Contracting Officer Representative (COR), 24 hours in advance, use the startup and test period for required operation and maintenance instructions to VA personnel in accordance with Section 01 00 00, GENERAL REQUIREMENTS.

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