S02 Projects Specs.docx

01-01-21

SECTION 11 41 21

WALK-IN COOLERS AND FREEZERS

GENERAL

DESCRIPTION

This section covers the replacement of refrigeration system components serving the Kitchen, Canteen, and Lab walk-in refrigerators and freezers at the Wilmington VAMC. Work includes removing existing refrigeration equipment and installing new condensing units, evaporators, line sets, controls, alarms, and related electrical and mechanical components.

Existing walk-in insulated wall panels and doors will remain in place; door gaskets/seals will be replaced Replace floor panels as needed.

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 five (5) 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.

SUBMITTALS

Manufacturer's Literature and Data:

Condensing units, with mounting rack/pad where required.

Unit coolers (evaporators).

Temperature controls and alarms.

Diagrams and details of piping, wiring and controls.

Operational test reports.

Final field test reports.

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.”

Independent Refrigeration Systems Each walk-in cooler and freezer shall be equipped with a fully independent refrigeration system including its own condensing unit, evaporator, refrigerant piping, controls, alarms, and defrost systems.

WALK-IN REFRIGERATOR/FREEZER Panels and Components Door Panel and Door:

Existing doors shall remain in place. Replace existing door gaskets with dual flexible blade wiper gaskets on the bottom, and new replaceable magnetic gaskets on the top edge and along both sides.

Floor Panels:

Replace floor panels as needed.

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

Provide prefabricated floor panels as needed, of the same construction as wall/ceiling except with 1.9 mm (0.78 inch; 14 gauge) aluminum diamond treadplate, sealed watertight. Provide nonskid floor strips 101 x 915 mm (4 x 36 inch) and field apply at 305 mm (12 inch) spacing in all aisles. Install prefabricated floor panels so the finished surfaces are flush with surrounding floor panels.

CONDENSING UNITS

Comply with ARI Standard 520. Air cooled, water cooled or combination air/water cooled type 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.

For units racked above each other and for units installed in a closet, provide a factory fabricated steel rack extending approximately 1143 mm (45 inches) above the floor.

Provide two (2) condensing units and unit coolers with independent refrigeration systems for freezer when shown on construction documents or recommended by manufacturer due to size or freezer.

Do not locate compressors on top of refrigerators or freezers.

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

Compressor Motor: Squirrel cage induction type of ample size for continuous operating at maximum compressor performance. Provide inherent protection, in compressor terminal box, for each phase of motor.

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

Air Cooled Condensing Units:

High efficiency type piped and automatically controlled to operate at lower head pressures during low ambient temperature conditions. Designed and weather‑proofed for outdoor installation, to operate satisfactorily at winter ambient temperatures down to -17 degrees C ( 3 degrees F) and be provided with crankcase and receiver heaters.

The condenser fans are to be driven by permanent split capacitor motors.

UNIT COOLERS

Comply with ARI Standard 420. Units to be UL listed, forced‑ventilation type. Provide demand defrost controllers for defrosting, internal or external refrigerant distributor, single or multiple fans and motors, drip‑pan, deflectors, aluminum or baked‑enamel steel housing, hangers, and all accessories. Unit coolers for kitchen walk‑in units to be NSF approved.

Motors: Permanent split capacitor type. 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 to be as needed 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.

2.5 Control systems and alarms

Provide new 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. 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.

BAS Integration All new walk-in cooler and freezer temperature controls, defrost controls, fan controls, and associated monitoring hardware shall be fully integrated with the existing Building Automation System (BAS).

EXECUTION

Demolition Remove existing refrigeration components including condensing units, evaporators, refrigerant piping, insulation, and controls.

3.2 Installation

Install refrigeration equipment as described in the respective manufacturer's instructions.

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.

0. REFRIGERATOR/FREEZER START‑UP, AND PERFORMANCE TESTS AND INSTRUCTIONS

Initial Start‑up 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.

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