23 81 23.00 20.pdf

P381 Multi-Mission Drydock #1 eProjects # 1604959 Portsmouth Naval Shipyard, Kittery, ME

SECTION 23 81 23.00 20

COMPUTER ROOM AIR CONDITIONING UNITS

02/10

PART 1 GENERAL

1.1 REFERENCES

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

AMERICAN SOCIETY OF HEATING, REFRIGERATING AND AIR-CONDITIONING

ENGINEERS (ASHRAE)

ANSI/ASHRAE 15 & 34 (2016) ANSI/ASHRAE Standard 15-Safety Standard for Refrigeration Systems and ANSI/ASHRAE Standard 34-Designation and Safety Classification of Refrigerants

ASHRAE 52.2 (2012; Errata 1 2013; INT 1 2014; ADD A, B, AND D SUPP 2015; INT 3 2015; Errata 2 2015; ADD C 2015; ADD E, F 2016) Method of Testing General Ventilation Air-Cleaning Devices for Removal Efficiency by Particle Size

ASHRAE 55 (2010) Thermal Environmental Conditions for Human Occupancy

ASHRAE 62.1 (2010) Ventilation for Acceptable Indoor Air Quality

ASME INTERNATIONAL (ASME)

ASME B31.1 (2018) Power Piping

ASME B31.5 (2016) Refrigeration Piping and Heat Transfer Components

ETL TESTING LABORATORIES (ETL)

ETL DLP (updated continuously) ETL Listed Mark Directory

NATIONAL FIRE PROTECTION ASSOCIATION (NFPA)

NFPA 70 (2020) National Electrical Code

U.S. NATIONAL ARCHIVES AND RECORDS ADMINISTRATION (NARA)

40 CFR 82 Protection of Stratospheric Ozone

UNDERWRITERS LABORATORIES (UL)

UL Elec Equip Dir (2011) Electrical Appliance and Utilization Equipment Directory

SECTION 23 81 23.00 20 Page 1

1.2 SYSTEM DESCRIPTION

Provide new computer room air conditioning unit (CRACU) complete and ready for operation. Size equipment based on Design Manual CS from the Air Conditioning Contractors of America; do not oversize.

1.3 SUBMITTALS

Government approval is required for submittals with a "G" designation;

submittals not having a "G" designation are for Contractor Quality Control approval. Submit the following in accordance with Section 01 33 00

SUBMITTAL PROCEDURES:

SD-03 Product Data

Computer room air conditioning units; G

Space temperature control system drawings; G

Filters

Refrigerants

SD-06 Test Reports

Field Test Schedule; G

Manufacturer's Field Test Plans; G

Field Test Reports; G

SD-07 Certificates

Credentials of the Manufacturer's Field Test Representative; G

Ozone Depleting Substances Technician Certification

SD-08 Manufacturer's Instructions

Installation Manual for Each Type of CRACU

SD-10 Operation and Maintenance Data

Submit in accordance with Section 01 78 23 OPERATION AND

MAINTENANCE DATA.

Computer Room Air Conditioning Units, Data Package 4; G

1.4 REFRIGERANTS

Refrigerants must have an Ozone Depletion Potential (ODP) no greater than

0.0. CFC-based refrigerants are prohibited. HCFCs and Halons are not permitted. Provide SDS sheets for all refrigerants.

SECTION 23 81 23.00 20 Page 2

1.5 QUALITY ASSURANCE

1.5.1 Ozone Depleting Substances Technician Certification

All technicians working on equipment that contain ozone depleting refrigerants must be certified as a Section 608 Technician to meet requirements in 40 CFR 82 , Subpart F. Provide copies of technician certifications to the Contracting Officer at least 14 calendar days prior to work on any equipment containing these refrigerants.

1.6 ENVIRONMENTAL REQUIREMENTS

For proper Indoor Environmental Quality, maintain positive pressure within the building. Ventilation shall meet or exceed ASHRAE 62.1 and all published addenda. Meet or exceed filter media efficiency as tested in accordance with ASHRAE 52.2 . Thermal comfort shall meet or exceed

ASHRAE 55.

PART 2 PRODUCTS

2.1 COMPUTER ROOM AIR CONDITIONING UNITS (CRACU)

ANSI/ASHRAE 15 & 34 . Provide self-contained or split-system units, designed, factory assembled, and factory tested. Unit shall be listed in UL Elec Equip Dir or ETL DLP for computer room application. Unit shall include room cabinet and frame, fan section, filter section, cooling coil, reheat coil, compressors, condensers, controls, and, interconnecting piping internal to the CRACU.

The ceiling-mounted direct expansion system shall be designed to control temperature conditions in rooms containing electronic equipment, with good insulation and vapor barrier. The system is also available with an optional humidity control system.

The self-contained and split evaporator units shall be designed for above-dropped-ceiling installation and serviceable from the front and bottom of the system.

Condensing unit for split system shall be designed for outdoor installation. System shall be supplied with UL 1995 for "Heating and Cooling Equipment".

2.1.1 Cabinet and Frame

The cabinet and chassis shall be constructed of heavy gauge galvanized steel and designed for easy installation and service access from front and bottom of unit only. Mounting brackets shall be integral to the cabinet design. Internal cabinet insulation shall meet ASHRAE 62.1 requirements for Mold Growth, Humidity & Erosion, tested per UL 181 and ASTM 1338 standards.

Removable panels shall allow access to the electric panel or refrigerant components for service or maintenance. Vibration isolators shall be provided with the chassis for mounting.

2.1.1.1 Condensate Pan

Condensate pans shall be minimum 22 gage Type 304 stainless steel, non-corroding, double-sloped, and shall be piped to drain.

SECTION 23 81 23.00 20 Page 3

2.1.2 Fan

The air distribution system shall be constructed with a variable speed, quiet, direct-drive fan assembly equipped with double-inlet blower, self-aligning ball bearings and lifetime lubrication. Fan motor shall be 1/5hp (149W), permanent-split capacitor, high efficiency type, equipped with two speeds for air flow modulation. The microprocessor controller shall use the lower fan speed for precise dehumidification control. Fan speed shall also be user selectable from the wall controller. System shall be suitable for supply and return air plenum.

2.1.3 Reheat Section

Electric low watt density 304 stainless steel fin tubular reheat element provides one stage of reheat to maintain room dry bulb temperature. Reheat includes one stage fan motor.

2.1.4 Condensing Unit

Split-unit condensing system shall be:

a. Indoor centrifugal blower (Lee-temp head pressure control) condensing unit.

b. Scroll compressor with hot gas bypass capacity control.

c. Starts and operates at low outdoor temperatures down to minus 30 degrees F.

d. High head pressure switch for system protection.

e. Nitrogen holding charge. System is field-charged, with field-supplied refrigerant.

Outdoor condensing unit cabinet shall be with horizontal air discharge.

Removable panel shall provide access to refrigerant components, electrical components and connections.

Install outdoor unit with minimum clearance required for proper air flow on both air inlet and discharge sides, and components access.

2.1.5 Microprocessor Control

The control system shall be microprocessor-based, factory-wired into the system and tested prior to shipment. The wall-mounted controller shall include a 2-line by 16-character liquid crystal display (LCD) providing continuous display of operating status and alarm condition and shall be capable of displaying values in degrees F. An 8-key membrane keypad for setpoint/ program control, fan speed selection and unit On/Off shall be located below the display. Controller shall be password protected to prevent unauthorized set point adjustments. Field-supplied 4-conductor thermostat wire shall be used to connect the wall-mounted controller to the unit control board.

Temperature and humidity sensors shall be located in the wall box, which shall be capable of being located up to 300 feet from the evaporator unit when using a remote temperature/humidity sensor in the conditioned space.

SECTION 23 81 23.00 20 Page 4

2.1.5.1 Monitoring

The LCD shall provide On/Off indication, operating mode indication (cooling, heating, humidifying, dehumidifying), fan speed indication and current day, time, temperature and humidity (if applicable) indication.

The monitoring system shall be capable of relaying unit operating parameters and alarms to the monitoring systems.

2.1.5.2 Control Setpoint Parameters

a. Temperature Setpoint 65-85 degrees F

b. Temperature Sensitivity 1-9.9 degrees F

c. Humidity Setpoint 20-80 percent RH

d. Humidity Sensitivity 1-30 percent RH

2.1.5.3 Unit Controls

2.1.5.3.1 Compressor Short-Cycle Control

The control system shall prevent compressor short-cycling by a 3-minute timer from compressor stop to the next start.

2.1.5.3.2 Common Alarm and Remote On/Off

A common alarm relay shall provide a contact closure to a remote alarm device. Two terminals shall also be provided for remote On/Off control.

Individual alarms shall be "enabled" or "disabled" from reporting to the common alarm.

2.1.5.3.3 Setback Control

The control shall be user-configurable to use a manual setpoint control or a programmable, time-based setback control. The setback control will be based on a 5 day/2 day programmed weekly schedule with capability of accepting 2 events per program day.

2.1.5.3.4 Temperature Calibration

The control shall include the capabilities to calibrate the temperature and humidity sensors and adjust the sensor response delay time from 10 to 90 seconds. The control shall be capable of displaying temperature values in degrees F.

2.1.5.3.5 System Auto Restart

For startup after power failure, the system shall provide automatic restart with a programmable (up to 9.9 minutes in 6-second increments) time delay. Programming can be performed either at the wall mounted controller or from the central, site-monitoring system.

2.1.6 Factory Installed Sensors

2.1.6.1 Filter Clog Switch

The filter clog switch senses pressure drop across the filters and shall annunciate the wall controller upon reaching the adjustable setpoint. The

SECTION 23 81 23.00 20 Page 5 filter clog switch shall be factory installed in every cooling unit.

2.1.6.2 High-Temperature Sensor

The high-temperature sensor shall immediately shut down the system when high temperatures (125°F) are detected. The high-temperature sensor shall be mounted with the sensing element in the return air of every cooling unit.

2.1.7 Alarms

2.1.7.1 Unit Alarm

The control system shall monitor unit operation and activate an audible and visual alarm in the event of the following factory preset alarm conditions:

a. High Temperature

b. Low Temperature

c. High Humidity

d. Low Humidity

e. High Water Alarm - Lockout Unit Operation

f. High Head Pressure

g. Loss of Power

h. Compressor Short Cycle

2.1.7.2 Custom Alarms

a. Humidifier Problem

b. Filter Clog

c. Water Detected

d. Smoke Detected

e. Custom #1

f. Custom #2

User-customized text can be entered for the two (2) custom alarms.

2.1.7.3 Alarm Controls

Each alarm (unit and custom) shall be individually enabled or disabled (except for high head pressure and high water in condensate pan) and can be programmed for a time delay of 0 to 255 seconds of continuous alarm condition to be recognized as an alarm. Each alarm can also be enabled or disabled to activate the common alarm (except high head pressure and high water in condensate pan).

2.1.7.4 Audible Alarm

The audible alarm shall annunciate at the wall-mounted controller any alarm that is enabled by the operator.

2.1.7.5 Common Alarm

A programmable common alarm shall be provided to interface user selected alarms with a remote alarm device. Alarms shall be enabled or disabled from reporting to the common alarm.

SECTION 23 81 23.00 20 Page 6

2.1.7.6 Remote Monitoring

All alarms shall be communicated to the remote monitoring system with the following information: date and time of occurrence, unit number and present temperature and humidity.

2.2 DIRECT EXPANSION SELF-CONTAINED SYSTEM COMPONENTS

2.2.1 Refrigeration System

The refrigeration system shall consist of a scroll compressor with vibration isolating grommets, evaporator coil, condenser coil, externally equalized thermostatic expansion valve, high pressure safety switch, filter drier, hot gas bypass circuit, factory refrigerant charge and externally equalized expansion valve.

Hot gas bypass shall be provided to reduce compressor cycling and optimize performance under low load conditions. The hot gas bypass shall be completely contained within the unit. Field installed third refrigerant line shall not be acceptable. Hot gas bypass shall be automatically deactivated upon a call for dehumidification.

High pressure switch shall protect the unit from abnormal refrigerant pressure conditions and shall deactivate the compressor and annunciate an alarm at the wall controller. The blower shall continue to circulate air. The wall controller shall be used to manually restart the compressor function after the automatic pressure switch resets. Three high head pressure alarms in a rolling 12-hour period shall lock out the manual restart feature until power is cycled to the evaporator unit.

2.2.2 Evaporator Coil

The evaporator coil shall have 2.4 square feet face area. It shall be constructed of copper tubes and aluminum fins.

The coil shall be mounted in a condensate drain pan with internally trapped drain line. The evaporator drain pan shall include a factory-installed float switch to shut down the evaporator upon high water condition.

2.2.3 Air-Cooled Condenser Coil

The air-cooled condenser section shall contain a factory mounted and piped condenser coil constructed of copper tubes and aluminum fins. No piping, brazing, dehydration or charging shall be required. The condenser coil shall be factory mounted within the unit cabinet.

2.2.4 Air-Cooled Condenser Fan

A factory-supplied condenser fan shall be field-mounted to the end of the evaporator cabinet. The system shall be provided with a fan speed control system to permit operation at minus 20 degrees F inlet ambient air temperature and sized to provide full rated cooling capacity at 95 degrees F entering air from plenum space.

Condenser fan electrical and refrigerant pressure connections shall be field attached to the cooling chassis using factory provided wiring harness and capillary tube/fitting.

SECTION 23 81 23.00 20 Page 7

2.3 OPTIONS AND ACCESSORIES

2.3.1 Factory Installed Options

Hot Gas Reheat

Provide factory-installed hot gas reheat. The complete hot gas reheat system shall include a copper tube, aluminum fin coil, three-way solenoid valve, and refrigerant check valve. Hot gas reheat shall operate only during dehumidification and capacity shall be offset by cooling coil capacity. Hot gas reheat shall not be used for space heating.

Remote Monitoring and Control

Provide BACnet monitoring capability to the system. Card shall employ Ethernet and RS-485 networks to monitor and manage a wide range of operating parameters pertaining to the cooling system. The card shall provide access to the unit remotely via a web interface and shall support system connectivity. The card shall be factory mounted on the unit, and shall be factory wired for power and unit communications. Ethernet cable providing network access to the world-wide web or to a BMS shall be field wired.

a. Non-locking disconnect switch

b. Filter clog indicator

c. High temperature sensor

2.3.2 Ship-Loose Accessories

Supply and Return Grille

A factory-supplied supply and return grille kit shall be provided for supply and return air delivery through a 2 feet by 4 feet T-bar ceiling grid. Kit shall include an air baffle plate, supply grille, hinged return grille, 1-inch MERV 8 (ASHRAE 52.2-2007) filter and mounting frame.

2.3.3 Filter Box

Filter box shall be constructed of galvanized steel, supplied with deep pleated MERV 8 filter. The box shall be provided with a 3/4-inch duct flange and discharge air duct collar. Filter shall be accessible via a hinged access door, without shutting the unit down.

2.4 ELECTRICAL

2.4.1 Electrical Motors, Controllers, Contactors, and Disconnects

Furnish with respective pieces of equipment. Motors, controllers, contactors, and disconnects shall conform to Section 26 20 00 INTERIOR DISTRIBUTION SYSTEM, as modified and supplemented by this section.

Provide electrical connections under Section 26 20 00 INTERIOR DISTRIBUTION SYSTEM. Provide controllers and contactors with maximum of 120-volt control circuits, and auxiliary contacts for use with controls furnished.

SECTION 23 81 23.00 20 Page 8

2.4.2 Electrical Control Wiring

Provide control wiring under this section in accordance with NFPA 70 and Section 26 20 00 INTERIOR DISTRIBUTION SYSTEM. Provide Space temperature control system drawings which include point-to-point electrical wiring diagrams.

2.5 METAL DUCTWORK

Requirements for HVAC metal ductwork is specified in Section 23 00 00 AIR

SUPPLY, DISTRIBUTION, VENTILATION, AND EXHAUST SYSTEMS.

PART 3 EXECUTION

3.1 INSTALLATION

3.1.1 CRACU System

Installation of each CRACU system including equipment, materials, installation, workmanship, fabrication, assembly, erection, examination, inspection, and testing, shall be in accordance with ASME B31.1 , ASME B31.5 , NFPA 70 , as modified and supplemented by the requirements of this section and the CRACU manufacturer's recommendations.

3.1.2 Installation Instructions

Provide a manufacturer's installation manual for each type of CRACU.

3.2 FIELD QUALITY CONTROL

Upon completion and before final acceptance of work, test each CRACU subsystem in service to demonstrate compliance with the contract requirements, including field testing specified below. Adjust controls and balance systems prior to final acceptance of completed systems. Test controls through every cycle of operation. Test safety controls to demonstrate performance of required function. Correct defects in work provided by Contractor and repeat tests. Furnish water, electricity, instruments, connecting devices, and personnel for tests. Flush and clean piping before placing in operation. Clean equipment, piping, strainers, and ducts. Prior to commencement of field testing, remove all filters and provide new filters. Perform and document that proper Indoor Air Quality During Construction procedures have been followed; this includes providing documentation showing that after construction ends, and prior to occupancy, new filters were provided and installed.

3.3 FIELD TESTING

Provide field test plan, field test schedule, field test and field test report on each of the CRACU. Field test each CRACU for Contracting Officer acceptance in accordance with the CRACU manufacturer's approved field test plan.

3.3.1 Manufacturer's Field Test Plans

Submit field test plans developed by the manufacturer for each CRACU.

Field test plans developed by the installing Contractor, or the equipment sales agency furnishing the CRACU, will not be acceptable.

The Contracting Officer will review and approve the field test plan for

SECTION 23 81 23.00 20 Page 9 each of the listed CRACU's prior to commencement of field testing of the equipment. The approved field test plans shall be followed for the field tests of the CRACU and test reporting.

3.3.1.1 Coordinated Testing

Indicate in each field test plan when work required by this section requires coordination with test work required by other specification sections. Furnish test procedures for the simultaneous or integrated testing of: CRACU controls which interlock and interface with controls factory prewired.

3.3.1.2 Prerequisite Testing

Each CRACU for which performance testing is dependent upon the completion of the work covered by Section 23 05 93 TESTING, ADJUSTING AND BALANCING FOR HVAC must have that work completed as a prerequisite to testing work under this section. Indicate in each field test plan when such prerequisite work is required.

3.3.1.3 Test Procedure

Indicate in each field test plan the CRACU manufacturer's published start-up, and field acceptance test procedures. Include in each test plan a detailed step-by-step procedure for testing automatic controls provided by the manufacturer.

Procedures shall be structured to test the controls through all modes of control to confirm that the controls are performing with the intended sequence of control.

Controllers shall be verified to be properly calibrated and have the proper set point to provide stable control of their respective equipment.

3.3.1.4 Performance Variables

Each test plan shall list performance variables that are required to be measured or tested as part of the field test.

Include, in the listed performance variables, requirements indicated on the CRACU schedules on the design drawings. Manufacturer shall furnish, with each test procedure, a description of acceptable results that have been verified.

Manufacturer shall identify the acceptable limits or tolerances within which each tested performance variable shall acceptably operate.

3.3.1.5 Test Configuration

Plans shall indicate that tests are to be performed for a minimum of four continuous hours in a wet coil condition. If test period is interrupted, the four hour test period shall be started over. Each test plan shall be job specific and shall address the particular CRACU and particular conditions which exist with this contract. Generic or general preprinted test procedures are not acceptable.

3.3.1.6 Tested Variables

Plans shall provide for air side testing which includes verification of

SECTION 23 81 23.00 20 Page 10 the airflow, total static pressure; fan drive motor KW, amperage and RPM;

and fan RPM. Provide entering air temperatures equal to those indicated on the CRACU schedules.

3.3.1.7 Thermal Testing

Plans shall provide thermal testing with temperatures equal to those indicated on the CRACU schedules. Thermal testing shall verify CRACU heating, sensible cooling, total cooling, and humidifying performance scheduled on the contract drawings.

3.3.1.8 Specialized Components

Include procedures for field testing and field adjusting specialized components, such as hot gas bypass control valves, or pressure valves.

3.3.1.9 Field Test Reporting Forms

Each test plan shall include the required test reporting forms to be completed by the Contractor's testing representatives.

3.3.2 Field Test Schedule

Notify the Contracting Officer in writing at least 30 calendar days prior to the testing. Within 30 calendar days after acceptable completion of testing, submit each test report for the review and approval of the Contracting Officer.

3.3.3 Manufacturer's Test Representative

Furnish a factory trained field test representative authorized by the CRACU manufacturer to oversee the complete execution of the field testing. This test representative shall also review, approve, and sign the completed field test report. Signatures shall be accompanied by the person's name typed.

Submit credentials of the manufacturer's field test representative proposed, including current telephone number, to the Contracting Officer for review and approval. Submit these credentials with the written advance notice of the field tests

3.3.4 Field Tests

Conduct the field testing in compliance with the Contracting Officer approved manufacturer's field test plan, and in accordance with additional field testing requirements specified herein. Record the required data using the test reporting forms approved of the approved field test plan.

Conduct the test for each CRACU for a continuous 24-hour test period. A CRACU shutdown before the continuous 24-hour test period is completed shall result in the 24-hour test period being started again and run for the required duration.

3.3.5 Deficiency Resolution

The test requirements shall be acceptably met; deficiencies identified during the tests shall be corrected in compliance with the manufacturer's recommendations. Corrections shall be tested again in compliance with the requirements specified in the paragraph FIELD TEST PLANS.

SECTION 23 81 23.00 20 Page 11

3.3.6 Field Test Reports

Use the test reporting forms approved in the field test plan. Final test report forms shall be typed, including data entries and remarks.

Completed test report forms for each CRACU shall be reviewed, approved, and signed by the Contractor's test director and the QC manager.

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SECTION 23 81 23.00 20 Page 12

1.6 ENVIRONMENTAL REQUIREMENTS

2.5 METAL DUCTWORK