Appendix I - CRAC Part 1 - Attch 1.pdf

DISA Computing Services Division (CSD) Facilities Engineering Team (GS452)

MINIMUM TECHNICAL SPECIFICATIONS

FOR

COMPUTER ROOM AIR CONDITIONER (CRAC) EQUIPMENT

1. SCOPE.

Scope: This specification covers the technical requirements for a Computer Room Air Conditioner (CRAC) that provides precision environmental control (including temperature, humidity (if requested as an option), and air volume) supporting IT equipment rooms.

Sizing of CRACs: Based on standard maximum cooling capacities of DISA raised floors (3.5kW per IT rack), each CRAC has a maximum number of IT racks it can be planned to support. CRACs shall be specified and sized based on anticipated numbers of racks (or similar equipment) that are to be supported by the CRAC:

One (1) ton of cooling capacity is needed per IT equipment rack, maximally loaded.

2. APPLICABLE STANDARDS.

The CRAC will be designed, manufactured, tested, and installed in compliance with the following standards:

• National Fire Protection Association (NFPA) Code 70

• Underwriters Laboratory (UL) Listed in accordance with UL 478, Standard for Electronic Data Processing

Units and Systems, at date of manufacture.

• Fully CSA (NTRL-C) certified at date of manufacture.

3. REQUIREMENTS.

3.1 Design Requirements. The unit shall have a total cooling capacity of no less than 20 tons for general use in

DISA computer data centers.

20 tons 25 tons 30 tons 40 tons 50 tons

3.2 Electrical Requirements.

3.1.1 Input. The input voltage to the PDU will be 460-480V AC at 60hz, three phase.

3.1.2 High Voltage Enclosure. The unit shall have a safety locked dead front panel to prevent accidental contact with high voltage components. The high voltage panel shall contain all of the contactors, transformers, overloads, ground bars, and other power gear.

3.1.3 Main Disconnect Switch. The CRAC will be equipped with a main front-panel mounted disconnect switch to provide a means of disconnecting power to the CRAC. This disconnect will be non-locking (the front panel can be opened without the switch being in the OFF position).

3.2 System Type. DISA employs chilled water at its data processing sites to provide cooling. The CRAC unit shall be designed to cool on conditioned chilled water.

chilled water glycol GLYCOOL dual source

3.3 System Discharge. DISA computer rooms are built on raised access computer floors designed for underfloor plenum cooling. Downdraft units are specified for use in these facilities unless special conditions otherwise exist.

downdraft updraft other

3.4 Cabinet and Frame. The exterior shall be powder-coated steel panels with minimum 1”, 1-1/2 pound density insulation on the interior for sound baffling. The cabinet shall be constructed of minimum 14 gauge welded tubular steel for seismic resistance. The maximum system height is typically 84”, but may be lower in some older computer rooms (Dayton and Chambersburg). Doors and side panels are finished in black cream white blue green pink.

3.5 Fans. The fan shall be the centrifugal type, double width double inlet, and shall be statically and dynamically balanced as a completed assembly to a maximum vibration level of 2 mils in any plane. The shaft shall be heavy-duty steel with self-aligning ball bearings with a minimum life span of 100,000 hours.

The fan shall be mounted on an adjustable slide base. The drive package shall be two-belt, variable speed, 1 Version Date: 18 April 2007 sized for 200% of the fan motor horsepower. Fans shall be located to draw air over an A-frame coil to ensure even air distribution and maximum coil performance.

3.6 Humidifiers. Humidifiers are not specified. DISA intends to use a humidification system independent of the CRAC units in its data center facilities.

3.7 Reheat. Reheat elements are not specified. DISA intends to use a humidification system independent of the CRAC units in its data center facilities.

3.8 Filters. A high efficiency filter (system) shall be installed to filter all air supplied to the computer room.

Because mechanical and electrostatic air cleaners operate on different principles, a different rating is specified for each type. Ratings are determined by using the test methods outlined in the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) Standard No. 52-76. Mechanical air filters must be rated at a minimum initial atmospheric dust-spot efficiency of 40 percent.

3.9 Coil. The unit shall employ an A-frame coil system to maximize face area, decrease necessary face velocity, and minimize pressure drop. The unit shall be equipped with a removable stainless steel corrosion-free condensate catch pan.

3.10 Local Monitoring. The CRAC will have a local monitoring panel affixed to the unit and will be a microprocessor-based system that includes the following:

• Password control.

• System auto restart, with programmable time delay.

• Sequential load activation.

• Sensor calibration.

• Monitoring – current temperature and humidity, current alarms.

• Sensitivity - responds to +/- 0.1 degree F temperature and +/- 1% relative humidity.

• Diagnostics on control board, fan, chilled water valve, alarm.

• Alarm log history.

• Run time log.

• Audible and visual alarm.

• Alarm conditions – change filter, loss of air flow, hi temp, low temp, hi humidity, low humidity, main fan overload, loss of power, loss of water flow.

• Mod bus

3.11 Variable Speed Drive (if available). If available, the unit shall have an internal VSD to control blower speed and chilled water valve operation to match room conditions.

3.12 Floor Stand. The unit shall be mounted level with the top of the raised floor on an adjustable seismic-rated floor stand designed for the equipment.

3.13 Turning Vane. If the CRAC units are downflow, provide and install a field-mounted turning vane system to mount to the floor stand. The typical raised floor height in DISA facilities is 18-24”. Coordinate with the site Facility Manager for exact height and underfloor obstruction information after award of the contract.

4. INSTALLATION, TESTING & CERTIFICATION.

4.1 Factory Testing. The CRAC will be completely factory tested before shipment.

4.2 Delivery. Plywood or masonite panels shall be used when delivering and installing the unit(s) to distribute equipment weight and prevent damage to carpeting, ramps, and raised floor surfaces.

4.3 Installation. Install in accordance with manufacturer’s installation instructions. Install units plumb and level, firmly anchored in locations recommended, and maintain manufacturer’s recommended clearances.

Minimum standard clearances shall be 34” on the front and sides of the unit, unless the manufacturer’s recommendation is greater.

4.4 Electrical Wiring. Install and connect electrical devices furnished by manufacturer but not specified to be factory mounted. Furnish copy of manufacturer’s electrical connection diagram submittal to electrical contractor. Use di-electric unions when mating dissimilar metals.

4.5 Piping Connections. Install and connect devices furnished by manufacturer but not specified to be factory mounted. Furnish copy of manufacturer’s piping connection submittal to piping contractor.

4.6 Field Quality Control. Start up units in accordance with manufacturer’s start up instructions. Test controls and demonstrate compliance with requirements.

2 Version Date: 18 April 2007

4.7 Submittals. Submittals shall be provided to the site Facility Manager at installation and start up. These shall include: Installation and Operations Manuals, Single-Line Diagrams, Dimensional-Electrical- Capacity Data, and Piping & Electrical Connection Diagrams.

5. SERVICE:

5.1 Startup, Maintenance, & Warranty. Inside delivery is specified on all orders. The manufacturer will provide one year of warranty against defects in materials and workmanship. This warranty will provide startup, maintenance, and emergency call back to ensure dependable operation through the warranty period.

3 Version Date: 18 April 2007