IT Equipment Rack Specifications.pdf

DISA Computing Services Division (CSD) Facilities Engineering Team (CD521)

Minimum Technical Specifications for Standardized IT Equipment Enclosures (“Racks”)

This specification defines the electrical and mechanical characteristics and requirements for IT equipment racks to be deployed at Computing Services datacenters. The products shall include EIA-310 standard 19” rack mount rails.

The systems are factory assembled, delivered ready for the installation of customer supplied electronic equipment.

All rack enclosures shall be powder-coated black with solid side panels, perforated metal front and rear doors, solid removable tops with cabling pathways, and specified accessories as noted herein.

IT equipment racks are subject to specific rigid specifications because products to be installed at DISA datacenters must meet the physical environment of our buildings first. Products that do not meet these specifications are not acceptable and will not be ordered, purchased, accepted, or installed on DISA computer floors.

Note: Other types of racks for specialized equipment (such as midrange and mainframe computers), complete rack-based vendor-provided systems, network zone distribution centers (ZDCs), and other special uses are possible and will not necessarily be fully compliant with this specification. Specific modifications to this specification will be made on a case-by-case basis for these specific needs. This specification is to be used as guidance based on the physical conditions at the datacenters.

Guidance for IT Equipment Racks:

• Placement of IT equipment racks must follow the master plan raised floor layout for the installation site, and must be approved by CD521 (Facilities Engineering).

• Equipment loads may be mixed in equipment racks to fill up to the heat & power load limitations, in order to optimize the usage of the entire raised floor.

• Each rack is limited to 3500W of equipment (rated power supply information), based on DISA datacenter cooling technologies. This is equivalent to approximately 16.8A at 208V or 29.2A at 120V.

• Loads in excess of 3500W per rack must be distributed into additional racks to physically spread out the heat load.

• All racks must be outfitted or retrofitted with blanking panels between equipment loads for proper airflow distribution.

• No racks shall be installed with rack-mounted UPS or fan (“supplemental cooling”) equipment. Both types of device are prohibited in DISA datacenters.

• All racks shall have wire management equipment to direct power and datacomm cabling to the rear edges/rear corner posts of the racks. This promotes proper airflow front-to-rear through the majority of IT equipment.

• An estimated 60% of IT equipment comes with either 5-15/20 or L6-20 plugs, and an additional 20% with C13 or C19 plugs. Therefore, the standard specified MPDU is defined herein to support these types of equipment. So that racks can be re-used through equipment technical refreshes, all racks must be supplied with MPDUs meeting the specifications herein. If planned IT equipment requires a different power configuration, the customer must provide equivalent (meeting the design intent of section 26 60 00 of the Facilities Standards) three-phase MPDUs with the same monitoring characteristics as those specified. The intent of this specification is to not require the customer to require extensive coordination to obtain utility support, but rather to provide a “plug-and-play” environment to the extent possible. When a different

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The following is a complete sample bill of materials (BOM) for ordering agencies. Ordering this sample BOM from one of the suggested vendors will result in a compliant rack system being delivered. Please ensure that the specification is included in all rack purchase requests; there have been numerous attempts by some vendors to propose equipment that is not compliant with this specification. Such proposed equipment is unacceptable for installation in DISA data centers.

Sample BOM for IT Equipment Rack (with required accessories):

Qty 1 Rack, 24”wide, 78.4” tall, 42” depth, steel, black, 42U, perforated locking doors

Qty 1 Blanking panel kit, 42U (various sizes)

Qty 2 Vertical wire management device, zero U

Qty 2 Horizontal wire management device

Qty 1 Removable stabilizer foot w/ hardware

Qty 1 Grounding strap, 6”

Qty 2 MPDU, 3-phase 208Y/120V input, monitored & metered output, 12 (min) 5-20R & 4 (min) L6- 20R outlets, with 6’ length (min) power cord

INSIDE DELIVERY IS SPECIFIED FOR ALL RACK EQUIPMENT

Technical Specifications for Equipment Racks/Components

Physical Dimensions & Construction:

• Racks to be supplied or installed shall meet the physical dimensional requirements stated herein based on life safety code requirements, national fire protection code requirements, and the facility cooling arrangements.

• WIDTH – 24” / 60.96cm MAXIMUM (to fit directly on 2’ floor grid)

Some racks may be 30” models ordered as sets of 4 for special purposes only. When 30” width models are ordered they must be ordered and installed in sets of 4 to maintain the integrity of the master floor layout plan. Double-depth or double-width racks are not acceptable.

• DEPTH – 42” / 106.68cm MINIMUM external depth, 45” / 114.3cm MAXIMUM external depth.

Racks that are shallower do not have sufficient space to install IT equipment, power distribution, and datacomm cabling while maintaining hot air exhaust pathways.

• HEIGHT – 78.4” / 199.1cm MAXIMUM (to fit under 2m doorways for installation)

• Racks shall provide a minimum of 42RU of rack space. One RU (rack unit, aka U) is an industry-standard 1.75” vertical space for mounting equipment.

• Most DISA datacenters have adequate ceiling clearance to support the standard maximum height stated. If racks are intended for a specific location or project with lower ceilings (less than 96.4” to the bottom of the sprinkler heads), the condition will be called out specifically, the following equation will be used to determine the actual maximum height of the rack, and other modifications to this specification may be necessary (e.g., a lower minimum number of vertical rack space units).

• Maximum height may be reduced at some sites with lower ceilings (i.e., Dayton, Chambersburg) using the following equation: HA = [SD – (RFH+CH+18)] where

HA = Maximum Rack Height Allowed

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SD = Slab floor to slab ceiling distance

RFH = Distance from Floor Slab to Raised Floor Top Surface

CH = Distance from Ceiling Slab to Bottom of Sprinkler Head Positions in Suspended (Visible) Ceiling

• Side panels shall be solid and removable, with locks. There shall be no ventilation on the side panels.

• Doors shall be perforated metal, secure latching doors with key lock, and reversible positioning for left / right hinging. Dual doors are acceptable.

• Racks shall not be supplied or installed with solid or plexiglass doors (inhibiting airflow) or non-removable tops (future cabling connections).

• Top panels shall be removable and solid with knockouts or holes for cable management.

• Each rack shall have a frame grounding lug for easy connection to the grounding grid or adjacent racks.

No shipping feet authorized.

• Rack front, rear, and top panels shall be capable of accepting retrofits for forced air ventilation and exhaust.

• Racks shall be equipped with retractable casters and leveling feet at each corner.

• Shipping anti-tip plates shall be removed from all racks prior to installation. These plates interfere with cooling air distribution to IT equipment. In locations where seismic shocks are a consideration, equipment shall instead be installed in accordance with section 09 69 00 of the Facilities Standards.

Rack Accessories:

• All racks shall be supplied with 42U of black blanking panels in a variety of heights (1U, 2U, 4U, 8U, 16U) to allow for proper airflow through partially-filled racks. Blanking panels shall not be manufacturer proprietary (able to fit only specific models of enclosures).

• Each rack shall be supplied with a minimum of two (2) integrated vertical wire managers and two (2) 19” mountable horizontal wire managers for organization of patch and trunk cables within the cabinet.

Integrated vertical managers shall take up zero U of usable space and may be removable.

• One in ten (1 in 10) racks in any acquisition shall be supplied with a removable stabilizer foot system for loading and unloading of heavy equipment within the rack. Individual racks are not required to have stabilizers. Stabilizers shall be removed when not in use to maintain adequate cooling interfaces.

• All racks shall be supplied with a minimum 6” grounding strap with hardware for bonding to adjacent cabinets.

• Racks shall not be supplied, installed, or configured with fan (air recirculation) equipment (fans merely circulate air, increase rack heat loads, and do not provide cooling in most circumstances).

No cable management, blocked exhaust, unsightly and overheated equipment.

Effective and aesthetic cable management supports a sustainable environment.

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• Rack-mounted UPS equipment is prohibited in DISA datacenters base on life safety and technical concerns. Racks and systems shall not be designed, ordered, or configured with these rack-mount UPS devices. DISA facilities infrastructures are designed to provide generator-backed, uninterruptible dual power redundancy at a facility-wide level. See subsection “Cascaded Uninterruptible Power Supplies” in section 26 33 53 in the Facilities Standards for more details.

• Racks that are procured for DISA facilities by external IT systems integrators and “managed services” contractors shall meet all IT rack specifications. These systems are typically pre-loaded with IT equipment, power, and networking, and shipped intact to the operational site. Racks built in this configuration shall be procured, packaged, and shipped with specialized “shock pallets” to protect rack and IT equipment.

• Other accessories are acceptable on a case-by-case basis when necessary for the equipment to be supported. These accessories will be specifically called out in the CORAS request.

Rack Power Distribution:

• Each rack shall be supplied with two (2) each metered “modular power distribution units” (MPDUs) that mount vertically into the rear access/cabling spaces of the rack.

• Each MPDU will be connected to a separate UPS-backed power feed to provide redundant power to IT equipment within the rack.

• The MPDU will take zero (0) U of rack space when installed.

• Each MPDU shall be a three-phase, five wire 208Y/120V system providing a minimum of twelve (12) NEMA 5-20R spaces and four (4) NEMA L6-20R spaces to connect IT equipment. The alternative MPDU with C13 and C19 outlets is also acceptable when the planned customer equipment is provided with these types of plugs.

o An alternative MPDU shall have the same characteristics but shall come with a minimum of twelve (12) IEC C13 and four (4) IEC C19 outlets. This is a non-standard configuration but has been specifically requested to address certain IT equipment supplier requirements.

• Each MPDU shall be marked with which phase each receptacle draws from and present an alarm when any phase is overloaded. Overloaded is defined as in excess of the 80% limitation imposed by the National Electrical Code (16A for a 20A circuit, per phase). LED monitors for each phase showing actual amperage draws are preferred.

• Each MPDU shall have a power cord with a minimum 6’ length power cord.

• All MPDU receptacles should be logically addressable for future monitoring and rack level power management.

• A “sample” unit that meets these specifications is the AP7893 from APC. This does not indicate any preference of vendor or manufacturer – merely one unit that does meet these specifications.

o A sample of the alternative MPDU meeting the specifications above is the AP7894. This does not indicate any preference of vendor or manufacturer – merely one unit that does meet these specifications.

Rack Installation & Layout:

• Individual racks supporting IT equipment shall be placed side-by-side, not bayed/connected (baying racks allows airflow to bypass IT equipment intakes). Only racks designated as network distribution points may be interconnected; interconnected racks shall be specified separately and shall be delivered with appropriate baying hardware.

• Rows of racks shall be aligned perpendicular to the cooling unit faces where possible.

• Each individual facility shall have a “master plan” designating the installation of additional rack rows to support future equipment expansion.

• No row of racks shall be more than 50 feet in length without additional egress pathways being planned.

Page 4 of 5 Version Date: 3 November 2008 http://apcc.com/resource/include/techspec_index.cfm?base_sku=AP7893).

http://www.apc.com/resource/include/techspec_index.cfm?base_sku=AP7894

• Rows of racks shall be aligned in hot-aisle/cold-aisle configurations. Cold aisles shall be 48” or 72” wide (two or three tiles) to allow for access to multiple full rows of raised floor tiles. Hot aisles shall be a minimum of 36” wide (with two rear-to-rear maximal 42” depth racks) to allow for access to one full row of raised floor tiles.

• Layout shall take into account required access areas to the front and sides of utility equipment.

• Each rack shall be physically labeled for rack identification (location, zone, and row) and for vertical rack U level identification of installed equipment per guidance in the current Facility Standard.

• Racks shall be installed in planned zones and modules per the installation site’s Master Layout Plan. Rack configurations and layouts shall be captured via the DISA standard CAD solution, Aperture. Other methods of documentation shall be coordinated with the DISA Facilities Engineering group.

Auxiliary (Future) Cooling:

The specified MPDUs can provide almost three times the power to the rack as the cooling technology can support.

This means that for the current cooling constraint DISA is not optimizing power circuit usage. This takes into account the future cooling system designs that will raise the 3.5kW per rack constraint to the 10kW range, at which the power and cooling will both be optimized at the rack level.

Current raised floor plenum cooling technology limits our maximum heat and power density per rack to 3.5kW (1 ton cooling) rated power consumption. Additional loads installed in a rack will create “hot spots” unless auxiliary cooling is adopted. If specified on an individual rack basis based on planned electrical/heat density, install dual-fed rack Air Distribution Units (ADUs) for heat densities ≥ 1.5kW per rack; ADUs shall be air-filter augmented (minimum 30%). These specifications shall be developed on a case-by-case basis and are not a general item for procurement or installation.

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