BICSI DCDC flashcards
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32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Concurrently maintainable
- A Tier III attribute meaning any planned maintenance on power or cooling components can be performed without shutting down the IT load.
- Fault tolerant
- A Tier IV attribute meaning the facility can sustain an unplanned failure of any single component without affecting the IT load.
- 2N redundancy
- A configuration with two complete independent power or cooling systems, each sized to carry the full load alone.
- Basis of design
- A document recording design assumptions, applicable codes, load densities, redundancy targets, and growth plans for traceability.
- Availability formula
- Availability equals MTBF divided by the sum of MTBF and MTTR; higher MTBF and lower MTTR increase uptime.
- Design development phase
- The design stage after schematic design where systems are sized, layouts refined, and major equipment selections made before construction documents.
- Floor loading
- The structural load capacity of a data hall slab, typically 150-300 lb/ft2, which must be checked against rack and UPS weights.
- Hot and cold aisles
- An arrangement where racks face each other across cold aisles and back to back across hot aisles to separate supply from return air.
- Raised floor height
- The clearance between structural slab and finished floor, commonly 24-36 inches, housing cabling and supplying cooling air.
- White space
- The usable data hall floor area available for racks and supporting equipment, excluding electrical and mechanical rooms.
- Security zoning
- Layering access restrictions from building perimeter through data hall to individual cabinets, with each layer more restrictive.
- Site selection factors
- Power availability, fiber routes, natural hazard risk, fuel delivery, latency, and cost are weighed when choosing a data center location.
- Double-conversion UPS
- A UPS topology that rectifies utility power to DC, charges batteries, and inverts to clean AC, isolating the load from all disturbances.
- Power usage effectiveness
- PUE equals total facility power divided by IT equipment power; 1.0 is the theoretical minimum and lower values are better.
- Battery autonomy
- The runtime a UPS battery string provides at full load, typically sized in minutes to bridge until generators assume the load.
- Generator fuel storage
- On-site fuel capacity sized for a target runtime, commonly 24-72 hours, plus refueling contracts and fuel quality testing.
- Single-corded equipment
- IT devices with one power inlet that need rack-level ATS or dual-path PDU feeds to preserve power redundancy.
- Critical power path
- The chain from utility through switchgear, transformers, UPS, distribution units, and rack PDUs that delivers power to IT loads.
- ASHRAE inlet envelope
- Recommended IT inlet conditions of 18-27 C and dew point 5.5-15 C, with an allowable range extending to 15-32 C.
- Ton of refrigeration
- A cooling capacity unit equal to 12,000 Btu/h or about 3.517 kW, used to size chillers and CRAH units.
- Airflow per kW
- A planning rule of about 100-160 cfm of supply air per kW of IT load, verified against rack airflow and containment design.
- Hot aisle containment
- Enclosing the hot aisle so heated exhaust returns directly to the cooling units, preventing mixing with cold supply air.
- Economizer cooling
- Using outside air or a water-side heat exchanger to cool the facility when outdoor conditions are below the design threshold.
- Dew point control
- Managing moisture by dew point rather than relative humidity alone, preventing both electrostatic discharge and condensation.
- TIA-942
- The standard defining data center cabling topology, area types, and redundancy levels for telecommunications infrastructure.
- Main distribution area
- The centralized cross-connect space housing core routers, switches, and backbone terminations for the data center.
- Cat 6A distance
- Category 6A copper cabling supports 10GBASE-T to 100 meters and reduces alien crosstalk compared with Cat 6.
- MPO parallel optics
- A multi-fiber connector used for 40G and 100G multimode links, carrying multiple parallel lanes over one connector.
- Cable separation from power
- Maintaining physical distance, typically about 12 inches for unshielded cable, between communications cabling and power conductors.
- Level 5 integrated systems test
- A commissioning test that verifies the complete facility response to failures such as utility loss, UPS transfer, and generator start.
- Change management
- A controlled process requiring a documented request, risk review, approval, scheduled window, and rollback plan before changes.
- Infrared electrical scan
- A preventive maintenance inspection using thermal imaging to find loose connections and overloaded circuits before failure.