Resources / Glossary

Glossary.

Definitions for technical terms used on the modular data center and power infrastructure reference pages. Consult the current standard and project documents for exact requirements.

A

ASHRAE A1 / A2 / A3 / A4

ASHRAE names these air cooling environment classes for data center equipment. Consult the current ASHRAE publication for the limits and test conditions.

ASHRAE W1 / W2 / W3 / W4

ASHRAE names these liquid cooling water classes for data center equipment. Consult the current ASHRAE publication for the limits and test conditions.

ATS · Automatic Transfer Switch

Automatic transfer switch. Project documents define the sources, transfer sequence, rating, and approval requirements.

B

BMS · Building Management System

Building management system. Project documents define which building systems, controls, and data interfaces it covers.

C

CDU · Coolant Distribution Unit

Coolant distribution unit. Project documents define the fluids, heat exchange boundary, connections, and operating conditions.

CRAC / CRAH · Computer Room Air Conditioner / Air Handler

Computer room air conditioner or computer room air handler. Project documents define the cooling plant, air path, and operating conditions.

D

DCIM · Data Center Infrastructure Management

Data center infrastructure management. Project documents define the monitored assets, data sources, and operational functions.

DLC · Direct Liquid Cooling

Direct liquid cooling. Project documents define the cooling method, fluid boundary, connections, and operating conditions.

F

FAT / SAT · Factory / Site Acceptance Test

Factory acceptance test and site acceptance test. Project documents define each test sequence, witness requirement, record, and acceptance rule.

I

IEC 61439

An IEC standard family for low voltage switchgear and controlgear assemblies. The current cited edition and project approval requirements control.

IEC 62271

An IEC standard family for high voltage switchgear and controlgear. The current cited edition and project approval requirements control.

IEEE C37

An IEEE standards family for switchgear, switching equipment, and related protection topics. The current cited standard and project requirements control.

ISO 9001

An ISO standard for quality management systems. A current certificate and its stated scope are required for any certification claim.

K

kW/rack · kilowatts per server rack

Kilowatts per rack. State the load basis, operating condition, and measurement boundary whenever this unit is used.

M

MV / LV · Medium / Low Voltage

Medium voltage and low voltage. The applicable code, utility, and project documents define the voltage boundaries.

N

NCP · NVIDIA Cloud Partner

NVIDIA Cloud Partner. Consult NVIDIA for the current program name, requirements, and participant status.

NFPA 70 / 75 / 110

NFPA publications commonly referenced for electrical, information technology equipment, and emergency power topics. The current adopted edition and project requirements control.

NRTL · Nationally Recognized Testing Laboratory

Nationally Recognized Testing Laboratory, a designation administered by the United States Occupational Safety and Health Administration. Verify the current laboratory scope for the exact standard and product category.

P

PUE · Power Usage Effectiveness

Power usage effectiveness. State the energy boundary, measurement period, load condition, and method whenever this metric is used.

S

SCADA · Supervisory Control and Data Acquisition

Supervisory control and data acquisition. Project documents define the monitored equipment, control authority, data interfaces, and security boundary.

T

Tier I–IV · Uptime Institute classification

Uptime Institute names these site infrastructure tier classifications. A current certification record is required for any project tier claim.

TTA · Type-Tested Assembly

Type tested assembly, an older assembly description that may appear in project records. The current cited standard and project documents control the required verification language.

U

UL 489

A UL standard for molded case circuit breakers, molded case switches, and related enclosures. The current listing record and project requirements control.

UL 891

A UL standard for switchboards. The current listing record and project approval requirements control.

UPS · Uninterruptible Power Supply

Uninterruptible power supply. Project documents define the topology, rating, runtime basis, interfaces, and acceptance requirements.

This page is a general reference. The current standard and project documents control the exact definition and requirements.

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