Standard

1.1 Scope This standard establishes nominal voltage ratings and operating tolerances for 60-hertz electric power systems above 100 volts. It also makes recommendations to other standardizing groups with respect to voltage ratings for equipment used on power systems and for utilization devices connected to such systems. This standard includes preferred voltage ratings up to and including 1200 kV maximum system voltage, as defined in the standard.

The standard describes FMEA and Failure Mode, Effects and Criticality Analysis (FMECA), and gives guidance as to how they may be applied to achieve various objectives by providing the procedural steps necessary to perform an analysis; identifying appropriate terms, assumptions, criticality measures, failure modes; defining basic principles; and providing examples of necessary worksheets or other tabular forms. All the general qualitative considerations presented for FMEA will apply to FMECA, as latter is an extension of the other.

The standard is applicable to mains- or battery-powered information technology equipment, including electrical business equipment and associated equipment, with a RATED VOLTAGE not exceeding 600 V. Also applicable are components and subassemblies intended for incorporation in information technology equipment. It is not expected that such components and subassemblies comply with every aspect of the standard, provided that the complete information technology equipment, incorporating such components and subassemblies, does comply.

This International Standard describes fault tree analysis and provides guidance on its
application as follows:
definition of basic principles;
describing and explaining the associated mathematical modelling;
explaining the relationships of FTA to other reliability modelling techniques;

description of the steps involved in performing the FTA;
identification of appropriate assumptions, events and failure modes;
identification and description of commonly used symbols.

The standard is intended to be a basic functional safety standard applicable to all kinds of industry. It defines functional safety as: “part of the overall safety relating to the equipment under control (EUC) and the EUC control system which depends on the correct functioning of the E/E/PE safety-related systems, other technology safety-related systems and external risk reduction facilities.”

This standard specifically applies to UPS with an electrical energy storage device in the DC link. It is used with IEC 60950-1, referred to in this standard as reference document (RD). It is applicable to UPS that are movable, stationary, fixed or for building-in, for use in low-voltage distribution systems and intended to be installed in any operator accessible area or in restricted access locations as applicable. It specifies requirements to ensure safety for the operator and layman who may come into contact with the equipment and, where specifically stated, for the service person.

This standard details methods for defining the DC loads and for sizing a Lead-Acid battery to supply those loads in full-float operation.

The ISO 9000 family addresses various aspects of quality management and contains some of ISO’s best known standards. The standards provide guidance and tools for companies and organizations who want to ensure that their products and services consistently meet customer’s requirements, and that quality is consistently improved.

Readiness of emergency power is a key consideration in safeguarding building occupants in the event of a disruption of the normal utility supply. NFPA 111 covers performance requirements for stored electric energy systems providing an alternate source of electrical power in buildings and facilities during interruption of the normal power source.