ISO 22734:2019 水の電気分解を使用する水素発生器—産業、商業、および住宅用途 | ページ 6

3.1

area classification

classification of hazardous areas (3.2) according to the probability of the existence of an explosive atmosphere, in order to relate the selection of electrical apparatus for use in the area to the degree of hazard (3.12)

3.2

hazardous area

area in which an explosive atmosphere is present, or may be expected to be present, in quantities such as to require special precautions for the construction, installation and use of electrical apparatus

3.3

built-in hydrogen generator appliance

hydrogen generator intended to be installed in a cabinet, in a prepared recess in a wall, or in a similar location

3.4

commercial use

use of hydrogen generators by laymen in non-manufacturing business facilities such as stores, hotels, office buildings, educational institutes, filling stations, warehouses, and other non-residential locations

3.5

containment system

part of the apparatus containing a flammable substance that may constitute a source of release

3.6

dilution

continuous supply of a purge gas (3.27) at such a rate that the concentration of a flammable substance inside an enclosure (3.9) is maintained at a value outside the explosive (flammable) limits at any potential ignition source (that is to say, outside the dilution area)

3.7

dilution volume

location in the vicinity of a source of release where the concentration of flammable substance is not diluted to a level below the lower flammability limit (LFL)

Note 1 to entry: Dilution (3.6) of oxygen by inert gas can result in a concentration of flammable gas or vapour above the upper flammability limit (UFL).

Note 2 to entry: Annex B provides information on the flammability limits of hydrogen.

3.8

electrochemical cell

assembly of electrodes, fluid containment, flow means, and electrical current conduction means that may include product gas separation membranes (3.19) and may be arranged as single unipolar cells or in bipolar cell stacks within or without a process containment vessel, for the purpose of producing hydrogen and/or oxygen from water

3.9

enclosure

containment and support structure(s) protecting a hydrogen generator from specific environmental and climatic conditions and protecting persons and livestock from incidental contact with the hazardous parts of the hydrogen generator

3.10

enriched oxygen atmosphere

gas that contains a volume fraction of more than 23,5 % oxygen with the remainder of its components being inert

3.11

factory-matched

engineered in a factory to correspond with each other and work together, separately packed for storage and transportation, and intended to be assembled together at the point of utilization

[SOURCE: ISO 16110-1:2007, 3.21, modified — The term has been changed from"factory matched unit" to"factory-matched"; the words"system components" have been removed.]

3.12

hazard

potential source of harm

3.13

hazardous condition

condition that may adversely affect the safety of the hydrogen generator operation

Note 1 to entry: Examples of hazardous conditions include having an enriched oxygen atmosphere (3.10) , a hydrogen concentration exceeding the lower flammability limit, an ignition source in a classified area, an overpressure, or an over temperature.

3.14

industrial use

use of hydrogen generators by qualified and experienced personnel in a controlled manufacturing or processing environment

3.15

ion transport medium

medium that provides ionic transport within the cell

3.16

maximum allowable working pressure

MAWP

maximum pressure permissible in a vessel or system at the temperature specified for the pressure

Note 1 to entry: The maximum allowable working pressure can also be defined as the design pressure, the maximum allowable operating pressure, the maximum permissible working pressure, or the maximum allowable pressure for the rating of pressure vessels and equipment manufactured in accordance with national pressure vessel codes.

3.17

maximum operating pressure

MOP

maximum pressure that can be expected by the pressure containing components when the hydrogen generator is functioning within its design and control parameters, including anticipated transients

3.18

mechanical ventilation

replacement of air inside an enclosure (3.9) with fresh air accomplished by a mechanical device (such as a fan) to prevent or eliminate hazardous concentrations of hydrogen

3.19

membrane

material that provides separation between oxygen and hydrogen product gases while allowing ionic transport within the cell

3.20

natural ventilation

replacement of air inside an enclosure (3.9) with fresh air accomplished exclusively by a natural draft caused, for example, by the effects of wind, temperature gradients or buoyancy effects, to prevent or eliminate hazardous concentrations of hydrogen

3.21

normal condition

condition in which all means for protection against hazards (3.12) are intact

3.22

normal use

operation, including stand-by, according to the instructions for use or for the obvious intended purpose

Note 1 to entry: In most cases, normal use also implies normal condition (3.21) , because the instructions for use will warn against using the hydrogen generator when it is not in normal condition.

3.23

pressure relief device

PRD

device designed to release pressure in order to prevent a rise in pressure above a specified value due to emergency or abnormal conditions

3.24

pressure-bearing component

part subject to a positive internal pressure of 100 kPa or greater

3.25

permanently connected

electrically connected to a supply by means of a permanent connection, which can be detached only by the use of a tool (3.34)

3.26

portable hydrogen generator

hydrogen generator that is not intended to be permanently fastened in a specific location and can be carried easily by a person

3.27

purge gas

gas used to maintain protective pressurization or to dilute flammable gas or vapour to a concentration well below the lower flammability limit

3.28

purging

passage of sufficient volume of a purge gas (3.27) through a pressurized enclosure (3.9) and its ducts, before the application of voltage to the apparatus, to reduce any ignitable (flammable) gas atmosphere to a concentration well below the lower flammability limit

3.29

residential use

use of hydrogen generators by laymen in private households (non-commercial and non-industrial use)

3.30

risk assessment

overall process of risk identification, risk analysis, risk evaluation, and risk mitigation

3.31

single fault condition

condition in which one means for protection against hazards (3.12) is defective or one fault is present which could cause a hazard

Note 1 to entry: If a single fault condition results unavoidably in another single fault condition, the two failures are considered as one single fault condition.

3.32

standard conditions

conditions to which the volume or other properties of a gas are referred, and which are represented by a temperature of 273,15 K (0 °C) and an absolute pressure of 100 kPa

3.33

supply cord

flexible cord, for supply purposes, that is fixed to the hydrogen generator

3.34

tool

external device, including keys and coins, used to aid a person to perform a mechanical function