TP223 - Pravilnik o grafičnih znakih za izdelavo prilog študij požarne varnosti in požarnih redov

This part of IEC 60079 is concerned with the classification of areas where flammable gas or
vapour hazards may arise and may then be used as a basis to support the proper selection
and installation of equipment for use in hazardous areas.
It is intended to be applied where there may be an ignition hazard due to the presence of
flammable gas or vapour, mixed with air, but it does not apply to:
a) mines susceptible to firedamp;
b) the processing and manufacture of explosives;
c) catastrophic failures or rare malfunctions which are beyond the concept of abnormality
dealt with in this standard (see 3.7.3 and 3.7.4);
d) rooms used for medical purposes;
e) commercial and industrial applications where only low pressure fuel gas is used for
appliances e.g. for cooking, water heating and similar uses, where the installation is
compliant with relevant gas codes;
f) domestic premises;
g) where a hazard may arise due to the presence of combustible dusts or combustible flyings
but the principles may be used in assessment of a hybrid mixture (refer also
IEC 60079-10-2).
NOTE Additional guidance on hybrid mixtures is provided in Annex I.
Flammable mists may form or be present at the same time as flammable vapour. In such case
the strict application of the details in this standard may not be appropriate. Flammable mists
may also form when liquids not considered to be a hazard due to the high flash point are
released under pressure. In these cases the classifications and details given in this standard
do not apply. Information on flammable mists is provided in Annex G.
For the purpose of this standard, an area is a three-dimensional region or space.
Atmospheric conditions include variations above and below reference levels of 101,3 kPa
(1 013 mbar) and 20 °C (293 K), provided that the variations have a negligible effect on the
explosion properties of the flammable substances.
In any process plant, irrespective of size, there may be numerous sources of ignition apart
from those associated with equipment. Appropriate precautions will be necessary to ensure
safety in this context. This standard is applicable with judgement for other ignition sources.
This standard does not take into account the consequences of ignition of an explosive
atmosphere.

This part of IEC 60079 is concerned with the identification and classification of areas where
explosive dust atmospheres and combustible dust layers are present, in order to permit the
proper assessment of ignition sources in such areas.
In this standard, explosive dust atmospheres and combustible dust layers are treated
separately. In Clause 4, area classification for explosive dusts clouds is described, with dust
layers acting as one of the possible sources of release. In Clause 7 other general
considerations for dust layers are described.
The examples in this standard are based on a system of effective housekeeping being
implemented in the plant to prevent dust layers from accumulating. Where effective
housekeeping is not present, the area classification includes the possible formation of
explosive dust clouds from dust layers.
The principles of this standard can also be followed when combustible fibres or flyings might
cause a hazard.
This standard is intended to be applied where there can be a risk due to the presence of
explosive dust atmospheres or combustible dust layers under normal atmospheric conditions
(see Note 1).
NOTE 1 Atmospheric conditions include variations in pressure and temperature above and below reference levels
of 101,3 kPa (1 013 mbar) and 20 °C (293 K), provided that the variations have a negligible effect on the explosive
properties of the combustible materials.
It does not apply to
– underground mining areas,
– dusts of explosives that do not require atmospheric oxygen for combustion such as
pyrophoric substances, propellants, pyrotechnics, munitions, peroxides, oxidizers, waterreactive
elements or compounds, or other similar materials.
– catastrophic failures which are beyond the concept of abnormality dealt with in this
standard,
– any risk arising from an emission of toxic gas from the dust.
This standard does not apply to where a hazard might arise due to the presence of flammable
gas or vapour, but the principles may be used in the assessment of a hybrid mixture (see also
IEC 60079-10-1).
NOTE 2 Additional guidance on hybrid mixtures is provided in Annex C.
This standard does not take into account the effects of consequential damage following a fire
or an explosion.

Establishes symbols to be used in architectural, engineering, building and allied design fields to provide details of equipment for fire protection, fire-fighting and means of escape on drawings for design, construction, renovation or fire certification purposes.