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1LES100008-ZB_Environmental, climatic fire classes

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1LES100008-ZBrev. 1

Environmental, climatic fire classes

Description

1 Climatic classes 2

2 Environmental classes 2

3 Fire behavior classes 3



1Climatic classes





With regard to the minimum ambient temperature to which the transformer can be exposed, the following climatic classes are defined:

Class C1 The transformer is suitable for operation at ambient temperatures not below –5ºC but may be exposed during transport and storage to ambient temperatures down to –25ºC



Class C2 The transformer is suitable for operation, transport and storage at ambient temperatures down to –25ºC.

Transformers for outdoor operation should normally be provided with an enclosure or be given other suitable protection.



The manufacturer shall declare and state on the rating-plate the climatic class for which the transformer is suitable. Special tests may be agreed to prove suitability to Class C1 or C2.

Enclosed or non-enclosed non-encapsulated-winding dry-type transformers are normally designed for installation indoors in dry locations. They will, however, operate successfully where the humidity is high providing precautions are taken to keep them dry if they are shut down for long periods.



2Environmental classes





Environmental conditions for dry-type transformers are identified in terms of humidity, condensation, pollution and ambient temperature. There are important not only during service but also during storage before installation.

With regard to humidity, condensation and pollution, three different environmental classes are defined:

Class E0 (normal service conditions):

No condensation occurs on the transformers and pollution is negligible

This is commonly achieved by a clean, dry indoor installation.



Class E1 Occasional condensation can occur on the transformer (e.g. when the transformer is de-energized)

Limited pollution is possible



Class E2 Frequent condensation or heavy pollution or combination of both.

The manufacturer shall declare and state on the rating plate the environmental class for which the transformer is suitable. Special tests may be agreed to prove suitability to class 1 or 2.



3Fire behavior classes





Three fire behavior classes are defined:

Class F0 No special fire hazard is envisaged.

Except the characteristics inherent to the design of the transformer, no special measures are taken to limit flammability.



Class F1 Transformers subjected to fire hazard.

Restricted flammability is required.

Self-extinction of fire (poor burning is permitted with negligible energy consumption) shall take place within a specified time period to be agreed between purchaser and manufacturer, unless specified by National Specification. The emission of toxic substances and opaque smokes shall be minimized.

Materials and products of combustion shall be practically halogen-free and shall contribute with a limited quantity of thermal energy to an external fire.



Class F2 By means of special provisions, the transformer shall be able to operate for a given time period if subject to an external fire. The requirements of class F1 shall also be met.



The manufacturer shall declare and state on the rating plate the fire behavior class to which the transformer belongs.



Special tests to prove the suitability of a transformer for a certain fire class may be agreed between manufacturer and purchaser.
































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