Thanks ELEP. The Article 450.27 / NFPA70 does mention that the fire safety measures are required (my concern is with regard to outdoor, mineral oil insulated transformers of all sizes).
I am looking for some guidelines like transformer rating vs separation required between the transformers. In addition similar guidelines for fire-resistant barriers (blast walls) and fire suppression systems.
I have referred IEEE Std 979 Guide for Substation Fire Protection, IEEE 850 and NESC. But the guidelines are a bit general.
In India, there are guidelines issued by TAC (Tariff Advisory Committee of Insuarance compenies). But, the place I work now there is no such institution. Hence, I am looking for any such European or American guidelines.
If you have access to IEC standards then IEC 61936 contains some information which might be useful. Local codes may over-rule the IEC document recommendations.
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Thanks ScottyUK for reference to IEC 61936.
The code has a table, Transformer oil volume vs required separation distance and is exactly the info I was looking for.
Surprise that the same is not available in IEEE codes!
NFPA 850 - the fire protection standard for power plants has recommnedations for separation of transformers based on amount of oil. Example: 500-5,000 gallons of oil, separate adjacent transformers by 25 feet or a blast/fire wall. Over 5,000 gallons- separation is 50 feet.
The separation prevents spread of transformer fires to adjacent units or critical buildings.
Same information is found in some Factory Mutual Engineering guidleines. Both of these organizations are insurance companies.
I work for a rural electric cooperative and our bylaws state that a transformer must be a minimum of 10 feet from the wall except if the wall has a minimum 1 hour fire rating.
