High-voltage transformer fire barriers

High-voltage transformer fire barriers, or transformer firewalls, transformer ballistic firewalls, transformer blast walls, are outdoor countermeasures against cascading failures in a national electric grid. The purpose of these barriers, like common fire barriers in building construction, is compartmentalisation of transformer fires, as well as transformer and bushing explosions where the fuel source of both fires and explosions is the transformer oil. Without compartmentalisation, one ruptured transformer could start its neighbouring transformer on fire and thus create a domino effect that can affect the surrounding electric grid, particularly during peak times.

High-voltage transformers with bushings on top, separated by a fire barrier

High-voltage transformer fire barriers are typically located in electrical substations, but may also be attached to buildings, such as valve halls or manufacturing plants with large electrical distribution systems, such as pulp and paper mills. Outdoor transformer fire barriers that are attached at least on one side to a building are referred to as wing walls. At times, high-voltage transformers can be located immediately outside and sometimes inside of buildings, requiring higher fire-resistance ratings than other fire compartments in a building.[1]