Fire precautions in major electrical stations

The paper discusses precautions to be adopted in respect of fire in power stations and major system substations arising from failures of electrical plant. General considerations are discussed first, and it is pointed out that whilst electrical duplication or multiplication of plant is recognized as essential, its complement¿true physical segregation of duplicates to secure against the fire or explosionrisk¿has not received as much attention. It is, however, emphasized that the rare occurrence of serious fires or explosion justifies a different treatment and that it suffices in general to segregate duplicates in two separate groups. The condition of rarity is secured only by the use of sound plant and good protective gear, and it is essential that this condition should be maintained and desirable that it should be improved upon. It is emphasized, nevertheless, that despite all precautions fire cannot be absolutely precluded and that the only ultimate safeguard must be a reasonable fire-sectioning of the plant, so that a fire or explosion is limited in its worst effect to a section or group of plant items which can in emergency be done without. Given these two conditions, the prime requirements are met. The second stage is the limitation of the consequential damage following a fire to a degree which will ensure that the subsequent emergency state shall not continue too long, as during this period the essential principle of electrical duplication no longer holds and electrical faults are relatively frequent. This leads to the discussion of additional precautions which can be taken to decrease the consequential damage by improvements in design within the agreed fire sections, and by fire-fighting arrangements. General details are discussed and examples given, and the explosion risk is referred to.