Electrical rooms/substations

Flammable gas detection should be provided in the HVAC inlet of any pressurized electrical room or substation building where release scenarios and dispersion modeling indicate potential gas concentration above Vt LEL. When dispersion results are not available, such buildings within 60 meters of high or low leak potential equipment should include detection. 

A process technician typically traces power to the unit from a motor control center (MCC). The primary components of an electrical system are the MCC, motors, transformers, breakers, fuses, switch gears, starters, and switches. Specific safety rules apply to the operation of electrical systems. The primary safety system is the isolation of hazardous energy through lock-out/tag-out measures. Process technicians are required to have training in this area. Figure 7-22 shows the basic symbols and flow path associated with an electrical drawing. Electrical lines are typically run in cable trays to switches, motors, ammeters, substations, and control rooms. 

Areas of special risk Flammable stores, foam plastic store, electrical substation, below ground rooms Storage of loose papers, mixed storage warehouses None... 

Switchgear and process control rooms are required to have smoke detection per NFPA 850, Recommend Practice for Fire Protection for Electric Generating Plans and High Voltage Direct Current Converter Stations and IEEE 979, Guide for Substation Fire Protection.The activation of the fire alarm should shut down the air handling systems. If the facility is especially critical to the continued process operation, consideration of a fixed fire suppression system should be evaluated. 

Battery rooms are provided for backup and uninterruptible power supplies (UPS) for process control functions. They are usually provided at or near the facility control room or electrical switchgear facilities. Battery rooms should be provided with ventilation to limit the concentration of hydrogen to 1% by volume. For further information refer to ANSI/IEEE 484, Recommended Practice for Installation Design and Installation of Large Lead Storage Batteries for Generating Stations and Substations. 

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