Fire-Safe or Not In many processes, it maybe necessary to minimize dangerous product leakage and maintain effective shutoff of a valve. Valves that satisfy this condition are known as fire-safe. This term fire-safe is one of the least understood valve specifications. To date, there is no test protocol to establish whether a valve is fire-safe. The common definition used fora fire-safe valve is when a valve is exposed to fire conditions, it will allow minimal leakage through the seat and stem, and continue to provide effective shutoff during or following afire or exposure to excessive temperatures. Gate and globe valves made from metals that do not melt during a catastrophic fire have also been classified as fire-safe. Their design and construction assured metal- to-metal seating before, during and after afire. Butterfly valves are commonly manufactured with a "tandem" soft seat over metal to achieve a fire-safe application. Cost Engineers must always consider cost when making design and operations decisions. Valves involve costs, but when selected properly they provide benefits. These must be quantified and a profitability analysis performed. In some cases, a valve can affect the operating costs of the process, where the pumping (or compression) costs can be high, and the pressure drop occurring because of the valve can significantly increase the pumping costs. In such situations, a valve with a low (nonrecoverable) pressure drop is selected. Remember that the total cost includes costs of transmission (wiring around the plant, installation, documentation, plant operations, and maintenance over the life of the valve.
