Louver failure

Louver Failure - Inadvertent louver closure may result from automatic control failure or mechanical linkage failure. The effect on heat transfer will depend on the degree of restriction to air flow in the closed position and the configuration of louvers in relation to tube bundles (e.g., louvers may not be installed over all tube bundles in a given service). 

Air Fin Exchanger Failure - Loss of air fm exchanger capacity may result from fan failure or inadvertent louver closure. 

With air coolers, louver closure is considered a total failure (10). Upon fan failure, or a fan drive (e.g., power or steam) failure, a credit is often taken for natural convection effects. This credit is usually 20 to 30 percent of the normal duty of induced-draft condensers. Forced-draft condensers have a considerably weaker chimney effect, and the credit taken is usually 10 to 15 percent of their normal duty. The above natural draft credit may not apply if a fire occurs near the cooler. 

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