How To Pick A Cooling Tower: Providing Safe Access For Service
/By Chad Edmondson
Servicing and maintaining cooling towers can be dangerous work. Since regular cooling tower maintenance is absolutely necessary for safe and efficient cooling tower operation, engineers have a responsibility to incorporate safety infrastructure into their cooling tower designs. That means providing safe access to all components that require regular inspection and maintenance, including water distribution systems, drift eliminators, fans, drives, etc., all of which may be located at dangerously high elevations. This paves the way for a successful maintenance program and helps ensure the safety of workers, while keeping owners free from liability.
Considerations for Crossflow and Counterflow Tower Access
Safety infrastructure varies depending on whether the tower is a crossflow or counterflow configuration.
Crossflow cooling towers require access to the interior for routine maintenance of strainers, basin cleaning, water level adjustment and fan drive maintenance. An interior walkway between the two access doors enables workers to perform these services without undue exposure to wet or slippery surfaces.
Internal ladder, service platform and walkway in crossflow cooling tower.
In many cases crossflow cooling tower cells are installed in two pieces, making them over 20 feet tall. In these cases an internal ladder and raised service platform will allow safe access for servicing the drive system. A “cage” or metal enclosure around the ladder may also be required for added safety and/or to meet local or OSHA requirements.
Motor removal system with davit arm, motor access platform and handrail package.
Counterflow cooling towers, which typically do not have any open interior space, must be outfitted for servicing from the outside. An external platform and ladder allow easy inspection and maintenance of the hot water spray distribution system. Some cooling towers, including BAC, have non-clog nozzles that can be easily removed for maintenance. A service platform may also be needed for safe access to an external gear drive on a counterflow tower. For single story counterflow cooling towers, an inclined ladder, shown below, may provide sufficient access to spray distribution nozzles but be careful of how high the cooling tower is off of the ground.
Inclined ladder on single story counterflow cooling tower.
Taller cooling towers may require vertical ladders, in which a case a safety cage around the ladder is required by OSHA. Also, don’t forget lockout/tagout requirements when working on a cooling tower. More info on this can be found at OSHA Control of Hazardous Energy.
Regardless of the tower design, engineers should always consult OSHA guidelines as well as local codes regarding safety requirements. There is a new OSHA Standard 1910.28 that states “For new equipment installed on and after November 19, 2018 with fixed ladders that extend more than 24 feet above a lower level, the employer must ensure that each fixed ladder is equipped with a personal fall arrest system or a ladder safety system”. Based on this it is important that you check to see whether OSHA 1910.28 standards apply to your project. Owners and facility managers can be held liable if proper safety infrastructure is found missing following an accident. As the saying goes, better safe than sorry!
