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When performing maintenance, it is important to always follow the cooling tower manufacturer's operation and maintenance instructions. Develop and maintain a regular preventive maintenance program for cooling towers to help ensure smooth, trouble-free operation. For an example, see the adjacent box.
Performing a detailed inspection of cooling towers on a regular basis will significantly improve the tower maintenance program. But before starting a cooling tower inspection, clearly identify all potential safety and health hazards associated with the work and identify how each hazard will be eliminated or controlled - thereby alerting maintenance workers to potential safety hazards and preparing them to take appropriate preventive action.
Cooling towers can create the potential for Legionella infection, particularly when biological growth is present. Operating cooling towers must be periodically inspected for good biological control - at a minimum, visual evaluation of condition of the water and the distribution basis.
- Good biological control - clean, clear water with no green or brown algae below the water line
- Poor biological control - cloudy, dirty, or foul smelling water; rust colored corrosion "pockets," which might be filled with black liquid that smells like rotten eggs - thoroughly clean the tower and evaluate water treatment system
When performing a cooling tower inspection - always follow:
- Local Safety and Health regulations - Regarding personal protective equipment, or PPE.
At the minimum:
- Make sure workers wear hard hats, safety glasses or goggles, work gloves, and high-top leather boots with non-slip soles.
- Provide fall protection, as required, when workers climb a cooling tower structure, including full body harness and shock absorbing lanyard at least six feet in length - single lanyard systems or safety belts DO NOT provide adequate fall protection.
- Basic safety precautions - including:
- Turn off cooling tower fans - before working inside any cooling tower
- Wear full of half face respirator - with HEPA (high efficiency particulate air) filters
Make sure persons using respirators are properly trained in their use - including a pulmonary function test and medical evaluation to determine the ability to wear and use the respirator.
Perform periodic inspections at the beginning of a scheduled unit outage that cover the cooling tower fill system, drift eliminators, water distribution system, and air-moving equipment. Focus on anomalous conditions that adversely impact thermal performance.
Following the inspection of the cooling tower, prepare a written report that documents the tower inspection findings, providing the location of all anomalous conditions and a punch list of inexpensive cooling tower repairs that can be carried out during the outage, as well as any recommendations to further improve cooling tower thermal performance efficiency.
Reducing feedwater costs
Controlling cooling tower scaling is a very expensive operation. The easiest control, of course, is no or minimal chemical control. The fewer chemicals put into cooling tower feedwater, the longer it will operate problem free and the lower chemical costs will be. Also, decreasing the frequency of blowdown in feed and bleed will further reduce chemical costs.