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Cooling Tower Fall Protection
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Industrial cooling towers are found across many different industries. One thing they have in common, however, is the need for periodic maintenance. Workers enter cooling tower shrouds to service fan blades, hubs and drive trains, as well as cooling tower structural support members and the cell shrouds themselves. These workers invariably face significant fall hazards due to unguarded wooden or synthetic walking surfaces presenting potential falls of at least 4’ , and often as much as 100’. Moreover, a typical cell environment has a slippery latticework of “two-by” wooden beams at the walking surface, upon which the fan assembly is mounted. These walking surfaces develop slimy green organic growth due to constant rain-forest conditions in the cell.
Just be careful...
If fall protection has not been addressed prior to shut-down with systems and procedures ready and in place, some facilities have been known to succumb to a Get it Done expediency, with all the potential consequences of injury (or worse). Rescue/recovery can be a challenge if the worker gets caught in the tower structure matrix, or made easier if the worker makes it all the way to ground level.
Historically, workers have used a wide range of approaches to enter cooling tower shrouds. These include:
100% Foot-level Tie-off... This approach is not compliant and could lead to serious injury. Most cooling towers do not provide the 17’ – 18’ minimum required clearance under a worker’s walking surface to arrest falls using foot-level anchorage. Striking a cross-member or two on the way down could put a damper on one’s day, not to mention the delays in getting medical help when there is no rescue plan in place.
Horizontal Anchorage Systems... Facilities sometimes install custom rail or cable anchorage systems in their cells, typically between a shroud access point and the center. If designed, engineered, installed and used according to standard, these systems are fine for tie-off and sometimes as a handrail. Unfortunately, these systems limit worker protection to specific areas of the cell and, of the few we have seen, they run more along the lines of home-made cable, eye and turnbuckle affairs, usually in materials not designed to hold up to the aggressive environmental conditions of cooling towers. We also have seen temporary and permanent fall protection systems installed using the fiberglass shroud as end-point anchorages – in no way approaching the strength required for such systems. Generally there is just not that much robust structural steel available atop cooling towers to anchor fall arrest systems
Permanent Grating... A great solution at first glance, permanent grating on the floor of the cooling tower cell would decrease cooling tower efficiency due to resistance.
Temporary Flooring... Many sites simply plan on one or more crews of carpenters to build floors in the cooling tower cells before workers enter to do service. First, the carpenters themselves are exposed to some degree of fall hazard, which often is addressed through fall restraint. The floor also usually limits access to lower elevations of the tower. Moreover, floor construction and removal is time-consuming during a shutdown and costly. One case study showed a conservative per cell of cost of ~$2,000.00.
CoolingTowerFallProtection’s Cool Gantry... A plant shutdown often involves a crane on site. Simply fly the Cool Gantry into place astride the cell your workers are to enter, pull down the self-retracting lifelines (via taglines) to tie-off, and enter to do work. When done, fly the Cool Gantry to the next cell. Should a worker fall and be arrested, workers can begin rescue with the Cool Gantry’s remote rescue system.
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