Yes, portable toilets will freeze on the upper floors of a high-rise construction site in Chicago winter conditions. Wind exposure accelerates freezing, and standard antifreeze solutions become less effective as temperatures drop below freezing. A standard portable toilet holding tank holds 50 to 70 gallons of waste and deodorizer, and without adequate antifreeze concentration or frequent service, it can freeze solid, making pumping impossible.
Push for more frequent service during freezing weather. Weekly service is the norm, but in sustained cold, service every three to four days may be necessary to prevent freezing. The rental company should use a non-toxic, formaldehyde-free antifreeze rated for low temperatures, not just standard deodorizer. High-rise units designed for construction sites often have thicker tanks and better insulation, but they still require diligent servicing.
Ensure the rental contract specifies cold-weather service adjustments. Blocked access due to ice or crane schedules can lead to missed service, so coordinate lift times with the service schedule. For 60 to 80 workers, OSHA 1926.51 requires two to three standard units plus one ADA-compliant unit per cluster, so your plan meets the minimum. Consider adding a handwash station with antifreeze if required, but note that units with fresh water tanks, like deluxe or flushing models, are prone to freezing and may not be practical for high-rise use in winter.
