Issue link: http://psai.uberflip.com/i/1426970
4 I PSAI Association Insight, November 10, 2021 Winterization: How to Prepare Restrooms and Equipment for Extremely Cold Weather (Part 1) (continued from page 2) vulnerable to cold and can be ruined if not drained overnight, even if the temperature only drops to just below freezing. The risk of frost damage can be reduced if water heaters are drained overnight, although operators may prefer not to rely on their customers to perform that task. A better solution is to ask a professional gas fitter to mount the heater inside the unit. Extreme cold can also affect water tanks, vacuum pumps, hoses, and pipes on service trucks stored outside overnight. If the air temperature drops below freezing, any water left onboard will freeze. Again, tanks, valves, pumps, and pipes will be vulnerable to internal pressure as water expands when it turns into ice. When trucks freeze, operators can't start working until things thaw out. In turn, this means they'll lose valuable work time. On Mulan, we had several late starts because the driver parked the truck outside overnight instead of in the shed. We lost half our daylight hours and the technician found himself working in the dark after 4 p.m. Some portable toilet cabins like the Satellite Vantage and Merlin Ultra have double-skinned walls, but most cabin walls are single skinned. Those plastic walls are often quite thin and provide very little insulation or protection from the cold. In a portable toilet, solids above the water line will start to freeze when the ambient temperature drops to 32°F (0°C). If you crack any surface ice with the wand, most of the waste below will still be in liquid form and will still pump through a suction hose. When the temperature drops below 25°F (-4°C), the wastewater in the tank will turn to lumpy slush. It will still pump because it's not completely solid, but the operator will likely need to break it up the ice with the wand. The coldest temperature I've experienced in New Zealand is 10°F (-12°C). That was cold enough to go ice skating on the river and everything in the toilet tank was frozen solid. When that happens, the waste is impossible to remove with a vacuum pump unless it is can be at least partially melted. Although they won't be visually appealing, end users will still be able to use frozen drop tank units. In flushing restrooms, frozen water in the tank, pump, filter, or pipes will prevent the unit being flushed. This is likely to put flushing units out of use. When water freezes and turns to ice, it expands. In a confined space like a pump or pipe, that expansion can create enough pressure to rupture pipes or split the housing on a pump. If that happens, any waste in the tank will leak out onto the ground when the ice thaws. On flushing units fitted with a foot- pump, the pump is usually mounted in the void beneath the base, just above the ground. That makes the plumbing more vulnerable to the cold, especially just before dawn when the air temperature is usually the lowest and latent heat loss is most profound. Cold weather can have an equally damaging effect on externally mounted water heaters fitted to portable restroom trailers or shower trailers. The thin-walled copper coils inside propane heaters are especially (continued on page 5)