Danger lurks when thawing frozen water lines

BOOM! THE 1/2-in. copper cap grazed my ear as a deafening roar announced its rocketlike ejection from inside the kitchen sink cabinet. Scalding steam followed its trajectory. Stunned, it took a second or two to collect my wits and think about what had just happened and why a copper cap had darn near embedded itself in my forehead. I had opened the basement-level washing machine boiler drains and the

BOOM! THE 1/2-in. copper cap grazed my ear as a deafening roar announced its rocketlike ejection from inside the kitchen sink cabinet. Scalding steam followed its trajectory. Stunned, it took a second or two to collect my wits and think about what had just happened and why a copper cap had darn near embedded itself in my forehead.

I had opened the basement-level washing machine boiler drains and the lines serving this new addition had been turned off. The system should have drained itself and no build-up of pressure should have existed. A few minutes' investigation revealed the hot and cold lines running to the kitchen had frozen shut while contractors were installing one of those preformed concrete basement stairways. Their plastic weather-and dust-shield enclosure inside the basement unfortunately included a few feet of our water lines.

The ice plugs effectively blocked gravity drainage and the copper cap I had heated to remove was connected to a stub that held water — water that had been superheated well above 212 ° F! Superheated water expands 1,700 times in volume as it flashes over to steam.

Brrrrrr, it's cold out there! Reminds me of the winter of ' 76 when, on a Sunday evening, the mercury dipped to a temperature below zero. The weatherman announced the wind chill was -50°F! While single-digit temperatures aren't completely unexpected in late December or early January, that was brutally cold. My boss dropped me off that Monday morning to break up a sidewalk so that we could install a new water service. I welcomed the physical exercise as I was not dressed for below-zero temperatures. The first blow with the 18-lb. sledge had an odd sound to it and the concrete didn't crack, break or even show so much as a blemish. Subsequent blows had little effect and after about 30 minutes of extreme pounding, all I had to show for my effort was a small depression with powdery concrete dust.

My boss returned a few minutes later and demanded to know what the heck I'd been doing. I tried explaining that the ground beneath the concrete had to be frozen solid and that the concrete wasn't breaking due to the rock-solid earth. It was obvious, from the look on his face, that he wasn't buying the explanation.

"Here, you give it a shot," and so he did — just once. He'd picked a new spot and the same tuning-fork-like noise I'd heard rang out as the sledge hammer's metal business-end bounced skyward. We went in search of a tow-behind compressor, which I would become quite intimately familiar with during the next three weeks of below-zero weather.

The other side of that winter's frosty coin was the abundance of frozen water lines inside homes and businesses. As an apprentice, I was taught to "trace" lines with the heat generated by my handheld torch. As the moisture evaporated from the pipe's surface, I moved on quickly to avoid overheating. That was back in the propane-only handheld torch days and if I tilted the torch just a tad too far, I'd suddenly find I was holding a river of fire as liquid fuel would overload the orifice. I was blissfully unaware of the explosive nature superheated water held and simply followed by example. Right up until the day, a few years later after I'd ventured out on my own, when I set fire to the tarimpregnated backing on fiberglass insulation in a very constricted crawl space while thawing copper water lines. No time to crawl out in search of some means to extinguish the flames, I had to grab the burning backing with bare hands and put out the fire. There had to be a better way!

Safety issues and plastic water lines shifted thawing methods from open flame to my wife's low-wattage handheld hair dryer. That revelation arrived as she was styling her hair: "Mind if I borrow your hair dryer"? If you're married, you know exactly the look that she gave me!

Today's models have robust blowers with multiple speeds as well as several heat settings. Little danger of superheating water or starting a fire exists, but electricity in close proximity to potentially split or separated joints that might leak can pose electrocution hazards. Paint stripping heat guns are utilized too, but they can quickly generate enough heat to superheat trapped water and the potential exists for ignition of combustible materials.

Frozen water lines are playing a major role in deep-freeze emergency calls this year. The sudden increase in fossil fuel costs have been a huge concern for customers and it seems everyone has turned down thermostats much lower than in previous winters. Baby boomers suddenly finding themselves "empty nesters" are, in many cases, turning off (or turning down) the heat in unused rooms or entire sections of their houses.

Best wishes for a safe, warm and happy New Year!

Dave Yates owns F.W. Behler Inc., a contracting company in York, Pa. He can be reached by phone at 717/843-4920 or by e-mail at [email protected]

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