Picture this—a family leaves for a beautiful all-inclusive trip; they go to the Bahamas to escape the cold, harsh Canadian winter for a week. It’s glorious and well-deserved. Flashforward to the journey home. After catching the red-eye, they arrive back to their beloved home, ready for a vacation after their vacation. But once they return, what do they see? A flooded house due to a burst pipe and a whole lot of headaches.
Residential pipe freezing is one of the most common inconveniences to homeowners and with winter approaching, people need to know how to handle this problem. “There is no annual checkup to make sure that something doesn’t freeze-up,” explains Phil Plath, technical sales representative for IPEX. Pipe freezing is something that can’t be 100 per cent prevented, but there are preventative measures that can be put in place.
Hierarchy of protection
“Plumbing pipes are the most common and likely pipes to freeze in the winter,” said Sammy Morana, an Oshawa, Ont. plumber. As most people already know, cold temperatures can cause pipes to freeze. Freezing in a pipe creates pressure inside the pipe which then causes the pipe to burst releasing water, which can lead to flooding. “A burst pipe may occur when ice forms in the pipe and when water freezes, it expands in volume and with tremendous force and given the amount of force, a pipe will not be able to hold that amount of pressure,” said Morana. “One of the most expensive and, to be honest, frustrating things you could have happen to the home is water damage.”
When it comes to freeze protection, there is an informal hierarchy of importance for which types of pipe absolutely needs to be protected. “If you had to categorize all the different plumbing applications and determine which one is more critical when it comes to freezing prevention, I would say it’s your flue gas venting pipes,” states Gaetano Altomare, category manager for IPEX.
Flue pipes are critical in a home’s function as it vents and exhausts gases from inside the house to the outside. “If your flue gas venting pipes freeze, it chokes off the exhaust being pushed out from indoors to outdoors, and you’re going to create a blockage that will trap carbon monoxide,” explains Altomare. The purpose of the flue pipe is to remove harmful by-products due to combusted or burned fuel from inside your home. If the by-products are not correctly ventilated from inside the house, you can have a dangerous buildup of carbon monoxide. He goes on to add that homeowners should have their carbon monoxide detectors checked regularly, as well as making sure the vents are always free to exhaust.
“Using pipe insulation on its own for freeze prevention slows heat loss but would be like wearing a long sleeve shirt outside in winter instead of a t-shirt—you’ll still get cold. It will just take slightly longer,” states Chris Waldner, North American marketing manager with nVent Nuheat and nVent Raychem. Insulation is one of the two most common practices in freeze prevention, and it works by slowing the rate of conductive cooling and providing protection against convective cooling, explains Waldner.
According to Dale Hanscomb, regional sales manager with Rehau, “Water or other fluids in pipes transfer their heat to pipe walls via conduction, since they are in contact. Heat also conducts from interior to exterior pipe walls, or vice-versa. A less conductive pipe material slows down this portion of heat transfer. Convective cooling occurs when cold air blows across pipes and carries heat away. This is typically how warm pipes lose heat directly to the surrounding air.”
Now, a common misconception that people have when it comes to pipes freezing is that they think of it getting colder, and yes, that’s something that happens, but that’s not the full story, explains Waldner. Essentially, the biggest issue is that water loses heat energy. “All temperature is a measurement of molecules moving, and the more they move, the warmer they get. So as water loses heat energy, the molecules move less. If the water is not constantly moving through the pipes, that also contributes to heat loss,” states Waldner. Thus, the main benefit of insulating pipes is that it helps slow down the heat loss process. Still, as Waldner explains, “insulation widens your margin of error, but it doesn’t solve your problem.”
The second most common method is to utilize heat tracing. Heat tracing is used to ensure that process, fluid, or material temperatures within pipes and piping systems are maintained above ambient temperatures during static flow conditions along with providing supplemental freeze protection in certain applications. Heat tracing can help with pipe freeze protection by preventing the freezing of fluids in pipes. This solution is designed to replace the heat lost through the thermal insulation and provide warmth where it is needed. Heat tracing is most commonly done with the use of a self-regulating cable. The cable is attached underneath the insulation on a pipe. It applies heating power in relation to the ambient temperature which will maintain a holding temperature above freezing.
Along with self-regulating cables, heat tracing can also be done with the use of heat tape. “Unlike its name, it is not actually tape—it is a type of resistance heating wire. You apply it along the pipe you want to heat trace,” explains Waldner. He also explains that, unlike self-regulating cables, heat tape comes in fixed, flexible lengths that cannot be adjusted on the fly. Additionally, they are not self-regulated and are a less expensive alternative to self-regulating cables.
When it comes to the different types of piping, the most common are copper, polyvinyl chloride pipes (PVC), and cross-linked polyethylene (PEX), according to Morana. Regarding how each material fairs against freeze prevention, Hanscomb explains that depending on the wall thickness and the dimensions of the material, the thermal characteristics of the materials would be very similar. However, he does add that some are slightly better than others. “PEX pipes are much less conductive than a metallic pipe like copper,” explains Hanscomb. He goes on to add that “if you had a copper pipe beside a PEX pipe in the same scenario, PEX would generally not freeze.”
According to Morana, PEX pipes might have the best chance at facing off against colder temperatures because “it is so flexible that it can stretch enough to accommodate the freezing of the water inside of it.”
In general, copper has been the most common material used for pipe installation, but there has been a switch over the years. “Copper is a great plumbing material, but it does have a big flaw as it loses heat too quickly, and its walls are thin,” explains Morana. So, while copper was the norm in the past, “there has been a huge swing towards polymer options,” said Hanscomb. Along with the benefits mentioned above, Hanscomb adds that PEX pipes have become more popular because they are easier to install and offer a cleaner product. He also adds that “the same heating cables that would be utilized for copper pipes are the same cables that would be used for PEX and plastic pipes.”