Pipe Freezing to Repair Plumbing Without Shutting off the Water
Pipe freezing works on copper, plastic and metal pipes.
Pipe freezing is a fast and efficient way to complete plumbing repairs or alterations when shutting off or draining the entire water piping system is not possible or practical. While repairing or changing water pipes in older houses or facilities, it’s not uncommon for the shut-off valves to fail. In apartments or commercial buildings, shutting off and draining the pipes can be an inconvenience to people using the buildings, and it can be a challenge to locate the shut-off valve.
Freeze kits form a small ice plug inside the pipe that can withstand water pressure long enough to allow you to install a tee or service valve. This method works on copper, plastic and metal pipes, both small and large.
There are two types of freezing kits: aerosol and electric. Both work on the same principle, evaporating a volatile fluid around the pipe. When evaporation occurs, gas molecules escape from the liquid drawing enough heat from the pipe to freeze the water within.
The aerosol freeze kit uses an insulated jacket that keeps the liquid in a closed atmosphere around the pipe.
The electric freezing machine retains the fluid in a closed circuit so nothing is lost during the process. The motor drives a pump that compresses the gas and a heat exchanger that cools it into a liquid state for circulation to the freezer head. The freezer head is clamped to the pipe and the fluid flows in via a small capillary tube. A larger space within the head allows the fluid to expand, and this evaporation cools the pipe to create the ice plug within. The expanded gas vapor flows back to the compressor and the process repeats.
Preparation for freezing
Before you begin, stop all water flow within the pipe. Even a small drip from a faucet is enough to prevent freezing. If you are working with a hot water pipe, be sure to shut off any circulation pump, and allow the pipe to cool.
If possible, freeze horizontal rather than vertical sections of pipe. Natural heat convection within a vertical pipe can cause movement and reduce the duration of the ice plug.
Heating system piping can contain anti-freeze or corrosion inhibitors. These can lengthen the time it takes to freeze the pipe.
Flame-free joints, such as compression fittings work well, especially if space is limited. Solder joints can be used but leave an inch or two between the fitting and the freezing jacket, so the solder doesn’t affect the ice plug.
Using the aerosol spray kit
When using the aerosol spray kit, keep the work space well ventilated; heat, flames or smoking near the freezing jacket or in contact with the spray itself can cause noxious fumes. Wear gloves and eye/face protection when working with the aerosol as skin will freeze on contact.
Place the freeze jacket around the pipe a few inches from the work area, and tie each end of the jacket tightly with wire ties or string. Connect the extension tube from the jacket to the aerosol can and follow the manufacturer’s instructions.
Inject the freezing dose into the jacket. The manufacturer’s instructions will include a chart that tells you how long you should pause after injection to allow the ice plug to form, based on the type and diameter of the pipe. The instructions will also give the length of time you can expect the ice plug to last (see tip chart). Leave the jacket in place until the work is complete and then remove the jacket. The ice plug will thaw in a few minutes.
Using a pipe freezing machine
With the pipe freezing machine, first clamp the freeze head to the pipe. Note that based on the size and type of the pipe, adaptors or additional freeze heads may be needed. Connect the machine to a power supply and switch it on.
Wait for the prescribed amount of time required by the freezing machine you are using before starting work, and leave the machine running until the work is complete. When you no longer need the ice plug, turn the machine off and remove the freeze head.
To select the method that will work best for you, remember that the aerosol freeze kit is used only once and has a relatively high “cost per freeze” price. If the work can not be completed in 30 minutes, more aerosol may be needed. Also, to use the aerosol kit, you must have access around the pipe to fit the freezer jacket.
The pipe freezing machine has a higher purchase cost, but can be used repeatedly. Complete access around the pipe is not required since the freezer head clamps are designed to fit along the side of the pipe. Another benefit is that even though the freezing machine takes longer to form the ice plug than the aerosol method, the pipe will remain frozen as long as the power is on, making it more suitable for lengthy repairs or alterations.
To verify the pipe is frozen, spray a small amount of aerosol next to the area being frozen. If the aerosol condenses to a white frost, the ice plug has formed.