Pipe Freezing 101

Pipe Freezing 101 Eliminate downtime, save money, and help the environment

“We had a leak on a hot water return pipe and did not want to drain the system. By freezing the pipe, we were able to make repairs and have the system back up and running within one hour. Great service, fast and reliable.” ~ Newton Rajapakse – Chief Engineer, Terminal City Club Vancouver

wHy do fRozen PIPes buRsT In wInTeR?

In winter ice forms inside the pipe and grows along the pipe when valves are closed tight. The ice expanding along the pipe presses against the water between the ice plug and the closed valve. Unlike air, water will not compress and so the pressure in the pipe rises. The ice continues to grow and press on the trapped water until the water pressure inside the pipe exceeds the pressurerating of the pipe and it bursts. In fact, it is water pressure that damages the pipe and not the ice.

This fact is proven in the case where a faucet is left dripping. The pipe may still freeze in winter but it will not burst. This is because the water is not trapped and so an increase in pressure does not occur. The drip from the tap is relieving any potential build-up of pressure.

In reality, however, a dripping tap may not save your pipes. Due to the uncontrolled nature of the freezing, there may be several pockets of trapped water which will cause damaging pressureincreases in multiple areas of the system.

wHaT Is conTRolled PIPe fReezIng?

Typically a containment unit is attached to the pipe and a refrigerant is passed through it. The freeze kit will uti-

“We had a dripping valve on an air-conditioning system in the middle of summer. Our option of shutting down the system, draining thousands of gallons of chemicals and spending the next few months purging air from the pipes was going to cost us many thousands of dollars. The inconvenience to the tenants in the building would have been substantial. By employing a pipe-freezing contractor, our A/C pump was turned off for one hour, a new valve installed, the pipe was defrosted and the pump turned back on. This option cost our building $300 for the freeze and $200 for the plumbing – $500, instead of $5,000, and zero inconvenience!” ~ Colliers International, Vancouver.

The freezing occurs only at the points of contact with the refrigerant, and precautions are taken when freezing close to dead-ends or a second freeze plug. Pressure-relief measures are carried out so that the ice can continue to form without increasing the pressure within the pipe.

With no outward expansion on the pipe, a stress-free plug is formed. Work can now be carried out with complete confidence. The freeze plug is maintained during the work and acts the work, the freeze is defrosted and the system is returned to normal.

“We had a dripping valve on an air-conditioning system in the middle of summer. Our option of shutting down the system, draining thousands of gallons of chemicals and spending the next few months purging air from the pipes was going to cost us many thousands of dollars. The inconvenience to the tenants in the building would have been substantial. By employing a pipe-freezing contractor, our A/C pump was

turned off for one hour, a new valve installed, the pipe was

defrosted and the pump turned back on. This option cost our

building $300 for the freeze and $200 for the plumbing – $500,

instead of $5,000, and zero inconvenience!” ~ colliers inter-

national, vancouver

NO MORE SHUTDOWNS

Don’t Drain it, Freeze it!

lize refrigerant such as R2, CO2 or LN2 (liquid nitrogen).

as a de facto shut-off valve during this time. On completion of

www.nitropipefreeze.com | 778.321.2653

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On-Site Service in BC since 2009

Photos courtesy of Nitro Pipe Freeze Inc.

wHIcH PIPe fReezIng sysTem Is THe besT?

There are three main types: 1. Refrigerant machine available in a packaged unit that will freeze pipes up to two inches and get the pipes down to approximately -30 Celsius. advantages: Plug and play, very easy and portable. Disadvantages: Very limited capabilities. It loses its freezing power over time. It needs a power outlet. 2. CO2 unit can get down to -70 Celsius and requires pressurised CO2 gas cylinders. advantages: Much colder than a machine and has the ability to freeze larger diameter pipes. Disadvantages: CO2 is a toxic gas. The equipment is bulky and has limited capabilities 3. Cryogenic pipe-freezing. A specialised trade service using liquid nitrogen creates super-chilled freeze plugs good to -200 Celsius. advantages:

Faster, safer, better. Disadvantages:

Specialised service and therefore one needs to hire a contractor.

Is PIPe-fReezIng a TRusTed alTeRnaTIve To dRaInIng a buIldIng?

The answer to this question lies in the chosen pipe-freezing system. CO2 and refrigerant machines are not the best method as there are many limitations and safety issues. For example, pipes containing some heat or chemicals or where there is flow present cannot be frozen effectively. With CO2 freezing on larger pipes, safety concerns arise due to a large build-up of gas over prolonged freeze times.

These types of freeze kits are usually operated by the same pipe trade professional who is carrying out the maintenance work. The inherent risks associated with these systems are amplified by the fact that these personnel are relatively inexperienced with potentially hazardous freezing situations.

On the other hand, liquid nitrogen pipe-freezing is the trusted alternative and has been worldwide for more than 40 years.

With this type of cryogenic pipe-freezing, pipes of any size can be frozen much more rapidly, safely and without the limitations of using a kit. Specialised liquid nitrogen pipe-freezing contractors are brought in to carry out the work. They are accustomed to the safe handling of liquid nitrogen and employ safe pipefreezing practices through years of training and experience.

This is the oldest type of pipe-freezing – and still the best. The first liquid nitrogen pipe-freezing company began in England in the 1970s. Since then, millions of pipes around the world have been safely isolated with this process.

LN2 is inherently safe, nontoxic, nonflammable and has vastly superior freezing capabilities. Almost any liquid in almost any size pipe can be frozen in this way.

“Our customers are looking to save money, save time and reduce or eliminate the inconvenience to the building occupants during essential maintenance work. If we can help them to do that, then we have done our job,” says Matt Farrell of Vancouver-based cryogenic pipefreezing contractor Nitro Pipe Freeze.

Farrell established Nitro Pipe Freeze in 2009. Originally from London, England, he recognised the need for a dedicated pipe-freezing contractor in B.C. A qualified plumber and gasfitter, Farrell has extensive cryogenic pipe freezing experience and has frozen pipes in Australia, Canada, and the U.K.

For more information on pipe-freezing, please contact Matt@nitropipefreeze.com or call 778-321-2653. b