Can you freeze moving water?

No. The water in the system needs to be static before it will freeze. In the case of a heating system, the pump would need to be shut off beforehand. If a valve or pipe is leaking then it is usually possible to freeze it. The leak needs to be stemmed as much as possible before starting to freeze the pipe.

How long does the freeze last?

As long as you would like it maintained. Typically freeze plugs formed in less than three inch diameter pipe, need only to be held for an hour at most as this is sufficient time to carry out the valve change or tie-in. On larger pipes more time may be needed to carry out the work, and the plug can be held accordingly.

Will the freeze plug let go at high pressure?

No. The freeze plug, once formed, will be extremely solid and is actually stronger when under pressure as the water is denser. Tests have been carried out showing that freeze plugs can withstand pressures in excess of 4000 psi. In fact, freeze plugs are used when pressure testing pipelines in order to isolate specific sections. In tests, the pipe has been shown to give way before the plug will move when pressure has been increased on one side of a freeze plug formed with Liquid Nitrogen.

How long does the freeze plug take to form?

A freeze plug in a half inch copper line will take less than 5 minutes, to form, rising to 3 – 4 hours for a ten inch diameter steel pipe. These times vary with different pipe materials and contents. Hot water or water containing heating chemicals will take longer depending on the individual circumstances.

Will the pipe be damaged by a freeze plug?

No. The pipe freeze is a controlled process where the ice that is created is very brittle (due to the very cold temperature). This means that the ice cracks and fills with water, re-freezes, cracks and so on, until a plug is created. The pipe freeze plug expands along the length of the pipe and the result is stress free ice.

Are you insured?

Yes. We carry $5 million in general liability insurance. We are registered with Worksafe BC and we are insured to work in all types of buildings including airports, hospitals and industrial plants.

Does liquid nitrogen damage the pipe?

No. Once the area has been defrosted the pipe returns to its original state. In fact, ‘heat-treating’ steel with cryogenic refrigerants such as liquid Nitrogen actually increases the material’s strength.

What precautions must be taken during a pipe freeze?

The pipe freeze needs to be supported at all times. Hot works need to be carried out a safe distance from the freeze plug. This distance varies according to the type of work and the size and orientation of the pipe.

What size pipe can you freeze?

Nitro can freeze almost any pipe up to 12 inches in diameter.

How long does it take to defrost?

It only takes minutes to defrost a frozen pipe. Our technicians will carry out a controlled defrost so that there is no loose ice left in the system before the circulation or flow is switched back on.

What about safety?

We take safety very seriously. Our technicians are highly trained in safe work procedures handling liquid nitrogen. We work to strict method statements and risk assessments that are site and job specific. Please contact us if you would like futher information.

Why not use rental equipment, CO2 kits, or pipe freezing machines?

There are many reasons to go with a pipe freezing contractor. A specialised pipe freezer using liquid nitrogen will freeze pipes faster, as well as freezing large diameter pipes and also chemicals including glycol. This is because Liquid Nitrogen can get down to -196C whereas most other systems can only get down to -40 or -50C at best.

A kit or machine is very limited in what it can safely isolate. Using a dedicated pipe freezing service will produce a better result and contractors can have complete confidence in the freeze plug while carrying out their work.