Frequently Asked Questions
PipeFreezer’s method of temporarily plugging a water or product-filled pipe by the engineered cryogenic rapid cooling of the pipes contents into a solid form sometimes causes customers new to this concept to be concerned.
Their most frequently asked questions and answers to same follow.
WHY DO ACCIDENTALLY FROZEN PIPES BREAK?
Pipes only break when a plug of ice forms inside the pipe near to a dead-end or a closed valve. As the ice plugs forms it seals off the interior diameter (I.D) and then expands longitudinally along the centre axis of the pipe pushing on the trapped water. This expansion increases the pressure of the entrapped unfrozen water area until it reaches a pressure level that the pipe can no longer hold. The pipe then breaks. Tests have shown that the radial expansion of the ice plug does not come close to exerting enough stress on normal piping systems to cause failure.
SO WHY WON'T PIPEFREEZERS PROCESS CAUSE AN EXPANSION BREAK?
PipeFreezer does not Cryo-Plug against a dead-end, our experienced technicians will make a full assessment of any potential risks and provide a pressure relief process as the situation dictates.
DOES THE PIPE FREEZING PROCESS CAUSE DAMAGE TO THE PIPER OR CHANGE THE METALLURGY OF THE PIPE?
No. In fact there are types of steel that are “heat treated” to improve their performance properties by cryogenically quenching them. For piping and pipeline metals, no damage or deformation occurs with PipeFreezer Cryo-Plugging.
HOW LONG WILL THE ICE PLUG TAKE TO FORM?
This depends on the diameter of the pipe, thickness of pipe wall, composition of the pipe, temperature of the contents and the air temperature. With over 250,000 successful Cryo – Plugs to our credit we will be able to give you an estimate at time of inquiry.
WHY WON'T THE ICE PLUG BLOWOUT WHEN WE CUT THE PIPE?
Ice has an amazingly high adhesion to steel, ever been snow skiing and watched the tow operators chip the ice of chairlifts with hammers, shovels etc at the start of the day? This adhesion combined with the friction of the long ice plug inside the irregular surface of the pipe would be enough to assure the ice plug isn’t going anywhere.
HOW MUCH PRESSURE WILL THE CRYO-PLUG HOLD?
The question I would ask you is how much pressure can your pipe hold? A “High pressure” Cryo-Plug can hold even when the pressure behind it is raised to cause stresses greater than 100% SMYS of the pipe. Our plugs can be hydrotested to whatever pressure you require, prior to depressurizing your downstream system.
IF THIS SYSTEM IS SO SAFE WHY WON'T PIPEFREEZER FREEZE OVER CERTAIN SECTIONS OF THE PIPE?
PipeFreezer is a safety conscious group. We know that Cryo-Plugging is a well engineered proven procedure with many safety factors built into it. However in some circumstances the site chosen by the client may not be the optimum place to form the Cryo-Plug for a variety of reasons. Our experienced technicians will advise and recommend alternatives once a site inspection and freeze plan is put in place.
WHAT ARE THE MECHANICAL HAZARDS?
There are some mechanical hazards while performing pipe freezing and alteration works. These may be impact or heat stress to the pipe near the freezing location. However our PipeFreezer technician is well versed in any potential hazard and is able to supervise and provide professional guidance to ensure that the project is carried out in a safe manner.
ONCE FORMED HOW LONG WILL THE CRYO-PLUG FREEZE LAST?
PipeFreezer can keep the pipe Cryo-Plug in place for as long as is required by the client, wether it be 15 minutes for a simple valve change or many hours, days even, for a more complicated infrastructure project. This will all be assessed during the freeze plan stage at the time of inquiry.
CAN YOU WELD BRAZE OR SOLDER NEAR A CRYO PLUG?
Yes. The distance will vary depending on the size and composition of the pipe.
HOW LONG WILL IT TAKE FOR THE CRYO PLUG TO THAW?
Once the client has completed the job and authorised the release of the freeze our technician will thaw the plug for you to establish if any leaks or defects can be detected whilst our technician is still on the job site. The time this takes depends on the method used and the size of the pipe.