The phone rings and it's your biggest customer. He has a serious problem there's a skyscraper downtown in need of on emergency pipe repair, and until the repair is completed, the entire system will have to be closed down. Or will it? Or perhaps it's a residential customer who has found the pipes frozen solid. You're going to have to rip the walls apart in search of the site of the blockage. Or will you? We investigate the products designed to speed up these jobs and bring an end to the crisis.
Seeing really is believing. At least that's what Wayne Chuck, General Manager of N-Two Cryogenic Enterprise Inc. finds when he demonstrates his services to contractors and property managers. "Unless a person actually sees it happening they can't believe it will work for them," he says of the service his company provides the freezing of pipes for selective repair.
"What we do in a nutshell is, in an emergency situation where there's a broken or leaking pipe and you can't afford to shut the building down, we isolate the leaking section and save the property manager shutting down the entire system."
The process works like this: a containment sleeve is placed around the pipe and liquid nitrogen at a temperature of-320�F is pumped into it. A set scale indicates how long it should take for the pipe to freeze. Once frozen, repairs can be made and blockages cleared without the need to shut down valves, drain the system or depressurize the line. Valves can also be repaired without interruption, and pumps without draining systems. With the leaking pipe frozen, that 'branch' may be out of commission but the rest of the system can operate as normal, except when it is the main water system itself which needs repair. Pipe freezing works on pipes ranging from 1/2" to 48" in diameter, on all metal pipes and, with extra time, plastic pipes.
There is, therefore, no need for a building manager to cut off a building's water main in order to make one minor repair. One recent job in the downtown core displayed the effectiveness: a damaged 8" pipe meant "holding back 73 floors of water" for two hours while the repair was made. Draining the building would have meant a disturbance of sediment in the pipe that would have cost a month's worth of labour costs to clean out.
Chuck also points out that the system involves no added costs for removal or storage of fluid and, with no need for drainage, it is environmentally friendly.
Once customers see the process in action, Chuck says, the callbacks are frequent. "We do lots of malls. If a manager can find a way to avoid a shutdown, he'll go for it."
Chuck says the technology his company utilizes has existed for 25 years, although it has only been in day-to-day use in this country in the last few years and the future is likely to see considerable expansion in demand once awareness is raised. In particular, Chuck sees pipe-freezing as coming into its own with buildings that are more than 20 years old and have a history of poor valve maintenance.
Similar products intended for residential and light ICI use also sidestep the need to drain systems. They freeze liquids in steel, copper, cast iron, aluminum and plastic pipes from 1/8" to 2" using CO2. Freezing times average three minutes for 1/2" cast iron and steel pipe, and approximately five minutes for 1/2" copper tubing. Hot water (up to l40�F) can be frozen using these systems, and three-way freeze systems are also available. Experience says that backup CO2 should be taken along on every job (the only means of checking how much CO2 remains in a given cylinder is by weighing it). Keep in mind that, should the cylinder need to be changed during work, the ice cannot be allowed to melt.
Other systems follow the same principle but use refrigerant as the fuel to isolate sections of copper or steel pipe with ice-plugs. Refrigerant systems are designed to operate continuously, maintaining the ice plug until the repair job is completed. They are effective in copper lines up to 2 1/2" and in steel pipes up to 2".
Frozen pipes, on the other hand, can be addressed with thawing machines. These units heat the pipe by running a very low voltage through it, thereby melting the blockage. Since the units use electricity this application is only useful with metal pipes.
The unit slightly electrifies the area between two of the systems clamps, making it safe to touch the pipe and faucets outside the electrified area. Reportedly, even touching the pipe between the clamps will not result in a shock or burn, although touching the clamps themselves could result in a burn. The electrified pipe is not a fire hazard.
The main advantage of these systems over more traditional methods, such as using torches to melt blockages in affected areas, is the elimination of torches, and the potential savings of time and money over more traditional methods. Torches, with their uneven application of heat, could result in one section of ice in the pipe being melted, turning to steam and, subsequently, splitting the pipe. Torches are also a job-site fire hazard, can scorch finished surfaces and cannot be used in difficult to access areas. Thawing machines offer thawing ranges extending up to 175 ft., meaning that even if a blockage occurs along a length of pipe that is difficult to access, the thawing machine can be hooked up to exposed pipe on either side of the blockage and can still efficiently be used to clear the pipe.
So, the next time the phone rings and it's a customer with a crisis, you can relax. Crisis - what crisis?
� With thanks to General Pipe Cleaners, The Ridge Tool Company, LynCar Products Ltd., N-Two Cryogenic Enterprise Inc., M & S Valves and Fittings, RnR Tools Ltd., Brady Woodruff of Braywood Mechanical Services Inc. and Anthony Tsakopoulos of Brothers Plumbing �Link to Top
What Every Contractor Should Know About Pipe Freezing
Its time we moved into the 21st century and stop draining and start freezing piping systems in order to make repairs, Wayne Chuck, Owner of N-Two Cryogenic Enterprises Inc. tells contractors, engineers, facility operators and anyone who will listen.
We've all been there at one time or another, you're on an emergency service call and discover you need to cut into a pipe to make a repair, install a branch line or valve but can't afford to shut down and drain the buildings water supply, heating or cooling system. What are your options?
We went into the field to find out what contractors do in these situations and what some contractors know about the relatively new technology of pipe freezing. Some contractors we spoke with were hesitant about using the increasing popular CO2 pipe freezing kits. We heard comments like:
- How do I know when the water in the pipe is completely frozen and when is it safe to cut the pipe?
- What if it starts to leak while I'm brazing the joint?
- How can you braze a pipe while it's frozen, won't the heat from the torch cause it to leak?
Others told us they leave this type of work to professional pipe freezing specialists like N-Two Cryogenic Enterprise Inc., a Concord, Ontario based company specializing in pipe freezing for all diameter pipes, especially larger diameters. We use a process incorporating liquid nitrogen, which is colder, then CO2 to more rapidly freeze virtually any diameter pipe and fluids such as water, glycol and some oils, says Chuck.
Pipe freezing offers huge benefits and savings versus draining piping systems and freezing can avoid problems that can arise from opening, draining and allowing air into a system. When you add up the amount of time spent draining, refilling, purging trapped air from a system freezing is the logical answer, says Chuck. Plus there's the increased corrosion arising when you open a system and disturb the sludge and sediment along with the noise that occurs in pipes after refilling and of course the cost of replacing chemicals to the system, freezing is the method that makes the most sense providing you know what your doing and can stop the flow in the pipe, Chuck points out.
Chuck, a freezing specialist for more than ten years says pipe freezing using Nitrogen has been used in England for more than 40 years and contractors need to know how to properly freeze if they choose to do-it-themselves. They also need to know when to call in the professionals to handle certain jobs. You needn't be afraid of pipe freezing, with proper training and preparation contractors can be successful in pipe freezing.
To understand how the popular CO2 pipe freezing kits work we talked to Mark McGuire of Mag Tool Inc., makers of Nordic Freeze portable CO2 pipe freezing kits and contractors using Nordic Freeze CO2 kits. Here are some of their comments:
Our business is primarily new construction and service in the high-rise apartment and condominium market. Draining and refilling the piping system was a time consuming and expensive process especially with the cost of chemicals. We realized that we needed an alternative to draining and refilling an entire system when we couldn't isolate the lines we need to work on. Freezing seemed to be the answer and we bought a Nordic Freeze CO2 pipe freezing system about two years ago and use it to freeze heating and chilled water lines up to 2 inches. We haven't experienced any problems according to Victor Dicalro, President Global Plumbing & Heating Inc., Etobicoke, Ontario.
Lockerbie & Hole Contracting Ltd. in Oakville. Ont is a non-residential contracting firm, which uses a Nordic Freeze CO2 pipe freezing kit when they need to tie into existing heating and chilled water lines up to 6 inches in diameter. We like our pipe freezing system; it enables us to make tie-ins on existing lines without having to drain and refill the entire system, reducing system down time and saving our customers inconvenience and money.
Q. What are the concerns for you when freezing?
A. Pressures are the major concern; the Sow in the pipe must be static in order for the freeze kit to achieve a safe and secure plug in the line according to Lockerbie's, Kevin Hughes. Our freeze kit works well and is easy to operate. For pipes larger then 6 inches we call in a professional pipe freezing firm.
These are some questions we put to COz pipe freezing expert Mark McGuire of Mag Tool Inc.:
Q. How does the Nordic Freeze CO2 pipe freezing system work?
A. Liquid carbon dioxide CO2 is held under pressure in a CO2 Siphon Cylinder and when the cylinder valve is opened, the liquid CO2 runs through the hose and into the cavity formed by the freeze Jacket, which has been secured around the pipe. The liquid CO2, upon reaching atmospheric pressure and temperature, immediately turns to a mixture of CO2 gas and dry ice. The dry ice has a temperature of - 43�C, (-109" F), and this intense cold will freeze the water in the pipe forming a solid freeze plug.
Q. How long will the ice plug take to form?
A. This depends on the diameter of the pipe and the water temperature. For example: a ? "iron pipe containing water at68°F will take approximately ten minutes to form a freeze plug using an eight inch jacket. Steel and copper pipe take about the same amount of time but plastic pipe takes 3 to 4 times longer to freeze. Pipe with higher temperature water takes longer to freeze than pipes containing cold water. It is important to note that both room and water temperature will effect freeze times and you should refer to the manufacturers freeze table for further details.
Q. How do I know if the freeze plug has formed?
A. 1st, by having followed the recommended CO2 injection and waiting time for the pipe size. 2nd, the pipe should have frost build-up on both sides of the freeze Jacket. 3rd, If you are not sure that an ice plug has formed, inject CO2 once more and wait a few more minutes. Do not test for an ice plug too early or, you may destroy a partially formed plug. It is a good idea to crack a flange, or, break a bonnet on a valve close to the freeze prior to cutting the line open. If neither exists, drill a 1/16-inch hole in the pipe to check for excessive pressure. If for some reason the freeze
Q. Once formed, how long will the ice plug last?
A. If the freeze jacket is kept full of dry ice, the ice plug will remain solid and will not melt. If the jacket is left on the pipe, the ice plug will melt in between a few minutes to a few hours, depending on the size of the pipe and how much of the dry ice has evaporated. If the freeze jacket is taken off the pipe, the ice plug will melt in 3 to 10 minutes depending on the diameter of the freeze plug and room temperature. If working on an extended repair, inject CO2 every 15 minutes once the ice plug has been formed. This procedure will maintain a freeze for as long as required.
Q. Can CO2 freeze hot water?
A. Yes, but it is difficult. Two freeze Jackets placed side by side and touching each other is the recommend method. This will act as a single, double - length jacket. Inject CO2 into both jackets simultaneously, which will produce a double convection current into the hot water creating a freeze plug. When double jacketing, keep the jackets butted together to prevent an ice plug from coming out the side of the pipe between the two jackets. Allow for longer freeze time and more CO2. We recommend that you carry extra CO2 tanks, as a greater amount of CO2 will be used. Warm horizontal pipes are easier to freeze than warm vertical pipes.
Q. Will the ice plug burst the pipe?
A. The ice plug will not extend beyond the width of the freeze jacket. Therefore, the pressure increase in the closed section of the pipe will be small. If you use two freeze jackets keep them about 61cm or 24 inches apart. In the above case, the pressure increase will be less than 50 lbs / inch2, (3 Bar).
Q. What pressure will the plug hold?
A. In a laboratory test, an ice plug withstood a pressure of 10,000 lbs. per square inch.
Q. Can you weld, braze or solder near an ice plug?
A. Yes, but be sure that the freeze jacket cavity is full of dry ice. Work at least the equivalent of 12 pipe diameters or a minimum of 41cm or 24 inches away from the jacket on a small pipe diameter to prevent the cold pipe from affecting the welding, brazing or soldering. Stay 61cm or 24 inches away from closed ends, bends or bull headed tees. The use of "Hot Dam" supplied with the Nordic Freeze kits, or a bucket of water and some rags to prevent the heat from traveling toward the ice plug is always recommended.
Q. When the job is finished, what should I do with the remaining dry ice in the jacket cavity?
A. The dry ice will evaporate by itself within a few minutes. It can be placed in a trash can or flushed down a drain. Be sure that children or animals do not come in contact with dry ice. Always wear protective gloves when handling dry ice. Do not thaw the frozen pipe with a torch.
Use Common sense and precautions:
CO2 is heavier than air and proper ventilation must be considered when using CO2 in a confined area, the waste carbon dioxide can displace the oxygen. After the initial injection if the jacket feels empty, inject again until the jacket feels full. Turn off the valve and wait the suggested waiting time between injections. Refer to the manufacturer's time chart. Be sure to complete the number of injections and wait times as per manufacturers recommendations and have extra COz on hand. If your jacket is full and rock hard prior to the last injection, do not add more COz as you may split the jacket. If uncertain what fluid is in the line, take a sample and place it in a freezer to determine if liquid will freeze. This is always recommended with fluids other then water. If the freeze application is greater than 203mm or 8 inches in diameter or if you are unsure as to what to do, consult the freeze kit manufacturer or a pipe freeze specialist. Prior to attempting a live freeze in the field it is highly recommended that a trial freeze be performed under controlled circumstance on a small diameter 1/2" or 3/4" pipe to become familiar with the freezing process and the performance of your freeze kit. Whether you choose to freeze pipes yourself or call in the pros, freezing can be the solution to draining a system and having a happy, satisfied customer.
� Editor's note: Thanks to Mark McGuire and Wayne Chuck for their expertise and recommendations. For more information contact: Mag Tool Inc. Toll free: 1-800-661-9983, www.magtool.net. N-Two Cryogenic Enterprise Inc. Toll free 1-888-410-6487, www.n-two.com �Download PDF Link to Top
IS PIPE FREEZING TRUST WORTHY?
Kelson thinks so. Interviews with three individuals from GEO A. Kelson Company Ltd. confirm that pipe freezing, performed by experienced technicians is trustworthy, efficient, and offers a great competitive edge. According to Joe Turner, who once thought pipe freezing was a scam, "the greatest need is education." This foreman at Kelson has since added Pipe Freezing by N-Two to the permanent file. Turner suggests that contractors educate themselves regarding the cost of draining versus the benefits of freezing.
Armed with more than 12 years of experience, Wayne Chuck, of N-Two Cryogenic Enterprise Inc. insists that pipe freezing is very dependable "when you use technicians who know what they are doing." N-Two offers pipe freezing as an on-site service. A containment unit is placed around the pipe close to the area to be repaired. Liquid nitrogen, which reaches a super cold temperature of -320�F is fed into the unit causing the liquid inside the pipe to form a secure ice plug. Trained technicians stay at the worksite to maintain the freeze while contractors continue the repair without having had to drain the system. Later, the ice plug is thawed. When the system is operational, less sediment is disturbed and the need to chemically retreat the liquid has been avoided. Chuck explains that once a contractor gets over the initial fear of using pipe freezers and witnesses a successful freeze they become lifelong believers. He adds that it is probably one of the best-kept secrets in the industry.
This is no wonder with clients like Chris Curr of Kelson who admits to not wanting the competition to discover his advantage. Curr was once also sceptical of pipe freezing since his past use included CO2 kits which "sometimes worked and sometimes didn't". Now Curr says he has had nothing but good experiences with N-Two. Where pipe freezing kits using CO2 may handle small diameter pipes and take a lengthier time, pipe freezers who use liquid nitrogen can freeze pipes up to 48" with less time and increased reliability. That's right, 48"! Recently, Curr called on N-Two to successfully freeze a 4" hot water pipe at South Muskoka Memorial Hospital. The water temperature at start was approximately 200�F. Because liquid nitrogen is so cold it can also freeze glycol, brine, oils and most other liquids. Curr is a fan of N-Two because it saved him the difficulty of draining the system, time and further costs of chemical treatment, which often takes several days to reach desired levels. He says the added benefits far outweigh the cost. Curr prefers to accumulate the jobs until there are at least a half dozen freeze plugs required. These are all done by N-Two on one outing.
When the Rogers AT&T building in the downtown region decided to add a 13-story tower, Turner from Kelson trusted in N-Two to freeze 36 pipes in one day. Each floor from the 2nd to the 12th required freeze plugs, some of which were in occupied areas. These ranged from 3/4" to 2 1/2". The contractors were able to cap and remove the risers without shutdown or hindrances. Turner, who has also used pipe freezing extensively at the Eaton Centre and Hershey Arena, describes N-Two as "the most professional in the city." He adds that very few companies ever get a recommendation from him. John Russell also of Kelson recalls his former belief that draining was always the better way until maintenance disallowed him to drain the system due to cost and inconvenience. He was forced to use pipe freezers. Since then he has not hesitated to call in N-Two. Russell says he has never heard of pipe freezers other than N-Two but probably wouldn't bother looking because N-Two is "professional, efficient and gets the job done."
� For more information about pipe freezing and N-Two write to #1 - 117 Planchet Road, Concord, Ontario, L4K 2C6, call 416-410-6487 or visit www.n-two.com. �Link to Top
N-Two Cryogenic Inc. is an innovative company that is focused on both reducing customer costs and preserving the environment.
N-Two was founded in 1996 by Wayne Chuck who has over 28 years expertise in the business. The company serves not only the Greater Toronto Area but also the Ottawa region with branches in Toronto, Ottawa, Kingston and London.
"I started working for someone else, but noticed ways that processes could be improved," Chuck said. "I decided to start my own company with my own improvements, and things have just advanced from there."
In fact, the company experienced i its greatest growth in a sector it hadn't anticipated.
"The I.T. sector helped us in a big way," he said. "As companies depended more on computers and servers, they dedicated entire rooms to them. Computers generate a lot of heat, so rooms required cooling systems, typically water pipes. When repairs were necessary, the cool water couldn't be drained or there would be a risk of over-heating computers, so our solution was the best by far."
N-Two specializes in a unique freezing technique that allows customers to repair pipes quickly and efficiently.
According to Chuck, "Many contractors, building managers and property owners have been faced with a similar situation: An immediate repair is required, but the shut down and drainage of the building's water supply, heating or cooling system is not an option. What are the choices?"
"Pipe freezing offers huge benefits and savings versus draining piping systems," he said. "Freezing can avoid problems that could arise from opening, draining and allowing air into a system. When you add up the amount of time spent draining, refilling and purging trapped air from a system, freezing is the logical answer."
N-Two uses liquid nitrogen to rapidly freeze almost any diameter pipe and fluids such as water, glycol and some oils. Unlike other companies who use carbon dioxide, liquid nitrogen is colder and freezes faster. Most importantly, freezing pipes is a far faster process and better for the environment.
Additionally, when a system is "opened up," there are a host of issues which may arise. There is a potential for increased corrosion within the pipes as well as a disruption to sludge and sediment which may have built up. As well, there is noise that occurs after pipes are refilled and additional costs involved when replacing chemicals to the system.
"Freezing makes the most sense to stop the flow within a pipe," Chuck said. "This method allows contractors to not only make repairs, but also easily add valves, meters, tie in new lines and much more."
From a green perspective, the freezing method offers two benefits. Firstly energy is conserved because the system does not have to be drained and there is no need to refill and re-heat / re-cool the contents. As well, freezing means not using any chemicals to create the plug and thus no harmful chemicals are being dumped when the job is complete.
According to Chuck, "Liquid nitrogen is safe � 78 per cent of the air we breathe is nitrogen."
A recent example of the companies freezing method was utilized at a job done at Lester B. Pearson Airport's Terminal Three. Shutting down the cooling system to relocate a six-inch line was not an option. Secure freeze plugs were formed in two separate areas of the line, which held 30 per cent glycol. This allowed workers to weld in four new joints. Moreover, it eliminated the need to displace thousands of gallons of glycol.
On the other side, N-Two also specializes in hot tapping, which involves the use of specialized equipment and highly trained technicians, who cut a hole into existing pipe containing liquid or steam, while the pipe is still under pressure and in service.
"Hot tapping allows for the addition of new branches without disruption of flow or leakage, "Chuck said. �For example, shutting down the system of a process plant might involve closing one or more production units for hours � maybe even days or longer. The plant owner is looking at lost-production time plus the cost to bring the system back on-line." Hot tapping is performed when a commercial building needs a branch line added to an existing line and shutting down the system is not an option, or a by-pass line has to be established before the main shut-off valve can be changed or serviced � so two hot taps could be done on either side of the main shut-off to provide a temporary or permanent by-pass loop in the system.
The process is completed as follows: The hot tap machine is connected to the valve and a hole is cut into the valve. The hot tap compartment fills, air is released and the valve is closed off. Now a new service connection can be installed.
N-Two's hot tapping equipment is capable of handling piping systems in a variety of materials. Hot taps ranging in size from one- to 12-inch diameters can be performed on piping of any size, and almost any type of material including cast iron, stainless steel, copper, brass and plastic. Additionally, the process can be completed on a wide range of high pressure systems.
To complete a hot tapping service, N-Two likes to be brought in as soon as a problem is detected.
"We have to access the feasibility of a particular operation and provide design considerations associated with the proposed operation and a cost estimate," Chuck said.
Whether by fire or by ice, N-Two Cryogenic Inc. has an effective method to repair piping systems quickly and efficiently.
For more information, contact N-Two Cryogenic Inc. at 1-888-410-6487 or visit the company's web site at www.n-two.comDownload PDF Link to Top