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Urgent 12” Copper Wrap Freeze

In May of 2022 a local mechanical contractor called with an urgent freeze requirement.  The freeze was on the supply and return of a large chiller system.  The chiller water was treated with rust inhibitors and there was a sensitive waterway nearby.  A temporary pond would have to be built in the parking lot to hold close to 200,000 gallons of treated water.  With parking space already an issue and the time and effort needed to build such a pond freezing the 2- 12″ lines was the only option.  The contractor wanted 2 – 12″ Accu Jackets in 1 day but had to use copper coils due to time constraints. 

COB was able to assemble the double freeze equipment in a day and were able to be onsite to help get the setup done properly.  The freeze was started after working hours of the facility and went on thru the night and was completed early the next morning.  Valves were successfully replaced with only a small amount of water left between the ice plugs and the valves to deal with. 

Courtesy Meridian Mechanical Orlando, FL

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Chemical Plant Freeze breaks all the rules

October 2018

Accu-Freeze, Chemical Plant Freeze breaks all the rules

Recently a specialty chemical plant in Canada had an issue with a waste storage tank that contained some environmentally “unfriendly” contents.  The outflow valves from this holding tank were slowly decaying and even with redundant valving there appeared to be no way to replace the faulty valves without draining down the entire tank.   The contents of the tank were going to require very expensive  specialty hazardous  material  teams,  tankers, storage and disposal to drain and remove. The company contacted COB industries with their situation to see if it was possible to freeze the contents of the outflow line to allow for repair.  The conversation revealed that many of the general guidelines suggested by COB for freeze site selection were in question.

Accu-Freeze chemical_1

1) proximity to a potential heat source.  The outflow line was welded directly to the wall of the storage tank which would act like a heat sink when trying to attempt a freeze.  2) Distance to a closed valve.  A series of redundant valves were placed very close together going downstream from the storage tank wall. This included an encapsulated valve that had been leaking for quite some time.  3) Distance to a valve or fitting. In this case a flange connection was only 5” away from the only available freeze site.  The standard 2” Accu Jacket was just over 8” long.  All of these factors created what would typically be a “no go” situation for a freeze selection but with limited options it was agreed to attempt to freeze the line.  A COB freeze technician was dispatched to the site and after a walk through and series of discussions with plant staff the okay was given to attempt the freeze.  To make matters worse the area was experiencing a heat wave and the freeze location was in direct sunlight with no way to shade the area.

Accu-Freeze chemical_3

A custom 2” Accu Jacket had been built to fit precisely between the tank wall and the flange and the fit turned out to be nearly perfect.  Only a little trimming of one of the bolts was required to make a good connection.  Extra LN was bought in  and staged nearby as it was expected that more time and nitrogen would be required to freeze the 2” line due to the tank wicking temperature away from the freeze site, the ambient conditions.  Not to mention the unexpected placement of heat tracing on the outflow lines running year round(normally a 2” line would take approximately 30 minutes to freeze).  The leaky valving actually helped in this situation because it allowed for visual confirmation of the freeze when the constant dripped stopped after 50 minutes.  It was suggested that the freeze be held for another 10 minutes with all of the downstream valves held open and this confirmed the freeze integrity.  The flange was unbolted and the concerns of a freeze plug stretching across the 2 flange faces making separation difficult (or impossible) were unproven as the ambient conditions prevented more growth of the ice plug and only a little trimming with a quickly fashioned “ice plug trimming tool” (a hacksaw blade with  protective handle made by duct tape at one end) cleared away the ice and allowed for quick fitup of the new manifold by plant personnel.



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Oaks Pioneer Park pipe abandonment

July 2018
Recently a large northwest utility had a potential environmental issue with an abandoned pipeline that traversed a protected area in Oregon.  The US Army Corps of Engineers had chosen the area to replenish a natural salmon hatchery that had been cut off from the Willamette River many years ago when a train crossing was built.

Accu-Freeze Oaks Pioneer Park It was determined that the line would have to be removed in order to allow for the construction of the new river access.  The line had been filled with water when it was abandoned and the highly contaminated water now posed a considerable problem.  Removing and disposing of the water would be a logistical nightmare as the line was miles long and the site was a mile from the nearest accessible road.  It was determined that creating 2 ice plugs on either side of the access stream and removing only the water between the ice plugs so the lines could be capped and the cut off pipe removed would be the best option.  COB Industries was contacted about the feasibility of the idea and availability of the equipment required to conduct the project in an urgent fashion as the project was on going and time was imperative.
Within a week the equipment was available (including borrowing a 10” freeze jacket from another customer) and a COB representative was dispatched to the site to provide training and consulting while the project progressed.  Logistics at the site were quite formidable as no vehicles other than UTV’s were allowed to access the site via a pedestrian foot path(heavy equipment was bought in via rail).  This meant bringing the liquid nitrogen supply in 1 tank at a time from over a mile away.  (It was determined that over 16 liquid nitrogen dewars would be required to perform this double 10” freeze.)    Adding to the problems the area was experiencing record heat which would make any freeze even harder. Oaks Pioneer Park Accu-Freeze
Accu-Freeze Oaks Pioneer Park Two pits were excavated on either side of the creek access exposing the pipe and the anti corrosion coating was removed.  Once the pits were open and secured the freeze equipment was installed. Freezing commenced early the following morning. Due to the record high temperatures combined with little to no shade on the pipe (or freeze equipment) higher pressure nitrogen supply was required.  The freeze was begun and the added flow rate of nitrogen was able to overcome the heat load in the environment and the ice plugs were successfully completed.



Oaks Pioneer Park Accu-Freeze
The pipe was cut on both sides and the remaining contaminated water drained to disposal containers that would have to be taken away.  Waiting welders quickly capped the open ends.   The freeze equipment was shut down and the ice plugs allowed to thaw naturally.  The proposed river access refurbishment was allowed to continue the following week bringing life back to a vital natural habitat.
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Pipe freeze training with our exclusive agents in Brazil “Senior Protecao”

Pipe freeze training with our exclusive agents in Brazil “Senior Protecao”

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In May of 2017 COB Industries President, Cletus O’Brien, traveled to San Paulo Brazil to conduct in depth pipe freeze training and demonstrations with their exclusive agent for the area, “Senior Protecao”. Senior is a fire suppression system sales and service provider who services everything from small buildings to major industrial plants.

COB traveled to Brazil for 4 days of visits with customers of Senior to conduct demonstrations on the viability of using the COB freeze systems to help with maintenance and repair of fire suppression systems.

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The demonstrations sites were at major steel producers who have extensive fire protection systems due to the hazardous environments that steel plants exist in. Senior was able to setup onsite demonstrations and even invited other potential customers to attend. Freezes were conducted on live lines but in non hazardous, outside areas where the freezes could be conducted with zero interference of operations and no risk to any critical systems. Customers were able to observe the ease of installation and proper procedure to conduct a freeze from start to finish.

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Pipe freezing is a relatively new procedure to the Brazilian market and all the attendees at each site were impressed at the usefulness of pipe freezing as a tool for maintenance and repairs.

Qwik-Freezer Kits

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S. Korea Completes Freeze Seal Test On 24” Pipe

Distributor in S. Korea Completes Freeze Seal Test On 24” Pipe With New Accu-Freeze® Jacket And Valve Manifold Prototype

December, 2014—GEOS Co., Ltd. is the agent in South Korea for COB Industries’ Qwik-Freezer® and Accu-Freeze® Pipe Freezing Systems, and they were contracted by a large power utility company to conduct a feasibility study with regards to performing freeze seals on large diameter steam lines. Directors from GEOS visited COB Industries in Florida to discuss this project, and COB Industries experts explained that while steam cannot be frozen there is a possibility of back-filling lines with water and creating freeze seals to isolate the lines which would accomplish the primary goal.

Following subsequent meetings in Seol, GEOS was then given the green light to contract with COB to conduct the first phase of testing by conducting a Freeze Seal Test using Accu-Freeze® equipment on a 24” Carbon Steel Pipe. GEOS and COB met once again and COB proposed a custom 24” Liquid Nitrogen Freeze Jacket with multiple LN2 inlets, a manifold prototype including multiple Accu-Freeze® solenoid valves and a custom control box containing (4) Accu-Freeze® digital controllers (see photos below). COB Industries built the equipment and shipped it to S. Korea where the test was conducted by GEOS personnel. The test was 100% successful and an ice plug was formed over a 16 hour period and then pressure was applied to pressure test the 24” ice plug to over 140 PSI.

COB Industries has been manufacturing Pipe Freezing Systems for over 45 years and their patented Accu-Freeze® equipment is used by the U.S. Navy, power plants and mechanical contractors around the world.

24" Pipe Freeze

  1. Custom 24” Accu-Freeze® Jacket
  2. 2. A600 Freeze Test Set-up Configuration
  3. Formation of 24” Ice Plug
  4. Pressure Testing 24” Ice Plug

24" Pipe Freeze

For more information contact Cletus O’Brien or Troy Palmer at

or call 321-723-3200.

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Multiple Freeze Plugs at Central Reference Library


freeze plugs

The work in the photographs was performed at the Central Reference Library in Cocoa Florida. Precision Air Conditioning of Brevard is the Prime Contractor performing a major mechanical renovation/upgrade to that facility for Brevard County.

The need to maintain temperature and humidity control is paramount as this facility contains many of the genealogic documents related to Brevard County. These particular line freezes were performed using the COB Industries Accu-Freeze System.

The work consisted of freezing (2) 6” dia. Chilled Water lines and (2) 4” dia. Hot Water lines all of which were Sch. 40 Carbon Steel Pipe. During the time six 3” butterfly valves and ten 2” ball valves were replaced downstream, which required the ice plugs to be maintained for approximately 4 hours. The line freezes and subsequent replacement of the isolation valves, will allow work on individual AHU’s in a localized manner, without shutting down the entire HVAC system.

The line freezes were utilized to prevent the need to drain/capture/re-fill approximately 1400 gallons of treated Chilled water and Hot Water, which would have been very time consuming and costly.

Mark Griffo No Comments

Custom Plug Testimonial

Custom Plug Testimonial


These are pictures of the 36″ River Water Main repair. The site uses river water for cooling water in the production units. This leak had one of three pump houses shut down. With one pump house off line units had to cut back production. Thanks to you and your company for expediting the repair plug that was ordered Friday afternoon and received and installed Tuesday morning. With the plug installed normal production operation could resume. Once again thanks, and we will call you for any future needs. Attached are pictures of the repair plug in place.

custom plug testimonial

If you would like more information please contact Cletus O’Brien at (321) 723-3200 or email to

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Accu-Freeze 12 inch freeze at CBC Radio-Canada

<h2>COB Industries Accu-Freeze 12 inch freeze seal</h2>

COB Industries

April 2014— Accu-Freeze was used by a mechanical contractor in Montreal to perform a freeze seal on a 12” water main in the boiler room of the CBC Building in downtown Montreal. A freeze seal, or “ice plug” was required in order to change out an old valve that was seized up without having to shut down or drain out the system. They decided to contact COB Industries in order to purchase Accu-Freeze® equipment and to receive training to prepare them to tackle a critical job of this nature. In addition, they hired COB to provide a pipe freezing specialist to be on hand as a consultant while the job was carried out. The job was scheduled for the third week in April.

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After a one-day Accu-Freeze® training session with COB Industries, the freeze seal was performed at the CBC building. An ice plug was achieved in approximately 6 hours in spite of moderate vibration caused by a nearby pump (vibration causes turbulence in the water inside the pipe which impedes the freezing process). Once the presence of ice plug was confirmed the old valve was disassembled and removed and the new valve was hoisted into position and attached. The valve replacement took approximately 2 hours and the ice plug was maintained throughout the process. Once the new valve was in place, the Accu-Freeze® equipment was removed, and within 2 – 3 hours the plug had thawed and the system was fully operational again.

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COB Industries has been manufacturing Qwik-Freezer® (portable CO2 Pipe Freezing Kits) for over 45 years and the patented Accu-Freeze® LN2 Freeze Systems for 20 years. Accu-Freeze® is a digitally controlled Liquid Nitrogen Pipe Freezing system that automates the LN2 injections and provides the ability to control the pipe wall temperature throughout the freeze seal process. Accu-Freeze® is in use worldwide at power generating facilities, power plants, at US Navy shipyards and by mechanical contractors and building maintenance personnel in many countries.

Mark Griffo No Comments

COB Helps Develop Revolutionary Pipe Purging Technology

COB Helps Develop Revolutionary Pipe Purging Technology PurgeGate Valve

November, 2013—COB Industries introduced revolutionary new PurgeGate technology which is certain to be a game-changer in the world of pipe purging. Tandem inflatable pipe purging systems have proven to be the fastest, most effective method of pipe purging when welding stainless steel, chrome, titanium and other materials that require an oxygen free weld, but the potential risk of bursting the dams due to over-inflation has always been an issue…until now.

COB Industries, working together with Huntingdon Fusion Techniques of the U.K. has introduced PurgeGate valves which are proprietary devices that function like an in-line regulator or pressure reducer that prevents the bladders from over-inflating no matter what pressure or flow rate is used. ANY other type of inflatable purge dam can be ruined if the gas flow / pressure is turned up too high or if the purge valves are not set or maintained properly. The new Argweld® QuickPurge® II systems with PurgeGate are the ONLY true plug-and-play purge system with no valves to adjust or maintain, and no risk of bursting bladders due to over-inflation.

The benefits of inflatable purge dams (faster purge times, less gas consumption, etc.) have been well established and now those benefits can be utilized with a longer lasting, more durable system. To see how quickly these systems pay for themselves (ROI) click here.


If you would like more information or to schedule an interview, please contact Cletus O’Brien at (321) 723-3200 or email to

Mark Griffo No Comments

Qwik-Freezer Used For Repairs At Etihad Tower In Abu Dhabi

Qwik-Freezer Used For Repairs At Etihad Towers In Abu Dhabi

July, 2013—Contractors at the world-famous Etihad Towers in Abu Dhabi (pictured above) used Qwik-Freezer® Pipe Freezing Systems to successfully perform multiple freeze seals for piping repairs on the 39th level of Tower 4.

Freeze-Sealing (also referred to as “pipe freezing” or “ice-plugging”) is a process that involves freezing the contents of a pipe to create an internal ice plug to isolate sections of pipe for repair and maintenance, valve replacements, etc. This process eliminates the need to drain long sections of pipe and reduces down time for repairs. Freeze-Sealing was first used by the US Navy in the 1940’s and is now a common practice in building maintenance and countless application in the piping industries.

Qwik-Freezer® Pipe Freezing Kits utilize liquid CO2 to create ice plugs for freeze sealing of up to 8” pipe and are probably the most widely used system around the world. Qwik-Freezer® equipment has been manufactured by COB Industries, Inc. in Melbourne, Florida for over 40 years.

If you would like more information or to schedule an interview, please contact Cletus O’Brien at (321) 723-3200 or email to