UPDATED: Tesco CO2 incident - Looking at the Facts...

By R744.com team, Dec 22, 2010, 14:29 4 minute reading

A faulty joint led to the rupture of a piping connected to a CO2 refrigeration system newly installed in Tesco’s Walkden store on 12 December, first investigations indicate. Tesco confirms that the “isolated” incident needs to be investigated before rolling out more R744 systems. Industry sources dispel safety concerns: “This could have happened with any refrigerant.” U

On 12 December, a ruptured pipe connected to a centralised CO2 refrigeration system led to what was perceived by consumers standing near the system as an “explosion” involving smoke and a loud noise. Although no human suffered serious harm, the incident at the Tesco Extra supermarket in Walkden, Greater Manchester, provoked reactions in the HVAC&R industry in the UK and beyond regarding the safety of R744 commercial refrigeration systems. Leading UK media had picked up on the issue to report about an evacuation of the store after a sudden discharge of the refrigerant that had created white smoke and a “loud bang”.

“Isolated incident” to change corporate R744 strategy?

Talking to R744.com, one spokesperson of Tesco confirmed that indeed a pipe had split open and that this was the result of a faulty piping feeding the CO2 refrigerant to the freezer, not a system failure. The source also confirmed that the problem had been quickly identified and after another thorough check of the store’s whole refrigerant installations the store was reopened only a few hours later.

More importantly, this “isolated incident” would have no impact on the company’s plan to roll out more R744 systems across newly-built stores and “use CO2 refrigeration as planned”, the source stated. Tom Hoskin, Head of Corporate Media Tesco, however, did not want to either contradict or confirm this statement officially. Hoskin maintained that the decision about future refrigeration systems and any lessons learned from the component failure would need to be based on results from the ongoing investigation of the piping.

Faulty joint possible reason for piping rupture


Other industry sources suspect a faulty joint to be the reason for the refrigerant discharge. As reported by another Tesco spokesman talking to the BBC and reflected by commercial refrigeration experts in HVAC&R discussion forums, the joint in the pipe feeding a refrigeration unit had failed. The reason could hence be a new lock ring technology that has been in use to replace traditional brazed piping. If confirmed, the result of a failing joint – the rapid opening of piping and discharge of refrigerant - would have been the same for any other type of system, including using conventional refrigerants, such as R404A or R410A.

“This could have happened with any refrigerant”, one industry source confirmed, stating that with traditional refrigerants only the noise effect of the piping rupture would have been less pronounced. As also reflected in industry discussions, the accident could hence be a problem of fittings expanding at a different rate to the pipe. Even with continuous checks this problem would be difficult to track from the outside.

UK round table debate confirms the facts, reassures the industry

RAC’s Natural Refrigerants Round Table debate confirmed that a joint failure of a pressurised CO2 pipe was the cause of the incident at the Walkden store and that the incident should not be seen as a serious obstacle to CO2 development. The investigation is yet to determine whether the failure was the result of a mechanical defect or because of an error in the installation or maintenance procedure.

One round table delegate said: “Frankly had any fridge pipe gone with any type of refrigerant in it, it would have been a similar situation, with a bang and oil going everywhere”.

The participants concluded that the incident should serve as a reminder that working from industry-agreed standards is key and that standards for the new refrigerants should be a key part of the forthcoming Code of Conduct for Retail Refrigeration that the British Refrigeration Association (BRA), the Institute of Refrigeration (IOR) and Carbon Trust are putting together.

The British Refrigeration Association is already working to incorporate various retailers’ CO2 approaches into a set of harmonised training standards.

HFC/HCFC incidents show: Safety is key

How important proper installation and handling of any refrigeration system is for ensuring high safety levels for employees and consumers likewise has been demonstrated by several incidents in the US involving fluorinated refrigerants. Reacting to R744.com’s reporting on the Tesco incident industry experts in the US made reference to the following examples of system failures and grave consequences for human beings that were covered by the press this year and which involved installations using HFCs or HCFCs, refrigerants that claim decades of safe use:

MORE INFORMATION

By R744.com team (@r744)

Dec 22, 2010, 14:29




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