Co2 Explosion in Tesco store Manchester

[supermarketguy]

Hi all,

Just read this on line,

HUNDREDS of people were evacuated from a supermarket and shopping centre after an explosion which left eight people injured.
Shoppers ran out in panic from the Ellesmere Centre in Bolton Road, Walkden, after a fridge apparently exploded in the new Tesco Extra supermarket.
Witnesses described hearing a loud bang and seeing the shop, which was packed with Christmas shoppers, fill with white smoke.
It is thought that a pipe in a refrigeration unit ruptured and spewed carbon dioxide into the store, which only opened in September at a cost of £25M.
Eight people were treated by paramedics after the incident for shock and smoke inhalation.
No-one suffered any serious physical injuries, but a pregnant woman, a 76-year-old man and two asthmatics were among those treated.
Five of the casualties were taken to the Salford Royal Hospital and one to the Royal Bolton Hospital as a precaution.
Firefighters from Farnworth and Eccles attended the incident, which happened near the meat aisle at about 3.10pm yesterday.
Security staff evacuated the whole shopping centre because of the possible hazardous gases that had escaped from the ruptured unit.

This may make up this particular retailers mind on which way to go with this particular system.

Supermarketguy

[Brian_UK]

It must be true, the BBC reported it as well.
http://www.bbc.co.uk/news/uk-england...ester-11979213

[cool runings]

.

I'm not suprised it has happened and I'm glad nobody was hurt.

C02 is going to be a big part of supermarket refrigeration, but reports like this may just convince the big names that C02 is not worth the risk.

Same reason Ammonia is not popular in shops...

All the best

coolrunnings

.

[lawrence1]

It was bound to happen,,,very luck no one was badly hurt.Can someone find out the cause of the leak?

[fridge-spark]

I heard it was a lok ring that failed. I'm not sure this is true but I do know Tesco have them fitted on installation.

I hope no one was seriously injured. But it dose raise the question what would have happened if an engineer was working on / near the pipework at the time.

[mad fridgie]

May I ask are these CO2 systems trans critical, or cascade based system (Main CO2 system at -10C, pump recirc for MT applications and a deadicated LT compressor)
If is the second option then your are working with system pressure similar to the high side of a R404a system. (20 -30 bar), so I see no need to scare anybody about CO2 usage, if transcritical (above 75bar) then these are pressures most are not used to dealing with.

I do remember on a number of occassions both in the UK and NZ when a liquid line flares had given away and filled a supermarket with R502 and/or R22 and went with a precieved bang.

CO2 is not explosive.

[desA]

I have always been surprised that transcritical hot-water heat-pumps have not seen more press - especially in Japan where they seem prevalent.

[Magoo]

Something was bound to happen that the rocket scientist did not predict, low ambients etc., sad really.
I will stick with ammonia, and drive my car with it like a NOS effect.

[RONB]

I have installed/commisioned quite a few sub crit systems and they have all been braized pipe systems. I know it is a nightmare fully purging and getting 100% penetration etc. But I dont care what anyone says a correctly braized pipe joint against ANY mechanical joint wins hands down. Just imagine if the cabinet in question was a FGD and the evap gave way with flying glass etc,it just dose not bare thinking about. As Magoo states the rocket scientists have a lot more R+D to do on CO2 systems. Yes I understand the benefits in running cost/gas price etc, but at the moment the negatives outweigh the positives in my opinion.

[lawrence1]

So does anyone know if it was a trans critical or sub critical/liquid pump m/t and what actually let go?

[Blinky]

it was trans-crit, a vulcan lock ring blew, and the pipework was a tangled mess on top of the cabinets as the tile and bed wasnt clipped down sufficiently.
i dont trust these fittings at all, i have had them blow on 404a, however Vulkan always say it it always human error why they fail!!

[bill1983]

"this may just convince the big names that C02 is not worth the risk"
come on! co2 was used for the first 60 years of commercially viable refrigeration on board ships
installed correctly, it's no more dangerous than hydrocarbons in your average integral. The pressures are only scary until you get used to them. The engineers of the early 20th century had to deal with it. surely we have advanced from then.
Admittedly lokring, if it was in this case, may have to revise their installation procedures. otherwise, strength test procedures and insurance certifiation may need investigation.

[Keef_Controls]

A Vid...

http://menmedia.co.uk/manchestereven...rd_tesco_store

I reckon most of joe public thought it was terroist attack ! not good....

[supermarketguy]

Hi All,

Now hearing on the grapevine, that this particular retailer is ending its C02 installations. It appears that they may fufill their current commitments into next year and then these installs will cease

Where they will go next, will be anybodys guess, Ideas on a postcard please!!!

[cool runings]

"this may just convince the big names that C02 is not worth the risk"
come on! co2 was used for the first 60 years of commercially viable refrigeration on board ships
installed correctly, it's no more dangerous than hydrocarbons in your average integral. .

C02 is one way forward and it is a good refrigerant as refrigerants go.

C02 has been used for decades, but it is quite new in the supermarket industry.

Now as for my "this may just convince the big names that C02 is not worth the risk" statement.

C02 and Ammonia are unknown to lay people, they do not know the benifits but they hear the scare stories and think they kill..

Now we have had an "Explosion" as reported in the press. A fitting burst, but people only read C02 = 8 injured.

You try selling C02 to Tescos now!!!!!


So before you jump on my coment just remember I'm sold on C02, its the public who shop in these places and if a few of them
are heard to be saying I won't shop in there, it has fridges that explode...

coolrunnings

.

[coolhibby1875]

Hi All,

Now hearing on the grapevine, that this particular retailer is ending its C02 installations. It appears that they may fufill their current commitments into next year and then these installs will cease

Where they will go next, will be anybodys guess, Ideas on a postcard please!!!

if Tesco end its comitment to c02, you can bet the rest will too, and if this is the case it will be a disaster for the copanies that deal with supermarkets, as some have invested heavily into the co2 r&d, i can here engineers saying this stuff is safe if used properly and it is, however throw the general public into the mix and nothing is safe, store managers putting presure on engineers who havent the balls to say no and pressured into cutting corners and kaboom, another fridge blows.
i know every store that gets installed is different from any thats already been done, so lots and lots of tweeking controls here and there, this makes things interesting as controler manufactures and making it up as they go along!! this stuff is great for industrial equipment, yes!! for servovers and full glass door freezers in busy retail outlets!! I dont think so

[panda]

Well done Asda!!!!

They did 1 and decided stick with simple fridge. 1 scroll pack above 1 island, low entrained volume,no major issue if comp on pack fails and 1 engineer req to replace scroll if faulty. Hear hear Mr Churchyard!!!!!!!!! its about time you won all at the cooling awards in 2011!!!!!!!!!!

[desA]

In my view, CO2 trans-critical systems suffer from excessively high pressures. This has always been a concern to me, I have to admit. If this piping had been in another location, a few shoppers could very well have been seriously injured.

This aspect has to be considered for future implementations. Imagine the fiasco a few years down the line, as systems begin to wear.

Now translate this to trans-critical hot-water heaters. If the units do not use sanitary grade gas coolers, people will most definitely be injured. Not good.

[lawrence1]

Worse job around at the moment would have to be the old lok ring salesman.

[750 Valve]

Scary Co2..... blah blah blah....

A spoon full of cement is urgently required for Tesco and whinging fridge engineers the world over.

[coolhibby1875]

Scary Co2..... blah blah blah....

A spoon full of cement is urgently required for Tesco and whinging fridge engineers the world over.

due to some privacy settings on the company pc, i cannot post a link to footage taken from the store at the time of the explosion, but i can assure you that the women and children were not thinking blah, blah, blah when they were running from the store screaming in tears, i dont want to get into another debate on here with someone, however because you have C02 in stores down under which run perfectly well, that does not mean engineers all over the world are running scared of the stuff, if memory serves me correctly 2 engineers have been killed in Denmark using C02 and now this over here, no one wants to be hurt whilst out buying a pint of milk, and i can assure you as long as the diluted workforce of the refrigeration industry here in the uk are sent out to repair this stuff that is what will happen, there are fridge enginers out there not capible of looking at a simple pack on r404a taking a 2 day course on C02 then being let loose on the equipment, i know lots of guys who have done the training from many different companies and have the cert to say they are compidant to work on C02 plant and quite frankly they aren't capible of correctly changing out a pot on an integral cabinet, again i dont blame the engineers for this and i use the word ENGINEERS very loosely, i blame the companies for driving the cost of contracts down to a point that low that they canot pay the money to keep the real engineers within the industry in the supermarket sector, now thats whats SCARY!!!

[mr.cold]

I'm sorry, I may be wrong but I didn't find any direct reference to CO2 in the linked articles in previous posts.
Are you sure we're talking about a transcritical CO2 system?
If yes: usually the part of the circuit inside the store is at low pressure, that means in the worst case (dx expansion and long stand-by of the system) 40/45 bar versus a PS= 30 bar of a standard refrigerant system: not such an extraordinary difference... as long as same safety corefficients for dimensioning are used.

Bye

[fridge-spark]

I'm sorry, I may be wrong but I didn't find any direct reference to CO2 in the linked articles in previous posts.
Are you sure we're talking about a transcritical CO2 system?
If yes: usually the part of the circuit inside the store is at low pressure, that means in the worst case (dx expansion and long stand-by of the system) 40/45 bar versus a PS= 30 bar of a standard refrigerant system: not such an extraordinary difference... as long as same safety corefficients for dimensioning are used.

Bye

The intermediate pressure after the high pressure valve and up to the evaporator expansion valves (liquid line) has a PRV rating of circa 75 bar I guess that is why lokring fittings are used and pipework is not brazed.

[fridge-spark]

Hello Coolhibby,

I totally agree.

due to some privacy settings on the company pc, i cannot post a link to footage taken from the store at the time of the explosion, but i can assure you that the women and children were not thinking blah, blah, blah when they were running from the store screaming in tears, i dont want to get into another debate on here with someone, however because you have C02 in stores down under which run perfectly well, that does not mean engineers all over the world are running scared of the stuff, if memory serves me correctly 2 engineers have been killed in Denmark using C02 and now this over here, no one wants to be hurt whilst out buying a pint of milk, and i can assure you as long as the diluted workforce of the refrigeration industry here in the uk are sent out to repair this stuff that is what will happen, there are fridge enginers out there not capible of looking at a simple pack on r404a taking a 2 day course on C02 then being let loose on the equipment, i know lots of guys who have done the training from many different companies and have the cert to say they are compidant to work on C02 plant and quite frankly they aren't capible of correctly changing out a pot on an integral cabinet, again i dont blame the engineers for this and i use the word ENGINEERS very loosely, i blame the companies for driving the cost of contracts down to a point that low that they canot pay the money to keep the real engineers within the industry in the supermarket sector, now thats whats SCARY!!!

[vladsabin]

Scary yes, High Pressure yes and if this were not enough resons against CO2, lets not forget that an installation with CO2 is far more complex.
A more complex system needs more atention for maintenance.
Even more the price of the components and their maintenance is higher.
This would actualy rise the potential risk of an accident.

Let's not forget that CO2 was used before, but they did discover the ***** gases because CO2 was a problem.

[supermarketguy]

Hi All,

I have to say C02 as a refrigerant, from what i have seen does what it says on the tin and is an extremely efficent refrigerant. I have no real issues working on these systems, it is more about the quality of the installation and the equipment that needs to be concentrated on and that all contractors involved are given adequate commissioning time on site to check everything over.

I have been involved in a few jobs and i am still getting commissioning times cut on them and then the reailler gets all uppity, when there is problems on and after opening day.

All the retailers have coe(centre for exellence) and have published commissioniong time scales, but when brought to site meetings, all they do is use them for scrap paper, as the store development managment dont have the balls to give us more time to commission if the builder holds us all up.

I am not saying that the problem that has occured in the store in question is down to commissioning time, but people are in a hurry to install everything as the retailer presses to reach their deadlines and things can be missed.

Rant over!!!!

[Paul maye]

I work on co2 packs at tesco I won't say what company I work for but they have had me working on the stuff with no training,it took just over a year to have my one day course from star refrigeration.so does that make me qulified? Think not...still ****s me up every time,anyone who says you should tell your company or health and safety manager the situation do not work for a big fridge company cause it falls on deaf ears..some day someone will kop it cause we have not enough engineers and tesco just keep on demanding and demanding,it was only a matter of time..

[mad fridgie]

I have had problems with lokrings, but I must say the problem was human error. They are great when you have easy access, "on a bench" but out on site where room for positioning is not always ideal,is where the problem lies.
You think that your tubes are inserted fully, but the time you jiggle you tool and stress the piping, the tubes are not always fully inserted. You end up with only a very small point of contact between the tube and the lokring crimp.

[jonjon]

must of been the samw firm that put up the roof in tesco in s****horpe


http://www.thisiss****horpe.co.uk/ne...l/article.html

[750 Valve]

Coolhibby it is not Co2 that is the problem here - a joint failed so look at why it failed, learn from it and move on. I have seen people run from a 404a leak just like that when a builder sawed through some underground lines - was there ever any thought of not using R404a???? I have seen header end caps blown off and discharge lines peeled open - all with r404a - once again was there ever any thought of not using R404a???

Don't get caught up in the whole scary Co2 thing - take the time - instead of whinging, to help those techs less mentally endowed than yourself by giving them pointers on what NOT to do, take the time to point out (and document) your concerns and the implications of sending untrained staff there to work on the equipment - no OHS rep wants to have a death at work on their head and they will do anything needed to ensure that they make the required recommendations to alleviate any exposure (ie cover their arses), this can only be a good thing as it means more training and exposure for techs.

Now I agree that all we have is a short course and we are let loose on Co2 systems, problem is you need to LISTEN and LEARN in the courses - you can lead a horse to water but you can't make it drink, aside from the safety concerns there is nothing you will learn at a co2 course that you should not have already comprehended from basic training during your apprenticeship (critical points, triple points, enthalpy diagrams, etc) so how many times do you need to be told that it is high pressure and can kill you? Guess what hydraulics are high pressure and can kill you too - look at how common they are! If you look at the amount of ammonia out there and the courses for that, given somewhat parity between the training required to service R744 and R717 (at least in Australia) why do we not have a groundswell of people saying how bad R717 is???? Engineers the world over can cope with it - all you need to do is show the proper respect, so too with Co2. It seems like the installer did not pay the proper respect to the systems high pressure requirements when installing the Lokring if it failed - this can and will come down to time and pressure from the likes of Tesco wanting a store open but this unfortunate accident needs to be highlighted as an example and the installing contractors need to stand up and say NO, safety first and that requires adequate installation, pressure and integrity testing and then commissioning time. Put the pressure back onto the builder and not the fridgie.

Bottom line from me is don't whinge - learn from it and do something about it so it doesn't happen again.

And for those who say "oh he mustn't work for a supermarket company - get real they don't listen" I have been in the supermarket game for 10 years and some of that working directly for a major chain - let me tell you they are anal about safety and **** scared someone will get hurt in their stores - contracting companies need to grow a set and use it to their own benefit, once a safety concern is documented it needs to be addressed.

[750 Valve]

Another factor is putting the cart before the horse.

Yes we can do sub and transcritical systems and they work. Do we have the knowledge, skills, training, parts infrastructure, materials and tech support to make it a reality right now??? Maybe not.

Maybe we hold off on transcritical until the trade catches up with sub critical (less pressure, less exposure to new materials and joint methods) or if we go trans build in a safety factor, ie steel pipe all welded and x-rayed.

Because an engineer sits in an office and says "I want", does it mean he gets? As I mentioned before contractors need to get real and grow a spine - if it means staying out of the Co2 game until they are confident to enter then so be it. There are quite a few supermarket contractors over here that have done just that, their doors are still open and they still have employees working in supermarkets that get paid each week.

So too the individual techs, if it scares you to work on it then don't! Try to explain to your company and if they won't listen then leave. Its fine to say "but there are no jobs out there in this climate" - these are the same people saying they don't want to die at work - so don't and actively do something about it. Go work A/C for a while until the right job comes along.

Don't get me wrong - this is a serious incident and I'd hate to think what would happen if someone was actually working on the case at the time but if the knee-jerk reaction is to ban co2 in all Tesco then what do they do about the existing installations - do they need to be investigated from an integrity standpoint? Do you rip them out? Eventually someone else is going to come across the same thing and to me it makes more sense to get to the root cause of the problem before taking any action - sure its fair enough to put any transcritical stores on hold until a full investigation can be done but without going through the motions there is a possibility this can happen again on another site. And then if the problem can be resolved and provide minimal exposure to a reoccurrence then why stop rolling out Co2 as the exposure to another similar incident has just been rectified?

Too many people sit back and whinge these days and won't do a thing to help their own cause. If nobody ever speaks up then nothing will ever change, supermarket retailers should not be feared or loathed by engineers - its how we CHOOSE to make our money and the retailers are full of people just like you and me - blokes that put their pants on one leg at a time, who have families and lives outside of work - sure they are usually under a good bit of pressure at work (this is the nature of retailing on a large scale) and can be a little short at times but they are human just like you and me. The decisions they make can affect millions of people and this not only needs to be understood but can be used by smart contractors to their advantage or to help shape an outcome that is a win/win for all those involved.





***** END OF RANT *****

[desA]

I'm seeing lots of pro's & con's in preceding posts. What is becoming obvious is the need for a solid manufacturing, building & maintenance code for these high-pressure machines - whether CO2, R404a - whatever.

Codes exist in the petrochemical industry - for very good reason. We work with pressures in excess of 160 bar, but, very, very carefully. No shortcuts, or dodgy lockrings.

[mr.cold]

The intermediate pressure after the high pressure valve and up to the evaporator expansion valves (liquid line) has a PRV rating of circa 75 bar I guess that is why lokring fittings are used and pipework is not brazed.

Good point Fridge -spark, thak you for explanation.

Bye

[coolhibby1875]

hi valve 750 again i stress the fact, i belive that C02 is good economical refrigerant, and should be rolled out more, however i find that having parts in fridges less than 12 inches away from where kids will be moving around containig gases in excess of 700 psi is just not good, parts will always break ect ect, and i think its wrong of you to compare r404a in a multideck chiller at 170 psi (liquid) and 45psi (suction) to 700 psi on co2, getting hit by a bit flying debris at 170 psi will hurt you possibly take out an eye, getting hit by a flying debris at point blank range at 700 psi will kill you.
i agree that your point of improving on the systems is the way forward, however tesco and the likes do not have the time to do so, whatch the footage of the people running from the building and tell me if you were a director of tescos would you want this to happen again, they do not need this type of publicity and more importantly they do not need to be banged up in the courts on lawsuits with people being hurt buying a pint of milk!!

[Wingco]

Have heard it was due to a compression fitting on copper to copper conection failing. Cannot confirm this is true but given the nature of the failure this would explain what has been reported.

If joints are correctly made, compression or brazed there should be no such issues. Personally I would prefer to see brazed connections where ever possible. If these fail, they do not fail as a rue catastrofically, but compression fittings could.

There is no issue with Co2 as long as standards are adheared to and followed and correctlly engineered. There are many other industries out there that use far higher pressures without incidents.

Co2 can only be good for our industry as long as the training given is sufficient.

[750 Valve]

and i think its wrong of you to compare r404a in a multideck chiller at 170 psi (liquid) and 45psi (suction) to 700 psi on co2, getting hit by a bit flying debris at 170 psi will hurt you possibly take out an eye, getting hit by a flying debris at point blank range at 700 psi will kill you.

Mate its all relative to the burst pressure (actually to the design pressure) of the pipework carrying the refrigerant. As i said before perhaps an alternative pipe and jointing method is required to ENSURE things like this cannot happen.

As I have said before I have seen copper peeled open due to liquid hammer on a 404a system, the same lines that are less than 12 inches away from the kiddies getting their milk with the same potential for an incident. Now the leak that ensued sure scared the hell out the people that were present, evacuated the shopping centre and made the nightly news.... I don't see a big difference in the people's reactions in that video. The problem was the piping method used - not the R404a in the lines.

It seems you just do not understand - it is not the refrigerant, it is the manner in which the installation has taken place that has created the risk. By your logic (blaming the refrigerant) all we should have is chilled glycol pumping through cases at 2 bar as anything else has exactly the same potential, so too air conditioning on that nastily high R410a - you think we have untrained staff in supermarkets, look at all the cowboy A/C guys getting around.

[fridge-spark]

The main issue here is cost. Should the entire installation be steel and tig welded? The only real issue with CO2 is containment.

Mate its all relative to the burst pressure (actually to the design pressure) of the pipework carrying the refrigerant. As i said before perhaps an alternative pipe and jointing method is required to ENSURE things like this cannot happen.

As I have said before I have seen copper peeled open due to liquid hammer on a 404a system, the same lines that are less than 12 inches away from the kiddies getting their milk with the same potential for an incident. Now the leak that ensued sure scared the hell out the people that were present, evacuated the shopping centre and made the nightly news.... I don't see a big difference in the people's reactions in that video. The problem was the piping method used - not the R404a in the lines.

It seems you just do not understand - it is not the refrigerant, it is the manner in which the installation has taken place that has created the risk. By your logic (blaming the refrigerant) all we should have is chilled glycol pumping through cases at 2 bar as anything else has exactly the same potential, so too air conditioning on that nastily high R410a - you think we have untrained staff in supermarkets, look at all the cowboy A/C guys getting around.

[GreenCooling]

Thank you 750 Valve for being such a sensible voice of reason in response to some of the misplaced speculation on the future of CO2 from more excitable participants, remarkable that in spite of frequent similar failures of R22 and HFC systems some people are so quick to rush to judgement on CO2.

Certainly the change to higher pressure gases presents challenges for the industry, and there will always be laggards that resist rather than embrace change in any field. The critical point is that there are lessons to be learnt from this incident, and all the comments about the need for better training deserve to be heeded.

Life long learning and keeping up with new developments is a requirement in any profession - engineers exist to solve problems and deliver safe systems to meet the needs of their customers and society. It's just silly to be suggesting that CO2 is all too hard and suggest the industry should hang on to the environmentally damaging refrigerants that all responsible users are rapidly trying to move beyond.

In case anybody missed it the global commercial refrigeration industry, under the umbrella of the "Consumer Goods Forum" announced on day 1 of the Cancun climate conference that they want to go HFC-free by 2015 (admittedly they've left some wiggle room in this goal) and move to natural refrigerants. So anyone wanting to do business with these 400+ global companies would be well advised to adopt an innovative mindset and invest in the training needed to handle high-pressure and flammable refrigerants.

Those interested in keeping informed on this incident may like to check out the story at r744.com/articles/2010-12-15-tesco-co2-incident-looking-at-the-facts.php and their follow up articles...

[phil Landon]

Hey there, Have been working on CO2 systems for a couple of years and all our pipework is brazed, dont have a problem with the system itself as it works really well. It sounds like the lok-ring coupling was the culprit as reported on R744.com. That comes down to using a new type of coupling, maybe they should go back to the old tried and true methods of pipework

[Mark]

www.r744.com/articles/2010-12-16-british-refrigeration-association-to-develop-co2-training-standards.php

www.r744.com/articles/2010-12-15-tesco-co2-incident-looking-at-the-facts.php

www.racplus.com/news/industry-in-discussions-to-produce-co2-training-standard/8609176.article

[TriplepointPerk]

hi all,

i have to say c02 as a refrigerant, from what i have seen does what it says on the tin and is an extremely efficent refrigerant. I have no real issues working on these systems, it is more about the quality of the installation and the equipment that needs to be concentrated on and that all contractors involved are given adequate commissioning time on site to check everything over.

I have been involved in a few jobs and i am still getting commissioning times cut on them and then the reailler gets all uppity, when there is problems on and after opening day.

All the retailers have coe(centre for exellence) and have published commissioniong time scales, but when brought to site meetings, all they do is use them for scrap paper, as the store development managment dont have the balls to give us more time to commission if the builder holds us all up.

I am not saying that the problem that has occured in the store in question is down to commissioning time, but people are in a hurry to install everything as the retailer presses to reach their deadlines and things can be missed.

Rant over!!!!

hear hear!!

[trampus]

This was bound to happen sooner or later,the higher the pressure of refrigerants the more likely a rupture will happen. I may be wrong but Co2 will not take over as a serious refrigerant.

[CAPTAINBIRDSEYE]

Cant wait to see the HSE report mind you i tend to agree the high pressures i.e upto 75KPa 0r approx 1100 psi PRV on the low side is more than a tad silly its verging on crazy. heard all the stats etc but assuming were talking about the external compound trans critical packs

[panda]

Guys

Anyone know how much this has cost tesco? Would not have happened under Dave Downs. Are Space picking up the bill for the loss of trade me expects around 1 million?????? PS don't crimp when you can braze....

Regards

P

[Spencer.Guy]

Guys

Anyone know how much this has cost tesco? the bill for the loss of trade me expects around 1 million???

I know Tesco is quite profitable, but the store only lost 40 minutes trade, 15.20 to 16.00, then re opened at midnight.

They couldn't possibly turn over 1 million in 40mins let alone make a profit of 1 million.

Judging by the size of the store, over 100,000 sqft, I would expect they only turn over around 2 to 2.5 million a week max.

I would also expect that the publicity from this has come out fairly neutral overall, yes they had an incident, but now everyone knows about co2 and that Tesco are using it and that they have a new store in Walkden..
.

[acb]

750, im currently training on co2 in scotland, and got to side with coolhibby on this one.

its not about the co2 itself, its all about the chain of events after a company is awarded the install contract.

firstly, contracts are awarded to the lowest bidder and not the company with the best trained engineers, and from experience these companies (2 in particular) cant even put in a 404a sytem that doesnt leak, why?? because in order to win the contract with lowest bid they cant afford the best engineers nor can they afford to spend any more time on site than absolutly neccessary or they loose money.

secondly, its clear that cases being put in are the cheapest going, cos the case manufacturers cant even get something as simple as getting the water to flow towards the drain correctly, this just shows even more cost 'savings' are being implemented.

add all this together and boom, someone gets hurt, i dont want that to be my wife or kids.

[GGMarquez]

The difference between CO2 designs in Denmark and the one from Tesco, is that the working pressure in cases (doesn't matter if it is a transcritical or subcritical installation) never exceeds that of 30-35 bar. That is not much higher than MWP of R404A. All standard components can cope with that. I think the discussion should be about system configuration and not CO2 as a refrigerant.

[multisync]

must of been the samw firm that put up the roof in tesco in s****horpe


http://www.thisiss****horpe.co.uk/ne...l/article.html

Newsflash::

Tesco to ban roofs!

[taz24]

The difference between CO2 designs in Denmark and the one from Tesco, is that the working pressure in cases (doesn't matter if it is a transcritical or subcritical installation) never exceeds that of 30-35 bar. That is not much higher than MWP of R404A. All standard components can cope with that. I think the discussion should be about system configuration and not CO2 as a refrigerant.

I think that the systems are the same.

Running pressures do not rise that high.
But standing pressures do???

The tesco job failed from what appears to be a faulty or poorly fitted joint??
That joint coud have failed with any refrigerant behind it

I bet when it is looked into it will come back to the guy who installed the joint
Someone will be blamed and then we will carry on as normal untill the next incident (if there is one).

taz

Ps valves and joints failing is not new.

I was once called to a supermarket with R22 subcooled liquid compound packs and the hot gas defrost
mag valve had blown completely off.

High pressure, misty refrigerant vapour vented into the store from the top of a case.

The fire crews were wearing BA equipment and were not too keen on me going in I walked
in unsupervised by a side door, 3 valves, 30 secs later = all sorted.

Chief fire officer threatend to report me publicly but thanked me when we were away from the crowds

Red tape stops the fire services using civilians, even if they are more experienced than themselves.

taz

.

[tajger]

The difference between CO2 designs in Denmark and the one from Tesco, is that the working pressure in cases (doesn't matter if it is a transcritical or subcritical installation) never exceeds that of 30-35 bar. That is not much higher than MWP of R404A. All standard components can cope with that. I think the discussion should be about system configuration and not CO2 as a refrigerant.

I'm quite sure you are using Green&Cool trans-crit machines in Denmark, and the liquid line working pressure is higher than 35 bar. I'm looking at one right now. Pressure is as follows:

After gascooler: 62 bar
Liquid line: 48 bar
Suction for cooling: 24 bar
Suction for freeze: 11 bar

Outdoor temperature is -9C.