Suppression System

[nearlythere]

Has anyone any experience of or views on a suitable suppression system for an industrial deep oil fryer? There seems to be quite good claims about water mist systems but I am a little concerned about its oil cooling ability to prevent re-ignition.
The fryer is essentially enclosed other than where the raw material to be cooked is fed in and out and the equipment requires the location of the operating heads inside this enclosure.
The whole shebang is to be located inside a 2hr FR enclosure, as is required by the insurance company.

[kurnal]

Whats wrong with CO2 if the environment is enclosed?

[nearlythere]

I know where you are coming from K. It's not entirely enclosed. It has an opening at each end to allow the meat to go in, through the frying process and out again. It also has a flue. I am thinking it might take the oil a time to cool down below flash point and if the containment was air tight the Co2 could be the job.

[kurnal]

if they did have a fire would the oil have to be thrown away or is there a chance of salvaging it for futher use.

Is there potential for an ansul system?

Perhaps its time to ask the specialist installers what they can do- tyco et al.

I have experience of oil quenching in the steel industry and CO2 works well there but always in conjunction with dampers or lids. I recognise your flue may be an issue but if theres no flow into the base of the flue little CO2 will escape from the top?

Is this Mrs NTs new kitchen we are discussing? If so I would put it on the barbie and be done with.

[Mr. P]

No experience of enclosed systems for frying an ansul type would appeal to me. The contamination from a fire would mean total replacement in any case.

[David Rooney]

Ansul or Amerex would be my vote ...........

[nearlythere]

if they did have a fire would the oil have to be thrown away or is there a chance of salvaging it for futher use.

Is there potential for an ansul system?

Perhaps its time to ask the specialist installers what they can do- tyco et al.

I have experience of oil quenching in the steel industry and CO2 works well there but always in conjunction with dampers or lids. I recognise your flue may be an issue but if theres no flow into the base of the flue little CO2 will escape from the top?

Is this Mrs NTs new kitchen we are discussing? If so I would put it on the barbie and be done with.

There will be a draw of fresh air into the enclosure through the two meat feed apertures. Would be simple sorted if we could get these to close some way on actuation of the suppression system but the meat is delivered to and from the fryer by conveyor belts through the apertures and a dropping fire damper at these points would not be able to achieve a fire seal.
I have to say that these conditions are being imposed by the insurance company which wants the whole shaboodle enclosed in a 2hr fr enclosure. Don't ask about the apertures for the conveyor belts. For some reason that doesn't  seem to matter too much.

[nearlythere]

if they did have a fire would the oil have to be thrown away or is there a chance of salvaging it for futher use.

Is there potential for an ansul system?

Perhaps its time to ask the specialist installers what they can do- tyco et al.

I have experience of oil quenching in the steel industry and CO2 works well there but always in conjunction with dampers or lids. I recognise your flue may be an issue but if theres no flow into the base of the flue little CO2 will escape from the top?

Is this Mrs NTs new kitchen we are discussing? If so I would put it on the barbie and be done with.

They do accept that a fire could result in the loss of the oil but I would suspect they would be concerned by a contamination issue of a food stuff by any extinguishing media. They are keen to ensure that in the event of a fire the machinery can be cleaned up and the process got back into operation asap.

Ah yes the new kitchen bit you refer to. Mrs NT going away for a few days next week and I am getting geared up for a greasefest. Cant deep fry rabbit or bird food and I really do need to get some essential oils down me. My hair is losing its gloss.

[nearlythere]

Ansul or Amerex would be my vote ...........

Looking at all options David but have to bear in mind a media with can cool the oil. I have heard of a similar situation where they had a system where fresh cool oil was introduced  as the fire was being extinguished to help cool the existing oil.

[AnthonyB]

I don't usually venture into food production factories, but in the last I dealt with, which used similar conveyor fryers, but for fish, they had a two stage system, the first using 45kg of CO2 per line to try and extinguish the fire without contamination and an Amerex KP Wet Chemical system for Stage 2 to tackle a developing fire that the CO2 couldn't keep down. Water mist was used for the area outside the frying lines and for the ammonia plant areas.

Water mist is evolving with a variety of system types (low, medium & High pressure) and I'd contact some of the specialist manufacturers and installers for advice before totally ruling it out - you should get cooling from it as well. I believe some Birdseye factories are now protecting their conveyor fryers with water mist.

[kurnal]

So perhaps step 1 would be to understand the fault conditions, other causes and nature of the likely fire scenarios that might arise and having eliminated them as far as possible then provide a proportionate firefighting response to each fire scenario. If for example splashes of fat falling onto hot surfaces will cause small flash fires a local topical short burst of CO2 would extinguish the fire with minimum contamination and disruption to the process but if a serious fire occurs in the fat then the big guns come out, the process is stopped, the product is lost and the priority then is a system that will be sure to put the fire out to protect the plant and equipment and mimimise consequential losses.

I guess a list of malfunctions that might lead to scenario 1 might include splashes of fat onto hot surfaces, poor cleaning of fat residues or decomposition of oil leading to a reduced flash point, whereas failures of temperature controls, jamming of conveyors, use of wrong grade oil might lead to scenario 2 when the cooling of the oil becomes an option for the fastest extinction of the fire. There must be a whole range of other scenarios that can lead to a fire and a whole range of expensive solutions for all of them. There was an interesting legal case involving a popcorn manufacturing plant a couple of years ago that would be worthy of review.

http://alpha.bailii.org/cgi-bin/markup.cgi?doc=/ew/cases/EWHC/TCC/2011/1936.html&query=trebor+and+bassett&method=boolean

h

[nearlythere]

Thanks people. Meeting a couple of installers shortly to discuss their systems.

[Fishy]

Recommended a water mist system for an enclosed conveyor fryer containing Palm Oil at a large food production factory - we did a verification burn on a full-scale mock-up to demonstrate its effectiveness and it worked fine.  Can't remember the details of whose system it was (it was a good few years ago) but I can confirm that the tests we did showed that a properly-designed water mist system is capable of extinguishing a large fire of this type & preventing re-igniition.

As always, with water mist it's the evidence of performance that's key - we used NFPA 750 as the spec, I seem to recall - hence the need for the full-scale test.

[nearlythere]

Recommended a water mist system for an enclosed conveyor fryer containing Palm Oil at a large food production factory - we did a verification burn on a full-scale mock-up to demonstrate its effectiveness and it worked fine.  Can't remember the details of whose system it was (it was a good few years ago) but I can confirm that the tests we did showed that a properly-designed water mist system is capable of extinguishing a large fire of this type & preventing re-igniition.

As always, with water mist it's the evidence of performance that's key - we used NFPA 750 as the spec, I seem to recall - hence the need for the full-scale test.

How did it prevent re-ignition Fishy?

[Fishy]

Pure cooling by the water, I presume - to be honest we didn't really analyse why the kit worked; we just established that it did.  We let the fire get nice and hot before the system was triggered, so far as I recall (bearing in mind we're talking 12-15 years ago). 

Can't recall the discharge duration, nor whose the kit was but it was a stored presurrised gas system with not that many bottles. I seem to recall that knock-down & extinguishment was fairly rapid & there was no dramatic reaction between the oil and the water.  Tray size was about 4m or 5m x 2m-ish & it was partially enclosed to about 1.5m height above the oil (to mock up the 'real' configuration).  Was a UK installation using NFPA 750, which at the time basically obliged you to verify performance by appropriate testing (not sure whether it still does).