12 replies to this topic

[jamesH]

Dear Fellow members, 

 

Please could you tell me what supermarkets recommend as a preferred rinse pressure for wash hoses in the food process area?

 

We have an audit very soon and trying to interpret the following (from Tesco TFMS Section 9.7.1). Also My manager is quite worried about it: "High pressure hoses must not be used due to aerosol generation/movement of debris"

 

What do they define as High/Low/Medium pressure in bar/psi???

 

Also, if anyone knows specific pressures recommended by other standards, I would be really glad to know, as I am struggling to find this.

 

 

Thank you for your help.

 

James

[Charles.C]

Hi James,

Welcome to the Forum !

Do you mean compressed air washing units or direct from mains type hoses ?

[jamesH]

Thanks Charles, the equipment in question is pressure washers (around 100bar).

 

We do have hoses direct from mains in one part of the factory (3 bar), but cannot clean the rest of the factory with 3 bar, it just is not effective.

 

Look forward to hearing from you.

[RMAV]

Being in the US, I think in psi.  100bar = 1450 psi.  I went to a training years ago where an expert with one of our larger sanitation chemical companies presented.  If I recall correctly, one of the slides showed psi vs aerosol of microbes where the significant aerosols started around 500-600 psi and had increased exponentially around 1800psi.  It quoted a study that I have yet to obtain for my library.  If anyone knows of this study or one like it I'd love to know where to find it!

 

I would think 100bar would be in their high pressure range.

[Charles.C]

Hi James,

 

Having used mobile units rated at ca. 30 bar and 100 bar respectively i can appreciate both yr comment and Tesco's.

 

IMEX a 30 bar unit which was designed for home cleaning of cars had insufficient power to clean floors, friers etc but appeared, visually, relatively hygienic with respect to "aerosols". It was also mechanically inadequate for long sessions, ie not "heavy duty".

In contrast, 100 bar worked beautifully but was accompanied by a cloud of spray and would nearly knock someone off their feet if misdirected. "Training" for safety and non-interactive usage was necessary.

 

From memory the output presure / direct force was adjustable via the nozzles but, predictably, reduction threw away the maximum penetration.

 

I fear a tricky compromise from a  Tesco POV but maybe dependent on yr target.

 

PS - posted before i saw Post 2. Maybe the interpretation  of "aerosol"  varies ?.

 

PPS - another quote -

 

Generally high pressure cleaners work at around 70 to 200 Bar (1000 to 3000 psi) but the volume of water is just as important Today's machines use around 8 to 21 Litres per minute - too little volume and the cleaning effect (calculated in kW) is simply reduced. Specialist machines of up to 20,000psi are also available

http://www.morclean....ghpressure.html

Edited by Charles.C, 20 June 2016 - 03:28 PM.
original quote prob. misconstrued

[jamesH]

Thanks RMAV, that helps, I would also be very interested to see it if it could be found! That pressure range is useful, thanks.

 

Thanks Charles, According to that part of the standard though, it appears 5.5 bar is 'High pressure'. But if in the para I referenced it says that -  'high pressure' must not be used - then why are they asking for backflow prevention fitting, when they immediately outlaw that pressure???

 

It would seem the 2 times they mention 'High pressure' they mean 2 different things??

 

Please help me interpret this!

[jamesH]

(sorry, I meant to say, *do not* need backflow -prevention fitting)

[Charles.C]

addendum - JFI - there appears to be some variance of opinion as to pressure terminologies. This is from a food plant sanitation text -

 

 high pressure cleaner.png   126.53KB   1 downloads

[Charles.C]

Thanks RMAV, that helps, I would also be very interested to see it if it could be found! That pressure range is useful, thanks.

 

Thanks Charles, According to that part of the standard though, it appears 5.5 bar is 'High pressure'. But if in the para I referenced it says that -  'high pressure' must not be used - then why are they asking for backflow prevention fitting, when they immediately outlaw that pressure???

 

It would seem the 2 times they mention 'High pressure' they mean 2 different things??

 

Please help me interpret this!

 

After re-reading i also decided that the applications being discussed were different. So the terminology "high" might be different also. Hence my edit. If otherwise, yr guess is as good as mine.

 

also note post 8.

 

Tesco produce a huge range of documents / Library relating to individual aspects of their general standard. There may be finer details in such document if it exists. Some other UK posters here are following Tesco so may have more direct information if you wait a little.

[RMAV]

Charles C. makes a good point that "high" can be different according to the application.  We should probably back up some and identify the what, where, how, and why, and the subsequent risk assessment.  Among other considerations:

 

-soils

-equipment

-facility/room/conditions

-proximity to other equipment or product (raw or finished)

-risk to product

-etc.

[Charles.C]

Hi James,

 

I could not find any official/semi-official classification schemes for classifying output of pressure cleaners in food industry use. Rather surprising if true.

 

I looked at a few (ca. 10) articles on food plant,  portable  units. The data is predictably scattered. Around  70%  of specs  mentioned fell into these approximate ranges –

 

(1) Low Pressure units -  maximum delivery pressure not exceeding 15-25 bar

(2) High Pressure units -  delivery pressures of 30-50 bar up. (“Up” was a maximum of 200bar but commercial units can go higher of course).

 

The above are subject  to revision  if any more details forthcoming.

 

Tesco may be more conservative than the above of course. Interesting to know.

 

As noted earlier, 100bar is likely to be designated  “high” although, personally, I would not put 30bar in the same grouping  from a performance  POV. As previous post the individual choice is likely determined by the specific objective/difficulty.

 

As far as aerosols are concerned, this is a recurring warning in almost all the articles but there seems little recent  data available other than perhaps in the non-public domain.

 

FYI I have attached one example of high/medium/low suggested pressures to illustrate rather than typify. Plus another relating to micro. cleaning efficiency vs pressure which has a side-mention to aerosols.

 

 Effective_Cleaning_and_Sanitizing_Procedures, JIFSAN.pdf   1.49MB   25 downloads

 effectiveness cleaning techniques to remove biofilms.pdf   295.52KB   23 downloads

 

PS - note that, as given, the data in my Post 8 fails (2) but could comply with (1).

[jamesH]

Thanks Guys that is very useful, really appreciated your help on this. we will aim for >5.5bar in our low risk zones and where higher pressure is required we will carry out the best preventative measures we can.

 

Have a great day, and thank you again.

[Charles.C]

Thanks Guys that is very useful, really appreciated your help on this. we will aim for >5.5bar in our low risk zones and where higher pressure is required we will carry out the best preventative measures we can.

 

Have a great day, and thank you again.

 

Good Luck !

 

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