Compressed Air Filtration

What is an acceptable micron size for compressed air filters? 

This air is in contact with a soy protein isolate powder.

SQF has no specific standard. We currently use 0.01 micron primary filter.

The 0.01 is really quite perfect for the application as it should eliminate 99.9% of contaminates.  I am unaware of any FDA or USDA standard on this. Normally I see 0.01 for this type of application.

The 0.01 is really quite perfect for the application as it should eliminate 99.9% of contaminates.  I am unaware of any FDA or USDA standard on this. Normally I see 0.01 for this type of application.

Dear GOC,

Seems rather amazing if no US standard. The earlier attachment rather suggested otherwise ? Perhaps most people not too sure what a micron equals ?  :smile:

For high risk, BRC would probably go for the 99.9999 option ? 

Rgds / Charles.C

^Cbowers,

^{I know your frustration with air quality in the USA. When developing my SQF system on air quality I never received a concrete answer for what is acceptable for compliance. It boggles my mind that SQF put into place a system and did not specify the requirements to meet this standard. My companies process uses direct air contact with product as well as non-direct contact. With the research I have done and talking with individuals within the air testing field, .01 micron level is very good in terms of acceptance. However, with no guidelines to follow you could theoretically say .03 micron level is acceptable for compliance.}

^{The SQF system also does not state what is required for testing. So once again I worked with an outside labratory on what should be tested. I came up with 5 key testing areas; aerobic plate count, enterobacteriaceae count, mold count, total coliform and yeast count. Whether this is how other companies conduct their air quality program or not, this has been accepted by auditors in the passed.}

^{Good luck on this rather vague element!}

 

What is an acceptable micron size for compressed air filters? 

This air is in contact with a soy protein isolate powder.

SQF has no specific standard. We currently use 0.01 micron primary filter.

British Compressed Air Society (BCAS)3 and the British Retail Consortium (BRC)4 seems to be widely accecpted.

Is there an FDA or USDA standard to consider?

 

CompressedAirContaminationinFoodIndustryWhite-paper6_11.pdf

 

 CB

 

Hi CB,

I believe your answer was already in your white paper?:

'A typical system should consist of a first stage, high efficiency coalescing filter with a rating of at least 99.99% at 0.01 micron which provides the necessary protection to the second stage of filtration – the sterile air filter. A sterile air filter with an efficiency rating of at least 99.9999+% at 0.01 micron is necessary in order to achieve the class 1 rating and safeguard food product from becoming exposed to bacteria and other micro-organisms. In order to achieve the filtration specification as outlined above, it is necessary to install at least a two stage filter system as close as possible to the point of use. If there is excessive condensate, a third stage, prefilter stage should also be installed.'

Here is an example of a typical filter:

FiltersAndDryersForTheFoodIndustry.pdf   936.73KB   758 downloads

BRC do not quote an absolute standard for the filters 'the grade required is dependent on the source of the air and the time of exposure of the product'

SQF offer the following guidance:

'Wherever the compressed air comes in contact with the food, either directly or indirectly, high efficiency filters are to be in place at point-of-use where the air enters the final section of tubing (not in the compressor room). This will significantly reduce the risk of microbial contamination of the food from the air.'

'The recommended final stage of filtration in these food contact areas should have a rating of 0.01 micron with an efficiency of 99.999% (or as determined by appropriate risk analysis).'

Regards,

Tony

Balston Sterile Air Filters are in full compliance with the requirements of the FDA

 

Encouraging, but what are the requirements of the FDA?

Rgds / Charles.C

Dear GOC,
Seems rather amazing if no US standard. The earlier attachment rather suggested otherwise ? Perhaps most people not too sure what a micron equals ?
For high risk, BRC would probably go for the 99.9999 option ?
Rgds / Charles.C

I guess you mean GOC is included as 'most people', apparently he is an SQF Consultant :rofl2:

Balston Sterile Air Filters are in full compliance with the requirements of the FDA
Encouraging, but what are the requirements of the FDA?
Rgds / Charles.C

Almost certainly the same as BRC.........your 'BRC would probably go for the 99.9999 option' isn't accurate.

I'm a bit surprised you're asking questions rather than posting answers?

Regards,

Tony

 

Almost certainly the same as BRC.........your 'BRC would probably go for the 99.9999 option' isn't accurate.

 

I'm a bit surprised you're asking questions rather than posting answers?

 

Regards,

 

Tony

Hi Tony,

:spoton: as per usual.

Rgds / Charles

:off_topic:

PS (afterthought) – I found the “professional” document below quite interesting as an example of the  effort  which some forums expend on attempting the regulation of a, basically, rather simple activity. Some valid thoughts but a lot of the proposals are more likely to drive people away from sharing useful knowledge  IMO.

How To Ask Questions The Smart Way.pdf   101.05KB   356 downloads

Dear All,

Perhaps not surprisingly (Lowest common Denominator ?)(but see SQF/ Table co1), the "SQF Code" currently seems popular (see co1, 2 below).  Regarding FDA, previous post 2 (GOC) looks quite accurate although there is a "RTE guideline (particulate removal) "  in the Table/co1. CFR have also issued qualitative "specifications". 

There is a voluminous resource on Google. A few relevant-looking documents below, mostly US commercial origins. The first one (Parker-Balston) looks quite impressive / informative in scope within a business opportunity orientation.

co1 - White paper, 2013, Compressed Air for Food GMPs.pdf   526.29KB   541 downloads

co2 - Food safety Rule Changes - Compressed Air Will Play a Role.pdf   1.96MB   392 downloads

co3 - Compressed air, its whats for dinner, 2008.pdf   5.06MB   320 downloads

co4 - question response, ca.2012,Food Grade compresser-vacuum pump oil.pdf   992.33KB   270 downloads

co5 - application of food grade compresssed air standards in food processing facility, Aug 2012.pdf   375.02KB   508 downloads

co6 - Air Quality in the Pharmaceutical industry, ca 2012.pdf   2.54MB   380 downloads

Rgds / Charles.C

Dear All,

 

 Regarding FDA, previous post 2 (GOC) looks quite accurate ...issued qualitative "specifications". 

.....

 

Rgds / Charles.C

Hi Charles,

Whilst informative ....and thank you for the information, a high specification of filtration is required.

'The 0.01 is really quite perfect for the application as it should eliminate 99.9% of contaminates' - This is poor advice and doesn't specify the standard of the filter, basically it is an uneducated answer.

This air is in contact with a soy protein isolate powder, which means the question is not about the standard for compressed air, it is about air that is being used to transport product with a high incidence of contact in a potentially high risk product. (check your attachments and see what you think)

Regards,

Tony

'Wherever the compressed air comes in contact with the food, either directly or indirectly, high efficiency filters are to be in place at point-of-use where the air enters the final section of tubing (not in the compressor room). This will significantly reduce the risk of microbial contamination of the food from the air.'

 

What type of flexible air line does everyone use to blow down equipment? We were informed we could not use the standard red colored line, it must be clear.

Dear cbowers,

Yr  OP asked regarding whether 0.01 micron capability would be an acceptable grade for SQF and yr product (presumably RTE).

Consider these partial extracts from the SQF Guidance –

Wherever the compressed air comes in contact with the food, either directly or indirectly, high efficiency filters are to be in place at point-of-use where the air enters the final section of tubing (not in the compressor room).  This will significantly reduce the risk of microbial contamination of the food from the air.  The recommended final stage of filtration in these food contact areas should have a rating of 0.01 micron with an efficiency of 99.999% (or as determined by appropriate risk analysis).  Sufficient filtration is to be in place

directly upstream of the final stage to protect the final stage from oil and water aerosols.

The site may consider the following controls for particulates

i.        Intake filters to remove atmospheric dirt and solid particulates.

ii.        Microorganisms – A point-of-use filter, minimum 0.01 micron, prevent pathogenic microorganisms from contaminating food. An effective PM program should be in place to maintain the integrity of the filter. Validation from the filter manufacturer is often considered adequate validation.

iii.        Water, including vapor, liquid, condensed. A dryer in the compressed air system provides effective control. An effective PM program should be in place.

iv.        Oil, including vapor, liquid and aerosols. The presence of coalescing filters in the compressed air

system effectively removes contamination. An effective PM program should be in place to maintain the integrity of the filter.

 

AFAI can see, SQF does not mandate any specific (small) size of particle which must  (at a minimum) be “highly” excluded. If any specific FDA values existed these would presumably (in USA) take precedence. An FDA Item (see 2  below) does exist but only in Draft form (albeit updated to 2013).

However (as noted post 5), SQF  does “recommend” in its Guidance the options quoted above, viz  implementation of a  filter which  (near 100%) retains particles of  0.01 micron. Nonetheless, based on  user experiences of SQF as occasionally reported in this forum (and generically implied within the SQF standard itself), suggestions in  SQF Guidance articles in no way assure  that an auditor will use the same logic. (although two guidances seems "quite" assured :smile:  ) Additionally, one notes above the now almost ubiquitous phrase  “(or as determined by appropriate risk analysis)”. 

The Guidance also contains some comments regarding  existing air purity standards, eg ISO. SQF seem unaware of the (food, risk-oriented) BCAS-BRC Code of Practice  (attached below). Neither of the previous documents include particle sizes as low as  0.01 micron.

cx0 - BCAS, food grade compressed air.pdf   179.84KB   382 downloads

(recently updated, eg 

http://www.hpmag.co....idelines/1/208/

(added later) - a few comments from an abstract of the 2013 revision -
 

The quality of compressed air is as before defined by ISO 8573-1 (2010) where levels of particles, water content and total remaining oil content i.e. liquid, aerosol and vapour are specified. For the user there are again 2 categories of compressed air usage; direct contact and indirect contact. Direct contact is where there is direct impingement onto the product, ingredients or packaging. Indirect is the situation where pneumatic equipment is present and the exhausted compressed air from cylinders, actuators etc are present in the production or packaging areas.

The air treatment requirement for the main contaminants has been adjusted to reflect changes in ISO 8573:2010 and the light of experience with the previous version of the guide. The particle class chosen for both direct and in-direct contact has been relaxed to mirror easily available filtration. The humidity levels identified have been chosen to help with the control of microbiological contaminants and will require the use of different drying techniques. There has also been a relaxation of oil levels for indirect contact applications

 

http://www.processin...e-guideline-102

From a purely safety POV, one could presumably make some predictions on filter requirements based on the known sizes of relevant bacteria, viruses. (as an analogy, water filtration units do consider such aspects). Perhaps this would support  SQF’s Guidance nominated recommendation of a minimum 0.01 micron rating  which otherwise  seems IMO to be a somewhat random choice (?).

To add some context to the choice of  micron size and related issues, I have enclosed a few  other opinions which, in contrast to my previous post, are mainly not from commercially interested parties. :smile:

(1) (SQF) Code FAQs

What are the parameters and what methods are required for air purity testing on compressed air to address element 11.5.7?

Purity is defined in the SQF Code (Appendix 2: Glossary) and means the absence of contaminants that could cause a food safety hazard. Pure air means the air is free of risk of cross-contamination to the products. Essentially, the air must not contribute any contamination to the product.

Food processing facilities need to operate from a fundamental assumption that compressed air can be a source of chemical and microbiological contamination. The site must verify and validate that the compressed air used in the facility is appropriate for use and not a source of contamination. Where compressed air comes in contact with exposed product, direct product contact surfaces and interior surface packaging, the air compressor should use food grade oil.

Preventive maintenance programs need to ensure that an appropriate filtration program is in place at the point of use and the filters are cleaned/changed at a frequency appropriate to the product and process or following any maintenance to air supply source or equipment. Maintenance must be done in a hygienic manner. Air should be filtered at the point of use for most operations (recommended filter size at point of use is 0.1 micron, or as determined as appropriate by a risk analysis). Nozzles and air hoses are to be in good condition, properly repaired and maintained in a hygienic state (e.g., cleaned and sanitized). Hoses and nozzles are to be kept off the ground.

Testing is to be conducted to validate the air-filtration control system for the compressed air is effective based on the risk to the product, but at a minimum of once a year. Testing can be done in-house or by a contracted party. Test requirements and number of samples will be based on the risk to the product and process. Microbiological testing can include testing for aerobic plate count and/or indicator organisms as appropriate to the operation. Testing for moisture should be considered if moisture is a potential risk to the product (e.g., dry operations). Aseptic sample collection should be used. There are a wide variety of measures available including the use of air sampling equipment, use of sterile sponges, membrane filtration and others.

 

0.1 micron is perhaps for a low risk situation  ??  Or just a typo ?

cx1 - SQF Code FAQs.pdf   154.36KB   254 downloads

(2) (FDA)

We recommend that you dry and filter compressed gases or air used directly in or on RF-RTE food, or on RTE food-contact surfaces. We recommend that dehydration be done at the source of gas or air supply and that filtration be done at the point of use, using a filter that can retain particles larger than 0.3 micron. You should take appropriate steps to maintain the filters

 

.

cx2 - Guidance for Industry, Control L.mono., RTE foods.pdf   317.08KB   250 downloads

(3)(IFSQN thread)  http://www.ifsqn.com...ge-2#entry57361

Interesting post and also reprised in current thread. When compared to post 4 in this thread, there appears to be some  possible confusion in the micron decimal points,  I suspect both posts are  partially correct.

(4) (commercial) Sterile Air Filter Rating Information

Balston grade SA filter cartridges, rated at 00.9999+% efficiency for 0.01 micron particles, is at least 30 times better than the accepted standard for sterile air filters developed by independent research organisations in the U.S. and U.K. Balston Sterile Air Filters are in full compliance with the requirements of the FDA

 

(attachment post 5)

I speculate that  0.3 micron (FDA) / 30 = 0.01 micron :smile:

(actually the factor is more technically meaningful, see cx4 below)

cx4 - Processed Air Ensures Food Quality.pdf   277.75KB   300 downloads

(5)(Australia)(general impartial comment)

Do food manufacturers need to comply with ISO 8573.1 Class 0?

No,  the  BCAS/BRC  Code  of  Practice recommends  minimum  acceptable  levels  of  compressed  air  quality,  which  is specific  to  the  food  industry  and  does not  require  the  extra  expense  required to  meet  Class  0.

How can food manufacturers comply with requirements such as the Code of Practice?

It  is  important  to  remember,  the  aim of  such  Codes  is  to  provide  air  quality recommendations  to  the  food  industry that  will  protect  both  the  manufacturer and  the  consumer,  not  to  over-specify air  quality  in  an  attempt  to  sell  plant equipment. Compliance may require little on the part of the food manufacturer as many will find that they already comply with  most  or  all  of  the  requirements.

A  full  audit  of  the  compressed  air system  should  be  conducted  as  part  of the HACCP process and where required, equipment  updated  or  additional  purification  added.

Remember  that  additional  filters can  be  installed  simply  and  relatively inexpensively  at  point  of  use.  Costly compressors  do  not  have  to  be  changed in  order  to  comply.

 

cx3 - compressed air in food plants.pdf   286KB   268 downloads

I anticipate that yr current 0.01 micron unit is actually, at least, a pair of filters with an appropriate manufacture’s performance assurance. Assuming you can validate the overall efficiency as per SQF’s requirements, looks good chance  to be “acceptable” IMO.

Rgds / Charles.C

Here is a document on ISO air quality requirements that one of customer's directed us to follow.  Hope it is of use.

Introduction to ISO Air Quality Standards.pdf   384.52KB   609 downloads

In respect to the validation part of the air supply. When SQF states; "Microbiological testing can include testing for aerobic plate count and/or indicator organisms as appropriate to the operation", thats fine and dandy but what are considered acceptable aerobic plate counts and indicator organisms and what is not acceptable? I consulted with a certified lab about this question I had and they told me testing areas should not exceed 15 microorganisms (bacteria, yeasts and molds).

Is this exceptable ranges for validation methods? Does anyone else validate differently?

Maybe Charles or Tony knows.

Our air tests are for APC, Yeasts and Molds with acceptable levels of >25, >15 and >15 respectively.

Looks like it depends on the "certified lab".

CB

Dear oronogirl,

(occasionally slightly OT as far as SQF is concerned)

Thks for the (2009) publication. Some useful explanatory comments in a  highly confused terminology-driven  subject.

There is also a later 2011 version (contains less ISO explanation) which includes suggestions from the BCAS (2007) document,  notably concerning HACCP / risk analysis aspects (see cib1 below). The same source was also responsible for item No.4 (2007) in my previous post #12, this noted the close linkage in BCAS air purity data to the ISO grading scheme.

cib1 - compressed air for the food industry.pdf   2.02MB   376 downloads

Despite all this discussion over “micron ratings”  the primary objective (assuming SQFlevel2)  under present discussion presumably remains safety. This comment is given in BCAS document –

6.2 Microbiological contaminants

HACCP shall establish the risk of contamination by microbiological contaminants. The level of viable microbiological  contaminants in the compressed air shall not be detectable using the method described in clause 7.6.

 

Use of a "sterilising" grade filter presumably offers the highest probability of attaining the above. I have not seen any commercial statements as to which  % retention  efficiency / micron particle size paired values will typically be compliant to the BCAS requirement as stated above.

(note that the SQF guidance refers to "pathogenic" microorganisms)

AFAI can see, BCAS implies the above requirement applies to foods of all  "Intrinsic risk" levels which are in a direct contact scenario. SQF includes a "risk analysis" proviso of unknown (to me) significance.

If anyone still interested enough in this topic to view some published validations, attachment cib2  includes the microbiological evaluation of a commercial unit stated to generate  “commercially sterile air”. Same document also illustrates the technical complexity of measuring retention efficiencies  > 99.9+% etc at the 0.01 micron, particle size level.

cib2 - study on efficiency of air filter for commercially sterile air.pdf   49.28KB   204 downloads

ISO appears to avoid expressing any opinions regarding tolerances for  viable microorganisms. Other organisations, eg the pharmaceutical industry, FDA, have added their own "viable count" requirements on top of the ISO grading scheme.  

So 1 explicit question -

Do SQF intend to uniformly demand implementation of their own (five-9s efficient), 0.01micron  guidance recommendation, eg for all (undefined) risk products?.  I very much doubt it however numerous auditors / auditees must already know the answer to this one. (of course, if this superlative equipment is practical and inexpensive, why not use it anyway ?)(some documents indicate that the US meat industry has already welcomed such devices).

@ DL1988 / cbowers - Sadly, this topic is definitely not my area of expertise and, as you can see, i find SQF's objectives / requirements confusing, particularly the true intention of their detailed guidance material (hardly a unique experience :smile:) . The microbiological possibilities if using the "best" filtration options (eg very, very close to 100% / 0.01 micron retention) are illustrated in cib2 and would presumably  laugh at / fly under  the limits mentioned in previous 2 posts. :smile:

Rgds / Charles.C

Cbowers,

Could you elaborate on why your APC is set at >25? Does that come from the certified lab you are using i would assume?

Thanks.

Dear DL / cbowers,

Regarding yr request for micro. limits, AFAI have seen, there are no existing official values for individual microbiological species / compressed air. On the other hand, "total counts" are in use as discussed below. If yr lab suggests any detailed values, I suggest to (politely) ask as to their source since will be a useful part of any later validation.

The following analysis is a speculative  response to yr request.

I present 2 interpretations below. 1^st one is more deeply validated but conceptually rather dubious IMO, 2^nd is less validated but perhaps more practically meaningful (only SQF know).

It is perhaps again worth noting that various of the parameters being discussed are not normally regarded as directly related to food safety.

(It is necessary to remember that the ISO air purity standards frequently quoted in recent  posts are used in various versions  together with other standards doing similar “things”. The whole topic is a chaos of mixed-up classifications.)

(1) The  BCAS/BRC  code  of  practice  is aligned  with  the  compressed  air  purity levels  shown  in  ISO  8573.1:2001  and although  not  directly  stated,  the  purity level  for  air  that  is  in  direct  contact with  food  or  could  come  into  contact with  food  is  equivalent  to  ISO  8573.1, Class  2.2.1. Category 2.2.1 approx correlates to level 5 as listed in the FDA table (pg2) of  attachment cpc1 below (the gradings were i think primarily developed for cleanrooms / drug manufacturing, not food). The FDA table (and others)  include action limits / limits for microbiologically active particulates ( also known as viable counts [VC]).

Specifically  the VC action limit for level 5 is 1 cfu/m3. For level5 this is interpreted as a requirement for   “nil detection” of micro.active particulates and so is equivalent to  paragraph 6.2 of  the BCAS (2006) document.

cpc1 - microbial monitoring of compressed gas lines.pdf   163.21KB   616 downloads

(added later) the recent 2013 BCAS revision of cx0 has apparently relaxed some of the ISO requirements (see the  sample extract/link in post #12) so the FDA level-action level correlated above may have also changed. ( para 6.2 :dunno: ).

(2)  A  compressed  gas  should  be  of  appropriate  purity  (e.g.,  free  from  oil)  and  its microbiological and particle quality after filtration should be equal to or better than that of the air in the environment into which the gas is introduced (quoting cpc1).

The above  principle enables some utilisation of appraisals of environmental air micro. quality.

A Campden article on general, ambient, air micro.quality in food factories , cpc2, suggests that –

Total viable counts can range from 10 ^1 – 10^4 /m3 and yeasts and moulds can range from 10^1 -10^3 /m3 in different food factories.

cpc2 - campden, air sampling for micro quality.pdf   427.29KB   986 downloads

Taking the most conservative options (ideally should perhaps be risk based),  can deduce –

TVC= max 10cfu/m3

Y&M = max 10cfu/m3

Interpretations  (1,2) above are obviously rather mutually incompatible. :smile:

Input from other posters is of course welcome, Laura TG perhaps ?

Rgds / Charles.C

Compressed air is vital energy source and is utilized in multiple operations in food processing units. Don't know about FDA or USDA, but ISO had set some standard which make the basisi for air treatment product selection much easier. According to ISO, I think 0.01 micron is acceptable. Though, you can go through this pdf for better understanding: http://www.balstonfi...e-paper6_11.pdf

We use a .1 micron filter system and have not had any issues with inspections.

We use a .1 micron filter system and have not had any issues with inspections.

Sorry, .01 micron filter system

If you've validated and verified the 0.01 micron filter it would seem to be doing what you need it to