asasa11

Air filter ISO 5011 testing process

Messages
886
Location
California
Thread starter
I e-mailed Southwest Research Institute and asked them for information on ISO 12103-1 A4 coarse test (ISO 5011) testing as it relates to automobile air filters. I thought I'd pass along their reply...

.."we perform ISO 5011 testing of automotive and heavy duty intake air filtration systems.

The A4 Coarse test dust is just one of the dusts used in filter testing. For air filtration, the other common dust type is the A2 Fine test dust. These are selected depending on the clients interest. For information on the test dust, I would suggest looking at the suppliers website: https://www.powdertechnologyinc.com/ . They have some information the test dust distribution and have a write up on the history of test dust.

As far as air filtration testing goes, ISO 5011 has three primary tests, Restriction/Differential Pressure Test, Initial Efficiency Test, and Cumulative Efficiency/Capacity Test. All tests are completed at a standard conditions for temperature and humidity. Efficiency results are determined gravimetrically with an absolute filter located downstream of the test article.

The Restriction/Differential Pressure Test is a sweep of flow rates, relative to the rated air flow for the filter element. These rates are typically 50%, 75%, 100%, 125%, and 150% of rated flow.

The Initial Efficiency Test is typically a 30 minute test where we feed a set amount of dust to the element. This is done to see what the efficiency of an element is before it starts to load and get more efficient.

The Cumulative Efficiency/Capacity test is ran until the terminal condition for the element is reached. A typical value here for on road is 10 inWC above initial restriction/differential pressure. Cumulative Efficiency and Capacity includes any loading and dust penetration measured during an initial efficiency test. Typically in automotive, the cumulative efficiency is the only number that is publicized."



Ed
 
Messages
24,196
Location
PNW
Good info on some of the details of ISO 5011 air filter testing. IMO, some companies use the course dust in the test to boost the filter's efficiency numbers, so I always try to find out if the fine or course dust was used when looking for a good air filter.
 
Messages
886
Location
California
Thread starter
I really don't understand why they make "coarse" dust and "fine" dust for filter testing. That just seems like an easy way for filter manufacturers to mislead people as to their filter efficiency by using the coarse stuff. Baffling!

Ed
 
Messages
650
Location
USA
I really don't understand why they make "coarse" dust and "fine" dust for filter testing. That just seems like an easy way for filter manufacturers to mislead people as to their filter efficiency by using the coarse stuff. Baffling!

Ed
Then I'll clear up the mystery for you. In layman's English for those who never actually seen them

Filters generally roll up into 2 categories- those that filter by orifice (perfed) and those who filter by "fiber"

(Think a stainless steel sieve- holes of size "X" and nothing bigger is going to pass versus a woven mat[ all kinds of fibers interwoven)

Both have advantages and disadvantages.( beyond the scope of this answer)

The coarse media is more often used in woven or synthetic filters because they trap and hold particles by lowering velocity then ctching them like in a kudzu vine.

The fine media generally is used more for the perfed filters

They can both be gotten in the same geometric class (size)
 
Messages
42,630
Location
Ontario, Canada
Then I'll clear up the mystery for you. In layman's English for those who never actually seen them

Filters generally roll up into 2 categories- those that filter by orifice (perfed) and those who filter by "fiber"

(Think a stainless steel sieve- holes of size "X" and nothing bigger is going to pass versus a woven mat[ all kinds of fibers interwoven)

Both have advantages and disadvantages.( beyond the scope of this answer)

The coarse media is more often used in woven or synthetic filters because they trap and hold particles by lowering velocity then ctching them like in a kudzu vine.

The fine media generally is used more for the perfed filters

They can both be gotten in the same geometric class (size)
In the context of the "media" here we are talking about the dust itself, fine particle versus coarse particles, not the filter media.
 
Top