Air filters Tested, Interesting results


This report presents the results of an ISO 5011 test of several air filters designed for the GM Duramax Diesel. The test was independently performed under controlled conditions using a $285,000 machine at Testand Corp of Rhode Island (manufacturer of the machine). Arlen Spicer, a GM Duramax Diesel owner/enthusiast organized the test. Ken an employee of Testand offered to perform the tests at no charge. (These tests typically cost approx $1700.00 per filter). Ken, also a Diesel enthusiast and owner of a Ford Power Stroke Diesel, shared Arlen’s interest in performing an accurate unbiased test of different types and brands of diesel engine air filters. The filters used in the test were purchased retail and donated by Arlen and other individual Duramax Diesel owners. The detailed reports from the test have been compiled and are presented in the following pages. The final pages of this report present the behind the test.

ISO 5011 Test:

The ISO 5011 Standard (formerly SAE J726) defines a precise filter test using precision measurements under controlled conditions. Temperature & humidity of the test dust and air used in the test are strictly monitored and controlled. As Arlen learned in attempting his own tests, there are many variables that can adversely affect filter test results. A small temperature change or a small change in humidity can cause the mass of a paper filter to change by several grams. To obtain an accurate measure of filter efficiency, it’s critical to know the EXACT amount of test dust being fed into the filter during the test. By following the ISO 5011 standard, a filter tested in Germany can be compared directly compared to another filter tested 5 years later in Rhode Island. The ISO 5011 filter test data for each filter is contained in two test reports; Capacity-Efficiency and Flow Restriction.

Capacity and Efficiency:

The Capacity and Efficiency test report presents the test results of feeding an initially clean filter with PTI Course Test Dust (dirt) at a constant rate and airflow. The course test dust has a specific distribution of particle sizes ranging from less than 2.5 microns to greater than 80 microns (see table below). Every filter is initially tested at 350 CFM and the Initial Restriction or differential pressure across the filter is recorded in IN-H20 (Inches of Water). The filter is then tested by feeding test dust at a nominal rate of 9.8 grams per minute with a constant airflow of 350 CFM. The test is continued until the flow restriction exceeds the Initial Restriction + 10 IN-H20. At this point the test is terminated and the amount dust passed through the filter – Accumulative Gain – is measured. Dirt passing through the filter is captured in the Test Station’s Post Filter. The exact amount of dirt passed is determined by measuring the before and after weight of the Post Filter. Similarly, the amount of dirt retained by the Filter under test – Accumulative Capacity – is measured by taking the difference between the before and after weights of the Filter. From these results the overall % Efficiency of the filter is calculated. This test also indicates how long a Filter will last before replacement is required (or cleaning for reusable filters).

Flow Restriction:

This report presents flow restriction of a clean filter resulting from an increasing airflow. The differential pressure restriction across the filter is reported in inches of water (IN H2O) versus Air Flow in cubic feet per minute CFM.

Data from these reports has been compiled and presented in the following bar graphs, Plots and data tables.

Filter Efficiency:

Filter efficiency is a measure of the filters overall ability to capture dirt.

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