Filter efficiency test method text explanation

Weighting method
The test dust source is a large particle size, high concentration standard dust. The main component of the dust is the selected floating dust in the specified area, and then the specified amount of fine carbon black and short fibers are incorporated. Most countries require the use of Arizona Road Dust in the Arizona desert area. The Chinese standard has stipulated the use of dust from a village on the Loess Plateau. The Japanese standard stipulates the use of “Kandong clay” from Japan. The "quantity" measured is the dust weight.
The filter is installed in the standard test wind tunnel, and the wind is continuously dusted on the windward end. At intervals, the dust weight passing through the filter or the amount of dust collected on the filter is measured, thereby obtaining the filtration efficiency of the filter at the stage according to the dust weight. The final weighing efficiency of zui is the weighted average of the efficiency of each test stage.
The conditions for the termination test of the weighting test are: the agreed final resistance value, or when the efficiency is significantly reduced. The so-called "contract" here refers to the agreement between the client and the tester, or the tester's own regulations. Obviously, the conditions for terminating the test are different, and the weighting efficiency value is different.
When the test is terminated, the weight of the filter containing the test dust is referred to as the "dust holding capacity".
The weighting method is used to measure low efficiency filters, which are typically used for pre-filtration in central air conditioning systems.
The gravimetric test is a destructive test and cannot be used for the daily product performance test of the manufacturer.
Relevant standards: American ANSI/ASHRAE 52.1-1992, European EN779-1993, China GB12218-89.

Colorimetric method Dust-spot
The test bench and test dust are the same as those used in the weighing method. The dust “quantity” is the amount of light passing through the high-efficiency filter paper at the sampling point.
Sampling before and after the filter, there is high-efficiency filter paper on the sampling head. Obviously, the degree of contamination of the high-efficiency filter paper at the sampling points before and after the filter will be different. In the test, each time a section of the dust test is carried out, the amount of light passing through the high-efficiency filter paper of the filter before and after the filter is measured, and the so-called "filtration efficiency" is obtained by comparing the difference in the amount of light passing through the filter paper. The final colorimetric efficiency of zui is the weighted average of the efficiency values ​​according to the amount of dust generated in each stage of the test.
The conditions for terminating the test are similar to those for the weighting method: the agreed final resistance value, or the efficiency is significantly reduced.
The colorimetric method is used to measure the more efficient general ventilation filter, and most of the filters in the air conditioning system belong to this type of filter. Colorimetry has been a test method abroad, and this method has gradually been replaced by counting methods.
Strict colorimetry is a destructive test.
Related standards: American ANSI/ASHRAE 52.1-1992, European EN 779-1993.

Atmospheric dust counting
The dust source is the "air dust" in the natural atmosphere. The "amount" of dust is the number of all particles larger than or equal to a certain particle size. The instrument for measuring dust is a general optical or laser dust particle counter. The efficiency value is the initial efficiency of the new filter.
Name explanation
A, B, C, D
Classification of airborne molecular pollutants in integrated circuit manufacturing. A represents acid gas (Acids), B represents basic gas (Bases), C represents a condensable compound (Condensables), and D represents other doping gases (Dopants).
Absolute Filter, absolute filter
In the early days, a foreign company was a trade name with a separator high-efficiency filter, which corresponds to a filtration efficiency of 99.97% (0.3mm DOP).
AC fine (Air Cleaner Test Dust, fine), AC fine gray
The United States stipulates standard dust for filtration and performance testing of dust removal equipment, which is common to all countries except China and Japan. The dust was taken from the Arizona desert area, commonly known as Arizona Road Dust.
Incorporating a specified amount of short fibers and carbon black into the AC fine ash becomes the ASHRAE standard dust commonly used in filter tests.
The International Organization for Standardization (ISO) specifies the use of AC fine ash to measure the filtration effect of automotive filters.
Aerosol, aerosol
A relatively stable suspension system of solid or liquid particulate matter with a gas.
Internationally, most people who engage in filtering theory participate in the activities of the Aerosol Society, but those who engage in filtering applications prefer to get together in the HVAC industry.
AFI (Air Filter Institute), American Air Filtration Institute
Test Method for Filtration Efficiency The weighing method and colorimetric method were first used by AFI, and some were called AFI efficiency. If you see "AFI efficiency," you have to judge whether it is Arrestance or Dust-spot.
AHU (Air Handling Unit), central air conditioner
Central air conditioning is where Zui often sees air filters.
Air Filter, air filter
When used in central air conditioning and clean rooms, it is called air filter; it is used in piston engine and small air compressor, it is called air filter.
AMC (Airborne Molecular Contaminant), airborne molecular pollutants
The term "molecular contaminants" is used in semiconductor manufacturing.
Arrestance, weight efficiency
The efficiency of the low efficiency filter using the weighting method.
ASHRAE Efficiency
The efficiency measured by the American Society of Heating, Refrigerating and Air-Conditioning Engineers Standard ASHRAE 52.1. Generally referred to as the dust-spot efficiency, sometimes referred to as NBS efficiency, AFI efficiency.
b value
A common parameter describing the filtration effect of liquid filter materials and liquid filters. The b value is also called the filtration ratio. The b value is the reciprocal of the transmittance, and the relationship with the filtration efficiency is: filtration efficiency = 1 – 1/b
B5 = 200, indicating particles with a particle size of 5 mm, one of the 200 passes.
Cellulose Media, wood pulp filter paper
Filter paper with wood fiber (wood pulp) as the main raw material. Wood pulp filter paper is a common filter material for making a filter.
Chemical Filter, chemical filter
In the field of air conditioning, chemical filters generally refer to activated carbon filters.
CNC (Condensation Nucleus Counter) Condensation Tuber Counter
With tiny dust as the core, other substances are condensed to make the particles larger, and the instrument can detect it. In the test of the filter, the CNC can be used for the scanning test of the high-efficiency filter and the detection of the filter material.
Deep-Pleat
A customary name for traditional baffle filters.
DOP dioctyl phthalate
DOP is a commonly used plasticizer in the plastics industry and a common cleaning agent.
Using 0.3 mm DOP droplets as the particles, the filtration efficiency obtained by measuring the high efficiency filter is called "DOP efficiency".
Dust-Spot, colorimetry
A test method for filters for general ventilation that has been popular internationally for many years.