ASTM F2519: How to Read a Grease Capture Efficiency Figure

ASTM F2519 is the test method behind a lot of the grease capture percentages quoted in commercial kitchen ventilation, and reading its scope changes how you read those percentages. Two clauses do most of the work: the method covers equipment that captures grease before the exhaust duct, and it measures new or clean filters rather than loaded ones. Once those two limits are in view, the useful question stops being “whose number is higher” and becomes “are these two numbers even on the same scale.”

This guide helps you decide whether an efficiency figure you have been given can be compared with another one.
It does not select or size equipment, quote a price, or judge any supplier’s figure as true or false.
For product-specific review, see the in-duct electrostatic precipitator page and our test reports.

Document	Product scope	What it supports	What it does not prove
ASTM F2519-05(2025) Grease Particle Capture Efficiency of Commercial Kitchen Filters and Extractors Committee F26, BOS Vol. 15.12	Components and systems capturing grease effluent prior to entering the exhaust duct	Capture efficiency and pressure drop of the item tested, in clean condition	Performance when loaded · performance of in-duct equipment · results comparable across other methods

What the method measures

The full title is the clearest summary of the boundary: Standard Test Method for Grease Particle Capture Efficiency of Commercial Kitchen Filters and Extractors. It sits with ASTM Committee F26, which covers food service equipment, and the current designation is F2519-05(2025): the 05 is the year of last revision and the 25 the year of last reapproval. The clauses quoted on this page were read in the 2011 reapproval, F2519-05(2011)e1; check them against the current edition before you cite one in a contract.

Clause 1.1 sets the object:

This test method can be used to determine the grease particle capture efficiency of components and systems used in commercial kitchens to capture grease effluent prior to entering the exhaust duct.

The clause continues by noting the results can be used to select a filter system suited to a particular application.

Read the last five words of the first sentence carefully. The method is framed around equipment that acts before the duct — hood filters and extractors. That is a boundary worth holding on to, because it decides which equipment a figure produced under this method describes.

It measures clean equipment

Clause 1.2 is the sentence that most changes how a quotation should be read:

This test method is applicable to filter components and systems. The performance information is obtained for new or clean filters and does not include the performance of used or loaded filters.

Every percentage produced under this method describes a clean condition. That is not a flaw in the standard; a repeatable test needs a defined starting state. But it means the number answers “what does this do when it is clean” and leaves “what does it do in week six” entirely open.

The practical consequence is that an efficiency figure and a maintenance regime are one conversation, not two. If a supplier gives you a capture percentage and no cleaning basis, half the picture is missing. We do not publish a cleaning interval as a catalogue figure for this reason — the interval depends on the cooking process, the run hours and the oil in use, so we give it in writing against your stated conditions at quotation.

One number is a point on a curve

Capture efficiency varies with particle size. Clause 5.2 describes what the result is actually for:

The particulate capture efficiency can be used with known particulate size emission data for a cooking appliance-food product combination to determine the total mass of grease particles captured by the filter, the total mass of grease particles that pass through the filter, and the particle size distribution of the grease particles that pass through the filter.

In other words, the percentage is an input to a calculation about your cooking line, not a verdict on the equipment. A charbroiler and a steamer emit different particle size distributions, so the same filter produces different real-world capture on each. This is also why the fine fraction matters so much in kitchen exhaust: the particles most likely to pass a coarse stage are the ones that go on to coat duct and fan, which is the problem an in-duct electrostatic precipitator is installed to address.

When you receive a single percentage with no size range attached, the honest reading is that it is a point taken off a curve you have not seen. Ask for the curve, or at least for the size range the figure applies to.

When two figures cannot be compared

This is the part worth taking away. Two efficiency percentages are comparable only if four things line up: the same test method, a comparable airflow, the same position in the system, and the same condition of the item tested. Change any one of them and the numbers stop being two points on one scale.

Variable	Why it breaks comparability	What to ask
Test method	Different methods define the challenge aerosol, the measurement points and the pass criteria differently	Which method and which edition?
Airflow	Collection depends on residence time; a figure at one flow does not transfer to another	At what airflow was it measured?
Position in the system	A hood filter and an in-duct unit see different particle populations, because the first stage has already removed the coarse fraction	Where in the system was the item installed?
Condition	F2519 clause 1.2 restricts results to new or clean items	New, clean, or loaded?

So that this is not an abstract point, here is how it applies to our own number. Our LK in-duct units measured up to 97.6% grease removal in CMA-accredited third-party testing under report ZY05W230298. That figure was not produced under ASTM F2519, and we would not present it as though it were: F2519 covers equipment capturing grease effluent prior to the duct, while an ESP of this type sits in the duct run. The figure belongs to its own test condition, and the way to use it is the way we are recommending you use everyone’s — request the report itself and check the serial-number link and test conditions before treating any efficiency figure as a performance basis. The Chinese method that report was run under, and the fields to check on any such report, are set out in our electrostatic precipitator test report guide.

We are pointing this out about our own documentation because the same question should be put to any supplier quoting a percentage, including us. A number whose method is not stated cannot be checked, and a number checked against the wrong method is worse than no number at all.

The pressure drop half

Efficiency gets quoted; resistance gets forgotten until commissioning. Clause 5.1 puts the second half back in view:

The pressure drop results can be added to the pressure drops of other components in an exhaust system to determine the total exhaust fan pressure requirement.

That is the whole reason a resistance figure has to come with the same conditions as the efficiency figure: it is an input to a system calculation, and the fan has to absorb the total. A complete Polygee in-duct unit including the standard air-distribution plate is rated at ≤150 Pa; ask for the figure at your design airflow rather than a catalogue maximum, and ask every supplier the same way, because a resistance quoted for the electrostatic field alone is not the same number as one quoted for the assembled unit.

Six questions to put to any figure

Copy this into your enquiry. It works on any supplier’s number, and it is the fastest way to find out whether two quotations can be compared at all.

#	Ask	A good answer	A weak answer
1	Which test method, and which edition?	A named method with its designation	“Third-party tested”
2	Where in the system was the item installed for the test?	In the hood, or in the duct — stated	Not mentioned
3	Was the item new, clean or loaded?	Stated explicitly	Avoided
4	Which particle size range does the figure apply to?	A curve or a size band	A single number only
5	At what airflow?	A value you can compare with your design flow	Not stated
6	What is the pressure drop at that flow?	Complete-unit value, plate included or excluded stated	Efficiency given, resistance not

This table answers whether two figures can be compared. It does not answer which equipment suits your kitchen; that depends on airflow, cooking process and duct layout.

Where this guide stops

Three layers again, and clearing one does not clear the next.

1. Test evidence. A report describes an item under a defined method and condition. Passing one layer does not clear the next. Where your conditions differ from the tested ones, ask for the difference to be stated rather than assumed away.
2. Site installation and interfaces. Capture at the hood, duct route, access and fan static margin decide what the equipment is given to work with. An ESP fed by a hood that is not capturing cannot recover what never entered the duct.
3. Whole-system operation in service. The cooking process actually run and the maintenance regime decide what happens after week one. No test report settles this in advance.

This page summarizes the published scope and significance statements of a test method for planning purposes. It is not a compliance determination, and it does not reproduce the test procedure, which is in the purchasable standard.

Buyer record

• Request with every efficiency figure: method name and edition · test airflow · position in the system · condition of the item · particle size range or curve · pressure drop at the same flow.
• Record for your own file: which figures came from which method, so later comparisons stay honest.
• Ask separately: the cleaning basis that keeps performance near the tested condition in your kitchen.
• Triggers a re-check: a change of menu or appliance line, a change of airflow, a model substitution, or a new report replacing the one you were given.

Key takeaways

• Scope: judge by where the tested item sat in the system, not by the percentage alone.
• Condition: judge knowing the figure is a clean-condition result, not a service-life average.
• Size: judge against the particle size range your cooking line actually emits, not against a single number.
• Comparability: judge two figures side by side only when method, flow, position and condition all match.
• Resistance: judge the pressure drop as part of the same answer, because the fan has to absorb it.

Frequently Asked Questions

What does ASTM F2519 measure?

ASTM F2519 is the Standard Test Method for Grease Particle Capture Efficiency of Commercial Kitchen Filters and Extractors. Its scope states the method can be used to determine grease particle capture efficiency of components and systems used in commercial kitchens to capture grease effluent prior to entering the exhaust duct, and that the results can be used to select a filter system suited to a particular application.

Does ASTM F2519 test filters in the condition they will be used in?

No. Clause 1.2 states that the performance information is obtained for new or clean filters and does not include the performance of used or loaded filters. Every figure produced under this method therefore describes a clean condition, which is why the maintenance regime belongs in the same conversation as the efficiency number.

Can I compare two suppliers’ efficiency percentages directly?

Only if both figures came from the same method, at a comparable airflow, on equipment in the same position in the system and in the same condition. Different test methods measure different things, so two percentages from different methods are not two points on one scale. Ask for the method name, the airflow and the condition of the item tested before putting two numbers side by side.

Was Polygee’s 97.6% figure measured under ASTM F2519?

No. ASTM F2519 covers components that capture grease effluent prior to entering the exhaust duct, while our LK units are in-duct electrostatic precipitators. The up to 97.6% figure comes from CMA-accredited third-party testing under report ZY05W230298 and belongs to that test condition. We say so because the same question should be put to any supplier quoting a percentage.

Why does an efficiency figure need a particle size range with it?

Capture varies with particle size, so a single percentage is a point taken from a curve. Clause 5.2 describes using capture efficiency together with particle size emission data for a given cooking appliance and food product to work out how much grease is actually captured and how much passes through. Without a size range, a percentage cannot be translated into what reaches your duct.

Send us the figure

Holding two efficiency figures you cannot reconcile? Send us both, with whatever the suppliers stated alongside them, plus your design airflow and cooking process. We will come back with which of the six questions each figure answers, which it leaves open, and our own report with its number, method and test airflow stated so you can apply the same test to us. You get back a comparison you can defend in a specification review.

Send the figures →

Why we write this

We build in-duct electrostatic precipitators, so we quote efficiency figures ourselves and we are asked to compare ours with other people’s regularly. The comparison is usually impossible as posed, because the numbers come from different methods and conditions. This page sets out what one widely referenced method actually covers, using its own published scope, so the limits are visible rather than taken on trust — including the limits on our own figure. It does not size or configure equipment; sizing and quotation live on the product pages.

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References & further reading

1. ASTM International — ASTM F2519-05(2025), Standard Test Method for Grease Particle Capture Efficiency of Commercial Kitchen Filters and Extractors. Committee F26, Book of Standards Vol. 15.12. Scope clauses 1.1–1.2 and Significance and Use 5.1–5.2 as published. store.astm.org
2. ASTM International — Subcommittee F26.07 on Commercial Kitchen Ventilation. astm.org
3. UL Standards & Engagement — UL 867, Standard for Electrostatic Air Cleaners, Edition 5. shopulstandards.com

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Related reading

• UL 867 — the electrical safety listing, and why it carries no efficiency figure at all.
• Commercial kitchen ESP buying guide — the six documents to ask for, of which the test report is one.
• Electrostatic precipitator vs baffle filter — what each stage is doing to the particle population.
• Certificates — what each of our documents supports, and what it does not.