If your filter datasheet, tender document or supplier’s technical page still cites EN 14387:2004+A1:2008, it cites a withdrawn standard. The current edition is EN 14387:2021, published in early 2021 and explicitly replacing 2004+A1:2008. Per an industry whitepaper on the revision, the 2021 edition removed the dolomite clogging test, abolished the R/NR reusable and non-reusable marking, added a manufacturer risk assessment requirement, and introduced “revised nominal values and tolerances for gas filter capacity” — together with revised test conditions — for types A, B, E and K. That last change is the one that touches every number in this article.
So here is the honesty note first. Every breakthrough figure below is verified against the 2004+A1:2008 text, because that is the edition whose full text we could obtain and read. We have not verified the 2021 values, and we will not print 2004 numbers as though they were current — the standard is paywalled, sold by CEN’s national members rather than published openly, and reproducing its capacity table may require permission from the rights holder. Every minute below therefore carries its edition beside it. If you are writing a purchase specification in 2026, buy EN 14387:2021 and check.
The short version
- EN 14387:2021 is current; EN 14387:2004+A1:2008 is withdrawn. Both are CEN standards from technical committee CEN/TC 79, Respiratory protective devices.
- A type letter is not a single-gas approval. In the 2004+A1:2008 edition a B1 filter had to pass chlorine at ≥20 min, hydrogen sulphide at ≥40 min and hydrogen cyanide at ≥25 min, all at 0.1 vol %.
- Class 3 is not universally 1.0 vol %. It is 1.0 vol % for B, E and K, but A3 is tested at 0.8 vol %, printed as 28.0 mg/l of cyclohexane.
- The 2004+A1:2008 test conditions were 30 l/min ± 3 %, 70 ± 5 % RH and 20 ± 1 °C, against NIOSH’s 64/32 lpm at 50 ± 5 % RH. The two sets of minutes are not comparable.
- SURSORB ABEK publishes 80 min on ammonia, 70 on hydrogen sulphide and 31 on sulphur dioxide at 1,000 ppm inlet, against 2004+A1:2008 Class 1 minima of 50, 40 and 20 — tested in our own laboratory, not by a notified body.
What is EN 14387, and who publishes it?
EN 14387 is Respiratory protective devices — Gas filter(s) and combined filter(s) — Requirements, testing, marking, published by CEN and drafted by CEN/TC 79, under ICS 13.340.30. Its scope covers gas and combined filters used as “replaceable components in unassisted respiratory protective devices” — filters that clip onto a mask and are changed out, on devices where the wearer’s own breathing draws air through the bed.
Two exclusions matter commercially. Escape devices are out of scope. And filters for carbon monoxide are excluded: there is no CO letter in EN 14387, and anything presented as one is not an EN 14387 class. When DIN EN 14387:2004-05 first appeared it superseded EN 141:2000, EN 371:1992 and EN 372:1992 together, which is why long-lived tender templates still carry EN 141 wording.
What changed in EN 14387:2021
The four changes above are documented in the RSG Safety whitepaper, marked Revision 10.2024 (October 2024), and the fourth of them — revised nominal values and tolerances for gas filter capacity, and revised test conditions, for types A, B, E and K — should stop you. If the capacity values moved for A, B, E and K, every breakthrough minute in the older table is potentially stale — and the whitepaper publishes no replacement figures. No free source we could find states the 2021 values. That is the largest single gap in the public record on this standard, and we would rather flag it than guess.
The type letters and colour codes
The letter says what the filter was tested against; the colour makes it legible at arm’s length. From Table 5 of the 2004+A1:2008 edition:
| Type | Colour | Tested against |
|---|---|---|
| A | Brown | Organic gases and vapours, boiling point above 65 °C |
| B | Grey | Inorganic gases and vapours — Cl₂, H₂S, HCN. Not CO |
| E | Yellow | Sulphur dioxide and other acid gases |
| K | Green | Ammonia and organic ammonia derivatives |
| AX | Brown | Organic gases and vapours, boiling point 65 °C or below |
| SX | Violet | Specific gases and vapours named by the manufacturer |
| NO-P3 | Blue + white | Nitrous gases (NO, NO₂) |
| Hg-P3 | Red + white | Mercury vapour |
| P (particle) | White | Particles, tested to EN 143 |
Three details are easy to miss. NO and Hg exist only as combined types, always paired with a P3 particle filter. AX filters must be marked “For single use only”, because a low-boiling organic adsorbed once can migrate through the bed on the next exposure. And SX filters must carry the chemical names and their maximum concentrations — the letter means nothing without the declaration beside it.
The class system, and the exception most summaries get wrong
Classes describe capacity: Class 1 low, Class 2 medium, Class 3 high. The class sets the challenge concentration at which the filter is tested — Class 1 at 0.1 vol %, Class 2 at 0.5 vol %, Class 3 at 1.0 vol % for types B, E and K.
A3 is the exception: 0.8 vol %, printed as 28.0 mg/l, not 1.0 %. Write “Class 3 = 1.0 % vol” as a universal rule and you are wrong on Type A — a small point that has propagated widely through secondary summaries.
Note the units too. The standard expresses challenge concentration in percent by volume and mg/l, not ppm. The familiar 1,000 / 5,000 / 8,000 / 10,000 ppm figures are arithmetic conversions made downstream by suppliers, ourselves included, and a specification is safer written in vol %.
The structural insight: the letter is a bundle test
A type letter is an approval against a set of gases, all of which must be passed at the class concentration. Type B is the clearest case: to be marked B, a filter must pass chlorine, hydrogen sulphide and hydrogen cyanide.
That is why H₂S sits under B rather than E. Chemically it is an acid gas and you would expect it beside SO₂ in Type E; EN 14387 classifies it as inorganic and puts it in the B bundle. Specify Type E because your hazard is “acid gas” and you have not specified an H₂S test at all.
The breakthrough table — EN 14387:2004+A1:2008, Table 2
Every figure here is from the 2004+A1:2008 edition. The 2021 edition revised capacity values and tolerances for A, B, E and K; we have not verified what it now says. The table below is reproduced from that superseded edition, summarised for comment; the current standard, EN 14387:2021, is sold by CEN’s national members and should be bought and checked before it is written into a specification.
| Type | Test gas | Class 1 (0.1 vol %) | Class 2 (0.5 vol %) | Class 3 (1.0 vol %) | Outlet limit |
|---|---|---|---|---|---|
| A | Cyclohexane | 70 min | 35 min | 65 min (at 0.8 vol %) | 10 ml/m³ |
| B | Chlorine | 20 min | 20 min | 30 min | 0.5 ml/m³ |
| B | Hydrogen sulphide | 40 min | 40 min | 60 min | 10 ml/m³ |
| B | Hydrogen cyanide | 25 min | 25 min | 35 min | 10 ml/m³ * |
| E | Sulphur dioxide | 20 min | 20 min | 30 min | 5 ml/m³ |
| K | Ammonia | 50 min | 40 min | 60 min | 25 ml/m³ |
* For the HCN rows, Table 2 adds that cyanogen may appear in the effluent air and that the combined C₂N₂ + HCN concentration must not exceed 10 ml/m³ at breakthrough.
Type AX sits in Table 3 and must pass both dimethyl ether at 0.05 vol % for 50 min and isobutane at 0.25 vol % for 50 min. Table 4 covers the special combined types: NO-P3 at 0.25 vol % for 20 min, and Hg-P3 against mercury vapour at 1.6 ml/m³ for 100 hours — four days of continuous challenge where everything else is measured in minutes. A published A2B2E2K2P3 datasheet from a European filter maker independently matches the Class 2 column at 30 l/min: cyclohexane 35, chlorine 20, SO₂ 20, ammonia 40.
The test conditions
Clause 7.8 of the 2004+A1:2008 edition fixes the gas capacity test at 30 l/min ± 3 %, 70 ± 5 % relative humidity and 20 ± 1 °C, with ambient laboratory conditions of 16–32 °C. The flow is continuous, not cyclic; nobody breathes like that. Thirty litres a minute is a moderate work rate. The 70 % humidity is applied in the test air itself — we found no separate pre-humidification soak in clause 7.8, though we treat that as only partially verified.
Filters are not tested only as received. The conditioning regime is a mechanical strength pre-treatment of roughly 100 rotations per minute for about 20 minutes — on the order of 2,000 rotations — then 70 ± 3 °C for 24 h and −30 ± 3 °C for 24 h. Samples are tested as received, after mechanical strength, and after mechanical strength plus temperature conditioning. That third sample tells you whether the impregnation survives a shipping container in July and a store room in January.
Breathing resistance is capped in Table 1 at 30 l/min and 95 l/min: Class 1 at 1.0 and 4.0 mbar, Class 2 at 1.4 and 5.6 mbar, Class 3 at 1.6 and 6.4 mbar. Higher class means more carbon and more pressure drop; the standard sets the ceiling on that trade.
The most important sentence in the standard
Clause 6.12.1 carries a NOTE. It says the minimum breakthrough time is intended only for laboratory tests under standardised conditions, and then, verbatim: “It does not give an indication of the possible service time in practical use.”
That is the standard disclaiming the interpretation the market puts on it. A B2 marking is a bench result at 30 l/min, 70 % RH and 20 °C on a conditioned sample — a comparability index between filters, not a quantity of minutes your worker has.
OSHA’s Respiratory Protection eTool, in its section on change schedules, quantifies why:
- Work rate. OSHA states that a worker breathing twice as fast as another draws twice the contaminant through the cartridge — the largest field variable, and not in the certification.
- Humidity. At 65 % RH, cartridge life may be reduced by a factor of two against a 50 % baseline; above 85 % RH, experimental testing becomes necessary.
- Temperature. Service life falls roughly 1–10 % per 10 °C rise, depending on the solvent.
- Concentration. Life scales inversely with the challenge concentration.
- Mixtures. OSHA describes them as “probably best determined by experimental methods”.
- Odour. OSHA prohibits odour threshold as the primary basis for a change schedule.
The US regulatory consequence is specific. 29 CFR 1910.134(d)(3)(iii)(B) requires the employer either to use a respirator with an “end-of-service-life indicator (ESLI) certified by NIOSH for the contaminant”, or, where no appropriate ESLI exists, to implement a change schedule “based on objective information or data” and document what it relied on. NIOSH adds that an ESLI is usually specific to one contaminant. For organic vapours, NIOSH MultiVapor (v2.2.6) is free, published by NIOSH, and handles mixtures with Wheeler–Jonas-type modelling — a far better basis for a change schedule than a certification minute.
EN 14387 against NIOSH 42 CFR Part 84 Subpart L
The US system is built on different foundations, and that is where cross-border specification errors happen.
| EN 14387 | NIOSH 42 CFR 84 Subpart L | |
|---|---|---|
| Nomenclature | Letters A/B/E/K/AX/SX/NO/Hg + class 1/2/3 | No letter codes — cartridges named by contaminant |
| Capacity tiers | Three classes at three challenge concentrations | No class tiers — one concentration per contaminant |
| Test humidity | 70 ± 5 % RH | 50 ± 5 % RH, plus equilibration at 25 % and 85 % |
| Test flow | 30 l/min | 64 lpm and 32 lpm |
| Temperature | 20 ± 1 °C | approx. 25 °C |
| Maximum use concentration | Not specified in the standard | Listed explicitly in §84.190 |
| Hydrogen sulphide | Mandatory Type B test gas | Not a listed cartridge category |
§84.190 lists maximum use concentrations directly: ammonia 300 ppm, chlorine 10 ppm, hydrogen chloride 50 ppm, methyl amine 100 ppm, organic vapour 1,000 ppm, sulphur dioxide 50 ppm, vinyl chloride 10 ppm; §84.190(b) allows approval for unlisted gases on request. The bench tests in §84.207, Table 11 run at 50 ± 5 % RH and about 25 °C, on cartridges tested as received and after equilibration at 25 % and 85 % RH:
| Cartridge | Test conc. (ppm) | Flow (lpm) | Min. life (min) | Max. penetration (ppm) |
|---|---|---|---|---|
| Ammonia | 1,000 | 64 / 32 | 50 | 50 |
| Chlorine | 500 | 64 / 32 | 35 | 5 |
| Hydrogen chloride | 500 | 64 / 32 | 50 | 5 |
| Methyl amine | 1,000 | 64 / 32 | 25 | 10 |
| Organic vapors | 1,000 | 64 / 32 | 50 | 5 |
| Sulphur dioxide | 500 | 64 / 32 | 30 | 5 |
Two things a buyer can act on. There is no US analogue to EN Type B’s hydrogen sulphide test — H₂S is not a Table 11 cartridge category, so a US-approved acid gas cartridge has not been bench-tested against H₂S the way a Type B filter has. If your hazard is H₂S and you are procuring to a US approval, that gap is yours to close with your own data.
And EN and NIOSH breakthrough minutes are not comparable numbers. Different humidity, flow, challenge concentrations and outlet limits: a 50-minute NIOSH ammonia life and a 50-minute EN K1 ammonia minimum are two different experiments that happen to share an integer, and they should never be tabled side by side without that caveat.
The humidity difference deserves care rather than a slogan. EN’s 70 % RH is the more conservative condition for physisorption-dominated capture, which is Type A’s mechanism — water competes for the micropore volume the organic needs, and OSHA’s factor-of-two between 50 % and 65 % RH shows how steep that penalty is. For chemisorbing filters the direction reverses: the acid–base and reactive chemistries behind K and E grades can require water for the surface reaction. A drier test is not automatically an easier one.
Where EN 14387 sits in the standards family
EN 136:1998 and EN 140:1998 certify the facepiece — full face masks and half or quarter masks respectively. EN 14387:2021 certifies the gas filter. EN 143:2021 certifies the particle filter. EN 149 covers filtering facepieces (FFP1/2/3), where mask and filter are one unit.
So “P3” is an EN 143 class, not an EN 14387 class — but a combined filter such as A2B2E2K2P3 is certified under EN 14387, with the particle element tested to EN 143. The P3 on the label is real; it is simply governed by the neighbouring document.
What Suracsh publishes, and what we do not
SURSORB ABEK is a granular, coconut-shell, multi-impregnated carbon for industrial respirator filters, and the only grade in our respiratory range that publishes a breakthrough table.
| Test gas | Inlet (ppm) | Outlet (ppm) | Standard min (min) | SURSORB ABEK min (min) |
|---|---|---|---|---|
| Ammonia | 1,000 | 25 | 50 | 80 |
| Hydrogen sulphide | 1,000 | 10 | 40 | 70 |
| Sulphur dioxide | 1,000 | 5 | 20 | 31 |
SURSORB ABEK against the Class 1 minima of EN 14387:2004+A1:2008. The standard minima are from the superseded edition, and the SURSORB results are from Suracsh Filters Pvt Ltd’s own laboratory, not a notified body.
Two things about that table change how you should read it. The standard minima are from the superseded edition — the 50 / 40 / 20 minute floors and the 25 / 10 / 5 ppm outlet limits match EN 14387:2004+A1:2008 Table 2, Class 1, exactly, and the 2021 edition revised capacity values for A, B, E and K. And the testing is by Suracsh Filters Pvt Ltd’s own laboratory, not a notified body, and not a CE certification of a finished filter. A finished cartridge’s conformity depends on bed depth, housing, flow path and a notified body — none of which we control.
The grade’s published specification is BET min 1050 m²/g, bulk density 600 ± 30 g/L, ball pan hardness min 95, in sizes 12×20, 12×30, 30×60 and 40×80. The datasheet footnote states breakthrough time in minutes, tested by Suracsh Filters Pvt Ltd per EN 14387, with ABEK Class 1 = 1,000 ppm and Class 2 = 5,000 ppm.
We also publish six further respirator grades — the single-letter SURSORB A (organic vapours above 65 °C boiling point), AX (below 65 °C), B (inorganic gases and vapours), E (sulphur dioxide and hydrogen chloride) and K (ammonia and organic ammonia derivatives), plus the combined ABE. All share moisture 10 ± 5 % and ball pan hardness min 98, in sizes 12×20, 7×16 and 14×35, with ABE also in 12×30. We do not publish breakthrough tables for any of those six — only ABEK carries one. If you are specifying one against a class requirement, ask for the test data before designing the bed.
Grades in our CBRN range are export-controlled: enquiries concerning them require an identified end user and end use before a quotation can be issued.
The full specification for every grade named here is published in HTML at suracsh.us, and every datasheet downloads without a form or an NDA. The companion article on ASZM-TEDA and the chromium question covers the military specification governing CBRN-grade carbon, and the selection guide maps contaminant to grade.
Sources
- EN 14387:2004+A1:2008, BSI Knowledge record
- EN 14387:2021, Genorma record
- BS EN 14387:2021, EN-Standard record
- DIN EN 14387 and the standards it superseded, DIN Media
- EN 14387:2004+A1:2008, Respiratory protective devices — Gas filter(s) and combined filter(s) — Requirements, testing, marking. CEN, technical committee CEN/TC 79. Superseded; available from CEN national members. Current edition: EN 14387:2021, BSI Knowledge listing
- RSG Safety whitepaper on the EN 143:2021 and EN 14387:2021 revisions, Revision 10.2024
- Clean-Air A2B2E2K2P3 filter datasheet
- BS EN 143:2021 — particle filters
- BS EN 136:1998 — full face masks
- DIN EN 140:1998 — half masks and quarter masks
- 42 CFR Part 84 Subpart L — Chemical cartridge respirators
- 29 CFR 1910.134 — Respiratory protection
- OSHA Respiratory Protection eTool — Respirator Change Schedules
- NIOSH — service life of respirator cartridges
- NIOSH MultiVapor™ application
- NIOSH-approved respirator cartridges and colour coding reference
Questions
Is EN 14387:2004+A1:2008 still the current standard?
No. EN 14387:2021 replaced it and the 2004+A1:2008 edition is withdrawn. The 2021 edition removed the dolomite clogging test, abolished the R/NR reusable marking, added a manufacturer risk assessment requirement, and introduced revised nominal values and tolerances for gas filter capacity for types A, B, E and K.
What does a B1 filter actually protect against?
Under EN 14387, Type B is a bundle test, not a single-gas approval. In the 2004+A1:2008 edition a B1 filter had to demonstrate at least 20 minutes on chlorine, 40 minutes on hydrogen sulphide and 25 minutes on hydrogen cyanide, all at 0.1 vol % challenge. Carbon monoxide is outside the standard's scope entirely.
Does Class 3 always mean 1.0 % by volume?
No, and this is the exception most summaries get wrong. Class 1 is 0.1 vol % and Class 2 is 0.5 vol %, and Class 3 is 1.0 vol % for types B, E and K — but A3 is tested at 0.8 vol %, printed as 28.0 mg/l of cyclohexane, not at 1.0 %.
Can you compare EN 14387 breakthrough minutes with NIOSH cartridge service life?
No. EN 14387 tests at 30 l/min and 70 plus or minus 5 % relative humidity; NIOSH 42 CFR 84 Subpart L tests at 64 and 32 lpm and 50 plus or minus 5 % RH, with no letter codes and no class tiers. The numbers are not interchangeable and should not be tabled side by side without that caveat.
Does a breakthrough time tell you how long a filter lasts at work?
No. EN 14387 says so itself: the minimum breakthrough time does not indicate possible service time in practical use. In the United States, 29 CFR 1910.134(d)(3)(iii)(B) requires either a NIOSH-certified end-of-service-life indicator or a documented change schedule based on objective data.