PPE standards explained
The codes printed on safety boots, hi-vis, flame resistant clothing, gloves, safety glasses, disposable masks and ear defenders each point to a standard that says what the product was tested for. This page explains the main ones in plain English. The level of protection a job needs is set by your own risk assessment.
Last updated 5 October 2026
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EN ISO 20345: safety footwear (SB to S7)
Every safety boot and shoe certified to EN ISO 20345 has a toecap tested against a 200 joule impact and a 15 kN compression load. The code after it (SB, S1, S1P, S2, S3, S4, S5, S6 or S7) tells you what else the footwear has been tested for, and each step adds to the one before.
| Code | What it means |
|---|---|
| SB | The basic requirements, including the 200 joule toecap. |
| S1 | SB plus a closed heel, anti-static properties and energy absorption in the heel. |
| S1P | S1 plus a penetration resistant insert in the sole. |
| S2 | S1 plus an upper that resists water penetration and absorption. |
| S3 | S2 plus a penetration resistant midsole and a cleated outsole. |
| S4 | Footwear made entirely of rubber or polymer, such as safety wellingtons. The basic requirements plus anti-static properties and energy absorption in the heel. |
| S5 | S4 plus a penetration resistant midsole and a cleated outsole. |
| S6 | S2 plus a water resistance test of the whole footwear. Added in the 2022 edition. |
| S7 | S3 plus a water resistance test of the whole footwear. Added in the 2022 edition. |
| Marking | What it means |
|---|---|
| P | A metal penetration resistant insert. |
| PL | A non-metallic insert tested with a 4.5 mm nail. Shown as L in a code, as in S3L. |
| PS | A non-metallic insert tested with a 3 mm nail. Shown as S in a code, as in S1PS, S3S or S7S. |
| Marking | What it means |
|---|---|
| SR | An extra slip test on ceramic tile with glycerine (2022 edition). |
| SRA, SRB, SRC | The slip markings of the 2011 edition: SRA on ceramic tile with a detergent solution, SRB on steel with glycerine, SRC both. |
| HRO | Heat resistant outsole. |
| HI | Heat insulation of the sole. |
| CI | Cold insulation of the sole. |
| WR | Water resistance of the whole footwear. |
| M | Metatarsal protection, for the top of the foot. |
| AN | Ankle protection. |
| CR | Cut resistant upper. |
| FO | Outsole resistant to fuel oil. Optional under the 2022 edition, so look for FO if you need it. |
Footwear certified to the 2011 edition shows P (or S3, S5) whatever the insert is made of. The L and S suffixes only appear on footwear certified to the 2022 edition.
Under the 2022 edition every safety boot must pass a basic slip test on ceramic tile with a detergent solution. SR marks the additional glycerine test.
ESD stands for electrostatic discharge. ESD footwear is tested to the EN 61340 series of standards, which sets a lower maximum electrical resistance than the anti-static range in EN ISO 20345.
EN ISO 20346 covers protective footwear, which has a 100 joule toecap rather than 200 joules.
Read our guide: Safety boot ratings explained
Common questions
What does S3 mean on a safety boot?
S3 is a marking under EN ISO 20345. It covers the basic requirements, including a toecap tested to 200 joules, plus a closed heel, anti-static properties, energy absorption in the heel, an upper that resists water penetration and absorption, a penetration resistant midsole and a cleated outsole.
What is the difference between S3 and S3S?
Both are S3. Under the 2022 edition of EN ISO 20345 a final S (as in S1PS, S3S or S7S) means the penetration resistant insert is non-metallic and tested with a 3 mm nail. Boots certified to the earlier 2011 edition show S3 without a suffix.
Is an S3 boot waterproof?
S3 tests the upper for water penetration and absorption, not the whole boot. The 2022 edition of EN ISO 20345 added S7, which is S3 plus a water resistance test of the whole boot.
Is a composite toecap as safe as steel?
Under EN ISO 20345 both must pass the same tests: a 200 joule impact and a 15 kN compression load.
EN ISO 20347: occupational footwear (O codes)
EN ISO 20347 covers occupational footwear: work shoes and boots with no protective toecap. Its codes start with O instead of S, so an O1 shoe has the same extras as S1 but no toecap.
| Code | What it means |
|---|---|
| OB | The basic requirements. No protective toecap. |
| O1 | OB plus a closed heel, anti-static properties and energy absorption in the heel. |
| O2 | O1 plus an upper that resists water penetration and absorption. |
| O3 | O2 plus a penetration resistant insert and a cleated outsole. |
If the job needs toe protection, occupational footwear is not enough on its own: look for footwear certified to EN ISO 20345.
Common questions
What is the difference between S1 and O1 footwear?
O1 footwear, under EN ISO 20347, has a closed heel, anti-static properties and energy absorption in the heel, like S1, but no protective toecap. S1 footwear, under EN ISO 20345, has a toecap tested to 200 joules.
EN ISO 20471: high visibility clothing (Class 1, 2 and 3)
EN ISO 20471 sorts high visibility clothing into three classes by the minimum area of fluorescent background material and retroreflective tape. Class 1 needs at least 0.14 m² of background and 0.10 m² of tape, Class 2 needs 0.50 m² and 0.13 m², and Class 3 needs 0.80 m² and 0.20 m².
| Class | Fluorescent background | Retroreflective tape |
|---|---|---|
| Class 1 | 0.14 m² | 0.10 m² |
| Class 2 | 0.50 m² | 0.13 m² |
| Class 3 | 0.80 m² | 0.20 m² |
The class is shown as a number next to the hi-vis pictogram on the label.
Because the class depends on the area of material, some garments reach a class only from a certain size upwards. Where that applies the maker's description says so.
The standard sets what each class must carry. The class a job needs is set by your risk assessment or your site rules.
Read our guide: Hi-vis classes explained
Common questions
What does Class 3 hi-vis mean?
Class 3 is the highest class in EN ISO 20471. A Class 3 garment carries at least 0.80 m² of fluorescent background material and 0.20 m² of retroreflective tape.
What does Class 2 hi-vis mean?
Class 2 is the middle class in EN ISO 20471. A Class 2 garment carries at least 0.50 m² of fluorescent background material and 0.13 m² of retroreflective tape.
Can I add my logo to hi-vis?
Yes. We place a logo on the areas that are not part of the certified fluorescent fabric or reflective tape, so the garment keeps its EN ISO 20471 rating.
EN ISO 11612, EN ISO 14116 and IEC 61482-2: flame resistant and arc clothing
Flame resistant clothing is certified to different standards for different hazards. EN ISO 11612 covers heat and flame, EN ISO 14116 covers limited flame spread, and IEC 61482-2 covers the heat of an electric arc. A garment only protects against the hazards its label lists.
| Code | Hazard tested | Levels |
|---|---|---|
| A1, A2 | Limited flame spread (A1 surface ignition, A2 edge ignition) | Pass |
| B | Convective heat | 1 to 3 |
| C | Radiant heat | 1 to 4 |
| D | Molten aluminium splash | 1 to 3 |
| E | Molten iron splash | 1 to 3 |
| F | Contact heat | 1 to 3 |
| Test | Result shown |
|---|---|
| Open arc test (IEC 61482-1-1) | An arc rating in cal/cm², given as ATPV (arc thermal performance value) or EBT. Higher is more protection. |
| Box test (IEC 61482-1-2) | Class 1 (tested at 4 kA) or Class 2 (tested at 7 kA). Class 2 is the higher. |
Every garment certified to EN ISO 11612 must pass limited flame spread (A1, A2 or both). The other codes appear only where the garment was tested, and a higher number means better performance.
EN ISO 14116 gives materials an index of 1, 2 or 3, and a higher index is better. Index 1 garments must not be worn next to the skin: they are worn over a garment of index 2 or 3. EN ISO 14116 tests flame spread, not protection against heat.
An arc rating is separate from flame resistance. A garment can meet EN ISO 11612 without having an arc rating, so check the label for IEC 61482-2 if arc flash is a risk.
Common questions
What is the difference between EN ISO 11612 and EN ISO 14116?
EN ISO 11612 is for clothing that protects against heat and flame, with codes for flame spread, convective, radiant and contact heat, and molten metal splash. EN ISO 14116 covers limited flame spread only, given as index 1, 2 or 3.
What does A1 mean on flame resistant clothing?
A1 is the EN ISO 11612 code for limited flame spread tested by surface ignition. A2 is the same test by edge ignition.
What does ATPV mean?
ATPV stands for arc thermal performance value. It is the arc rating in cal/cm² from the open arc test used for IEC 61482-2. A higher value means more protection against the heat of an electric arc.
EN 388: gloves for mechanical risks
EN 388 is the standard for gloves that protect against mechanical risks. The marking under its shield pictogram reads, in order: abrasion (1 to 4), coup cut (1 to 5), tear (1 to 4), puncture (1 to 4), ISO 13997 cut (A to F) and P if the glove passed the impact test. X means not tested or not applicable.
| Position | Property | Levels |
|---|---|---|
| 1 | Abrasion resistance | 1 to 4 (100, 500, 2,000 and 8,000 cycles) |
| 2 | Cut resistance, coup test | 1 to 5 |
| 3 | Tear resistance | 1 to 4 (10, 25, 50 and 75 newtons) |
| 4 | Puncture resistance | 1 to 4 (20, 60, 100 and 150 newtons) |
| 5 | Cut resistance, ISO 13997 | A to F |
| 6 | Impact protection | P if passed |
| Level | Minimum cut resistance |
|---|---|
| A | 2 newtons |
| B | 5 newtons |
| C | 10 newtons |
| D | 15 newtons |
| E | 22 newtons |
| F | 30 newtons |
For example, 4X42C means abrasion level 4, coup cut not applicable, tear level 4, puncture level 2 and ISO 13997 cut level C.
The ISO 13997 cut test was added in the 2016 edition. Where a material blunts the blade in the coup test, the ISO 13997 result is the reference cut result.
The puncture test uses a steel point, not a hypodermic needle, so it does not show protection against needles.
Common questions
What does EN 388 4X42C mean?
4X42C means abrasion level 4, coup cut not applicable or not tested (X), tear level 4, puncture level 2 and ISO 13997 cut level C, which is at least 10 newtons.
What is the highest cut level in EN 388?
Under the ISO 13997 test it is level F, a cut resistance of at least 30 newtons. The older coup test runs from 1 to 5.
What does X mean on a glove?
X means the glove was not tested for that property, or the test does not apply to it.
EN 166: eye protection
EN 166 is the standard for eye protection: safety glasses, goggles and face shields. The marking shows the optical class (1 is the best), the impact strength (S, F, B or A, with A the highest) and, where tested, the hazards it protects against, such as 3 for liquid droplets and splashes.
| Marking | What it means |
|---|---|
| S | Increased robustness. |
| F | Low energy impact (45 m/s). |
| B | Medium energy impact (120 m/s). |
| A | High energy impact (190 m/s). |
| T after the letter | Impact tested at extreme temperatures as well. |
| Marking | Protects against |
|---|---|
| 3 | Liquid droplets and splashes |
| 4 | Large dust particles |
| 5 | Gas and fine dust particles |
| 8 | Short circuit electric arc |
| 9 | Molten metal and hot solids |
| Marking | What it means |
|---|---|
| 1, 2, 3 | Optical class. Class 1 suits continuous wear, class 3 occasional use only. |
| K | Resistance to surface damage by fine particles (scratch resistance). |
| N | Resistance to fogging. |
Safety spectacles can be rated up to F. B is available on goggles and face shields, and A on face shields only.
Where the frame and the lens carry different impact letters, the lower one applies to the whole eye protector.
Common questions
What does F mean on safety glasses?
F is the EN 166 marking for low energy impact, tested at 45 m/s. It is the highest impact rating safety spectacles can carry.
What does 3 mean on safety goggles?
3 is the EN 166 field of use marking for liquid droplets and splashes.
EN 149: disposable respirators (FFP1, FFP2, FFP3)
EN 149 is the standard for disposable filtering facepiece respirators. FFP1 filters at least 80% of test particles, FFP2 at least 94% and FFP3 at least 99%, and the limits on total inward leakage are 22%, 8% and 2%. FFP3 is the highest class.
| Class | Minimum filter efficiency | Maximum total inward leakage | Assigned protection factor (HSE) |
|---|---|---|---|
| FFP1 | 80% | 22% | 4 |
| FFP2 | 94% | 8% | 10 |
| FFP3 | 99% | 2% | 20 |
| Marking | What it means |
|---|---|
| NR | Not reusable: for a single shift only. |
| R | Reusable. |
| D | Passed the dolomite dust clogging test. |
The assigned protection factor comes from HSE guidance (HSG53). It is the level of protection a correctly fitted and worn mask of that class can be expected to give.
EN 149 masks filter particles such as dust, mist and fume. They do not protect against gases or vapours.
HSE guidance says tight-fitting masks, including disposable FFP masks, should be fit tested for each wearer, and facial hair where the mask seals stops it sealing.
Common questions
What is the difference between FFP2 and FFP3?
Under EN 149 an FFP2 mask filters at least 94% of test particles with total inward leakage of no more than 8%. An FFP3 mask filters at least 99% with no more than 2%. HSE guidance gives FFP2 an assigned protection factor of 10 and FFP3 20.
What does NR mean on a dust mask?
NR means not reusable: the mask is for a single shift only. R means reusable.
Do FFP masks protect against gas?
No. EN 149 masks filter particles such as dust, mist and fume, not gases or vapours.
EN 352: hearing protection
EN 352 is the standard for hearing protectors. Part 1 covers earmuffs, part 2 earplugs and part 3 earmuffs fitted to a safety helmet. The SNR on the pack is the single number rating: one figure, in decibels, for how much the protector reduces noise.
| Marking | What it means |
|---|---|
| EN 352-1 | Earmuffs. |
| EN 352-2 | Earplugs. |
| EN 352-3 | Earmuffs attached to a safety helmet. |
| EN 352-4 | Level dependent earmuffs. |
| EN 352-5 | Active noise reduction earmuffs. |
| SNR | Single number rating: the overall noise reduction in decibels. |
| H, M, L | The noise reduction for high, medium and low frequency noise. |
| Daily or weekly exposure | What applies |
|---|---|
| 80 dB(A) | Lower exposure action value: the employer must make hearing protection available to anyone who asks for it. |
| 85 dB(A) | Upper exposure action value: hearing protection must be provided and worn. |
| 87 dB(A) | Exposure limit value, taking hearing protection into account. |
Choose a protector by the noise it has to reduce. The H, M and L values help match it to the frequency of the noise on site.
Common questions
What does SNR mean on ear defenders?
SNR is the single number rating from EN 352: one figure, in decibels, for how much the earmuff or earplug reduces noise.
At what noise level is hearing protection required in the UK?
Under the Control of Noise at Work Regulations 2005, employers must make hearing protection available on request at a daily or weekly exposure of 80 dB(A), and at 85 dB(A) it must be provided and worn.
Not sure which standard you need?
Tell us the job and the site rules. We will suggest a shortlist that meets them.