A Complete Guide to Safety Shoe Standards: EN ISO 20345, ASTM F2413 and CSA Z195

Safety footwear is one of the few products where the label is more important than the price. A boot can look identical to a certified one and still fail the hazard you actually work in, because the three major certification systems do not test the same things in the same way. European buyers work to EN ISO 20345, US buyers work to ASTM F2413, and Canadian buyers work to CSA Z195. Over the years these systems have converged in some areas and diverged in others, and the divergence is where purchasing mistakes happen.

The practical goal is not to memorise every clause. It is to be able to read a marking, understand what was actually measured, and match that measurement to the real hazard on the job site. This guide breaks down each system, lines the tests up against each other, and ends with the checks that prevent rejected shipments and injured feet.

EN ISO 20345: Classes, Codes and How to Read the Marking

EN ISO 20345 is the European (and increasingly global) standard for safety footwear. It is built in layers: mandatory basic requirements apply to every certified product, then additional requirements (identified by letters) and optional supplementary requirements are added on top. The standard separates footwear into three classes based on the hazards the product is designed to cover, and each class is identified by the letter S followed by a number.

The three classes: S1, S2 and S3

S1 is the baseline. It requires a closed heel, heel energy absorption, an oil-resistant outsole and an upper that resists water penetration. S2 adds a water-resistant upper capable of withstanding 30 minutes of surface water exposure, so it is the minimum sensible level for outdoor or wet-area work. S3 combines the S2 water resistance with a puncture-resistant midsole, which is why S3 is the default choice on construction sites, in recycling plants and anywhere nails, wire or offcuts are on the floor.

Class	What the standard requires	Typical application
S1	Basic safety requirements plus closed heel, heel energy absorption, oil-resistant outsole, upper resistant to water penetration	Indoor workshops, assembly lines, dry warehouses, light mechanical work
S2	All S1 requirements plus an upper with water resistance tested over 30 minutes	Outdoor site offices, farm and utility work, wet or muddy ground without a puncture risk
S3	All S2 requirements plus a puncture-resistant midsole and prolonged water resistance of the upper	Construction, fabrication, recycling, forestry, metal working

The letters: additional requirement codes

After the class comes a string of codes. Each one tells you something specific about the construction or the test it passed. This is where most buyers misread, because codes such as E or A are frequently skipped over.

Code	Meaning	Why a buyer cares
A	Antistatic footwear	Dissipates static charge; resistance typically between 0.1 and 100 megaohms. Essential for electronics, fuel handling, powder and explosive atmospheres
C	Conductive footwear	Lower resistance ceiling than antistatic, used where charge must drain quickly. Not intended as general-purpose anti-static
E	Energy absorption at the heel	Compresses to reduce load transmitted to the heel and lower back on hard floors; often specified for standing and walking work
FO	Fuel oil resistant outsole	Protects against diesel, petrol and oils; standard on automotive and logistics footwear
CI	Cold insulating footwear	Insulation tested down to minus 20 degrees Celsius; check the rating if you work outdoors in deep winter
HI	Heat insulating interlining	Thermal barrier inside the boot, relevant for boots exposed to heat or long shifts near hot processes
HRO	Heat resistant rubber outsole	Outsole compound tested for contact heat; frequently required in foundries and metal fabrication
TA	Thermal insulation of the foot	Insulating layer for very cold or very hot environments, above the CI minimum
P	Penetration resistant midsole	Midsole plate or material passes a nail penetration test of at least 1,100 newtons
CR	Chemical resistant penetration resistance	Penetration protection tested against chemicals, for chemical and pharmaceutical plants
WR / WRU	Waterproof / water-repellent upper	WR is a full waterproof membrane build; WRU is a water-repellent treatment. Not interchangeable
T6, T7, T8	Heat resistant contact heat	Outsoles tested for contact heat at approximately 300, 250 and 250/300 degrees Celsius depending on the code and the test method

Reading a real marking

EN ISO 20345 S3 SRC HRO CI E FO A

Translated: S3 class (water-resistant upper plus puncture-resistant midsole), slip resistance rated SRC (the hardest of the three slip codes, tested on ceramic tile with detergent and on steel plate with glycerol), heat resistant rubber outsole, cold insulating to minus 20 degrees Celsius, heel energy absorption, fuel oil resistance, antistatic. That one line tells a competent buyer more than a ten-page specification. Where the marking includes the standard year, such as EN ISO 20345:2011 or the current 2021 revision, check which version applies to your market and to the version referenced in your contract, because requirements and transitional deadlines were revised.

ASTM F2413 and CSA Z195: What North American Buyers Should Look For

North America uses a performance-rated rather than a class-based system. Instead of declaring a class, the manufacturer declares which optional tests the product passed, and marks the result. The advantage is flexibility; the disadvantage is that a bare marking tells you very little.

ASTM F2413: the impact and compression codes

ASTM F2413 requires a leather upper, a lining, a midsole, an outsole and a heel counter, then adds optional or additional features that are marked when achieved. The two codes buyers see most often are the impact and compression ratings. The current version of the standard uses the I/9 designation, meaning the toe cap survives a 9 kg striker drop test, and C/90, meaning it withstands approximately 22.4 kN (9,000 lbf) of compression. You will still see older specifications written as I/75 and C/2500 from the earlier ASTM F2413-05 version; these are lower load requirements and should not be treated as equivalent when you compare two supplier offers.

Optional features worth specifying

Code	Feature	Notes for the buyer
P / PR	Puncture-resistant midsole, non-metallic	PR is the F2413 version of the same idea as EN ISO 20345 P; useful where metal detectors or step-through metal grating make a steel plate a problem
EH	Electrical hazard rated	Withstands an applied voltage of 14,000 volts for 60 seconds under controlled current. Not the same as insulation for working on live conductors
NR	Non-conductive footwear	Tested on a high-resistance surface; the correct designation for electrically insulating overshoes
SD	Static dissipative	Typical resistance window of 100 kOhm to 1 MOhm. If your electronics facility specifies an ESD program, confirm the housekeeping procedure as well, since resistance figures alone do not make a person compliant
WD	Waterproof upper	Waterproof construction, generally combined with a sealed outsole
ST	Oil and slip resistant outsole	Commonly written as ST on the outsole marking

Note also ASTM F2412, which is a penetration-only standard. It is often specified for footwear supplied into food processing, waste handling and other environments where a steel plate would contaminate or be magnetically detected. F2412 carries the P/1100 designation and is not a safety shoe standard on its own.

CSA Z195.1 and CSA Z195.2

CSA splits its footwear standards by product type. CSA Z195.1 covers occupational footwear, including both leather and rubber safety shoes and boots, and it divides products into two protection grades, with Grade 1 representing the more demanding impact and compression performance. It also includes electrical hazard ratings and a graded slip resistance system for leather footwear (SLC ratings), evaluated on leather surfaces both dry and contaminated. CSA Z195.2 applies to non-voltage-rated rubber overshoes and rubber footwear. A shoe that carries CSA Z195 is normally accepted in both the United States and Canada, but the marking must show the grade and the specific features tested.

Side-by-Side: Hazard Coverage Compared

The table below is the one to keep in your purchasing file. It maps the same hazards across the three systems so that a supplier quotation in mixed currencies and mixed standards can still be compared on a technical basis.

Hazard	EN ISO 20345	ASTM F2413	CSA Z195.1
Toe impact	200 J energy absorbed	I/9 drop test (legacy I/75)	Grade 1 or Grade 2 test level
Toe compression	15 kN	C/90, approximately 9,000 lbf (legacy C/2500)	Grade-dependent load
Puncture resistance	P or P CR, minimum 1,100 N	P / PR, or F2412 P/1100	Penetration-resistant grade variants
Slip resistance	SRA (tile/detergent), SRB (steel/glycerol), SRC (both)	Marked per outsole evaluation	SLC grades on leather, including oily and wet conditions
Electrical	Insulating footwear tested as a separate product class; antistatic A and conductive C	EH (14,000 V for 60 s) and NR	Electrical hazard rating
Static control	A antistatic, C conductive	SD static dissipative	Specified by grade and facility requirement
Heat	HRO outsole, T6/T7/T8 contact heat, HI and TA insulation	Optional outsole and material evaluations	Grade-based requirements
Cold	CI cold insulating to minus 20 degrees Celsius, TA for extreme conditions	Not a standard category; specified by the buyer	Specified by the buyer
Chemical	Material resistance per the standard; CR penetration resistance	Material and outsole selection by the buyer	Material resistance by specification
Fuel oil	FO	ST outsole	Specified by the buyer
Water	S2 and S3 upper performance, WR or WRU	WD waterproof	Specified by the buyer

Two observations are worth drawing out. First, EN ISO 20345 explicitly encodes cold, heat and chemical performance into the marking, while North American practice tends to handle those hazards through material selection and buyer specification. Second, slip resistance is the only test in the table where European and North American methods are fundamentally incompatible: SRC, SRA and SRB are ceramic and steel based, while North America evaluates footwear on leather and on contaminated surfaces. A boot marked SRC is not automatically the best choice on a greasy steel floor, and vice versa.

Matching Certification to the Actual Hazard

Once you can read the standards, the purchasing decision becomes straightforward: start from the hazards, then work backwards to the marking.

Work environment	Minimum sensible specification
Dry indoor workshop, machine operation	EN ISO 20345 S1 E, or ASTM F2413 with I/9 and C/90
Construction site with nails, rebar and offcuts	EN ISO 20345 S3 P or S3 P CR, with A added where static is a concern
Cold store or winter outdoor work	S3 with CI; for severe cold, specify a boot whose insulation has been tested at the temperature you actually work at, not only to minus 20
Hot workshop, welding spatter, molten metal nearby	S3 with HRO or the appropriate T-code, plus a metatarsal guard if heat reaches the instep
Fuel depot, refinery-adjacent, oil handling	S3 with FO; add chemical resistance and EH only if the risk assessment requires it
Electronics or explosive atmospheres	S1 or S3 with A antistatic, or ASTM F2413 SD, integrated with a documented housekeeping regime
Live electrical work	Insulating footwear specified by the applicable electrical work standard, not simply EH
Smooth, oily workshop floors	SRC slip resistance plus an oil-resistant outsole; check whether the slip marking reflects the actual floor surface

Five errors that recur in purchasing files

• Treating EH as insulation for live work. EH is a withstand rating, not permission to work on energised conductors.
• Comparing I/75 with I/9 as equal. Legacy and current ASTM versions carry different loads and should be evaluated separately.
• Reading S1 as equivalent to any of the classes above it. S1 is not a cheaper S3; it omits both water resistance and penetration protection.
• Assuming a report covers the model you received. Test reports are model-specific. Verify that the model number, the standard and the year on the report match the marking in the carton.
• Ignoring slip method differences. SRC, SRA, SRB and North American leather testing are not the same test, and the outsole compound matters as much as the rating.

Records to keep for every purchase order

• The full marking line for each model, photographed from the actual carton and from the footwear itself.
• The test report or certificate, its issuing laboratory, its number and its date.
• The Declaration of Conformity or equivalent declaration referenced by your contract.
• A written risk assessment stating which hazards the chosen class and codes cover.
• A written confirmation of the standard version applied, especially where the 2021 revision of EN ISO 20345 or a recent ASTM edition changed test conditions or marking.

Standards references and the latest standard versions are published by the three standards bodies themselves at iso.org, astm.org and csagroup.org, and it is worth checking the transition rules whenever a specification has been in place for more than a couple of years.