EN 397 vs. EN 12492 vs. ANSI Explained

Safety helmets save lives – but not all helmets are built to the same standard. If you’ve ever noticed codes like EN 397, EN 12492, or ANSI Z89.1 stamped inside a hard hat or climbing helmet, these aren’t random numbers. They refer to specific safety standards that dictate how helmets are designed and tested. In this post, we’ll demystify these key helmet standards, focusing on those relevant in the EU, UK, and US. We’ll explain what each standard covers, how they differ in testing and performance, and which types of work each is intended for. By the end, you’ll understand the differences between an industrial hard hat and a climbing helmet – and why choosing the right standard could be a lifesaver.

Why Helmet Standards Matter

Wearing the correct helmet can literally be the difference between a close call and a serious injury. In the UK alone, being struck by a moving or falling object is a leading cause of fatal workplace injuries​. Regulatory bodies like the Health and Safety Executive (HSE) in the UK and OSHA in the US require employers to provide appropriate head protection wherever there’s a risk of head injury​. Helmet standards are in place to ensure that head protection meets minimum safety requirements for those risks.

Different environments and activities pose different hazards, so one helmet design does not fit all. For example, a construction worker on the ground needs protection from falling bricks, whereas a telecom tower climber needs a helmet that won’t fall off if they slip. This is why we have separate standards for industrial safety helmets (like EN 397 in Europe or ANSI Z89.1 in the US) and mountaineering or climbing helmets (EN 12492 in Europe). Each standard defines specific tests (impact, penetration, etc.) and design criteria (like chinstrap strength, ventilation, electrical insulation) tailored to those scenarios.

Below, we break down the big three helmet standards – EN 397, EN 12492, and ANSI Z89.1 – explaining what they cover and highlighting their key differences. We’ll then compare them side-by-side in a handy table and discuss how to choose the right helmet for the job.

EN 397: Industrial Safety Helmets (Europe/UK)

EN 397 is the European standard for industrial safety helmets, commonly used in construction, manufacturing, mining, and other industries where there is a risk of falling objects or impacts to the head​. If you have a hard hat on a UK or EU worksite, it’s most likely certified to EN 397 (often notated as BS EN 397 in the UK). This standard ensures basic impact protection from above and other safety features suitable for ground-level industrial work.

Key Requirements of EN 397: A helmet must pass all of the following tests to be EN 397 certified​:

• Shock Absorption (Vertical Impact): The helmet is struck on the crown with a falling mass (usually 5 kg) from 1 meter. The force transmitted to a headform must not exceed 5 kN (about 1124 lbf)​. This tests that the helmet can absorb impact energy from falling objects and protect the skull and brain.

• Penetration Resistance: A pointed striker (3 kg) is dropped from 1 meter onto the top of the helmet. The tip must not make contact with the headform inside​. This ensures the shell can prevent sharp objects (like rebars or tools) from puncturing through.

• Flame Resistance: The outer shell is exposed to a flame for 10 seconds. It must self-extinguish within 5 seconds after the flame is removed​. Industrial helmets are often used around welding, grinding, or other hot work, so they shouldn’t catch fire easily.

• Chinstrap Anchorage (if fitted): If an EN 397 helmet has a chinstrap, the strap must release (break away) if a force of 150–250 N (approx 15–25 kgf) is applied​. In other words, the chinstrap is designed to break under excessive load. This might sound counter-intuitive, but it’s a crucial anti-strangulation feature – if the helmet snags on something (like machinery or scaffolding), it will pop off rather than choke the wearer.

• Markings and Info: EN 397 helmets must be permanently marked with the standard number, the manufacturer, model, year/quarter of manufacture, and size range, among other details. This helps users identify that the helmet meets the standard and is within its usable date.

Optional (Additional) Tests: EN 397 also defines some extra tests that are not mandatory unless the manufacturer wants to claim those specific protections​. Helmets passing them can carry corresponding markings:

• Extreme temperatures: tested at -20°C or -30°C (cold) and/or at +150°C (heat) to ensure the helmet still performs in very cold or hot conditions.

• Electrical insulation (440 V AC): tested to withstand brief contact with low-voltage (440 volt) electrical wires without transmitting a shock​. (For working with higher voltages, a separate standard EN 50365 for insulating helmets is used).

• Molten Metal Splash (MM): helmet shell tested against splashes of molten metal (as in foundries or welding) – the material shouldn’t ignite or melt through​.

• Lateral Deformation (LD): the helmet’s ability to resist compressive force from the side (to protect against squeezing or crushing) is tested​.

Industrial helmets per EN 397 typically have a rigid external shell (often ABS or polycarbonate) and an internal suspension harness that creates a gap between shell and head to dissipate impact. They often include a small brim or peak in front (for rain or sun deflection). Many do not come with chinstraps by default, or have a simple thin strap as an option, since on ground level the risk of the helmet getting snagged can outweigh the risk of it falling off. Ventilation on EN 397 hard hats is usually limited: if there are vents, their total area must be less than 4 cm² (to ensure enough material coverage and also to prevent small debris ingress)​. Some models are completely unvented, especially if they are rated for electrical insulation or molten metal (vents would let in liquid metal or expose the head to a live wire).

Use Cases: An EN 397 hard hat is intended for traditional occupational safety: construction sites, factories, road work, mining, utilities, etc. These are environments where the primary hazard is something falling on you from above. EN 397 helmets are not specifically tested for off-center or side impacts (beyond the basic penetration test on the crown) – they assume most dangerous impacts will be to the top of the head (e.g. a brick dropped from height). They also assume the wearer is mostly upright and on ground level. If your work involves climbing, high angles, or potential falls, you might need a different standard (enter EN 12492). But for everyday industrial use, an EN 397 helmet (or its equivalents in other regions) is the baseline protection required by law in Europe and the UK.

Finally, helmets meeting EN 397 undergo certification by authorised bodies in the EU/UK. Under the PPE regulations, they get a CE marking (or UKCA marking in the UK) to indicate compliance. Always look for the EN 397 marking inside the helmet, along with the CE/UKCA mark and possibly the identifying number of the notified body that certified it. This ensures the helmet is not just “designed to” but actually tested and approved to the standard.

EN 12492: Climbing and Mountaineering Helmets (Europe/UK)

EN 12492 is the European standard for mountaineering and climbing helmets, which has been adopted for work-at-height and rescue helmets as well. Originally developed for sport climbers and alpinists, it addresses hazards one encounters in vertical or rugged environments – not just falling objects, but also falls by the wearer, swinging impacts into structures, etc. In recent years, industries like construction, utilities, and wind energy have started using “climbing style” helmets (certified to EN 12492) for workers at height, because of the added protection and security they offer​.

Compared to EN 397, EN 12492 has stricter or additional requirements in some areas (and looser in others) to reflect its different use case. Here’s what EN 12492 entails:

• Multi-directional Impact Protection: Like EN 397, these helmets are tested for vertical impact (a 5 kg mass dropped), but EN 12492 doubles the drop height to 2 meters. This higher-energy impact allows up to 10 kN of force to be transmitted to the headform (since the impact is more severe)​. Moreover, EN 12492 requires additional impact tests on the front, sides, and rear of the helmet (tilting the headform and using appropriate strikers) to ensure protection from angles a climber could hit their head (for instance, swinging into a wall). In all cases, the transmitted force must stay ≤ 10 kN. This means a climbing helmet can absorb significant impact energy from various directions.

• Penetration Resistance: The test method is similar to EN 397 – a 3 kg conical striker dropped from 1 m – with the helmet needing to prevent contact with the headform​. However, under EN 12492 the penetration test can be done on any point around the shell (including the sides), not just the top​. This ensures all-around penetration protection, recognizing that in climbing or rope access, falling objects could strike the helmet from above or from the side (e.g. rock fall ricocheting).

• Retention System (Chinstrap Strength and Effectiveness): Here is one of the biggest differences. An EN 12492 helmet must have a chinstrap that stays securely fastened. The chinstrap (and its anchorage) is tested to make sure it does not break under less than 500 N of force (≈ 50 kgf)​. In fact, it’s tested by applying a 50 kg load for a defined time – and it must hold. The strap may elongate a bit (up to 25 mm) but must not fail​. Additionally, the helmet is strapped onto a test headform and subjected to shock/tug tests to ensure it stays on the head (doesn’t slip off) when pulled​. All this is to simulate a climber falling or being jarred: the helmet should remain in place to protect them throughout a fall or impact. Bottom line: an EN 12492 chinstrap is designed not to release in an accident – the opposite of EN 397’s philosophy​. (The trade-off, as safety experts note, is a potential strangulation hazard if a worker wearing this helmet gets it caught on protrusions; thus these helmets are recommended when the fall hazard outweighs the snag hazard​.)

• Ventilation and Design: Climbing helmets typically have more ventilation – EN 12492 even specifies a minimum vent area of 4 cm² total (and usually they have much more)​. This is because they assume active, strenuous use where heat dissipation is important (climbing, etc.). The shells often cover more of the head (down the back of the head and sides) for lateral impact protection. They usually don’t have a brim; a brim could obstruct upward vision when climbing and can catch on ropes. Instead, they have a rounder, smoother shape. Many EN 12492 helmets incorporate an internal foam layer (EPS foam) similar to bike or ski helmets, in addition to a webbing suspension, to absorb impact energy. Overall they tend to be lighter weight and lower profile than industrial hard hats, but designed to cradle the head more snugly.

• Other Requirements: EN 12492 includes a field of vision check to ensure the helmet design doesn’t overly impede what the wearer can see​. Unlike EN 397, there is no requirement for flame resistance or molten metal in EN 12492​ – a climber’s helmet isn’t intended for use in an environment with open flames or hot metal splash. Also, EN 12492 doesn’t address electrical insulation at all (most climbing helmets have large ventilation openings and many have some metal rivets or clips, so they are not suitable for electrical hazard work unless specifically tested to another standard).

In practical terms, EN 12492 helmets are meant for work at height, rope access, climbing, mountaineering, rescue, tree work (arborist) – any scenario where you might fall, swing, or get hit from the side, and where keeping the helmet on your head is critical. For example, a telecom tower climber or a wind turbine technician often wears an EN 12492-type helmet so that if they misstep and their fall arrest harness catches them, their helmet won’t pop off at the worst moment. The HSE acknowledges EN 12492 as the standard for “work at height” helmets in contrast to EN 397 for ground work​.

It’s worth noting that some advanced helmets now meet both EN 397 and EN 12492 – either by having interchangeable parts or adjustable chinstrap settings. For instance, a helmet like the JSP EVO®5 DualSwitch is dual-certified to both standards; it has a switch that changes the chinstrap’s release force to go from EN 397 mode to EN 12492 mode​. Petzl’s Vertex and Strato helmets similarly have a configurable chinstrap (they call it DUAL) that can be set to break away or stay tight​. These hybrid designs are popular for workers who sometimes are at height and other times on the ground, providing flexibility to adapt to the hazard. However, unless a helmet is explicitly certified to both, you should assume it meets only the standard printed inside and use it accordingly.

As with EN 397, helmets must be CE/UKCA certified by a notified body to EN 12492 for sale in the EU/UK, and they will be marked with EN 12492 inside, along with the manufacturer info, etc. Always check your helmet’s markings to know what standard you’re relying on.

ANSI Z89.1: Industrial Head Protection (United States)

Moving across the Atlantic, the dominant standard for work helmets in the United States (and many other countries who adopt US standards) is ANSI/ISEA Z89.1, often simply called “the ANSI hard hat standard.” OSHA (the Occupational Safety and Health Administration) requires head protection for workers and accepts helmets that meet ANSI Z89.1 (current or recent past editions) as compliant​. This standard is somewhat analogous to EN 397, as it primarily covers industrial safety helmets for protection from impacts and penetration. However, ANSI Z89.1 has its own classification system and some differences in test methods.

ANSI/ISEA Z89.1 (latest revision as of this writing is 2014, reaffirmed 2019) defines two types of helmets and three classes:

• Type I vs. Type II: Type I helmets provide impact protection only to the top of the head (crown impact), whereas Type II helmets provide protection to the top and sides (lateral impact)​. In simpler terms, Type I is like the traditional hard hat that mainly addresses things dropping from above, and Type II is more like a climbing or biking helmet in that it also covers side blows. All helmets must be one or the other – there’s no Type in-between​.

• Class G, E, C: These classes relate to electrical insulation. Class G (General) helmets are tested to withstand 2,200 volts, Class E (Electrical) to 20,000 volts, and Class C (Conductive) have no electrical insulation​. Class E is usually a non-vented hard hat made of dielectric material for electricians, linemen, etc., while Class C often refers to vented helmets or those with metal parts where electrical protection is sacrificed (the “C” basically means not for electrical work).

Testing Requirements: To earn an ANSI Z89.1 certification (which in the US is typically done by the manufacturer, sometimes with third-party lab verification), a helmet must pass several tests:

• Impact Attenuation (Force Transmission): A weighted striker is dropped on the helmet, and the force transmitted is measured. For Type I, the test is a vertical impact on the crown. The ANSI standard allows no more than 1,000 pounds-force (lbf) transmitted to the headform, and the average of tests cannot exceed 850 lb. (In metric, 1,000 lbf is ~4.4 kN, comparable to EN 397’s 5 kN allowance). Type II helmets are tested with additional side impacts: the headform is tilted and impacts delivered to front, back, and sides with a striker, to ensure the helmet attenuates impacts from those directions as well. The pass/fail criterion is similarly based on a max force around 4450 N.

• Apex Penetration: A pointed steel penetrator is dropped onto the top of the helmet. To pass, the tip must not penetrate or touch the headform​. (This is conceptually similar to the EN 397 penetration test.) For Type II, they also do off-center penetration tests (dropping the striker at various angles on the helmet above a certain “test line”) to verify side protection​.

• Flammability: The helmet material is exposed to a flame and must not continue to burn for more than 5 seconds after the flame is removed​. This ensures the helmet won’t act as fuel in a fire.

• Chinstrap Retention: Interestingly, the ANSI standard historically did not require a chinstrap at all for Type I helmets, and many traditional hard hats come only with a suspension and no chinstrap. However, if a chinstrap is present, it must not fail under mild load. For Type II helmets, if a chinstrap is provided, it is tested for retention: it should stay attached and not stretch by more than 1 inch under a chinstrap strength test​. (There isn’t a specific breaking strength range like in EN standards; the focus is that it doesn’t rip off or excessively elongate. Essentially, ANSI expects a chinstrap, if used, to be an additional retention aid, not a breakaway device – somewhat aligning with the EN 12492 philosophy but ANSI doesn’t mandate the strap in the first place.) Many ANSI Type II helmets on the market now are “climbing style” and do include chinstraps for the reasons we discussed, whereas typical ANSI Type I hard hats either omit them or offer them as optional accessories for situations like windy conditions or working at height.

Additionally, ANSI Z89.1 has tests for helmet stability (to ensure it doesn’t easily fall off during normal movement) and for water absorption, etc., and requires certain labeling on the helmet. The inside of an ANSI-rated helmet will typically list the manufacturer, the ANSI standard (e.g. “ANSI/ISEA Z89.1-2014”), the Type and Class, and the head size range, among other info. Unlike the EN system, there’s no CE mark since ANSI is a voluntary industry standard; however, OSHA regulations make it effectively mandatory by requiring compliance.

Design and Usage: An ANSI Type I Class G hard hat is pretty similar in form to an EN 397 helmet – usually a brimmed hard hat with a suspension cradle. ANSI Type II helmets, which have become more popular in construction lately, often resemble the European “climbing” helmets (compact shape, foam liner, chinstrap included) but with added features to meet the side impact and electrical tests. For example, a Type II Class E hard hat might look like a beefed-up mountaineering helmet with no vents (to keep Class E) and a tougher outer shell.

In the US, the trend (and OSHA’s recommendation) is moving toward Type II helmets for better all-around protection, especially in construction and high-risk industries​. OSHA even notes that for construction sites and work at height, helmets with chin straps (which usually means Type II, often imported from the climbing world) should be considered to prevent the helmet from falling off during a fall or sudden movement​. That said, millions of workers still use the normal Type I hard hats for most jobs on the ground. It often comes down to a company’s risk assessment and policy – and increasingly, companies are opting for helmets that meet both ANSI and EN 12492 criteria, to cover all bases. (Many products now advertise dual compliance, like “meets ANSI Z89.1 Type I and EN 12492”. Always verify the exact certifications, though – some “climbing style” helmets sold in the US are only tested to ANSI, with “EN 12492 aspects” but not fully certified to EN 12492​.)

Lastly, ANSI Z89.1 doesn’t directly cover chinstrap breakaway vs non-breakaway like EN standards do, but because it doesn’t mandate a weak link, most ANSI chinstraps are built to stay on (they might use quick-release buckles for convenience, but not designed to auto-release under load). This means if you’re using a chinstrap on an ANSI hard hat, treat it like an EN 12492 scenario – be mindful of snag hazards. Conversely, if you need a breakaway, you might use a chinstrap that is designed to break (some manufacturers offer chinstraps with a built-in weak point around 20–25 kg, specifically for that reason, marketed to meet the EN 397 requirement).

Choosing the Right Helmet for the Job

For safety officers and PPE procurement managers, matching the helmet to the hazard is a key responsibility. Here are some guidelines on usage environments and which standard might be appropriate:

• General Construction & Industry (Ground Level): If workers are primarily on the ground and the main hazard is tools or materials falling from above, an EN 397 (in EU/UK) or ANSI Z89.1 Type I (in US) hard hat is suitable. These are the classic hard hats seen on construction sites. They are comfortable for all-day wear, often have rain brim and accessory slots for ear muffs or face shields, and meet the basic legal requirements. Ensure any electrical work uses Class E or the helmet has the necessary electrical rating if needed.

• Working at Height (Scaffolding, Roofing, Tower Climbing): When there’s a significant risk of the worker themselves falling or being jostled (e.g. steel erectors, tower climbers, rope access techs), a climbing-style helmet is strongly recommended – one that conforms to EN 12492 or an ANSI Type II with a secure chinstrap. These helmets are far less likely to fall off during an incident and provide additional side impact protection. In fact, OSHA’s guidance suggests using chinstrap-equipped Type II helmets for construction sites with fall risks​. Many companies in Europe now require EN 12492 helmets for any work at height. Just be cautious of snag hazards – keep chinstraps fastened only when needed and tidy up any loose ends.

• High Voltage Electrical Work: If working near live electrical conductors (utility linemen, electricians working on live panels), the helmet should have an electrical insulation rating. In practice that means: in Europe, use an EN 397 helmet with the 440 V test (marked on it) or even better an EN 50365 helmet (tested to 1000 V AC). In the US, use an ANSI Class E helmet (20 kV rated). These helmets will be non-vented (solid shell) and made of dielectric materials. Do not use a vented climbing helmet or metal accessory in such scenarios​.

• Rescue and Emergency Services: For fire and rescue, oftentimes specialized helmets are used (EN 443 for firefighting, etc.), but for technical rescue or mountain rescue, EN 12492 helmets are typical to protect against various impacts during rescue operations. Some rescue helmets also meet ANSI and EN 12492 to cover multi-national requirements.

• Welding/Grinding/Hot Work: If there’s a risk of sparks, molten metal, or heat, prefer an EN 397 helmet with a molten metal (MM) rating and flame resistance. Avoid helmets with large vents or plastic that isn’t flame-retardant. In the US, most ANSI hard hats are okay around sparks (they meet flammability tests), but also ensure they’re class G or E (no vents) if there’s any chance of electrical issues from welding equipment.

• Confined Spaces & Underground: In tight spaces (like tunneling or sewer work), a helmet with a chinstrap is wise (to prevent it falling off in awkward positions)​. This could be an EN 12492 helmet or just an ANSI/EN 397 helmet with a chinstrap accessory. The chinstrap in such cases should ideally be breakaway if there are entanglement hazards, unless a fall is a greater concern.

• Sports vs. Occupational Use: Note that EN 12492 is also a sport climbing helmet standard. If you are procuring helmets for work, make sure the helmets carry the proper certification (CE/UKCA marking for EN standards, etc.). A sport climbing helmet sold in a shop will meet EN 12492, which is fine, but if you need ANSI approval for OSHA you’d want a model that is dual-certified to both EN and ANSI. Many leading manufacturers like Petzl, Kask, 3M, etc., produce helmets that meet multiple standards (EN 397, EN 12492, ANSI, CSA) to accommodate international use​.

Maintenance and Lifespan: Regardless of standard, helmets should be cared for and inspected regularly. Over time, UV exposure and wear can degrade plastics. Most manufacturers suggest a working life of around 5 years for the shell (less if heavy use or exposure to harsh conditions). Always follow the manufacturer’s instructions on inspection and replacement. A helmet that has taken a serious impact should be retired – it’s done its job in that one impact and may not protect as well the next time.

Engaging Your Team: It’s not enough to buy the right helmets; workers need to wear them (properly). Training staff on why, say, a chinstrap helmet is needed for height work can improve compliance. When people understand that standards like EN 12492 or ANSI Type II are there for their safety in specific scenarios, they’re more likely to embrace the slightly different style of helmet. It can help to point out that modern safety helmets can be more comfortable and even stylish – many have improved padding, wheel ratchet adjusters, and even customization options, which can increase wearer acceptance.

Conclusion

Safety helmet standards might seem like a flurry of codes, but they boil down to one goal: prevent head injuries. EN 397, EN 12492, and ANSI Z89.1 each define a level of protection tailored to different risks – whether it’s a brick falling on a builder’s head, or a climber banging against a steel beam during a fall. Understanding these standards helps safety professionals choose the right equipment for the job and helps workers trust that their helmet will perform if the worst happens.

In summary, remember this: EN 397 = industrial hard hat (think falling objects on site), EN 12492 = climbing helmet (designed not to fall off, for work at height), and ANSI Z89.1 = hard hat standard in the US (with Type I for top impact, Type II for all-around). Each has specific tests for impact, penetration, and other factors that match the hazards in question. By comparing EN 397 vs EN 12492 vs ANSI, we see that no one standard covers everything – but by using the appropriate standard for each task, we can cover all our bases.

For those in the EU or UK, always look for the CE/UKCA marking and the EN standard number on your helmet to ensure it’s officially certified. In the US, check for the ANSI label inside the helmet. And wherever you are, if you’re responsible for safety, keep up with the latest developments – helmet technology is evolving (as seen with dual-standard helmets and new materials) to provide better protection with less discomfort.