A glove for hot work carries a flame pictogram with six digits under it. Read only “heat level 4” and you’ve read half of it. Whether that digit is contact heat or flame changes which hazard it actually guards against. (← continued from Work Glove Certifications: The Full Map)
Summary
EN 407 does not treat “heat” as one thing — it splits it into six hazards, each with its own level. The six digits under the flame pictogram run in this order: flame spread, contact heat, convective heat, radiant heat, small molten-metal splashes, large molten metal. The most confusing one, contact heat, has four levels at 100·250·350·500°C, each defined by whether the inside stays cool for 15+ seconds. The key 2020 change: to claim level 3 or higher in any heat property, the glove must also pass flame spread.
Why heat is not one type
The same “hot” reaches your hand in different ways, and each needs a different defense. That is why EN 407 splits into six boxes.
Gripping a hot pan (contact heat), standing by a bonfire (convective heat), the heat off a furnace without touching it (radiant heat), and weld spatter landing on you (molten metal) are all different hazards. A glove can handle a hot pan yet get a hole from weld spatter. So it gets six numbers, not one.
The 6-digit code under the flame
The digits below the flame pictogram are always in the same order — six of them. Each is level 1–4, where X = not tested and 0 = below level 1.
| Position | Hazard | What is measured |
|---|---|---|
| 1 (a) | Flame spread | afterflame / afterglow time after flame |
| 2 (b) | Contact heat | seconds withstood against a hot surface |
| 3 (c) | Convective heat | seconds for heat above a flame to reach inside (HTI) |
| 4 (d) | Radiant heat | seconds for radiant heat to reach inside |
| 5 (e) | Small molten metal | droplets needed to heat through |
| 6 (f) | Large molten metal | grams of molten iron causing damage |
So 4143XX means flame spread 4, contact heat 1, convective 4, radiant 3, molten metal not tested.
Contact heat: how many degrees for how many seconds
Contact heat is the most hands-on case — your hand directly touches a hot plate, pipe or mold.
The test presses a heated disc at a set temperature onto the glove material and measures the threshold time for the inside surface to rise 10°C. If that time is 15 seconds or more, the glove passes that level.
| Contact-heat level | Contact temp | Pass criterion |
|---|---|---|
| 1 | 100°C | threshold time ≥ 15 s |
| 2 | 250°C | ≥ 15 s |
| 3 | 350°C | ≥ 15 s |
| 4 | 500°C | ≥ 15 s |
In plain terms, a level-4 glove keeps the skin side within +10°C for at least 15 seconds even at a 500°C touch. But that is a “let go within 15 seconds” margin, not “safe forever.” One trap: a higher level does not automatically include the lower temperatures. Each level is one result at one temperature.
Convective and radiant heat: measured in time
Convective heat is the hot air rising above a flame; radiant heat is the warmth you feel without touching. Both are scored by the seconds it takes for heat to reach inside.
Convective heat uses HTI (Heat Transfer Index — seconds for the inside to rise 24°C, per EN ISO 9151): L1 ≥4s, L2 ≥7s, L3 ≥10s, L4 ≥18s. Higher means it holds longer. Think of how many seconds you can hold your hand near a bonfire.
Flame spread and molten metal
Flame spread is what happens when a flame touches the glove and is removed: how long the flame lingers (afterflame) and how long it glows (afterglow). Higher levels go out faster (afterflame level 4 ≤ 2s).
Molten metal is the welding and foundry hazard. Small splashes are scored by the number of droplets needed to heat through (levels 1–4 = 10·15·25·35 droplets); large pours by grams of molten iron causing damage (30·60·120·200g, EN ISO 9185). If you have welded, you know one spark can burn a hole in clothing. This counts that amount as a level.
The 2020 change: fail flame, lose your heat levels
EN 407 added an important rule in 2020. To claim level 3 or 4 in any heat property, the glove must also pass flame spread (the first digit) at level 3 or higher. If it cannot, that heat property is capped and reported as level 2.
Why? A glove that resists 500°C is pointless if it bursts into flame. “Resists high heat” and “doesn’t catch fire” are different abilities, and the old rules let them run separately. Also, the flame pictogram itself may now be used only if flame spread is at least level 1.
How Korea sees it
A KS standard number matching EN 407 exactly could not be confirmed by public search, so no number is stated by guess. Internationally, ISO 23407:2021 (gloves against thermal risks) is the sister standard to EN 407; Korea tends to adopt ISO glove standards as “KS K ISO ~,” but a KS adoption of EN 407 / ISO 23407 is unverified. Heat gloves are not a mandatory-certification item in Korea (only chemical and electrical gloves are).
So which glove do you pick
Work backwards from the use. Ovens, kitchens and general hot objects → contact heat level 2–3 (250–350°C); furnaces, casting and welding → flame spread 4 plus the molten-metal digits. Don’t read just “heat 4” — read the digit among the six that matches your hazard.
Thicker heat fabric means less dexterity. A study on thermal protection of firefighting/high-heat gloves (Textile Research Journal, 2023) found fabric construction and thickness are the key variables driving protection time. Pick the level on the digit that matches your hazard.
Sources
Primary standards:
– EN 407:2020 (BSI, heat/fire protective gloves)
– ISO 23407:2021 (gloves against thermal risks, EN407 sister standard)
Academic:
– Thermal protection of firefighting gloves (Wang & Wang, Textile Research Journal 2023, DOI 10.1177/00405175231171734)
– PCM firefighting glove thermal protection (open access, PMC11403355)
Test body (secondary): EN 407:2020 explained (SATRA)
⚠ Claude Opus 4.8 (2026-06-28): The EN 407:2020 standard text (paywalled) was not read directly. Levels and test conditions are cross-checked against CEN-recognized test bodies (SATRA) and other authoritative sources. The Korean KS equivalent could not be confirmed and is left unverified. Verify against the purchased standard before relying on it.
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