Heat-resistant gloves: what the ANSI/ISEA 105 heat and flame levels mean

How does the ASTM F1060 contact heat test work?

A sample of the glove material, all its layers together, is placed on a hot plate set to a fixed temperature and a sensor on the other side records how fast heat comes through. From that curve the lab reads three times: the time until the sensor reaches the pain threshold, the time until it reaches the second-degree burn threshold, and the difference between them, the alarm time, which is the window the wearer has to feel heat and let go. The sample is run at increasing plate temperatures. The glove’s level is the highest temperature at which the time to burn was at least 15 seconds and the alarm time at least 4 seconds. A glove rated level 3 held 200°C for 15 seconds before burn conditions with 4 seconds of warning; it does not mean the glove is comfortable at 200°C or that it can be worn there indefinitely.

The test is contact only. It says nothing about radiant heat from a furnace, convective heat from flame or hot gas, molten metal splash, or steam. ANSI/ISEA 105 rates only contact heat and flame; the European EN 407 standard adds convective heat, radiant heat and small and large molten metal splash as separate digits, and many of the gloves in the band publish an EN 407 code alongside the ANSI level.

What do the flame resistance levels mean?

Flame resistance is a separate ANSI/ISEA 105 classification using the ASTM F1358 vertical flame test. The material is exposed to a flame for 3 seconds and then for 12 seconds, and the lab records whether it ignites and how long it keeps burning after the flame is removed (after-flame time). Level 0: ignited in the 3-second exposure with an after-flame over 2 seconds. Level 1: 3-second exposure, after-flame of 2 seconds or less. Level 2: 12-second exposure, after-flame over 2 seconds. Level 3: 12-second exposure, after-flame of 2 seconds or less. Level 4: no ignition in either the 3-second or the 12-second exposure. A glove can carry a heat level and no flame level, or the reverse; aramid and aluminized gloves usually publish both.

A third heat classification, heat degradation resistance under ISO 17493, puts the glove material in a hot oven and checks that it does not melt, drip, separate or ignite: level 1 at 100°C, level 2 at 180°C, level 3 at 260°C, level 4 at 340°C. It is published less often and matters for gloves that will spend time near a heat source without touching it.

How do you choose a heat level from the task?

• Measure or look up the surface temperature of what the hand touches, not the air. A 500°F oven rack and a 500°F casting need the same level; a hot room needs a different glove entirely.
• Match the level to that temperature with margin, then check the task time against the 15 seconds the level is built on. Longer holds need a higher level, a tool, or both.
• Read the whole code. A hot mill glove at level 3 with no cut level is for castings; the same temperature in a stamping plant with sharp edges calls for an aramid glove that publishes both a heat and an ANSI cut level.
• Steam, hot oil and molten metal pass through or stick to a fabric glove regardless of its contact rating. Those need a coated or aluminized glove the maker rates for the hazard.
• OSHA’s hand protection rule puts thermal burns and harmful temperature extremes on the list of hazards the employer must select gloves for; the heat level is the performance characteristic that selection rests on.