Strength band
Kevlar 49 class: very high tenacity and modulus versus nylon
Numbers below are bands used by working engineers, not live quotes. Tensile note: Kevlar 49 class: very high tenacity and modulus versus nylon.
Fire performance in this atlas is editorial. Real projects need the assembly report.
Mechanical
Stiffness
Modulus follows chemistry and orientation — not the marketing nickname.
Toughness
Crack growth, not peak stress, retires most real parts.
Fatigue / creep
Cyclic and time-dependent damage dominate certificates issued on static coupons.
Hardness / hand
Indentation, drape or compressive class — whichever the trade actually measures.
Thermal
Conductivity
low radial; fibre anisotropic — Aramid is not a substitute for a dedicated λ layer.
Service temperature
Melting / softening / decomposition band: does not melt; decomposes ~500 °C.
Expansion
Joints and clearances must follow the expansion class of Aramid, not of steel-by-habit.
Thermal mass
Density ~1.44 g/cm³ sets how fast a section changes temperature.
Ageing of λ
Foams, VIPs and moist batts drift; quote aged values.
Electrical
Conductor or dielectric
Aramid is generally a dielectric or semiconductor film, not building wire.
Static / EMI
Fillers and moisture change resistivity more than brochures admit.
Standards language
IACS, volume resistivity or dielectric strength — pick the quantity the job uses.
Fire
Reaction to fire
Typical declared class: inherently FR vs commodity PA. This is not a universal passport.
Resistance vs reaction
Euroclass is reaction. EI/R ratings are assemblies — boards, coats, cavities.
Melt-drip / char
Aramid tends to char or stay inorganic rather than melt-drip like commodity olefins.
Smoke / toxicity
CO, HCN, HF or fibres — the species depend on chemistry. Name the test (ISO 5659, EN 45545, NFPA 1971).
If a salesperson quotes a single “safety score”, ask which standard, which thickness, which year.
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