Nitric Acid (HNO₃)
Real material compatibility from 10% through 98% concentrated/fuming — where common elastomers fail well before you'd expect.
Nitric acid becomes aggressive to common elastomers faster than many specifiers expect — EPDM fails at room temperature by 50% concentration, and both FKM and EPDM fail at room temperature by 65%. At concentrated/fuming strength (98%), nearly every common plastic and elastomer fails even at 68°F, and only true fluoropolymers (PTFE partially, FEP, PFA) remain reliably resistant.
What Survives, By Concentration
10-30%
PVC/CPVC resistant through 104-140°F. FKM and EPDM both drop to conditional by 104-140°F, failing by 176°F.
50%
CPVC fails by 140°F. PP conditional at 68°F, fails by 140°F. FKM conditional at 104°F, fails by 140°F. EPDM fails even at 68°F — a real, low-temperature failure point.
65%
HDPE and PP both fail even at 68°F. PVC fails by 140°F. FKM and EPDM both fail even at 68°F — neither common elastomer survives room temperature at this concentration.
98% (concentrated/fuming)
PVC, CPVC, HDPE, PP, FKM, EPDM, and NBR all fail even at 68°F. Even ECTFE is only conditional, not fully resistant. Only PTFE (partially), FEP, and PFA remain reliably resistant.
Source: combined chemical resistance chart, 858 real data rows. Confirm current ratings with the manufacturer before final specification.
Frequently Asked Questions
At what nitric acid concentration do standard elastomers fail?
By 50% concentration, EPDM fails even at room temperature (68°F). By 65%, both FKM and EPDM fail even at room temperature — neither common elastomer survives at that concentration regardless of temperature control.
What material is required for concentrated (98%) nitric acid?
At 98% (concentrated/fuming) nitric acid, nearly everything fails even at room temperature — PVC, CPVC, HDPE, PP, FKM, EPDM, and NBR are all not resistant. Even ECTFE, normally a strong performer, is only conditional. Only PTFE (partially), FEP, and PFA remain reliably resistant at this concentration.
Is PP suitable for nitric acid service?
Only at low concentration and controlled temperature. PP is conditional at 68°F and fails by 140°F at 50% concentration, and fails outright even at 68°F by 65% concentration. It's not a reliable default for nitric acid above dilute concentrations.
Confirm your exact concentration before you specify
Send LibertyCES your real HNO3 concentration and temperature — we'll confirm the right material, not the generic answer.
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