Nitric Acid (68%) vs PVC Compatibility
Verified chemical resistance rating (Caution: Short-Term or Emergency Use Only), thermal boundary limits (Short-term exposure only; avoid continuous pressurized service), and material specification guide for PVC exposed to Nitric Acid (68%) in Strong Oxidizing / Mineral Acid service.
Nitric Acid (68%) vs PVC: C1-Fair
Exposing PVC to Nitric Acid (68%) (Formula: HNO3 (68% Azeotropic Concentrated), CAS: 7697-37-2) carries an official rating of C1-Fair (Caution: Short-Term or Emergency Use Only). Maximum recommended thermal operating limit: Short-term exposure only; avoid continuous pressurized service. Best Grade A alternative materials for continuous or high-temperature service: Stainless Steel, Viton, PTFE, PVDF.
Technical Specifications and Operating Parameters
| Chemical Medium | Nitric Acid (68%) |
|---|---|
| Chemical Formula | HNO3 (68% Azeotropic Concentrated) |
| CAS Registry Number | 7697-37-2 |
| Chemical Functional Class | Strong Oxidizing / Mineral Acid |
| Wetted Material | PVC |
| Official Resistance Rating | C1-Fair (Grade C) |
| Engineering Service Verdict | Caution: Short-Term or Emergency Use Only |
| Max Temp and Concentration Limit | Short-term exposure only; avoid continuous pressurized service |
| Best Grade A Alternatives | Stainless Steel, Viton, PTFE, PVDF |
| Backtest and Audit Verification | Verified against Cole-Parmer, ISM, Graco & CP Lab Safety industrial chemical resistance charts. |
Nitric Acid (68%) Cross-Material Comparison Matrix (9 Materials)
Direct benchmark ratings across all 9 reference industrial materials for Nitric Acid (68%):
| Material Name | Compatibility Rating | Service Verdict | Temperature Limit | Datasheet |
|---|---|---|---|---|
| Buna-N | D-Severe Effect | Incompatible — Immediate Failure Risk | Not recommended at any temperature or concentration | Report |
| EPDM | D-Severe Effect | Incompatible — Immediate Failure Risk | Not recommended at any temperature or concentration | Report |
| HDPE | D-Severe Effect | Incompatible — Immediate Failure Risk | Not recommended at any temperature or concentration | Report |
| Polypropylene | D-Severe Effect | Incompatible — Immediate Failure Risk | Not recommended at any temperature or concentration | Report |
| PTFE | A-Excellent | Safe for Continuous Industrial Service | Ambient to elevated operating temperatures within standard material limits | Report |
| PVC | C1-Fair | Caution: Short-Term or Emergency Use Only | Short-term exposure only; avoid continuous pressurized service | Report |
| PVDF | A1-Excellent | Safe for Continuous Industrial Service | Up to 120°F (49°C) verified; up to material thermal limit in non-pressurized service | Report |
| Stainless Steel | A1-Excellent | Safe for Continuous Industrial Service | Up to 120°F (49°C) verified; up to material thermal limit in non-pressurized service | Report |
| Viton | A1-Excellent | Safe for Continuous Industrial Service | Up to 120°F (49°C) verified; up to material thermal limit in non-pressurized service | Report |
Chemical and Material Interaction Analysis
Engineering Compatibility Verdict
Nitric Acid (68%) vs PVC: C1 – Fair (Moderate Effect up to 120°F / 49°C)
Summary Verdict: PVC Type I (Unplasticized Polyvinyl Chloride / uPVC) is rated C1-Fair (Caution: Short-Term or Emergency Use Only) when exposed to Nitric Acid (68%) (Formula: HNO3 (68% Azeotropic Concentrated), CAS: 7697-37-2). Not recommended for permanent pressurized piping or critical O-ring seals. Use only for short-duration flushing or non-critical gravity drain lines.
Quick Engineering Specifications
| Chemical Media | Nitric Acid (68%) |
|---|---|
| Chemical Formula | HNO3 (68% Azeotropic Concentrated) |
| CAS Registry Number | 7697-37-2 |
| Chemical Classification | Strong Oxidizing / Mineral Acid |
| Wetted Material | PVC Type I (Unplasticized Polyvinyl Chloride / uPVC) (Amorphous Rigid Halopolymer Thermoplastic) |
| Official Resistance Rating | C1 – Fair (Moderate Effect up to 120°F / 49°C) (Grade C) |
| Recommended Temperature Window | Short-term exposure only; avoid continuous pressurized service (Material limit: 32°F to 140°F (0°C to 60°C)) |
| Top Grade-A Alternatives | Stainless Steel, Viton, PTFE, PVDF |
| Data Verification Status | Verified against Cole-Parmer, ISM, Graco & CP Lab Safety industrial chemical resistance charts. |
Chemical & Material Interaction Analysis
Nitric Acid (68%) is classified as a strong oxidizing / mineral acid (corrosive proton attack combined with strong oxidative potential). Used in chemical synthesis, metal pickling, pH neutralization, and industrial etching. When selecting wetted components for PVC, engineers must account for both concentration-dependent chemical attack and thermal stress:
- Reaction & Failure Mechanism: Induces moderate chemical attack, noticeable elastomeric swelling (10%–20%), loss of tensile modulus, or measurable metal pitting/etching (20–50 mpy).
- Material Profile (PVC): Cost-effective, rigid corrosion resistance against mineral acids, alkalis, sodium hypochlorite bleach, and inorganic salt brines at ambient temperatures. However, low upper temperature limit (140°F/60°C) and immediate solvation/softening upon contact with ketones, esters, ethers, aromatic hydrocarbons, and chlorinated solvents.
- Application Scope: Common wetted components include Schedule 40/80 chemical feed piping, water/wastewater treatment headers, acid scrubbers, and ball/diaphragm valves.
Cross-Material Compatibility Comparison for Nitric Acid (68%)
To help you select the longest-lasting piping, valve lining, or O-ring seal for Nitric Acid (68%), the table below compares PVC against 8 other common industrial engineering materials:
| Wetted Material | Compatibility Rating | Service Recommendation | Material Temp Range |
|---|---|---|---|
| Polypropylene (PP Homopolymer & Copolymer) | D-Severe Effect | Incompatible — Immediate Failure Risk | 32°F to 180°F (0°C to 82°C) |
| 316 / 304 Austenitic Stainless Steel | A1-Excellent | Safe for Continuous Industrial Service | -325°F to 800°F (-198°C to 426°C) |
| Viton® (FKM Fluoroelastomer) | A1-Excellent | Safe for Continuous Industrial Service | -15°F to 400°F (-26°C to 204°C) |
| PTFE (Teflon® / Polytetrafluoroethylene) | A-Excellent | Safe for Continuous Industrial Service | -328°F to 500°F (-200°C to 260°C) |
| EPDM (Ethylene Propylene Diene Monomer) | D-Severe Effect | Incompatible — Immediate Failure Risk | -60°F to 300°F (-51°C to 149°C) |
| PVC Type I (Unplasticized Polyvinyl Chloride / uPVC) (Current Page) | C1-Fair | Caution: Short-Term or Emergency Use Only | 32°F to 140°F (0°C to 60°C) |
| PVDF (Kynar® / Polyvinylidene Fluoride) | A1-Excellent | Safe for Continuous Industrial Service | -40°F to 280°F (-40°C to 138°C) |
| Buna-N (Nitrile / NBR Elastomer) | D-Severe Effect | Incompatible — Immediate Failure Risk | -40°F to 250°F (-40°C to 121°C) |
| HDPE (High-Density Polyethylene) | D-Severe Effect | Incompatible — Immediate Failure Risk | -60°F to 140°F (-51°C to 60°C) |
Frequently Asked Questions (FAQ)
Is PVC compatible with Nitric Acid (68%)?
PVC is rated C1-Fair (Caution: Short-Term or Emergency Use Only) with Nitric Acid (68%) (Formula: HNO3 (68% Azeotropic Concentrated), CAS: 7697-37-2). Induces moderate chemical attack, noticeable elastomeric swelling (10%–20%), loss of tensile modulus, or measurable metal pitting/etching (20–50 mpy). Not recommended for permanent pressurized piping or critical O-ring seals. Use only for short-duration flushing or non-critical gravity drain lines.
What is the best alternative material for handling Nitric Acid (68%)?
If PVC does not meet your temperature or pressure requirements for Nitric Acid (68%), the highest-rated Grade A alternatives are Stainless Steel, Viton, PTFE, PVDF. Always verify O-ring elastomers and metallic fasteners separately before full-scale deployment.
Technical Engineering FAQs: Nitric Acid (68%) vs PVC
Click any question below for chemical failure-mode specifics, thermal derating limits, and material selection rules: