When selecting materials for fittings in chemical transfer, consider the chemical compatibility, temperature, pressure, and mechanical properties. Here are some common materials and their suitability:
1. **Stainless Steel (316/316L):** 
   - Best for: Acids, alkalis, and solvents.
   - Advantages: High corrosion resistance, good mechanical strength, and temperature tolerance.
   - Limitations: Not suitable for hydrochloric acid or chlorine.
2. **Polypropylene (PP):**
   - Best for: Acids, alkalis, and aqueous solutions.
   - Advantages: Lightweight, cost-effective, and good chemical resistance.
   - Limitations: Limited temperature range and not suitable for strong oxidizers.
3. **Polyvinylidene Fluoride (PVDF):**
   - Best for: Acids, halogens, and alcohols.
   - Advantages: High chemical resistance and good mechanical properties.
   - Limitations: More expensive than other plastics.
4. **Polytetrafluoroethylene (PTFE):**
   - Best for: Almost all chemicals, including strong acids and bases.
   - Advantages: Excellent chemical resistance and wide temperature range.
   - Limitations: Low mechanical strength and high cost.
5. **Polyethylene (PE):**
   - Best for: Acids, alkalis, and some solvents.
   - Advantages: Good chemical resistance and cost-effective.
   - Limitations: Limited temperature range and not suitable for strong oxidizers.
6. **Hastelloy:**
   - Best for: Highly corrosive environments, including strong acids and chlorine.
   - Advantages: Exceptional corrosion resistance and high strength.
   - Limitations: High cost.
7. **Brass:**
   - Best for: Water, air, and non-corrosive fluids.
   - Advantages: Good mechanical properties and cost-effective.
   - Limitations: Poor resistance to acids and ammonia.
8. **PVC (Polyvinyl Chloride):**
   - Best for: Water, acids, and alkalis.
   - Advantages: Cost-effective and easy to install.
   - Limitations: Limited temperature range and not suitable for organic solvents.
Always consult chemical compatibility charts and consider the specific conditions of your application when selecting materials.