### 1. Which is better 304 or 316 stainless steel?
**316 is generally better for corrosive environments**, especially near saltwater or chlorides. **304** is more cost-effective for general use. **Key difference**: 316 contains 2–3% molybdenum, enhancing corrosion resistance against chlorides, acids, and industrial chemicals. For plumbing in aggressive conditions (e.g., coastal areas), 316 is superior. In mild environments, 304 is often sufficient and more economical.
---
### 2. Why isn't stainless steel used in plumbing?
**Cost and installation complexity** are primary reasons. **Copper, PEX, and CPVC** are cheaper, easier to install, and more flexible. Stainless steel requires specialized tools for cutting/threading, and skilled labor. **Historical preference** for established materials also plays a role. It *is* used in niche applications (e.g., commercial buildings, coastal areas, chemical plants) but is less common in residential plumbing due to economics.
---
### 3. Is stainless steel good for water pipes?
**Yes, it's excellent for water pipes** when correctly specified. **Advantages**:
- Exceptional corrosion resistance (long lifespan).
- Hygienic (no leaching, FDA-approved for potable water).
- Strong and durable (handles high pressure/temperature).
**Common uses**: High-end water systems, hospitals, ships, and areas with aggressive water chemistry. Ensure the **grade (316 vs. 304)** matches water chlorinity/pollution levels.
---
### 4. What are the disadvantages of stainless steel pipes?
- **Cost**: 2–5× more expensive than copper/PEX.
- **Installation**: Harder to cut/thread; requires specialized tools/training.
- **Thermal expansion**: Higher than plastic pipes, requiring careful support.
- **Crevice corrosion**: Risk in stagnant water or under deposits (e.g., sediment).
- **Chloride sensitivity**: 304 can corrode in high-chloride water; 316 is better but pricier.
- **Weight**: Heavier than plastic alternatives.
---
### 5. Will stainless steel be ok in water?
**Yes, stainless steel is highly resistant to water corrosion** when:
- The **correct grade** is used (e.g., 316 for chlorinated/salty water; 304 for mild conditions).
- Water is **flowing** (stagnant water increases corrosion risk).
- No **galvanic corrosion** occurs (e.g., avoid direct contact with carbon steel/copper).
Properly selected, stainless pipes can last 50+ years in water systems.
---
**Summary**:
- **304 vs. 316**: 316 wins in corrosive settings; 304 for cost savings.
- **Plumbing use**: Limited by cost/installation, not performance.
- **Suitability**: Excellent for water pipes with correct engineering.
- **Disadvantages**: Cost, installation challenges, and chloride sensitivity.
- **Water exposure**: Safe and durable with proper grade selection.
