Pipe Fittings Guide: Brass vs. Bronze vs. Galvanized vs. Black
When you're working on commercial plumbing, fire protection, or mechanical systems, the material you choose for your fittings isn’t just a matter of preference—it’s a matter of performance, longevity, and compliance.
Whether you're roughing in a new riser, running backflow assemblies, or replacing system components, knowing the difference between brass, bronze, galvanized, and black iron fittings can save time, prevent corrosion issues, and help you pass inspections without delays.
Quick Comparison: Pipe Fitting Materials
| Material | Best Uses | Pros | Cons |
|---|---|---|---|
| Brass | Potable water, compressed air, some fire protection | Corrosion-resistant, easy to thread, durable | Pricier than galvanized, must be lead-free for drinking water |
| Bronze | Fire sprinklers, marine, humid environments | Strong, long lifespan, great corrosion resistance | Heavy, more expensive, not always needed |
| Galvanized | Outdoor, low-pressure water, non-potable lines | Affordable, widely available | Zinc coating wears down, not for gas or fire, can clog |
| Black Iron | Gas, propane, dry sprinklers, steam | Low-cost, strong, easy to thread | Rusts quickly, not for potable water, limited in some codes |
Brass Fittings: Durable and Versatile
Brass fittings are commonly used in potable water systems and some mechanical applications because of their corrosion resistance and durability.
When to Use Brass:
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Potable water lines (lead-free versions)
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Compressed air and gas systems
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Some fire protection applications
Pros: Highly corrosion-resistant, good with moderate heat and pressure, easy to thread and seal
Things to Watch: Must meet lead-free requirements for drinking water, pricier than galvanized or black
Shop brass nipples, elbows, tees, and adapters — all lead-free and UL/FM approved → Shop Brass Fittings
Bronze Fittings: Similar but Not the Same
Bronze fittings are often confused with brass, but they're typically stronger and more corrosion-resistant in marine and high-moisture environments.
When to Use Bronze:
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Fire sprinkler systems
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Marine or high-humidity applications
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Valve bodies and specialty fittings
Pros: Excellent corrosion resistance, UL/FM ratings common, long lifespan in harsh environments
Cons: Heavier and more expensive, often only required if specified
Galvanized Fittings: Coated for Protection
Galvanized fittings are steel with a zinc coating, designed to resist rust—but that coating only goes so far.
When to Use Galvanized:
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Low-pressure water systems
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Outdoor plumbing exposed to weather
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Non-potable water lines
Pros: Affordable, easy to source, standard sizing available everywhere
Cons: Zinc layer wears down, not suitable for gas or fire lines, may flake or clog over time
Browse galvanized fittings in all standard sizes → Shop Galvanized Fittings
Black Iron Fittings: Simple and Strong
Black iron fittings are uncoated steel, the go-to for gas, oil, and certain fire protection setups. Economical and widely used, they just need extra care against rust.
When to Use Black:
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Natural gas and propane systems
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Dry fire sprinkler systems
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Steam and oil lines
Pros: Low-cost, easy to thread and seal, strong in industrial settings
Cons: Rusts easily if exposed to moisture, not safe for potable water, limited approval in some jurisdictions
Stock up on black pipe elbows, nipples, and tees — ready to ship in bulk
Match the Fitting to the Job
Choosing the right material isn’t just about price—it’s about making sure your work holds up under pressure (literally) and passes inspection the first time.
At Nasco Supply, we carry:
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Brass and bronze fittings for fire and water systems
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Galvanized fittings for general-purpose installs
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Black fittings for gas and dry sprinkler lines
Need help sourcing a hard-to-find fitting? Call us or check availability online — we’ll help you get it done right.
FAQ: Pipe Fittings Explained
Are brass fittings safe for drinking water?
Yes, as long as they are lead-free brass fittings. These meet NSF and federal requirements for potable water systems.
What’s the difference between brass and bronze fittings?
Brass is more versatile and affordable, while bronze is stronger and excels in high-moisture or marine environments. Fire sprinkler specs often call for bronze.
Can I use galvanized fittings for gas lines?
No. Gas line codes prohibit galvanized because the zinc layer can flake and clog the system. Use black iron instead.
Why can’t I use black iron for potable water?
Black fittings rust quickly when exposed to water, which contaminates drinking systems. They’re only approved for gas, oil, steam, and some fire setups.
Which fitting lasts the longest?
Bronze typically lasts the longest in harsh environments, while brass performs well in most applications. Galvanized is shorter-term, and black fittings need rust protection.
Ready to find the right fitting? Browse all pipe fittings at Nasco Supply — trusted by plumbers and fire protection pros nationwide. → Shop All Fittings