Can You Use Brass Fittings on Iron Pipe? What You Need to Know?

Can You Use Brass Fittings on Iron Pipe? What You Need to Know?

Why would you want to fit brass fittings on iron pipes? Because, brass fittings are strong, durable, corrosion and heat-resistant, and also easy to install. But, you need to consider a few things before the alignments. 

Now, the question is, can you use brass fittings on iron pipes?

Yes, you can use brass fittings on iron pipes if you match the size, type, diameter, temperature and pressure measurements for both. Along with that,  you need to maintain some procedures such as dielectric union and zinc coating. These processes go for all kinds of iron pipes used in the heater. 

That’s not all. There are other concerns depending on your heater’s situation and context. But, no need to worry. Let’s discuss whether you can use brass fittings on iron pipes like we did with fitting plastic caps on top of water heaters.

When to Use Brass Fittings on Iron Pipes

So, you can use brass fittings on iron pipes in certain situations. You need to check variables such as corrosion resistance, temperature, compatibility and cost. If the variables are checked between brass fittings and iron pipes, you’re all set to use. This also goes if you’re thinking of piping water heaters in parallel.

Corrosion Resistance: Brass fittings are more corrosion-resistant than iron. So, if your piping application entails exposure to moisture or other corrosion elements, brass is a good choice. 

Temperature: For high-temperature applications, brass fittings are a good choice. Note that brass can withstand higher temperatures than iron. 

Compatibility: Brass fittings are usually used for copper pipes. So, if you’re using brass fittings on iron pipes, better check the compatibility. This entails size, type, diameter, temperature and pressure compatibility. 

Cost: Brass fittings are more expensive than iron fittings. So, before making the decision, check the cost of your specific application. 

Not only that, as brass and iron are dissimilar materials, you need to be aware of some considerations for long-term use. 

When Not To Use Brass Fittings on Iron Pipes

not use brass fittings on iron pipes

Source: coppertubingsales.com

Brass is a softer metal and will eventually result in leaks and cracks in long-term use. Also, brass is more likely to corrode when on iron pipes without precautions. If you do not follow specific considerations and procedures, these things can happen. 

Let’s see some reasons why and when you should not use brass fittings on iron pipes. See the reasons below.

Reason 1: Constant High Temperature and High-Pressure 

Brass has a lower melting point than iron. So, it can lead to thermal expansion if temperature changes for your boiler’s pressure in different psi. And when temperature changes, brass contracts and expands at a different rate than iron leading to damages and leaks. 

Although brass can withstand higher temperatures and pressure, it is not advised for long-term use. Exposure to constant high-temperature and high-pressure heating applications, brass fittings may result in deformation and melting. This results in major leakages and other issues for your heating system. 

Reason 2: Galvanic Corrosion

Brass is an alloy of copper and zinc. This might be a problem when you’re directly putting it on iron pipes. This is simply because dissimilar metals can lead to galvanic corrosion when coming in contact with one another. 

Here, the dielectric union works as a protective barrier between these two dissimilar metals. Thus, electrons are prevented from flowing from one metal to another. 

On the other hand, zinc coating does the same thing by working as a corrosion agent to protect the iron from rust and corrosion. As a result, your pipe gets a long-lasting assurance. You need to use one or the other. 

Reason 3: Water Additives

What kind of water is in your heating system can also impact the brass fittings and the iron pipes. If the water has dissolved minerals or solids or is highly acidic, this lead to corrosion and the heating system fails. 

Brass fittings often contain lead. Lead is highly toxic. So, you should not use brass fittings for drinking water applications. 

Reason 4: Brass Has Low Strength

Generally, brass is harder than many other metals, such as copper or aluminum, but it is not as hard as steel. However, brass is a relatively soft metal compared to some other metals used in plumbing, such as stainless steel.

In terms of long-term pipe applications, brass fittings can be durable and reliable if they are properly designed, installed, and maintained. The brass alloy, however, can be susceptible to corrosion and dezincification, which results in a porous and weak material, which can eventually fail and leak.

Reason 5: Dezincification

Dezincification is a form of corrosion that often occurs for brass fittings. This is because brass has zinc as an alloy material. So, this leads to corrosion and thus leaks and rust. That’s why to prevent dezincification, selecting high-quality brass fittings with a low zinc content is recommended.

Reason 6: Complex Installation

Installing brass fittings requires special equipment and also it takes a complicated procedure. So, unless you have the right tools or expertise, it is advised to contact professionals. Hence, before making a decision, you might as well discuss it with your local heating contracts. 

Now, you might think of what are the materials that come with the best compatibility with brass fittings. I would have asked that too, so let’s find out.

So, Now you know when not to use brass fittings on the iron pipe and all the considerations. Let’s see things to consider for brass fittings on iron pipes.   

Things to Consider when Using Brass Fittings on Iron Pipes

Using Brass Fittings on Iron Pipes

First things first. The short answer to the problem is yes, you can use brass fittings on iron pipes. But there are some considerations that you need to make before putting this to work. 

Brass is more corrosion-resistant than iron and lasts much fewer years (up to 45 years) than iron (up to 100 years). So, compatibility is a major issue. You also need to match the size, type, diameter, temperature and pressure applications of brass fittings and iron pipes.

Now, after matching compatibility and other measurements, brass fittings still might lead to corrosion or rust on your iron pipe. So, the question is how can you use brass fittings on iron pipes safely? Well, here’s how. 

Dielectric Union:

First of all, mixing dissimilar metals in your heater’s piping system can lead to galvanic corrosion and rust. Well, there’s an easy remedy for that which is called “Dielectric Union.” 

It prevents corrosion and rust by separating the two metals with materials that are non-conductive (rubber, plastic etc). Here’s how to do dielectric union. 

Tools Needed:

  • Dielectric union (Rubber/Plastic)
  • Hacksaw or pipe cutter
  • Teflon tape
  • Pipe wrench

Step-1: First, you need to turn off the supply pipe you’re working on. The main water shut-off valve is typically located near the water meter, which is usually in the basement, crawlspace, or outside the house.

Turn the valve clockwise until it is fully closed. This will stop the flow of water to your home and allow you to work on the pipes without water coming out.

Now, you should open the faucets and let the water drain from the pipes. This will release any remaining water pressure.

Step-2: Using a hacksaw or pipe cutter, cut the iron pipe according to the required length. Be aware of removing any sharp edges or burrs from the pipe’s cut end.

Step-3: Using a pipe wrench, tighten the brass fittings onto the iron pipe’s end. Tighten it securely but refrain from over-tightening it. 

Step-4: Now wrap around the brass fittings with Teflon tape for a tight seal.

Step-5: Screw the dielectric union that works for you (rubber/plastic) onto the brass fittings. Then, using a pipe wrench tighten the connection a quarter turn after it’s hand-tight. 

Step-6: Now, connect the second half of the dielectric union by following the same steps. 

Step-7: Finally, turn on the supply line. If there are no water drops, dampness or discoloration around the union, then there are no leaks. Also, check the water pressure. Low water pressure than the appropriate level means there is a leak. 

Also, you can use leak detection tools such as a moisture meter or water leak detector to find out any leaks.   

Precautions: Always start this process by turning the supply line off. This will prevent any injuries. Also, use the manufacturer’s instructions properly to securely complete the procedure. Wear protective gloves and eye protection while working on pipes. 

This process helps to prevent galvanic corrosion from happening and thus increases the pipe’s lifespan. Dielectric union is commonly used in heating systems and can be found in most heater supply stores. You can do it yourself at home. 

Also, their availability may vary depending on the location and specific application of your heating system.

The cost of dielectric union varies depending on the setting. If your heating system is for small residential applications, the cost may vary from $10-100$. But if on an industrial-level heating system, the cost varies from $100-$300 based on the specific application. 

Zinc Coating:

In this process, a layer of zinc is coated on the iron pipe. Here, the coated zinc protects the iron by corroding before iron if corrosion were to happen. As a result, this also helps to extend the pipe’s lifespan.

Zinc coating is available widely and also has decorative value. The cost of zinc coating, on the other hand, depends on the size, system and extent of the required coating. But usually, this is more expensive than the dielectric union. 

Additionally, zinc coating is not durable in seawater environments. So, if you live near the sea, it is best not to use this process. 

Remember, this is a process that you cannot do by yourself unless you have professional expertise. So, you need the expertise of heating professionals to do this. Still, if you have the right tools and thinking of doing it at home, here is a little DIY help for you.

So, now that you know these two essential processes, let’s see what will happen if you do not follow them. 

What Metal Is Compatible with Brass Fittings?

Brass fittings are a popular choice for plumbing or heating applications. But, brass fittings are not compatible with all metals in piping applications. Let’s look at some metals that are compatible with brass. 

  • Copper: Brass fittings are most compatible with copper and are often used in plumbing or heating applications. 
  • Stainless Steel: Brass can be used with stainless steel (301,304,310) if proper connections and measurements are used. 
  • Iron: Brass fittings can also be used with iron with proper connections and measurements. 

What are Some Alternatives Of Brass Fittings on Iron Pipe?

If you have cost or other issues, some other fittings can be better options. Here, we’ll recommend some options for your ease. 

You can use the following fittings as well on your heater.

  • Malleable Iron fittings: These are common choices for their durability, strength and resistance to high pressure and temperature. They also come in various shapes and sizes such as tees, reducers, elbows, and couplings. 
  • Steel Fittings: These are extremely strong, corrosion-resistant and durable to use with iron pipes. However, to protect them from corrosion zinc coating may be applied. 
  • PVC Fittings: These are popular nowadays for their easy-to-install use,  cost-efficiency and corrosion-resistant. They also come in various shapes. However, these are not suitable for high-temperature and high-pressure applications. 
  • CPVC Fittings: These are a little more expensive than PVCs but still less than brass. They are popular for their use in high-pressure and temperature applications such as water heaters.

Moreover, we recommend using iron fittings or even stainless steel fittings with the right measurements. These are much safer, stronger and last longer than brass without possible errors.

Frequently Asked Questions (FAQs):

What Metal Is Compatible With Brass?

Brass is compatible with metals such as copper, stainless steel, aluminum, carbon steel etc. Being in the same galvanic series, these metals when used with brass will not cause galvanic corrosion to happen. 

Can You Use Brass Fittings For Gasoline?

The answer is no. Because gasoline has some chemical properties that, when in contact with brass, result in major corrosion, damage and leakages to the piping system. Gasoline also causes brass to crack and brittle from time to time.    

Can You Use Brass Fittings In Galvanized Pipes?

It is not advised to use brass fittings in galvanized pipes. Galvanized pipes contain a layer of zinc coating on both sides. So, the reaction between the galvanized pipe and brass can lead to major corrosion, leakage and other hazards. 

Concluding Words

So, you should be aware of the considerations discussed. It is clear that brass fittings are good with some metals and they are also popular for durability. But they also depend on various factors such as strength, compatibility, measurements etc. 

So, Can you use brass fittings on iron pipes? You can if you maintain the considerations discussed for your heater properly. So, good luck!


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