Are Plastic PEX Fittings Any Good? A Complete Guide to PEX Fittings: Brass vs Plastic

Hey there! If you‘re embarking on a plumbing project using PEX tubing, one of the first big decisions you‘ll need to make is whether to use brass or plastic fittings to connect up all that flexible piping. Both have their pros and cons, so let‘s take a detailed look to help you make the best choice.

Quick Intro to PEX Tubing

In case you‘re new to PEX, here‘s a quick overview. PEX stands for cross-linked polyethylene – it‘s a specially manufactured plastic tubing that‘s extremely useful for plumbing applications.

The cross-linking makes PEX piping extra flexible and durable compared to regular polyethylene tubing. This gives it some nice advantages:

• Easy to snake through walls and ceilings
• Resists scale buildup and corrosion
• Withstands temperature extremes from -40°F to 200°F
• Can withstand high water pressure – over 200 PSI
• Less prone to leaks and flooding
• Faster to install than copper or PVC piping

PEX has become a very popular solution for hot and cold water supply lines, radiant floor heating, and many other residential and commercial plumbing systems.

But to create those systems, you need fittings that securely connect the flexible PEX tubing to fixtures, valves, pumps and other components.

PEX Fitting Options: Plastic or Brass?

When it comes to PEX fittings, you mainly have two material options:

Plastic: Fittings made from plastics like PEX, PVC, acetal, and polyphenylene sulfide (PPS). The most common is PEX itself.

Brass: Fittings made from brass alloys, usually copper and zinc. Brass has traditionally been used for plumbing.

Both plastic and brass PEX fittings are widely available. But which is the better choice for your project? Let‘s compare some of the key factors.

Cost Comparison

One of the biggest differences between plastic and brass PEX fittings is cost. Plastic options tend to be much cheaper – often 75% less expensive for the same type of fitting.

For example, here‘s an actual price comparison for basic PEX fittings:

	Plastic	Brass
10 x 1/2" elbows	$3.50	$17.50
10 x 3/4" tee fittings	$6.25	$35.00
10 x 1" union fittings	$9.75	$45.00

As you can see, choosing plastic over brass for an entire plumbing system can lead to significant cost savings in materials.

Durability and Lifespan

Now let‘s look at expected lifespan. Brass is well known for its durability – a brass fitting should last 50 years or more.

Plastic fittings have a shorter lifespan, averaging 10-25 years depending on material and conditions. Higher temperatures, UV exposure, and stress can cause plastics to become brittle and crack over time.

Studies have found failure rates for plastic PEX fittings to be 5-10 times higher than quality brass fittings. One such study saw leaks develop in over 18% of plastic PEX fittings after just 10 years. [Source]

So while plastic is the cheaper option up front, it may need to be repaired or replaced much sooner than brass.

Ease of Installation

Installing plastic PEX fittings is generally quicker and simpler, especially for DIYers.

Many plastic fittings are just pushed together by hand without tools. Brass fittings, on the other hand, typically require crimping or expansion tools to properly secure the tubing.

Performance at High Temperature/Pressure

Brass fittings really shine when it comes to handling high temperatures and pressures. Most brass options are rated to pressures over 200 PSI at temperatures up to 200°F.

Plastic fittings vary in their ratings, but some may be limited to around 110°F and 100 PSI. So brass is the way to go for hot water lines and other high demand applications.

Code Approvals

The good news is both brass and plastic PEX fittings carry certifications from plumbing standards organizations like NSF, CSA, and IAPMO. This confirms they meet safety and performance requirements.

However, brass fittings tend to be approved for a wider range of applications, especially potable water and heating systems. Some plastic options may be restricted only to radiant heating or low pressure uses.

Where Can You Use Plastic PEX Fittings?

Considering its drawbacks, when does it make sense to use plastic PEX fittings? Here are a few scenarios:

Temporary Installations

For a plumbing system you only need working for a few years, plastic provides an affordable option. Just bear in mind you‘ll likely need repairs or full replacement down the road.

Easily Accessible Areas

Plastic fittings may work in installations where they can be easily accessed for inspection and replacement if needed. Under a sink or in unfinished utility areas are good examples.

Non-Critical Systems

For radiant floor heating, underfloor tubing, auxiliary lines, and other systems where a leak wouldn‘t be catastrophic, plastic fittings pose lower risk and cost.

Low Pressure and Temperature

If temperatures will stay under 110°F and pressure below 80 PSI, plastic fittings should hold up fine for low demand applications.

When to Use Brass PEX Fittings

Here are the types of plumbing systems where brass fittings really make the most sense:

Permanent Installations

Any time you need the system to last decades without issue, invest in quality brass fittings upfront. They‘ll provide peace of mind thanks to superior longevity.

Buried and Inaccessible Areas

When fittings will be hidden and difficult to access in floors and walls, brass is by far the safer choice. You want to minimize the risk of failures and leaks down the road.

Potable Water Lines

For fresh water supply plumbing feeding sinks, tubs, appliances, drinking fountains – spend the extra on brass. This ensures clean, safe water.

Hot Water Plumbing

Any hot water line or heating system with temperatures over 110°F should absolutely use brass fittings rather than plastic.

High Pressure Systems

In high pressure applications over 80 PSI, brass fittings provide the strength and reliability needed to avoid leaks and damage.

Corrosive Conditions

Brass stands up better to a wider range of water types and conditions. Plastic can become brittle and crack sooner when exposed to corrosive water.

Installing PEX Fittings the Right Way

To get the best results from either plastic or brass PEX fittings, proper installation is critical. Follow these tips:

Use the Proper Tools

• Plastic push-to-connect fittings can often be installed by hand, but backups like channel-lock pliers may help achieve a tighter connection.
• Brass fittings usually require a crimping or expansion tool to properly secure the tubing according to manufacturer specs.

A PEX crimping tool properly secures brass fittings.

Secure and Support the Fittings

• Use hangers and clamps to properly secure and support plastic and brass fittings. This prevents stress that could lead to leaks over time.
• Avoid letting fittings support the weight of the plumbing. The pipes themselves should be secured.

Proper support prevents strain on fittings.

Perform Leak Testing

• After installation, pressure test the plumbing system and check all fittings for leaks. Immediately address any leaks found.

Follow Manufacturer Guidelines

• Closely follow the tubing/fitting insertion depth, tool operation, temperature, pressure and other recommendations provided by the fitting manufacturer. This ensures optimal performance.

When installed correctly using the right methods, both brass and plastic fittings can provide a secure, leak-free connection. But it‘s vital to take the time to do it right. Rushing through the job can compromise the long-term reliability of any fitting.

Caring for Your PEX Plumbing System

To keep your PEX plumbing working well for years to come, here are some maintenance best practices:

• Inspect Annually – Take a close look at all fittings, pipe runs and connections. Look for damage, leaks, corrosion and other warning signs.

• Check Connections – Ensure tubing is still securely attached to fittings. Tighten or re-install any fittings that have become loose.

• Consider Replacing Plastic – For older systems, replace plastic fittings over 10 years old with new brass ones as preventive maintenance.

• Avoid Harsh Chemicals – Use care when cleaning PEX tubing to avoid degrading plastic fittings or damaging the pipe interior.

• Check Water Quality – Install filtration if needed to remove sediment and corrosive elements that shorten fitting lifespan.

Inspecting PEX fittings annually can avoid major issues down the road.

Staying on top of maintenance lets you address any problems with fittings early on before they become big headaches.

Helpful Tips for Choosing Quality Fittings

Since PEX fittings are such a critical component, you want to pick the right ones. Here are some tips:

For Brass:

• Stick with name brand, certified fittings from reputable manufacturers

• Ensure a minimum of 65% copper and zinc in the brass alloy

• Avoid fittings with cracks, gaps, rough edges or other flaws

For Plastic:

• Select fittings certified for potable water use (NSF-pw, CSA)

• When possible, match fitting brand to PEX tubing brand for optimal compatibility

• Fittings should have no cracks, gouges, cloudiness or other defects

• PPS plastic fittings offer maximum heat resistance and longevity

Buying the cheapest fittings available often leads to premature failures and leaks down the road. Spending a little more for quality provides excellent insurance.

The Last Word on Plastic vs Brass PEX Fittings

Hopefully this gives you a comprehensive overview of the brass vs plastic decision for your PEX plumbing project. To recap the key points:

Plastic fittings are much more economical but have a shorter lifespan, especially with hot water. Go plastic for low demand applications only needing temporary use.

Brass fittings are more expensive yet extremely durable. They‘re the wiser long term investment for any application needing to last decades without issue.

By understanding the pros and cons of each material and how to install them properly, you can make the optimal choice for your specific needs. Your plumbing will benefit from fittings selected based on performance rather than just cost.

That wraps up this in-depth look at PEX fittings. Let me know if you have any other questions!