Polybutylene Pipe Identification Made Simple

Tracing the web of pipes throughout your home can seem like an impossible task. Yet being able to identify the type of piping material is crucial for assessing potential risks and maintenance needs. Polybutylene (PB) plastic piping, widely used from 1978 until problems led to its discontinuation in 1996, has proven problematic in many households.

By understanding where to check for polybutylene pipes, what visual signs to look for, and how testing methods can help confirm the material, homeowners can simplify the identification process.

What Are Polybutylene Pipes?

Polybutylene (polybutene) is a form of plastic resin that was used extensively for water supply piping in residential construction from 1978 until the mid 1990s. The flexible piping was touted for its easy installation compared to copper pipes, as well as resistance to scale buildup. However, polybutylene has been found to become brittle and develop leaks over time, leading to major lawsuits and a nationwide class action settlement in the 1990s.

Why Identification Matters

Being able to identify polybutylene plumbing is important for assessing if and when pipes need to be replaced. The plastic piping has proven susceptibility to chlorine and other water chemicals, causing it to scale, flake, crack, and leak - resulting in water damage and potential mold growth issues. Replacement with copper, CPVC, or PEX piping prevents further degradation.

Overview of Identification Methods

Polybutylene pipes can be identified through visual inspection of pipe size, color, flexibility, markings, and location. Chemical testing with acetone and physical scratch testing can provide further confirmation. Tracing pipes to areas like crawl spaces, attics, and behind walls helps assess the full scope of polybutylene plumbing.

Visual Identification

The first step in identifying polybutylene piping is a visual inspection. Key signs to look for include:

• Size, diameter, and thickness: Typically 1/2 to 1 inch diameter in water supply applications.
• Color: Gray, blue, white, silver, black plastic appearance.
• Lettering: May be stamped "PB" and a manufacturing code or size designation.
• Flexibility: Polybutylene pipes maintain their curved shape.
• Location: Near water heater, under sinks, in crawl spaces.

Texture and Color Cues

The pipe texture feels smooth and slippery compared to rigid copper pipes or ribbed PEX and PVC pipes. Polybutylene is flexible enough that installers could bend the pipes to navigate tight spaces behind walls and under cabinets.

While copper maintains its bright orange-brown color, polybutylene pipes fade and discolor over years of water exposure. Their gray, blue, white, or black plastic coloring is a tell-tale sign of PB piping.

Lettering and Markings

Take note of any lettering printed on the pipes. "PB" labeling, along with a manufacturing code and size dimension, helps confirm polybutylene plumbing.

Lack of markings does not rule out polybutylene. Over time, lettering and size designations may fade. The pipe ends that connect to fittings are also typically unmarked.

Testing Methods

Visual identification provides a good starting point, but chemical testing and physical manipulation can help further pinpoint polybutylene pipes:

• Acetone test : Acetone lightly dissolves polybutylene on contact, causing surface tackiness and dullness. Drip a drop of acetone from a cotton swab on a short pipe section to check the reaction.
• Scratch test : Use a coin or key to gently scratch the pipe exterior. Polybutylene is soft enough that you'll make an impression without damaging copper or PVC.
• Torch test : Sparingly wave a small torch flame near the pipe surface (don't directly apply heat). Polybutylene scorches and gives off a wax or ammonia-like odor when burned.

Interpreting Test Results

The acetone drop test produces the fastest reaction, as polybutylene pipes turn sticky within 5-10 seconds. The scratch test requires more pressure but also leaves behind a visible scrape mark. Take precautions with the torch test - carefully wave the flame 6 inches away to avoid melting plastic pipes.

Negative test results are not definitive either, as plasticizer additives and pipe aging can affect chemical reactions. Weigh all evidence of pipe size, texture, color, flexibility and markings to make an accurate identification.

Where to Look for Polybutylene Pipes

Polybutylene pipes must be actively located, as much of the plumbing lies behind walls, under floors, and in difficult-to-access utility areas:

• Inside cabinet spaces exposed under sinks and behind toilets or showers
• Foundation slabs and crawlspaces
• Attics
• Basements
• Garages near water heater and supply lines
• Yard piping leading from municipal water supply line to house

Getting Past Limitations

Don't let closed walls, secured panels, or lack of home renovation experience stop you. With a strong flashlight, small mirror, and even your cell phone camera, you can peer behind nooks and crannies. Use a wire snake inspection camera to look behind pipes and scan inaccessible areas.

Remove interior or exterior panels as needed to trace supply lines. Building codes require access panels for this very purpose. Consult credentialed home inspectors if unable to fully trace pipe routes.

When to Suspect Polybutylene Piping

Homes built from 1978 up until the mid 1990s frequently used the once-popular flexible plastic piping. However, telltale signs of polybutylene pipe problems may show up years later:

• Low water pressure and leaks
• Browned, scaled pipes with cracks and holes
• Flood damage from pipe failures

Newer Isn't Always Better

Even newly built homes may unknowingly have polybutylene piping, as leftover supplies found their way into some late 1990s construction. Don't assume that polybutylene only exists in 70s, 80s, or 90s homes - identify pipes based on physical traits rather than age alone.

Also, inspection documentation for newer homes may lack detail on internal plumbing materials. Building codes have improved to require more pipe labeling, but gaps still occur in residential construction.

Polybutylene vs. Other Pipe Materials

Gaining familiarity with properties of copper, CPVC, PEX and PVC helps contrast against polybutylene traits:

• Copper : Rigid, brown-orange, soldered joints, no flexibility
• CPVC : Grayish-white plastic, harder than polybutylene, ribbed texture
• PEX : Red, blue, white flexible tubing with distinct periodic rings when bent
• PVC : Rigid white plastic pipe with purple primer at joints

How Polybutylene Differs

While cross-linked PEX has succeeded polybutylene as flexible supply piping, polybutylene pipes stand out for their smooth surface and uniform coloring without bands. The ease of bending polybutylene pipes helps distinguish from stiff copper, CPVC and PVC.

Final confirmation requires an acetone test, though, since modern PB pipe replacements mimic plastic or metal. Carefully examine any gray, blue, or black piping of unknown origins.