PVC (polyvinyl chloride) pipe is a popular plastic piping material used for plumbing, drainage, and industrial piping applications. PVC is lightweight, durable, corrosion resistant, and inexpensive compared to other piping materials. However, there are concerns about whether PVC pipe deteriorates over time. This article examines the factors that can cause PVC pipe to deteriorate and provides recommendations for maximizing the lifespan of PVC pipe systems.
What is PVC Pipe?
PVC pipe is made from polyvinyl chloride resin mixed with additives. The PVC resin can be rigid or flexible, allowing PVC pipes to be used for different applications.
Rigid PVC pipes are typically white or gray and are used for plumbing, drainage, and industrial piping. The rigid form of PVC makes it suitable for applications that require high pressure capacity and resistance to impacts.
Flexible PVC pipes are used for low pressure drainage and sewer connections. Flexible PVC can bend without breaking, allowing it to fit tightly in places where rigid pipes won’t work.
Both rigid and flexible PVC pipe are joined using PVC solvent cements that chemically melt and fuse the pipes together. Properly joined PVC pipe creates permanent, watertight seals.
Does PVC Pipe Deteriorate Over Time?
Like any material, PVC pipe will eventually deteriorate over a long enough period of time. However, PVC pipe has a reputation for being very durable and long-lasting if installed properly.
Several factors contribute to the deterioration of PVC pipe:
UV Exposure
Exposure to UV rays from sunlight can cause PVC pipe to become brittle and crack over time. Most PVC pipe installations are buried or indoors, protecting the pipes from sunlight. However, any exposed outdoor PVC pipe will deteriorate faster.
Using UV-resistant PVC formulations can slow this degradation. PVC pipe intended for outdoor use should be marked as UV-resistant. Painting or wrapping exposed PVC pipe also protects against UV rays.
Chemical Exposure
Certain chemicals can weaken PVC pipe and cause it to crack or leak. In particular, exposure to chlorinated hydrocarbons and aromatic hydrocarbons can degrade PVC. Gasoline, solvents like acetone, and oils like turpentine can soften and break down PVC pipe.
Care should be taken to prevent chemical spills or leaks from coming into contact with PVC piping. PVC pipe near gas stations, chemical plants, or industrial facilities is at higher risk of chemical degradation.
Temperature Extremes
PVC becomes more brittle and prone to cracking when exposed to freezing temperatures or temperature fluctuations. Sustained high temperatures above 140°F can also damage PVC pipe over time.
Properly buried PVC pipe maintains a more stable temperature and is less affected. But above ground or poorly insulated PVC pipe in attics and unheated warehouses can deteriorate faster when exposed to temperature swings.
Improper Installation
Flaws during PVC pipe installation can lead to premature failure. Using too much solvent cement can soften the interior walls of pipe joints. Under-tightening joints can allow leaks and separation over time. And excessive pressure surges can overload pipe joints.
Following manufacturer specifications for properly cutting, deburring, priming, and joining PVC pipe ensures tight, long-lasting seals. Careful pressure testing after installation can identify weak points before they fail.
Poor Quality Pipe
Not all PVC pipe meets quality control standards. Lower grade PVC resin or the use of insufficient stabilizer additives can greatly reduce the lifespan of PVC pipe. Reputable brands of PVC pipe marked with applicable standards organizations (ASTM, NSFF, etc.) will have the longest service life.
How Long Does PVC Pipe Last?
When properly manufactured, transported, installed, and maintained, PVC pipe can easily last 50 years or longer.
The plastic material itself does not degrade quickly. The Polyvinyl Chloride Coalition, an industry group that producers PVC materials, states that high quality PVC pipe has an estimated lifespan of 100 years or more.
While many factors affect actual PVC pipe lifespan, well installed buried PVC pipe is expected to last for decades without issue. One Florida study examined decades-old PVC plumbing pipes and found them to be “in excellent condition after nearly 30 years in service”.
With UV protection and chemical resistance taken into account, above ground PVC pipe is also estimated to have a lifespan of 50+ years.
The main causes of PVC pipe deterioration – UV light, chemical exposure, temperature extremes and improper installation – can be mitigated to maximize service life. Maintenance to repair damage from external factors as it occurs also allows PVC systems to operate reliably long term.
How to Extend the Lifespan of PVC Pipe
These tips will help prevent premature deterioration and extend the usable life of PVC pipe:
Use Pipe Approved for the Application
Select the proper PVC material and pressure rating for your application. Using pipe intended for drainage on a pressure water system can lead to failures.
Protect from Sun Exposure
Paint or wrap exposed PVC pipe and use UV-resistant formulations for outdoor installations. Bury pipe at sufficient depth whenever possible.
Insulate Above Ground PVC Pipe
Insulation reduces damage from temperature extremes. Foam covers, heat tape, and burying pipe below the frost line can help.
Cushion Against Vibration
Use hangers, braces, and anchors to prevent pipe movement and vibration damage.
Avoid Chemical Contact
Select alternative pipe materials if possible for systems with chemical exposure. Use containment to prevent leaks contacting PVC.
Join Pipe Properly
Follow manufacturer solvent welding instructions. Allow joints full cure time to maximize strength.
Pressure Test After Installation
Pressure test new PVC systems at 1.5 times the working pressure to identify weak joints before system use.
Clean and Inspect Regularly
Clean PVC systems prevent buildup of soils and chemicals that can accelerate wear. Inspect for leaks, cracks, and deterioration.
Repair Damage Promptly
Fixing issues quickly prevents small problems from cascading into major failures. Carry spare parts, solvents, and tools for emergency repairs.
Signs of PVC Pipe Deterioration
Watch for these warning signs of PVC pipe degradation:
– Discoloration or chalky appearance
– Hardening or brittleness
– Cracking or crazing marks on pipe surface
– Deformed pipe shape (flattening, sagging)
– Leaking or weeping joints
– Separated or misaligned joints
– Soft or tacky feeling pipe
– Loss of solvent weld at joints
Catching deterioration early allows for repairs before major pipe failures occur. Any observed damage should be documented and monitored for spreading. Loss of pipe function may necessitate full replacement of affected sections.
Replacing Deteriorated PVC Pipe
If PVC pipe deterioration becomes severe enough, full replacement of damaged sections will be required. Here are some guidelines for replacing deteriorated PVC pipe:
– Cut out damaged sections and solvent weld in new matching PVC pipe using couplings and joints. Remove 12 inches of good pipe past damaged areas.
– Support existing pipe during cutting to prevent system movement or collapse.
– Inspect surrounding pipe for additional deterioration. It may be time to replace entire pipe runs.
– Discard old PVC pieces after removal. Damaged PVC should not be reused.
– Pressure test repaired piping before returning system to full use. Monitor joints closely for leaks initially.
– Consider underlying causes of deterioration and preventative measures to increase lifespan of new PVC pipe.
With proper installation and maintenance, PVC pipe can last for decades without issue. But if deterioration does occur, targeted repairs and replacements can extend the useful life of the overall system.
PVC Pipe Deterioration FAQs
Does PVC pipe eventually crack?
Like any material, PVC will eventually crack given a long enough service life, especially if exposed to harsh conditions or stresses. However, high quality PVC pipe installed correctly can last 50-100 years before any cracking occurs. Ongoing maintenance checks for minor cracking can allow repairs before major failures happen.
Does PVC get brittle with age?
PVC can become brittle over time with exposure to sunlight or repeated freezing temperatures. This happens at a molecular level as UV radiation and cold temperatures cause the plasticizers in the PVC to evaporate, making it less flexible. Using UV-resistant formulations and insulating PVC pipe can minimize brittleness.
Can old PVC pipe be repaired?
Minor leaks, separations, and cracks in PVC pipe can often be repaired by solvent welding in couplings, replacing broken joints, or patching damaged sections. But extensive deterioration and brittleness may necessitate full replacement of pipe sections.
How do I get rid of old PVC pipe?
PVC scrap should not be disposed in landfills or recycling with other plastics. Check for PVC recycling options in your area, as recycled PVC can be reformed into new PVC products. If no other option, old PVC pipe can be discarded in waste-to-energy facilities or disposed at specialty construction waste facilities.
Does PVC pipe have a shelf life?
Before installation, PVC pipe has an indefinite shelf life and should not deteriorate over time if stored properly out of sunlight. The plasticizers and stabilizers in PVC prevent it from breaking down for many years in storage. However, very old stock or improperly stored pipe may become brittle and crack more easily once installed.
The Bottom Line
PVC pipe can last 50 years or longer with proper formulation, handling, installation, and maintenance. Avoiding UV light degradation, chemical contact, temperature extremes, and mechanical stress are key to maximizing PVC pipe lifespan. Minor damage can be repaired, but severe deterioration will necessitate replacing affected sections. Considering the lifespan and low cost, PVC remains an effective piping material across many residential, commercial, and industrial applications.
