When to Use Clear PVC Piping: Benefits and Pitfalls

Clear PVC is often one of the first things people think of when it comes to double-contained pipe. It shows up in many internet searches and is a natural first thought when it comes to non-metallic pipe. That’s because clear PVC lets users easily see when a leak is present and, when used in single-wall applications, can provide monitoring in settings like food processing and lab environments. Based on the desired outcome and installation, this may be the perfect choice for your piping system.

An advantage of using clear PVC pipe in combination with leak detection systems is the redundancy of both visual and digital sensors. Since continuous sensor cables are not suitable for a product line such as Pro-Lock®, the added visual inspection can meet the need. The clear pipe provides visual confirmation, while probe leak detection at low points throughout the installation can give operators an early warning.

PVC is a very versatile and durable material in many applications. Using clear PVC for containment can have many advantages, including the obvious reason of giving an unobstructed view of the carrier pipe. This can be true in certain situations but may not provide the same level of visibility over time. This is not to say it should never be an option, though: Pro-Lock® clear PVC pipe is available and a good choice for indoor installations in climate-controlled environments with a low risk of chemical attack or permeation by the chemical media. The constraints in such an environment are specific to maintaining the pipe’s clarity for its intended purpose.

Clear PVC is very expensive compared to the more commonly used gray or white PVC of similar size and schedule rating; any effect on the plasticizer and material will risk losing the very reason for purchase in the first place and would negate the value of the pipe system. Asahi/America moved away from fittings using clear PVC for this very reason, but still provides clear containment pipe in all product size ranges. To put it into perspective, today, a 2″ clear PVC Schedule 40 90-degree elbow from a prominent PVC OEM is approximately 10x more expensive than the same fitting in gray Schedule 40 from that same OEM. Users can save a significant amount of money by combining clear pipe with standard fittings, maintaining confidence and the ability to visually inspect the system for leaks.

Suppliers for transparent PVC are limited, with only a handful of manufacturers worldwide. Compared to standard types of PVC, the supply of these materials is more sensitive to global demand, so fluctuations can easily affect construction schedules if not carefully considered early in the planning process. The process to produce world-class quality products is complex and requires top-of-the-line equipment. The technology and materials are constantly improving, but the number of suppliers remains very limited. As such, Asahi/America is proud to have used the same supplier for years because of its consistent quality.

Clear PVC is very sensitive to UV exposure. Use of clear PVC in unprotected outdoor environments will cause the pipe to lose its transparency within months of installation. Coatings and other protective measures would also negatively impact the intent. Therefore, users should avoid these types of installations and keep the system inside or in well-protected locations away from UV.

Similar to UV exposure, outdoor environments with freezing temperatures can cause premature failures in PVC—even the non-transparent varieties. In these instances, the pipe will become brittle and prone to stress fractures. This type of failure is common in PVC, especially with days when the sun shines unabated but temperatures are still frigid (common in regions like New England).

The aesthetic appeal of clear PVC may be attractive early on; however, that can deteriorate over time. Clear PVC will show scratches, dust, wear, etc. much more clearly (no pun intended) than gray or even white PVC will. If the aim is for a visual appeal blended with function, one might consider this long-term effect.

Chemical attacks could also reduce material clarity if the piping system is exposed to the wrong types of chemicals. It is well documented that clear PVC tubing loses clarity when exposed to demineralized water and coolants. This result is also true when exposed to caustic vapors, since these attack the plasticizers that create transparency in the pipes. Users should always consider the chemical media being used during the design phase.

Considering all of the aforementioned factors, Asahi/America stands behind its Pro-Lock® double-contained products, which provide a full line of fittings, as well as clear containment pipe for installations. Many years of satisfactory use can be expected when the proper environment and additional application factors are considered early in the process.

EDITOR’S NOTICE: Please note, the information in this article is for educational purposes only and does not supersede any Asahi/America technical information or product specifications. Please consult Asahi/America’s technical department at 1-800-343-3618 or [email protected] on all product applications in regards to material selection based on the pressure, temperature, environmental factors, chemical, media, application, and more.