Technical FAQs

There are no governing bodies that require specific color coding; therefore, the PVC pipe industry has self-standardized color coding of PVC pipe. Below is the typical industry color coding standard of PVC pipe:

Note:

• There is no regulation of the actual shade of color used. Therefore, based on the manufacturer, the specific color may have slightly different shades. For example, Westlake Pipe & Fittings' Green PVC sewer may have a slightly different shade than other manufacturers.
• The color of the pipe material does not affect the pipe performance.

The following physical properties of the pipe must be regularly tested in order to be certified to AWWA C900: Sustained pressure, Burst pressure, Hydrostatic pressure integrity, Flattening, Extrusion quality (Acetone Testing) and Ring-tensile test. The testing of these physical properties assures the product quality of the finished products has not deviated from the design specifications.

For information about the testing required by AWWA for certification of PVC pipe and fittings, refer to Uni-Bell's Technical Brief: AWWA Standards for PVC Pipe: Product Testing

Note: similar testing is required for ASTM D2241 PVC Pipe.

Please contact Technical Services at 855-624-7473, Option 3 or technical@westlakepipe.com for more information.

Our PVC pipe is produced in the United States of America and in Canada.

PVC pipe sold in the USA is manufactured at facilities located only in the U.S. PVC Pipe sold in Canada is manufactured at facilities located in the U.S. and Canada. All of Westlake Pipe & Fittings' locations can be found here. 

Also, find our "Made in USA Certification" letter, located here. 

The PVC Pipe Association, A.K.A. Uni-Bell, estimates a design life expectancy of 100 years but in reality that estimate could be far exceeded. The 100 year estimate is primarily based upon engineering analysis of fatigue in PVC pipe wall, which is highlighted in numerous reports and independent studies, which are listed below. Also, Uni-Bell has various technical papers and articles that discuss PVC service life expectancy for water and sewer systems. These articles and papers are available, publicly and free of charge, on Uni-Bell's website. 

The direct links to a few of Uni-Bell's resources and reports are located below:

• Pvc Pipe Longevity Report: A comprehensive Study on PVC Pipe Excavations, Testing & Life Cycle Analysis. by Utah State University
• Life Cycle Assessment of PVC Water and Sewer Pipe and Comparative Sustainability Analysis of Pipe Materials. by Sustainable Solutions Corporation 

Dimension Ratio (DR) and Standard Dimension Ratio (SDR) both refer to the same ratio, (Outside
Diameter [OD] / Wall Thickness) – Refer to Figure 1 below.

Figure 1 - OD/t Ratio

For more information refer to the following link: Dimension Ratio (DR) Explained for PVC Pipe

The only difference between Schedule 40 & Schedule 80 is the wall thickness. The wall thickness also directly correlates with the pipe’s pressure rating. Schedule 40 (usually white) has a thinner wall thickness and therefore a lower pressure rating than Schedule 80 pipe (usually grey). Schedule 40 and 80 PVC pipe does not use the Outside Diameter / wall thickness ratio that DR and SDR use; therefore, the Schedule 40 and 80 pressure ratings are different for each pipe diameter size and must be looked up for every diameter and Schedule combination. NAPCO’s PVC Plumbing pipe (ASTM D1785) is available in both Schedule 40 and Schedule 80.

Refer to the applicable Technical Product Specification for more details on wall thickness and
pressure ratings for our PVC plumbing pipe. Technical Product Specification link here. 

CIOD stands for Cast Iron Outside Diameter and is the diameter standard used for AWWA C900 PVC pipe (e.g., blue potable water pipe). IPS is Iron Pipe Size, also known as DIPS or Ductile Iron Pipe Size, and is the diameter standard used for ASTM D2241 PVC pipe. (Note, other diameter standards do exist, such as, PSM – Sewer, PIP – Irrigation, Schedule 40/80/120 – Plumbing & Water Well)

Also, consider the following:

• Aside from compatibility with existing connections, there is no distinct advantage of using one pipe diameter standard over the other.
• No two are directly interchangeable.

No. According to AWWA M23: PVC Pipe - Design and Installation Manual of Water Supply Practices,
there is a zero leakage allowance. There is a make-up water allowance designated during acceptance
testing of PVC pipe, as detailed in AWWA M23; however, that is NOT to be misinterpreted as
“allowable leakage” of in-service PVC pipe.

The make-up water allowance during testing is in place to allow for the following:

• Make-up for entrapped air
• Make-up for movement due to seating of valves, joint restraints, etc.
• Make-up for slight increase in pipe diameter due to internal pressures

Refer to Uni-Bell’s Technical Brief for more details on AWWA’s stance on zero leakage in PVC pipe here. 

The warranties can be found at the following link:

• Warranty

The NSF 61 listing establishes the health effects requirements for the chemical contaminants
and impurities that are indirectly imparted to drinking water from products, components and
materials used in drinking water systems.

The NSF 14 listing pertains to the minimum physical, performance health effect, quality
assurance, marking and recordkeeping requirements for plastic pipe components. These
requirements are determined acceptable by various tests performed by NSF on PVC pipe
samples from the manufacturer.

Common engineering practice suggests a maximum flow velocity of 5 ft./s during normal (steady state) operating conditions for pressure pipe application. During surge conditions the recommended maximum allowable flow rate is 10 ft./s. Exceeding the recommended maximum flow velocity, for an extended period of time, could result in excessive internal pressures in the PVC pipe system, possibly leading to a joint or pipe wall failure.

For gravity sewer lines, which are not pressurized, the recommended maximum flow velocity is 10 ft./s before special considerations need to be taken for energy dissipation and internal erosion prevention.

Source: PVC Pipe Association: Handbook for PVC Pipe Design and Construction, 5th Ed.

Consider the following concepts when designing and installing PVC pipe in cold-weather environments:

• The tensile strength and modulus of elasticity are not negatively impacted.
• Impact strength may decrease to approximately 70-90% of PVC’s strength at an ideal temperature of 73.4°, dependent on actual temperature.
• All PVC pipe should be installed at least 12" below the frost line.
• Gasketed joints may require a slightly higher force to assemble.
• Proper installation practices become more important in cold weather conditions compared to moderate temperatures.
  • Proper installation practices include: handling pipe more carefully, proper lubrication and proper insertion of the spigot into the bell.

For more information, refer to Uni-Bell's Technical Brief: Cold Weather: No Practical Effect on PVC Pipe Installation and Use
 

PVC pipe works great for conveying water and sewage. PVC pipe may be exposed to various chemicals via direct contact with soil contamination or via chemicals in the fluids inside the pipe. The concentration of the chemical is important when considering chemical resistance.

• For a list of chemicals to which PVC Pipe is resistant refer to the table in Plastics Pipe Institute's Technical Report: TR-19 Chemical Resistance of Thermoplastics Piping Materials.
• For general Chemical resistivity of typical gasket material used with PVC pipe see the chart below:

General Resistivity of Typical Gasket Materials

*Note: NAPCO does not offer Neoprene gaskets as of 12/2019

There is also a detailed Chemical Resistivity chart available in Chapter 3 of the Handbook of PVC Pipe Design and Construction by Uni-Bell. Three chapters are available for free download.

If you have a specific question about chemical compatibility, please contact Technical Services at 855-624-7473, Option 3 or technical@napcopipe.com.

Exposure to sunlight can cause slight fading of PVC pipe surfaces. PVC pipe has not shown degradation of performance when exposed to sunlight for periods of time, up to two years. Physically blocking the UV energy from reaching the pipe surface prevents the fading. Methods of covering the pipe could include: permanently covering (‘wrapping’) the pipe, or painting with a light-colored paint that is chemically compatible with PVC (I.e., water based acrylic or latex).
 
Westlake Pipe & Fittings' Yelomine product line provides superior long-term UV protection and can be used outdoors. Yelomine contains an increased amount of high-purity TiO2 that is specially formulated to resist the effects of UV exposure.
 
Refer to Westlake Pipe & Fittings' Technical Bulletin: Ultraviolet (UV) Radiation Exposure of PVC Pipe Products

The length of PVC pipe expands and contracts with temperature change. The change in length is based
upon material properties and amount of temperature change.

The change in length of pipe per 10°F ΔT PVC pipe is reflected below:

For example, a length of 1,760 ft of PVC pipe with an initial installed temperature of 73°F and an operating
temperature of the pipe will be 83°F. The change of length over the entire length of pipe at operating
temperatures will be ~6.34”.

Source: PVC Pipe Association. Handbook of PVC Pipe Design and Construction, 5th Ed. New York: Industrial
Press, 2013. Print.

Note: Some pipe systems may require additional accommodation of thermal expansion and contraction
movement, than the standard integral bell joint can provide. In these cases, NAPCO offers expansion joints
up to 6” diameter.

The maximum operating temperature of PVC pipe is 140°F. The pipe’s pressure rating, and other
performance characteristics, must be de-rated for all temperatures above 73.4°F (23°C); refer to the table
below for the appropriate de-rating factors (Source: Handbook of PVC Pipe Design and Construction, Fifth
Edition; Published by PVC Pipe Association).

Notes:

• For temperatures in between those listed above, interpolate between the two closest temperatures to
  determine the specific de-rated pressure class.
• Pipe gaskets are typically not affected at the temperatures listed above.
• The de-rating factors assume sustained elevated service temperatures. When the contents of a PVC
  pressure pipe are only intermittently and temporarily raised above the service temperature shown, de-
  rating may not be needed.

The maximum burial depth is the maximum depth the pipe can be buried without the pipe deflecting
more than 7.5% for gravity sewer or 5% for pressure pipe. Some municipalities require a maximum pipe
deflection of 5% regardless of pipe type. Maximum burial depth depends on multiple factors such as
pipe stiffness, bedding material and compaction (Soil Modulus - E'), and the presence of any additional
above ground live loads.

Please refer to the following Technical Bulletin: Burial Depth Guidance for Gravity Sewer PVC Pipe

According to ASTM D2321, Standard Practice for Underground Installation of Thermoplastic Pipe for Sewer and Other Gravity-Flow Applications:

“The minimum depth of cover should be established by the engineer, based on an evaluation of specific project conditions.”

“In the absence of an engineering evaluation, the following minimum cover requirements should be used. For embedment materials installed in accordance with Table 3, provide cover (that is, depth of backfill above top of pipe) of at least 24 in. or one pipe diameter (whichever is larger) for Class I embedment, and a cover of at least 36 in. or one pipe diameter (whichever is larger) for Class II, III, and IV embedment, before allowing vehicles or construction equipment to traffic the trench surface, and at least 48 in. of cover before using a hydro-hammer for compaction.”

Also, the Uni-bell PVC Association Handbook of PVC pipe states:

“A minimum cover height of 12 in. is recommended for PVC (SDR35) pipe subjected to highway loads of up to 18 kip axle. To prevent cracking of the road surface, special attention should be given to the selection, placement, and compaction of backfill material around shallow buried flexible pipe (such as PVC pipe)”

Please refer to the following Technical Bulletin: Burial Depth Guidance for Gravity Sewer PVC Pipe

In regards to PVC pressure pipe the minimum burial depth is typically driven by the depth of the frost line.
Where there is no frost line, the minimum burial depth for PVC pressure pipe is 12”.

Source: PVC Pipe Association. Handbook of PVC Pipe Design and Construction, 5th Ed.

New York: Industrial Press, 2013. Print.

We recommend that the bell end be stationary and the spigot (Male End) be inserted into the bell
end, as seen below. This reduces the risk of debris entering the bell prior to installation.

Typically it is recommended that the bell direction is installed such that the fluid flows from the spigot
end into the bell end, as seen below; however, the direction of the bell is not critical and the joint will
seal regardless of flow direction.

Allowable angular joint deflection of Westlake Pipe & Fittings' pipe is as follows:

For more information on joint deflection and details about longitudinal bending of PVC pipe refer Westlake Pipe & Fittings' Technical Bulletin: Changing Direction of PVC Pipelines

Allowable angular joint deflection for Westlake Pipe & Fittings pipe:

For more information on changing direction of Westlake Pipe & Fittings' Gasketed Sewer Pipe and Kor-Flo® refer to the Gasketed Sewer Pipe and Fittings Installation Guide (Page 19 and 20)

CCTV inspection of PVC pipelines can reveal small longitudinal gaps between the spigot end and the
end of the bell of gasketed joints. These gaps are designed to accommodate expansion, deflection,
and slight over-insertion. This gap does not affect the hydraulic performance of the pipe.

Note: Pictures and videos from CCTV inspections cannot be used to determine exact measurements of
joint gaps due to viewing angles and camera lighting.

Example of typical gap in joint:

For more information, refer to Uni-Bell's Technical Brief about Expansion Gaps

PVC Pipe should not be air tested at high pressures!

A. PVC Pressure pipe requires pressure testing at high psi. A failure of a high pressure air testing
would result in high velocity and likely fatal projectile objects; therefore, air testing of PVC
pressure pipe is expressly prohibited. Water pressure testing is the only pressure testing
allowed to be performed on PVC pressure pipe.

B. Gravity Sewer PVC pipe (ASTM D3034/F679) can be air tested up to a maximum of 9 psig
(typical testing pressures are lower) according to ASTM F1417 "Standard Test Method for
Installation Acceptance of Plastic Gravity Sewer Lines Using Low-Pressure Air.” Even though 9
psig is low pressure, the resulting thrust forces on a pipeline, end plugs and caps can result in
projectile objects during a test failure; therefore, the following safety risks from Section 6 of
ASTM F1417 (the ASTM Air Testing Standard) should be considered:

• “No one shall be allowed in the manholes during testing”
• “When lines are tested, it is mandatory that all the caps and plugs be braced as an
  added safety factor”
• “A regulator or relief valve set no higher than 9 psi shall be included on all
  pressurizing equipment.”

For more information, refer to Uni-Bell's Technical Briefs: Air Testing of Installed PVC Pipelines and Considerations for Air Testing of PVC Sewer Pipes

Water tight joints – When installed correctly, gasketed joints are leak-free, allowing for
successful post-installation testing and a leak-free piping system.
 

Ease of Installation – Gasketed joints require minimal time to install, especially compared to
solvent weld, flanged, or welded joints. The gasketed joints can be easily pushed together and
are ready for use immediately following assembly.
 

Pipeline System Robustness – Gasketed joints allow for additional movement, within the joint,
due to joint deflection, minor surge pressures, and thermal expansion/contraction. Note:
restrained joints may be required when excess force is expected to occur at the joints.

Westlake Pipe & Fittings offers the following gasket materials:

• Styrene Butadiene Rubber (SBR) – Typically the standard offering
• Nitrile (NBR)
• Ethylene Propylene Diene Monomer (EPDM) Rubber

If you have a specific question about available gasket materials, please contact Technical Services at 855-624-7473, Option 3 or technical@westlakepipe.com.

Note: gasket types are specific to product types

Rieber gaskets have a metal stiffener ring located within the gasket, which helps the gasket stay in place in the gasket groove. The incorporation of a metal ring stiffener means Rieber gaskets are non-removable and can withstand higher insertion forces.

Example of a Rieber Style Cross-Section:

Non-Rieber gaskets, such as Fluid-Tite® gaskets (typically found in AWWA C900 PVC pipe) and O-rings, do not have an internal stiffener ring; therefore, they can be removed in the field, if needed.  If a non-Rieber gasket has been removed, it is required to inspect and clean the gasket and associated gasket groove. 
 
Rieber and non-Rieber gaskets both conform to ASTM F477, Standard Specification for Elastomeric Seals (Gaskets for Joining Plastic Pipe and ASTM D3139, Standard Specification for Joints for Plastic Pressure Pipes Using Flexible Elastomeric Seals.
 
Please refer to the associated NAPCO Installation Guide for proper joint assembly instructions.

Westlake Pipe & Fittings' Certa-Lok® self-restraining pipe system provides a restrained joint by utilizing precision-machined grooves on the pipe spigot and inside the pipe bell or coupling. When assembled, a spline is manually inserted or imbedded in the pipe bell, or coupling, engages a grove in the spigot resulting in a continuous circumferential restrained joint that locks the segments of pipe together.  A flexible elastomeric gasket located in a groove in the pipe bell, or coupling, provides a hydraulic pressure seal.

Certa-Lok® is available with a Restrained Joint (RJ) coupling or with a Restrained Joint Integral Bell (RJIB).

The advantages of the Certa-Lok joints are:

• Quick and easy joint installation
• Tensile strength in BOTH directions (PUSH and PULL), excluding CLIC
• Corrosion protection is not required
• Provides an a restraint system within the OD of the pipe system
• Eliminates the need for external restraints and thrust blocks (as applicable)

The Certa-Lok self-restraining joint is used in the following Product lines:

NOTE: RJ Coupling = Restrained Joint Coupling; RJIB = Restrained Joint Integral Bell

RJIB:

RJ:

All tensile force ratings can be found in the Technical Product Specification of the applicable product line (Yelomine, C900, 2241, Well Casing, Certa-Flo, Certa-Com, Etc.). For more information on Westlake Pipe & Fittings' process of Tensile Testing our products, refer to the following Technical Bulletin: Certa-Lok® Joint Tensile Strength Testing

In most cases RJ couplings and pipe can be used with RJIB pipe, but there are circumstances where they are not compatible. Refer to following Technical Bulletins for connecting different style joints for more specific scenarios.

For our C900 product line refer to: Connecting Different Joint Styles of AWWA C900 PVC Pipe

For our ASTM D2241 product line refer to: Connecting Different Joint Styles of ASTM D2241 PVC Pipe
 

Westlake Pipe & Fittings' Yelomine® products use a specially modified PVC compound* that contains impact modifiers that allow for higher impact strength and ultraviolet (UV) inhibitors that allow the pipe to be used continuously in exposed above-ground applications. Yelomine® PVC is certified to the specifications of ASTM D2241.

*Minimum cell classification of 12454, as defined in ASTM D1784.

RieberLok® gaskets are not approved for use with any of Westlake Pipe & Fittings' PVC Pipe or Fitting products.  
 
If Westlake Pipe & Fittings' gaskets are replaced with RieberLok gaskets or if RieberLok gaskets are used Westlake Pipe & Fittings products, then all applicable warranties and product certifications will be voided. 
 
RieberLok gaskets physically damage the pipe spigot, which negatively affects the performance of Westlake Pipe & Fittings' pipe. Please refer to Westlake Pipe & Fittings' Technical Bulletin for further information regarding RieberLok gaskets. 

•    AWWA C909 PVCO is defined by its pressure class (i.e., PC 235) where PVC is defined by its dimensional ratio (i.e., DR18).
•    Finished PVCO pipe has a Hydrostatic Design Basis (HDB) of 7,100 psi, whole traditional PVC has an HDB of 4,000 psi.
•    AWWA C909 PVCO Pipe has an approximately 10% larger internal diameter (ID).
•    AWWA C909 PVCO Pipe is approximately 40% lighter than traditional PVC pipe products. 
•    AWWA C909 PVCO is 40% easier to longitudinally bend than PVC pipe.
•    AWWA C909 PVCO has a maximum temperature of 130°F and PVC has a maximum temperature of 140°F.
•    AWWA C909 PVCO has a smaller pipe stiffness (psi) than PVC. The pipe stiffness of PVCO pipe is still suitable for most direct burial applications. 
•    AWWA C909 PVCO cannot be direct tapped.
•    AWWA C909 PVCO cannot be solvent welded (glued).

•    The minimum bending radius and allowable offsets for longitudinal bending of AWWA C909 PVCO pipe and AWWA C900 PVC pipe are the same.
•    Both AWWA C909 PVCO and AWWA C900 PVC are Cast Iron Outside Diameter (CIOD) pipe sizes.
•    AWWA C909 PVCO and AWWA C900 PVC are compatible with AWWA C907 injection molded fittings and AWWA C900 fabricated fittings.
•    AWWA C909 PVCO and AWWA C900 PVC can be assembled together. Correct Insertion depths must be accounted for.

PVCO stands for molecularly oriented PVC.  PVCO pipe starts as a piece of PVC pipe stock. During the manufacturing process, the PVC pipe stock is stretched over a mandrel to expand the pipe stock's diameter, this process is also referred to as biaxial orientation. The expansion of the pipe stock's diameter orients the PVC molecules in both the hoop and longitudinal orientation. The result of this biaxial orientation allows for the end product (PVCO pipe) to withstand greater stresses from internal pressure than it could before it was expanded. The final AWWA C909 PVCO product becomes stronger, tougher, and more flexible than traditional AWWA C900 PVC.

•    PVCO Pipe has the same pressure rating as PVC Pipe.
•    PVCO has 10% more internal flow area and over 40% reduced pipe weight compared to traditional PVC products. 
•    PVCO is easier to longitudinally bend than PVC pipe.

In order to verify proof of purchase as well as production and delivery information we will need the purchase order number for the product(s) involved.  We will also need the project location.  Forms may be directed through your local Westlake Pipe & Fittings sales representative or emailed to technical@westlakepipe.com.

Currently, all PVC pressure pipe and PVC municipal sewer pipe manufacturing specifications do not allow for post-consumer (PCR) or post-industrial (PIR) recycled content to be used in the product manufacturing process.   However, manufacturer’s may incorporate their own rework aka “regrind” material into the manufacturing process for both PVC pressure and non-pressure pipe.  The actual amounts of rework material used can change considerably depending on the product, manufacturing facility, and availability of rework material at the time of production.  Rework material is currently excluded from eligibility towards LEED credits.

LEED (Leadership in Energy and Environmental Design) is a rating system established by the U.S. Green Building Council.  The LEED rating system awards points for green and sustainable building materials and practices based on various requirements for each LEED category.

Where can I find out more information about LEED? 

• The U.S. Green Building Council website can be found here: https://www.usgbc.org/
• Basic LEED information can be found here: https://support.usgbc.org/hc/en-us/articles/4404406912403-What-is-LEED-certification-

The exact level of VOC’s present will depend on the primer or cement product used.  Generally, VOC levels range from approximately 400 g/L – 550 g/L.  Please refer to the safety data sheet for the product to be used for exact VOC levels.

For more information related to LEED credits, please refer to the Plastic Pipe & Fittings Association’s FAQ page at the following link: https://www.ppfahome.org/page/faq-solvent-cements-and-primers

LEED does not certify a manufacturer’s products therefore Westlake Pipe & Fittings products do not carry a LEED certification.  In fact, LEED rating systems exclude the pipe material from the material credits section of the rating system. Instead the credits are awarded for recycled content, reused materials, and regional proximity. As a result, LEED certifications focus on the construction project as a whole which puts project designers in the driver’s seat on the path towards LEED certification for their specific project.  For more information please refer to the Plastic Pipe & Fittings Association’s (PPFA) Sustainability topic on their FAQ page.  The page can be found here: https://www.ppfahome.org/page/faq-sustainability

Our location map can be viewed here: https://www.westlakepipe.com/en/locations

Plastic Pipe and Fittings Association (PPFA)

• FAQ: Sustainability: https://www.ppfahome.org/page/faq-sustainability
• FAQ: Solvent Cements & Primers: https://www.ppfahome.org/page/faq-solvent-cements-and-primers
• FAQ: PVC Pipe: https://www.ppfahome.org/page/faq-pvc

Uni-Bell PVC Pipe Association

• Homepage: https://www.uni-bell.org/
• Reports & Studies: https://www.uni-bell.org/Media/Reports-and-Studies

The Vinyl Institute:    

• https://www.vinylinfo.org/uses/water-delivery/
• https://www.vinylinfo.org/resources/pvc-pipe/

Vinyl Sustainability Council:

• Impact Categories: https://vantagevinyl.com/#impact-categories

In 2015 the Unibell PVC Pipe Association and its member companies including Westlake Pipe & Fittings, obtained an environmental product declaration for gasketed integral bell PVC pressure pipe and gravity sewer pipe.  The EPD was independently verified by NSF International in accordance with ISO 14025. The document may be obtained here: https://www.uni-bell.org/Portals/0/ResourceFile/environmental-product-declaration.pdf

The 2015 EPD expired in 2020 however a renewed EPD is scheduled to be published in late 2022.  Additional information about the EPD may be found at uni-bell.org. 

Westlake Pipe & Fittings is supplied with PVC resin from our parent company, Westlake Corporation. A complete list of Westlake Corporation facility locations can be found here: https://www.westlake.com/locations.  

LEED professionals should note that PVC resin supply to Westlake Pipe & Fittings plants is not based strictly on geographic proximity of the two facilities.