Technical Blog of PVC Pipe

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There are no smokestacks at PVC pipe facilities, which means PVC pipe manufacturing is often powered by green energy sources like wind and solar, further reducing its carbon footprint, which is already the lowest of all underground piping materials.  And PVC pipe is also completely recyclable. Contrast this with the cement industry – the third-largest emitter of greenhouse gases in the world.

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Best Choice for the Environment

PVC piping is one of the world’s most sustainable products, making it ideal for long-term term use in underground infrastructure. It requires less energy and fewer resources to manufacture than old-technology materials, and its production creates virtually no waste.

Moreover, it is produced with sustainable and abundant resources: chlorine, which is derived from salt, and domestically produced natural gas, which helps reduce consumption of imported oil. About 85 per cent of our medicines are manufactured with chlorine chemistry.

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PVC Pipe: The Eco-Friendly Choice

PVC piping stands out as one of the most sustainable solutions for underground infrastructure. Its production requires less energy and fewer resources compared to traditional materials, while generating minimal waste.

Made from abundant and sustainable resources like chlorine (derived from salt) and domestically produced natural gas, PVC reduces reliance on imported oil. Additionally, chlorine chemistry plays a vital role in manufacturing 85% of medicines.

PVC pipes ensure long-term performance, efficient resource use, and environmental responsibility. The North American PVC pipe industry is committed to fostering sustainability for a greener future.

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When a load of pipe arrives at the job site, it is your responsibility to check it thoroughly. If possible, inspect each piece for damage. Check quantities against the shipping list. Note that the policy of most pipe manufacturers is that once the pipe leaves the manufacturer’s plant, it becomes the property of the shipping company. Any damaged or missing items should be documented on the bill of lading. Set aside any damaged items and notify the shipper.

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PVC Fittings Design and Installation Guide

This guide by the Uni-Bell PVC Pipe Association outlines the design and installation of gasketed PVC fittings for potable water, force main, pressure irrigation, and reclaimed water systems. It covers fittings for PVC pipes up to 60 inches in diameter but excludes solvent-welded and fusible PVC fittings.

Manufacturing Methods

PVC fittings are made using three methods, all with gasketed push-on joints that meet or exceed the pipe’s pressure rating.

1. Fabricated FittingsConstructed from PVC pipe meeting AWWA C900 standards, these fittings include thermoformed bends, couplings, and reinforced structures. Available sizes range from 4 to 60 inches with pressure classes equal to or greater than the connected pipe. Products include tees, bends, reducers, and adapters.

2. Injection-Molded FittingsMade per AWWA C907 by injecting PVC into molds, these fittings feature a wall thickness 25% greater than DR18 pipe and meet specific strength standards. They are available in 4 to 12 inches and Class 235 psi. Products include bends, tees, couplings, and plugs.

3. Machined CouplingsProduced using molding and fabrication, these couplings meet AWWA C900 standards and are available in sizes from 4 to 60 inches.

Compatibility with Dissimilar Materials

PVC and ductile iron (DI) pipes share the same outside diameter (CIOD/IPS), allowing for straightforward transitions. PVC spigots fit into DI bells without couplings, while DI spigots require transition couplings. Note: DI spigots should never be inserted into PVC bells due to tolerance differences. Transition couplings ensure watertight joints.

Thrust Restraint Design

Pressurized systems can develop thrust forces at fittings, size changes, and dead ends. Restraint methods include:

Internally restrained joints

External mechanical devices

Concrete thrust blocks

Properly restrained pipelines transfer thrust forces to the soil via bearing strength and pipe-soil friction. Restraint device selection depends on factors like system pressure, pipe size, fitting type, and soil properties. Long-term considerations include construction, groundwater level changes, and monitoring activities near bends.

For accurate designs, specialized software is available to calculate restrained lengths and configurations.

To know more: https://www.uni-bell.org/Portals/0/ResourceFile/guide-for-pvc-pressure-fittings.pdf

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Design and Installation Guide for Gasketed PVC Fittings

This document has been developed by the Uni-Bell PVC Pipe Association to serve as a comprehensive guide for the design and installation of gasketed PVC fittings. These fittings are used in various applications, including potable water systems, force mains, pressure irrigation, and reclaimed water systems. The guide specifically addresses gasketed PVC fittings compatible with different dimension ratios and outside diameters of PVC pipes up to 60 inches. It is important to note that this document does not cover solvent-welded or fusible PVC fittings.

Types of PVC Fittings

The following are the various types of fittings available for use with gasketed PVC pipes:

Tees: These fittings have an outstanding leg positioned at a 90° angle to the main pipe, allowing for the creation of a T-shaped junction.

Crosses: Crosses have two outstanding legs that are opposite each other, forming a plus (+) shaped intersection.

Bends: Bends are used to change the direction of the pipeline. Standard angles available include 11.25°, 22.5°, 45°, and 90°. Custom-built angles can also be manufactured, ranging from 1° to 90°.

Sweeps: Sweeps are used to change the alignment or direction of the pipeline while minimizing hydraulic losses. They typically come in angles ranging from 1° to 5°.

Couplings/Sleeves: These fittings are used to join two pipes of the same diameter. Their applications include:

Connecting existing lines

Joining short pipe lengths

Repairing damaged pipelines

Changing pipeline direction using high-deflection couplings

Reducers/Tapers/Adapters: These fittings are used to transition between two different pipe diameters.

Tapped Couplings: Tapped couplings are one-piece fittings with pre-molded threads, designed for service taps. They can accommodate various mainline sizes and come with numerous tap configurations.

Plugs/Caps: Plugs and caps are used to stop the flow in a segment of the pipeline, typically at dead ends.

Custom Products: Custom products can be manufactured according to specific requirements and are available with either push-on or restrained joints.

Manufacturing Methods

There are three main manufacturing methods used for producing AWWA PVC fittings, all of which utilize gasketed push-on joints. The internal pressure capacity of these fittings is equal to or greater than the pressure rating of the pipe with which they are used.

Fabricated Fittings

Fabricated fittings are constructed from sections of PVC pipe that meet the AWWA C900 standard requirements. These fittings are made from the same materials as the pipelines they will be used with, ensuring compatibility and durability. The body of the fitting is made from extruded PVC pipe that has already passed standard testing. Fabricated fittings can include single thermoformed bends and couplers. Additionally, multiple segments of PVC pipe can be cut into wedge shapes or prepared to accept leg insertions and joined under factory-controlled conditions to form a homogeneous structure. Reinforcement may also be applied and permanently bonded to the outside surfaces of the fittings.

To Know More: https://www.uni-bell.org/Portals/0/ResourceFile/guide-for-pvc-pressure-fittings.pdf

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PVC Force Main Cyclic-Life Calculator

The PVC Pipe Association (PVCPA) has developed an online calculator specifically designed to determine the cyclic life of sewer force mains. This tool is based on research conducted by Steven Folkman, Ph.D., at Utah State University, with results published in the ASCE Pipelines 2020 proceedings.

Key Features of the Calculator The calculator allows users to input several critical parameters, including:

Pipe Dimension Ratio (DR): The DR of the pipe, which is essential in assessing the pipe's structural capacity. Maximum Recurring Surge Pressures: The highest surge pressures that the pipe experiences during regular operation. Minimum Recurring Surge Pressures: The lowest surge pressures experienced. Number of Surge Occurrences Per Day: The frequency of surge events impacting the pipe. Output and Functionality The primary output of the calculator is the cyclic life of the pipe, which reflects how long the pipe can withstand the varying surge pressures before failure. The tool can accommodate up to four different surge events, considering them separately and providing a comprehensive analysis of the pipe's cyclic life.

A standout feature of this calculator is its ability to facilitate sensitivity analyses. Users can efficiently explore the impact of changes in surge amplitude, surge frequency, and pipe pressure class on the pipe's longevity, thereby aiding in cost-effective pipeline design.

Comparison with Other Calculators Unlike other online calculators, PVCPA's tool does not restrict input values, allowing for more comprehensive and accurate assessments. This feature is particularly important for designing force main systems, where specific project conditions can vary widely. PVCPA advises against using calculators from other organizations for designing PVC pressure sewer pipelines, as they may lack the necessary precision and flexibility.

Supporting Documentation The use of the calculator is complemented by the "Force Main Design Guide for PVC Pipe," a new document that provides an in-depth discussion of cyclic surges, introduces the analytical methods employed by the calculator, and includes design examples for practical understanding. This guide, alongside the calculator, enables thorough analysis and design of PVC force main projects, ensuring robust and reliable pipeline systems.

By integrating these resources, PVCPA offers a valuable toolset for engineers and designers to accurately assess and optimize the design of PVC pressure sewer pipelines.

PVC Force Main Cyclic-Life Calculator

New online calculator for PVC sewer force mains uses project parameters to calculate expected cyclic life and determine the appropriate DR

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Manning's "n" for PVC Gravity Sewer Pipe

“Conservative” design is taught continually to all engineers during college and throughout their employment. I think we can all agree that

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Introduction to Molecularly Oriented Polyvinyl Chloride (PVCO) Pipe

Molecularly Oriented PVC Pipe — PVCO: light-weight, thinner-walled alternative with the same pressure capacity as thicker-walled PVC pipe.

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PVC and HDPE Pressure Pipes: Material Comparison

For municipal applications, PVC pressure pipe is manufactured and tested per the AWWA C900 standard and is available in sizes up to 60 inch

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Direct Tapping for PVC Pipes: Best Practices and Guidelines

Direct tapping involves drilling a hole into the pipe wall, cutting threads, and securely installing a corporation stop. This process is performed using specialized tapping machines designed for PVC pipes. The maximum outlet size for direct tapping is 1 inch.

Tapping Machine Requirements Several types of tapping machines can perform direct service taps. When selecting a tapping machine, ensure it meets the following criteria:

Adapter Base: Must be properly sized to seal securely against the PVC pipe. Cutting Tool: Should use a shell-design cutting tool suitable for PVC pipes. Compatibility: The machine and the valve used must mate properly. Manufacturer Recommendations: The machine should be approved by its manufacturer for use with PVC pipe, and the manufacturer's instructions should be followed during the tapping process. Features of a Suitable Tapping Machine Adapter Base:

Ensures a secure seal against the PVC pipe. Proper sizing is crucial to prevent leaks and ensure a clean tap. Cutting Tool:

Must be a shell-design specifically for PVC. Ensures clean cuts and proper threading without damaging the pipe. Design and Operation:

Should be easy to handle and operate. Should be durable and reliable under working conditions. Cutting and Tapping Tool Requirements A specialized tool is used to direct-tap PVC pipes, designed to bore holes and cut threads to match the corporation stop. The tool must meet the following specifications:

Slot Requirements:

Minimum of 1 slot for taps 5/8 inch or smaller. Minimum of 2 slots for taps 3/4 inch or larger. Coupon Retention:

The tool must retain the coupon (the piece cut from the pipe wall) and provide an easy method for its removal. Depth:

Sufficient depth to accommodate the thickness of the PVC pipe wall. Threading:

Must cut threads that match the thread pattern of the corporation stop (typically CC thread). Ensures secure and leak-free installation. Shank Compatibility:

The tool must have a shank compatible with the cutting machine being used. Shavings Management:

Must direct shavings into the throat of the shell cutter. Prevents stress risers and heat buildup which can weaken the pipe wall. Safety and Operational Guidelines Follow Manufacturer's Instructions:

Always adhere to the guidelines provided by the manufacturer of the tapping machine and tools. Inspect Tools and Equipment:

Regularly check the condition of the tapping machine and cutting tools. Ensure all parts are functioning correctly before use. Secure the Working Area:

Make sure the area around the tapping site is secure and free from obstructions. Proper Training:

Ensure the tapping crew is properly trained in using the equipment and understands the safety protocols. Preventative Maintenance:

Regularly service and maintain the tapping machine and tools to prevent malfunctions during operations. Direct tapping of PVC pipes is a precise process requiring the right tools and adherence to best practices. Selecting the proper tapping machine and cutting tools, following manufacturer guidelines, and ensuring the safety and training of the crew are essential for successful and safe direct tapping operations. Properly executed, direct tapping ensures a reliable and durable connection for your PVC piping system.