How to Size Your Water Lines (PEX & Copper)

Summary

In this video, plumber Quinn educates viewers on sizing PEX water lines for residential plumbing projects, following the 2018 Uniform Plumbing Code. The 75% method simplifies calculations for DIYers and professionals alike. Quinn explains how to determine fixture units, calculate developed length, and account for elevation and pressure. The video also addresses the nuances between PEX A and PEX B materials, offering practical advice for ensuring optimal water line sizing.

Takeaways

• 🛠️ The video is a plumbing tutorial focused on sizing PEX water lines, with applicability to PEX, copper, and other materials.
• 🏡 It's based on the 2018 Uniform Plumbing Code and uses the '75 method', which is suitable for private residences and DIY projects.
• 📏 The process starts with sizing the water meter to ensure it can handle the water demand of the project.
• 📋 Total fixture units are calculated by assigning values to each fixture from a code book and summing them up.
• 📏 The 'developed length' of the most remote outlet is determined by tracing the center lines of the pipes back to the meter.
• 📏 The elevation of the highest fixture is calculated to account for pressure drop due to height.
• 💧 The static pressure of the system at the source of supply is crucial, especially during periods of high demand.
• 🔍 The video uses Table 610.4 to determine the appropriate pipe size based on developed length, pressure range, and total fixture units.
• 🔄 The '75 percent method' is applied to fixtures with both hot and cold water supply to reduce the load on the system.
• 🔍 Sizing each branch involves calculating the total fixture unit load and referring to the table to determine the necessary pipe size.
• ⚙️ There's a discussion on the differences between PEX A and PEX B, with a suggestion to consider upscaling pipe sizes if using PEX B due to potential flow reduction from insert fittings.

Q & A

What is the purpose of the video by Quinn the plumber?

The purpose of the video is to educate viewers on how to size PEX water lines, including copper, and to discuss the differences between PEX A and PEX B, particularly in relation to sizing.

What method does Quinn recommend for sizing water lines in private residences?

Quinn recommends using the '75 method' for sizing water lines in private residences, which is based on the 2018 Uniform Plumbing Code.

What is the first step in sizing a water line according to the video?

The first step in sizing a water line is to size or verify the capacity of the water meter to handle the project's requirements.

What are the key factors considered when sizing a water meter?

The key factors considered when sizing a water meter are total fixture units, developed length of the most remote outlet, elevation of the highest fixture, and the pressure in the system.

How are fixture units calculated in the video?

Fixture units are calculated by assigning a value to each fixture from a table in the code book, which represents the demand each fixture puts on the water system, and then summing these values.

What is the significance of the developed length in water line sizing?

The developed length is the distance from the water meter to the farthest fixture in the house, traced along the center lines of the pipes, and it affects the sizing of the water lines.

How does the elevation of the highest fixture impact the water line sizing?

The elevation of the highest fixture impacts the water line sizing by affecting the pressure in the system; for every foot of elevation gain, there is a 0.5 psi pressure drop.

What is the '75 percent method' mentioned in the video?

The '75 percent method' is a technique used to size water lines where if a fixture has both hot and cold water supplied, the fixture unit is multiplied by 0.75 to reduce the load on the system.

How does Quinn address the difference between PEX A and PEX B in the context of water line sizing?

Quinn suggests that while there's no exact way to account for the difference in flow due to PEX B's insert style fittings, one might consider upsizing the pipe if they are on the border between pipe sizes to account for potential flow reduction.

What is the final check Quinn recommends after sizing all the branches in the water system?

After sizing all the branches, Quinn recommends checking that the total load on the main supply line matches or is less than the capacity determined during the water meter sizing process.