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How to Know When to Use Universal & Custom Tube Sizes in HVAC Applications

Posted by Mueller Custom Cut Solutions Team on Jan 20, 2020 2:19:00 PM

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The pipes that connect a unit are vital when it comes to HVAC applications. In order to keep a product up and running, pipes must remain free of moisture or stress, which is where insulation tubing comes in.

Proper tubing is a crucial aspect of any functional HVAC system. If you want your units to remain free of issues, you need to understand the difference between universal and custom tubing. 

In this guide, the HVAC experts at Mueller will detail the features and functions of both universal and custom insulation tubing, as well as give you some tips on how to select the right type of tubing.

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What Are the Differences Between Universal and Custom Tube Sizes?

The two main types of tubing in the HVAC industry (universal and custom) have a lot in common. They are both used to insulate and remove sweating of copper pipes and are made of the same materials, among other things. It’s important that both types match the size of the copper pipe to which they are applied. 

There are some important differences as well. 

Tubing used in HVAC applications have many different outer dimensions (ODs), which are determined by their wall thickness. However, only a select few have inner dimensions (IDs), which are determined by the copper piping they are insulating. The difference between those dimensions is what separates universal, standard tube sizes from custom ones.

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Universal tubes come standard in six-foot lengths. They have two main wall thicknesses, ⅛-inch and ¼-inch. Of the two, the ⅛-inch thickness is most commonly used in the HVAC industry. The tubes themselves are mainly made of PVC-NBR material, though EPDM tubes are sometimes used in other industries. Universal tubes are easy to acquire and very cost effective, often being 30% cheaper than custom tubing.

Custom tubes set themselves apart with their thicknesses. These tubes can be customized to meet almost any pipe thickness and come in lengths of 100 feet, 400 feet, and 800 feet. At those lengths, the tubes themselves are cheaper and can be cut to meet specific SKUs. However, custom tubes have higher labor costs because of the manual measuring and cutting required, making them more expensive overall compared to universal tubes.

There are also pre-slit variants of both tube types, meaning that the tubing has a cut that runs the length of the part. This tubing type is used in areas where piping is already in place, preventing the tubing from being slid on prior to placement. Pre-slit tubes have flaps with adhesive on them to ensure they have comparable performance to uncut tubing.

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How Do You Decide Which Type of Tubing to Use?

The type of tubing you use is determined by the application and the size of copper piping in the unit. Finding what tube best fits that piping is the most important factor when deciding on a tube size, and the customer will often tell you what wall thickness they need the tubing to be in a spec sheet.

However, there are certain factors to keep in mind if you want to avoid issues in your product. For example, using a tube that is too large for the piping can lead to air gaps. These gaps allow for condensation to build up on copper piping, which can lead to sagging or freezing pipes. These issues can be avoided by using a tube that fits snugly over the pipes.

There are also ways to reduce cost when it comes to insulation tubing (such as reducing the wall thickness of a tube). Tubing can occasionally be over-engineered, meaning that businesses are using a much thicker tube than is needed for their application. By assessing this tubing, you can reduce the wall thickness and lower the cost of the part, all while maintaining the same level of performance. 

Why Do Universal and Custom Tubing Sizes Matter?

The differences between universal and custom tubing might not be massive, but they are important. Understanding the effects of using an improper tube size is the difference between a functioning product and a broken one.

You can avoid issues like freezing and sagging pipes by familiarizing yourself with the different sizes of tubing and use that information to find the right fit for your application. It’s also important to make sure that you’re utilizing the most cost-effective option, taking note of wall thickness and any labor cost that might be necessary. 

Use this information to select the right tubing option for your HVAC units, and you’ll create products that are cost-effective and meet your performance standards. If the pipes in your unit fail, then your entire product fails with it. Whether you’re creating refrigerators or air conditioners, make an informed decision with your tubing.

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Topics: HVAC, Tubes

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