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They are produced following the American Society for Testing and Materials Standards (ASTM). There are 2 types which are ASTM B88 (Type K & L) and JIS H330 C1220T.


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1. What is Copper Tube?

Copper tube is a seamless and almost pure copper material manufactured in accordance with the requirements of ASTM B88 or JIS H3300 standard. There are three basic wall thicknesses for seamless copper tube dimensions known as types K, L, and M with type K being the thickest and type M being thinnest and type L being the intermediate thickness. All three types of tubes are made from copper alloy C12200, which has a chemical composition of 99.9% copper (Cu) minimum and 0.15% - 0.40% of Phosphorus.

As per the JIS H3300 standard, the minimum tensile strength for the copper tubes is 315N/mm², while under the ASTM B88 standard the minimum tensile strength is 250N/mm².

Deoxidizing is applied to copper tubes to clear out porosity and decrease cuprous oxide. Oxygen content is being removed via oxidation during the manufacturing process, it's important to remove oxygen content as it's unfavorable to the quality of copper tubes. Our Phosphorus deoxidized copper tubes are good for flaring, welding, bending, and their strong corrosion resistance with good heat conductivity.

2. What are the measurement of the size of Copper Tube?

The outer diameter (OD) of a copper tube is commonly measured using Inches (“), nominal Bore (NB), and metric sizes. The nominal bore and outer diameter sizes are aligned with each other, outer diameter value is usually 1/8 inch larger than the nominal size. For example, a 2" nominal bore copper pipe has a 2 1/8" outer diameter. 


The diameter for metric size ranges from 6 mm to 54 mm, while nominal bore sizes range from 1/8” to 4”.

3. What are the different types of Copper Tubes?

Under ASTM B88, there are a few types of copper tubes such as Type K, Type L, and Type M. The main difference between different types of copper tubes represents a series of sizes with different wall thicknesses, the wall thickness of Type K tube is thicker than Type L tube while wall thickness of Type L is thicker as compared to Type M.

Another determining factor for types of copper tubes is temper. Temper is used to describe the degree of strength and hardness of copper tubes. Generally drawn temper copper tubes are referred to as “hard” tubes and annealed as “soft” tubes. Hard temper tubes are often connected by brazing, usually via capillary fittings or welding. While soft temper tubes are usually joined using flare-type fittings and compression fittings.

On the other hand, JIS H3300 copper tubes are available in two types which are Inches & ​Metric. Inches OD or Metric OD are commonly used to measure the outer diameter of these standard copper tubes. JIS H3300 standard copper tubes are also suitable as heat exchangers, in the chemical industry, and in water supply applications.

copper tubes

Copper Tubes

4. The differences between Type M and L

Wall thickness and pressure rating are the two main differences between type M and type L copper tubes. While the two most commonly used sizes are 1/2 inch and 3/4 inch.

For example, Type M 1/2 inch copper tube has a wall thickness of 0.028 inches while Type L is 0.040 inches, and Type M 3/4 inch copper tube has a wall thickness of 0.032 inches while type L wall thickness is 0.045 inches.

Type L is more expensive than tType M as Type L with its thicker walls weighs more and requires more copper to construct, thereby costing more to manufacture and also to transport.

Copper pipes of the same type and size all have the same outside diameter (OD), which allows them to be used in the same system for connections. However, the inner diameter varies by type due to the different wall thicknesses.

5. Type M and L Residental suitability are what?

Type M or Type L Copper tubes may be used for indoor water supply lines unless local codes specify otherwise. Both copper tube types are rated well above common water pressures rating requirements found in municipal water supply systems. 

Apart from that, most homeowners would opt for Type M instead of Type L due to relatively lower costs for large projects. However, before deciding, it is advised to always check your local code requirements for building materials and permits before starting projects or buying building materials.

6. What are the applications for the 3 types of Copper Tubes?

Copper tubes are commonly used in water supply lines, refrigerant lines for heating, ventilation, and air-conditioning systems (HVAC) in the construction industry. Below table displays Type K, L, and M usage in different system applications.

Install: Tubes



Due to formability, copper tubes are very flexible for installation. With the right tools and methods, a quick change of bend and length can be easily done on-site. Copper tube will not weaken or break from bending. 

Copper pipe bursting strength can be greater than it was before bending according to a testing report, this means copper tubes sometimes grow even stronger after bending. Copper tubes are easily installed using joints, welding, or flanges.

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