We discussed in the previous sections the three types – L, K, and M. However, there is a fourth type called copper DWV pipe. It stands for drain, waste, and vent. By its name, its only approved use is in vent and drain lines.
It is the only copper type not primarily used in water systems, making it the odd one among them. These come in larger diameters than the rest. It also has thinner walls, allowing it to withstand a maximum pressure rating of 15 psi.
You will only find this in older homes. Newer homes use PVC pipes because DWV is already obsolete.
Tube vs. pipe
Most people interchangeably use these two terms. They are similar in several aspects, but there is one particular distinction between them.
We usually use tubes in structural applications, so the outside diameter is more relevant. We also use it in medical applications, especially devices requiring precise outside diameters.
We use pipes to transport liquids to gases, making capacity important. Knowing how much can flow through it is the answer. We classify pipes through nominal diameter and schedule size. Manufacturers sell these in nominal pipe size (NPS) standard and wall thickness.
Different pipe sizes can have the same NPS but have different wall thicknesses. On the other hand, manufacturers sell tubes by wall thickness and outside diameter. The gauge number defines the thickness of the walls, with a larger gauge number indicating a smaller diameter.
The following are some characteristics of pipes and tubes.
Shape
Pipes are round. Tubes can come in rectangular, round, or square shapes.
Telescoping Attributes
You can telescope a tube. It is a perfect application to sleeve different pieces or expand inside one another.
Rigidity
You can bend or coil tubes without getting too much wrinkling, distortion, or fracturing. On the other hand, pipes are generally rigid and need special equipment to morph.
Uses
We use copper pipes in the water line and heating systems. For several years, we heavily depend on copper to satisfy these applications. However, recent technological advancements have introduced PEX.
One of their primary purposes is to deliver safe, clean water. It can either be hot or cold, potable or non-potable. Aside from providing a drinking water supply, we also use it to:
- wash our vehicles
- do the laundry
- water the plants
- and even flush our toilets.
Water Service and Distribution
We use it to transport safe, clean water through several domestic applications. Copper has proven to deliver a cost-effective and reliable water supply.
Refrigeration and Air Conditioning
We have air conditioning at home to make our living conditions more comfortable, productive, and safe.
Copper helps us cool in the summer and warm in the winter by offering resistance to extreme weather conditions. It offers corrosion resistance, making it last longer and requires less maintenance.
Vacuum and Medical Gas
Hospitals and other medical facilities use copper linings to deliver medical gases needed in treatment and recovery.
We need gasses, such as carbon dioxide, nitrous oxide, and nitrogen, in healthcare facilities. This metal prevents microbial buildup in gas systems, so they remain pure and contaminant-free.
Fire Sprinklers System
Sprinkler systems serve as another security layer in case of fire. The reliability of copper makes it an excellent material in fire sprinkler systems. It will not support combustion, decompose to toxins, or carry fire. In emergency situations, it will continue delivering water to the sprinklers.
Fuel Distribution
Smaller tubes and fittings are effective against delivering gases in non-residential and residential buildings. All major codes in the United States recognize it for fuel gas distribution systems.
Other Relevant Applications
Other applications, such as snow melting, agricultural sprinkler, drain vent, and geothermal cooling/heating, are where you can take advantage of copper.
The most common types you will find in the market are types L, M, and K. You will find more details and explanations in the following sections.
Type L
We use Type L in fire protection, HVAC, and plumbing applications. These are available in soft or rigid forms. It makes them compatible with flare, compression, and sweat fittings. We consider the L-type the most common one in the market. You can use it in more applications than the K-type.
You can use the flexible one for old water line replacement or repair. However, the rigid form is more durable. You can use it outdoors under direct sunlight exposure. These are particularly best for interior water lines. Type L is thinner than K but thicker than M.
Type M
Type M is thinner than L or K. It is also available in soft and rigid forms. Its typical applications are vacuum and domestic water service systems.
We can use flare, compression, or sweat fittings to join two tubes. It is also a favorite choice for residential applications because it is cheaper. Thinner walls mean there is less copper in the material. It translates to a lower manufacturing cost, affecting the retail price of these items.
The caveat here is that several plumbing codes in the United States do not permit the use of M copper. We recommend checking with the local authorities for restrictions.
Type K
Type K has the thickest wall among the three. We recommend using it for:
- HVAC
- water distribution
- oil
- fire protection
- and other construction industry applications.
It is available in soft or rigid forms, allowing you to use compression or flare fittings.
Underground installations and water lines are some of the major application strengths of Type K. Its thickness help withstand pressure underground. Avoid using it for handling natural gas applications because it can damage the joints.
Copper type L vs. M
These two may have the most similar applications among the three. The difference lies in the wall thickness and pressure rating, with 1/2 and 3/4 inches being the standard sizes most applications need.
In terms of cost, Type L is more expensive than the M because it has thicker walls. It also needs more copper material to manufacture, adding cost to the production process. Transportation cost is also higher because it weighs more.
In comparison, a 3/4 inch type L has a working pressure of 1,002 lbs / square inch, while type M rates at 701 lbs / square inch. The pressure decreases as the pipe diameter increases. Let us use the L type to compare. A 1/2-inch has a maximum working pressure of 1,242 lbs / square inch. In contrast, a 1-inch rates 850 lbs / square inch.
