Back to top

Knowledge base

Where pipes operate at below-ambient temperatures, the potential exists for water vapour to condense on the pipe surface. Moisture is known to contribute towards many different types of corrosion, so preventing the formation of condensation on pipework is usually considered important.

Pipe insulation can prevent condensation forming, as the surface temperature of the insulation will vary from the surface temperature of the pipe. Condensation will not occur, provided that (a) the insulation surface is above the dewpoint temperature of the air; and (b) the insulation incorporates some form of water-vapour barrier or retarder that prevents water vapour from passing through the insulation to form on the pipe surface. to preventing the corrosion on pipe line, insulation are required with proper thickness and density.

The top producers of copper are found throughout the world. The number one producer is Chile, a South American country. Chile produces 5,750,000 tons of copper annually. The country attracted foreign private investments in the 90's when the government passed a mining law that compensation regulations for the case of mine nationalisation.

Copper pipe corrosion may occur when water is in contact with copper pipes. Higher copper levels can occur when the water is not used for a period of time.


Why copper tubes is prefered for air conditioning?


Because copper tube has many advantages, such as

  • Resistant to corrosion
  • High level of heat transfer
  • Machinability and
  • Consumption of less refrigerant

 Why not use aluminum for instead?

Because the copper's performace of belowing aspect is better.

In 1970, revisions to the Canadian Plumbing Code of Canada permitted the introduction of Type M copper tube for above-ground water systems inside houses and buildings. Prior to that time, Type L and Type K copper tube had been used for decades in domestic water systems.

At the time there were skeptics who did not believe that Type M, which has a thinner wall than Types K and L, would be suitable for hot and cold water lines. This was in spite of studies that showed that the tubes with the heavier wall were over-engineered, and they could be reduced without detracting from the excellent performance record of copper water systems. Also, lighter gauge copper tube, nearly identical to Type M, had been in use without any problems in the United Kingdom for a number of years and similar types had been adopted in several other countries. In fact, Type M tube had been used in the United States since the early 1950s.

A table to indicate the size of different plumbing copper tubes

Selecting Field-Supplied Copper Tubing

Copper is the only approved refrigerant pipe material for use with LG Multi V commercial air conditioning products, and LG recommends seamless phosphorous deoxidized ACR type copper pipe, hard-drawn rigid type “K” or “L”, or annealed-tempered, copper pipe.

• Drawn temper (rigid) ACR copper tubing is available in sizes 3/8 through 2-1/8 inches (ASTM B 280, clean, dry, and capped).

• Annealed temper (soft) ACR copper tubing is available in sizes 1/4 through 2-1/8 inches (ASTM B 280, clean, dry, and capped).

The production technology of copper unannealed tubes

Calculation of weight copper pipe according to the formula: Q = (D - S) × S × π × γ: 1000

  • Q - weight per meter pipe, kg;
  • D - an outer tube diameter, mm;
  • S - wall thickness, mm;
  • π - constant "pi" (about 3.14);
  • γ - density of copper, a constant value (8.9 kg / l).

The difference is the wall thickness of the pipe and therefore the pressure it can handle. The exterior dimensions are identical, meaning you use the same copper fittings. You also use the same tools, materials and techniques to cut and sweat them. The beefier Type L is often used underground, in hot water heating systems, for commercial plumbing and for gas line (where permitted). Most plumbers use the less-expensive Type M for residential projects: One told me, “Type L pipe will last 300 years and Type M only 250.” But check with your building inspector; some areas require Type L.

Winland Trading Co., Ltd. is a copper pipe & fittings supplier in China. We offer various types of copper pipes, you could contact us by

Causes of copper corrosion, how to stop copper corrosion and the way we could prevent copper corrosion.

Very useful tips for air conditioning, refrigeration, heating, construction and other fields.

The refrigerant R410A requires strict cautions for keeping the system clean, dry and tight.

  • Clean and dry: foreign materials (including mineral oils or moisture) should be prevented from getting mixed into the system.
  • Tight: R410A does not contain any chlorine, does not destroy the ozone layer, and does not reduce earth's protection against harmful ultraviolet radiation. R410A can contribute slightly to the greenhouse effect if it is released. Therefore we should take special attention to check the tightness of the installation.

Dakin VRV REFNET Joint pipe specification and technical drawings

Copper elbow for shipbuilding


Ø15 Ø16 Ø18 Ø19 Ø22 Ø28 Ø35 Ø42 Ø54 Ø67