Types of Carbon Steel Pipes Used for Chilled Water

for chilled water applications, carbon steel pipes have three types. each type is used for different pipe sizes. at the same time, they are manufactured in accordance with different pipe standards.

a) welded mild steel to bs 1387 class c

chilled water pipe sizes from 15mm to 150mm are using welded mild steel pipes manufactured in accordance with bs 1387 class c standard. such manufacturing technique involved welding as opposed to seamless which is done through cold draw or hot roll.

carbon steel mainly has three types which are low carbon, medium carbon and high carbon. low carbon steel is usually referred to as mild steel. some people break carbon steel down into 4-5 types, each with a different percentage of carbon but we don't need to go into that detail.

bs 1387 class c is also called bs 1387 heavy gauge. the “class c” is equivalent to the “heavy gauge”. they are the same thing. nevertheless, if you are looking for a cheaper option, class b or medium gauge is feasible.

b) welded carbon steel to jis g3452

chilled water pipe sizes from 200mm to 450mm are using welded carbon steel pipes manufactured in accordance with jis g3452 standard. such manufacturing techniques also involved welding and have weld lines. pipes are more suitable for transferring water rather than gas when you have weld lines.

some manufacturers use welded carbon steel to jis g3452 only for chilled water pipe sizes from 200mm to 350mm. however, pipe sizes from 15mm to 450mm are available for jis g3452 standard.

welded carbon steel pipes to jis g3452 are considered standard carbon steel pipes. they don't split further into different types.

often, this type of chilled water pipe accounts for the largest percentage of the overall chilled water pipe cost due to the quantity and unit rate.

c) erw carbon steel to api 5l grade b

chilled water pipe sizes from 500mm to 600mm are using erw (electric resistance welded) carbon steel pipes manufactured in accordance with api 5l grade b standard. such manufacturing techniques also involved welding and have weld lines.

actually, welded carbon steel pipes are the same as erw carbon steel pipes. the reason why the word “erw” is added for this type of pipe is to differentiate it from seamless carbon steel pipes because both the erw and seamless chilled water pipes in this pipe size category are often used frequently.

projects that required high build quality may call for seamless carbon steel pipes that are about 20% better at handling working pressure. furthermore, seamless carbon steel pipes hardly leak because there are no weak weld points. hence, seamless pipes are often used for transferring gas.

however, seamless pipes are more expensive than erw or welded pipes. so, most chilled water pipes are using erw or welded carbon steel pipes instead of seamless carbon steel pipes.