Cast iron pipes have been used for centuries as sewer lines due to their durability. They’re still used in many regions in Sydney plumbing jobs where local building codes allow them.

Black pipes are also used in several household constructions. The most commonly used black pipes are the ABS sewer pipes and black coated steel gas pipes.

Sewer pipes and gas pipes are very different from each other. They’re also different from cast iron pipes.

cast iron black pipes

Diameter Sizes

Sewer pipes (ABS) have a diameter that ranges from 1 ½ to four inches. The diameter depends on the plumbing fixture that the pipe connects to. ABS pipes come in a length of eight feet.

On the other hand, cast iron pipes are generally installed in sections measuring four inches in diameter and eight feet in length. Gas pipes come with a smaller diameter of ½ inch or ¾ inch and are available in several different lengths.


The Process Used During Installation

The process used in connecting each type is different. Traditionally, cast iron pipes were sealed with melted lead and oakum. Today, they’re connected with stainless steel bands and rubber gaskets.

Gas pipes are usually connected using female threaded couplings made of steel and a threading compound. ABS pipes are connected with ABC cement and ABS couplings.


Fixing or Removing Broken or Cracked Pipe Sections

Although cast iron pipes are extremely tough, they can crack or break when knocked heavily. Since the size of cracks in cast iron increase over time, you must cut out the cracked section and replace it with a new piece.

You can use PVC pipe as a replacement where plumbing codes permit. ABS pipes are also durable. However, they also crack or break when knocked heavily.

Smaller cracks may be fixed using epoxy putty. If the cracks are large, the cracked section should be replaced using a new piece of ABS Pipe.

In case the gas pipe is leaking or broken, it should be replaced immediately with a brand new pipe to ensure there are no fears of gas leakage.


Other Differences

Cast iron pipes are more challenging to work with than ABS sewer pipes. Cast iron is also more expensive than ABS. Cast iron is heavier than ABS. Since ABS is lighter, there’s less risk of body injuries when working with it.

However, the thick walls of cast iron act as a good insulator against irritating noises resulting from the water flowing along a pipe.

Cast iron pipes are cut using a snap pipe cutter. You can rent the special tool from a DIY rental house. On the other hand, ABS pipes are cut using a regular handsaw, miter saw, or circular saw.

Gas supply lines differ from both ABS and cast iron supply lines in that they come with threaded ends to fit tightly into couplings.

Thus, in case a gas supply line is cut with a hacksaw or tubing cutter, each end has to be threaded before being fitted back into the coupling.


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