Virtues of Cast Iron Pipe
Cast Iron Pipe Has Advantages Over PVC
Noise Considerations
Do you live in an older home? Did you grow up in one? Do you ever remember hearing water rush across a ceiling or down a wall? The reason is simple: cast iron piping. Cast iron is a very dense, non-flammable material. It is so dense, that the sound waves produced by water crashing and splashing against the inside of the pipes simply can not be heard.
Plastic PVC piping is just the opposite. While it appears to be very solid, its molecular structure is very open. This allows sound to travel through it as if it were a piece of paper.
The density of cast iron also provides another advantage with respect to sound. Cast iron does not readily expand or contract in response to temperature changes. This means that when you run hot water down a sink or tub drain, you will not hear the cast iron piping popping or crackling within your walls. These types of sounds are very common with plastic PVC piping systems.
Cost Considerations
Cost is a factor in just about every job. Everybody has an upper limit to spending. However, cost shouldn't be a problem if you choose to use cast iron piping in your next project. Cost comparisons have shown that on average, the use of cast iron piping only increases costs by about $150 per bathroom. This is a one time charge, as the cast iron will outlive you and the next four owners of your house! It is also a small price to pay for a quiet plumbing system.
If you try to use plastic PVC piping and then attempt to insulate it so that it does not transmit sound, you will probably save nothing. By the time you calculate the cost to purchase and properly install sound deadening insulation around the piping, you might actually have spent more money than had you used cast iron in the first place. It's food for thought.
You can minimize the upgrade cost of switching to cast iron by mixing both cast iron and plastic piping within your new home or remodeling project. This is easy to do, it's accepted by virtually every plumbing code, and the cast iron and plastic PVC are compatible with one another using simple adapters.
You can utilize the combination of materials in this fashion. Use the less expensive plastic PVC materials for the majority of your underground drainage system. Make the switchover to cast iron just before the pipes turn up to become vertical stacks. Continue to use the cast iron for all pipes that carry liquids and solid waste.
Switch back to plastic PVC piping at each fixture vent. Use plastic PVC piping for all vent pipes, as you can't hear the air that rushes through these pipes each time water drains from a fixture.
Using the two materials in conjunction will save you money. There will be no sacrifice in quality or durability.
The Environment
Finally, cast iron is great for the environment. It's made from 100 percent recycled scrap iron and steel. At the end of its service life it can be recycled again and again. PVC, on the contrary, is not so friendly. Crude oil is used in the manufacturing process. The solvents that are used to weld the pipe and fittings together are carcinogenic and dissipate into the atmosphere. PVC piping cannot be easily recycled. It simply takes up space in landfills or pollutes the air with toxic fumes if burned. Cast iron is simply a better choice.
Sources of Information
For more information than you ever wanted to know about cast iron pipe, go to the web site of the Cast Iron Soil Pipe Institute and read their book (in PDF format) called Pipe & Fittings Handbook.
Cast Iron Pipe Manufacturers and Associations
- American Brass & Iron Foundry
- American Cast Iron Pipe Company
- Charlotte Pipe & Foundry Company
- Griffin Pipe Products Company
- Tyler Pipe Industries
- Cast Iron Soil Pipe Institute
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