Building a Lasting Legacy

How do you choose the right materials if the wrong ones all promise to be perfect?

Facility managers and building owners today are navigating a construction landscape shaped by increasingly stringent codes, sustainability goals, budget limits and tenant expectations. Plumbing systems — while often hidden from view — play a foundational role in building performance, safety and longevity.

One of the key decisions every project faces is what kind of piping material to use for drain, waste and vent (DWV) systems. Traditional cast iron soil pipe has been around for generations.

Meanwhile, plastic options like PVC and ABS have gained traction for their perceived affordability and ease of use.

So which one is better?

The short answer: it depends. The longer — and more useful — answer comes from taking a closer look at how these materials perform across a range of real-world considerations. From sustainability and fire safety to acoustics and cost, this article explores how to make an informed, practical decision based on the long-term needs of your building.

Sustainability: What happens before & after the pipe goes in

Recyclability & environmental impact

Sustainability is no longer a buzzword — it is a building standard. If you are pursuing LEED certification or simply trying to reduce your environmental footprint, the recyclability of building materials is worth a close look.

U.S.-made cast iron is notable for its circular lifecycle: it is made from more than 96 percent post- consumer recycled materials and is fully recyclable at end of life. That means when it is time for a remodel or demolition, the pipe can go back into the manufacturing process rather than to a landfill.

PVC, by contrast, is technically recyclable but is rarely processed as such in practice. Once installed, it often becomes waste that is difficult to reclaim — and may break down over time into microplastics that enter the environment.

Carbon footprint & manufacturing

Production methods differ, too. American-made cast iron manufacturing makes use of scrap materials and more energy-efficient melting methods. Plastic piping involves petroleum extraction, chemical processing and higher greenhouse gas emissions throughout its lifecycle.

Summary: If long-term sustainability, recyclability and embodied carbon are priorities, cast iron made in the U.S. offers clear advantages.

Resilience: The strength to withstand time and trouble

Fire safety & code compliance

In high-occupancy buildings like hospitals, apartment complexes and commercial spaces, fire performance is a critical concern. PVC and ABS are combustible materials. They can ignite quickly, emit toxic smoke and require additional firestopping systems to meet code — each of which adds both cost and complexity.

American-made cast iron is non-combustible and naturally fire-resistant, often reducing the need for these added measures. It offers a margin of safety that is built in, not built around.

Load-bearing & structural integrity

DWV systems are not immune to structural stress. Pipes endure the cumulative effects of temperature fluctuations, expansion and contraction due to those fluctuations and building movement. American-made cast iron systems tend to hold up better under load and are more resistant to warping, cracking or collapse. Plastic pipes, while lighter and easier to handle, are more vulnerable to damage from physical impact or sustained stress — factors that may increase repair or replacement needs over time.

Corrosion & chemical resistance

Modern U.S.-made cast iron systems offer enhanced protective coatings that resist corrosion even in aggressive DWV and storm drainage applications. For facilities with commercial kitchens, coastal climates and low-flow systems, this resilience can be a significant advantage.

Summary: When it comes to safety, strength and staying power, cast iron made in America delivers a higher level of confidence—especially in demanding commercial settings.

Acoustics: Because your plumbing shouldn’t be heard

Noise transmission

Whether a guest in a hotel room, a patient in a hospital or a tenant in a multifamily unit, no one wants to hear water draining through the walls. Yet plastic piping is notorious for sound transmission — requiring added insulation, isolation hangers and special fittings to control noise levels.

American-made cast iron, with its naturally dense structure and joining methods, dampens sound as a matter of design. It is often referred to as “the quiet pipe,” and for good reason: it performs well acoustically without requiring extra treatments or materials.

Comfort = Quality

A quieter building feels more thoughtfully built. That perception can lead to better tenant satisfaction, lower complaint volumes and a greater sense of quality throughout the space.

Summary: If occupant comfort matters — and it always does — American-made cast iron offers a built-in acoustic advantage.

Cost: Looking beyond the initial cost

Initial material cost vs. Installed cost

PVC piping is generally cheaper per foot than cast iron and that upfront difference can be tempting. But the full picture includes installation labor, firestopping systems, noise insulation, hangers and long-term maintenance.

Because American-made cast iron does not require many of these add-ons, its total installed cost is often closer to parity — and sometimes even lower.

Lifetime value

American-made cast iron systems can last 50 years or more with minimal maintenance. By comparison, plastic systems may require earlier replacement due to cracking, degradation or chemical damage.

Fewer repairs and replacements not only lower cost — they reduce disruption. That’s especially important in facilities where downtime is expensive or hard to schedule.

Insurance & risk

Material choice can affect insurance premiums as well. Some providers consider fire-resistance in their underwriting, meaning American-made cast iron systems may qualify for more favorable rates.

Summary: Cost is not just what you pay today — it is what you pay over time. American-made cast iron makes a strong case when you look at total cost of ownership.

It’s only 1% of your budget, until it isn’t

In most commercial projects, DWV systems represent just 1 percent of the total construction budget. But that 1 percent supports every floor, every tenant and every utility for decades to come.

Choosing a system based only on material price can backfire if it leads to frequent repairs, safety risks or compliance issues. A slightly larger investment upfront may save considerably more over the life of the building.

Why CISPI cares (and why you should, too)

At the Cast Iron Soil Pipe Institute (CISPI), we don’t just promote American-made cast iron because it is in our name. We advocate for it because the data backs it up.

• Decades of verifying quality control measures are in place at domestic foundries

• Real-world performance benchmarks

• Up-to-date code guidance and installation resources

Need help navigating local regulations or comparing options for your next build? CISPI is your trusted, independent resource.

And yes — if there is a scenario where PVC is the right choice, we will tell you. Our mission is not to sell, it is to inform. Because at the end of the day, smarter builds make safer, stronger and more sustainable communities.

Final thought: Think long-term, build iron-clad

There is a reason American-made cast iron has been the backbone of buildings for over a century. It works. It lasts. It protects.

So when you are choosing materials for your next project, do not just think about today’s savings. Think about:

• Future maintenance calls

• Tenant complaints

• Environmental impact

• Fire safety

• Soundproofing

• Insurance premiums

Because that 1 percent can save you a whole lot more than money.

For more information, specifications and case studies, visit CISPI.org/ironcladtruth and get the Iron-Clad Truth about building materials for your next project.