When designing the plumbing system for a high-performance commercial building, the right products and installation techniques can improve the comfort, health, and well-being of building occupants. They can also provide the owner with a low-maintenance, long-lasting facility.

To accomplish these goals, a building’s plumbing system should:

• Make environmental sense

• Support occupant health and well-being

• Be cost effective over the life of the structure

Cast iron soil pipe is the go-to solution for plumbing engineers when designing reliable, long-lasting DWV plumbing systems in commercial buildings. Read on to learn more and explore how Charlotte Pipe and Foundry’s cast iron soil pipe and fittings help accomplish these objectives.

Why Cast Iron Soil Pipe Makes Environmental Sense

Charlotte Pipe’s U.S.-made cast iron soil pipe is produced with 96% post-consumer recycled content and is 100% recyclable. Every year, Charlotte Pipe recycles more than 150,000 tons of scrap iron and steel to produce its cast iron soil pipe and fittings. In addition, recycling scrap iron eliminates the need for the use of pig iron, which has a much larger environmental footprint.

“The benefits of cast iron extend beyond the manufacturing process — it also reduces the exposure to volatile organic chemicals on a project,” said Brian Helms, training manager at Charlotte Pipe. “When installing cast iron soil pipe and fittings, no cleaning fluids or solvent cements are needed to join them.”

Charlotte Pipe’s cast iron also uses a low-VOC coating versus the high-VOC epoxy coating often used by non-domestic manufacturers.

“Plumbing engineers can rest assured that coatings used on cast iron pipe and fittings systems manufactured by Charlotte Pipe are in full compliance with EPA regulations,” noted Helms.

How Cast Iron Positively Impacts Building Occupants

High-performance buildings should deliver a comfortable and productive environment for future occupants. Cast iron soil pipe provides the best sound attenuation properties of any DWV piping material. From office buildings to schools, excessive building noise is distracting, hinders productivity, and can lead to increased stress levels.

“For projects with shared walls, plumbing engineers should evaluate whether the building’s plumbing components and systems either contribute to or reduce noise pollution — and consider specifying cast iron soil pipe as a reliable solution,” Helms said.

Often called “the quiet pipe,” cast iron pipe is known for its sound-dampening properties, reducing the noise generated by water flow. According to the Cast Iron Soil Pipe Institute, installing cast iron for waste piping can create a plumbing system that is up to 11 times quieter than an all-plastic system.

In buildings where sleep is necessary for physical and mental health — such as multifamily residential housing, dormitories, hotels, and health care facilities — cast iron soil pipe contributes to a quieter and more peaceful environment.

Why Cast Iron Is a Cost-Effective Solution

It is important to design a building with low-maintenance systems that will perform as intended for many years. Not only does this lead to lower operational costs over time, but it also limits the need for ongoing repairs that create waste and disruptions for the building’s occupants.

Burying Cast Iron Versus PVC

Cast iron, which has very high load ratings and is eight times stronger than thermoplastic pipe, requires less site preparation for underground applications. This can help save time and expedite plumbing system installs.

Unlike plastic pipe, which is considered flexible, there are only a few special requirements for burying cast iron soil pipe:

• The bottom of the trench should be stable enough to support the pipe, with small indentations for hubs and couplings.

• The trench should be slightly larger than the pipe.

• No special beddings are required.

Alternatively, PVC requires specific techniques for burying, as detailed in ASTM D2321. These include:

• Excavating the trench width in direct proportion to the size of the pipe

• Carefully preparing the trench to provide a minimum of 4” of firm, stable and uniform bedding material (6” if rock is encountered).

• Providing critical haunch support for the pipe by backfilling the appropriate aggregate in six-inch layers, with each layer sufficiently compacted 85% to 95%

By using products that contribute to the longevity of a plumbing system, such as cast iron soil pipe, the DWV system can be operated and maintained within the limits of existing resources for years to come.

“In our throwaway society, very few products last more than even a decade,” Helms said. “With routine flushing and maintenance of adjoining systems, such as grease interceptors, cast iron soil pipe is designed to last the life of the building.”

From environmental benefits and sound-deadening qualities to positive economic factors, cast iron soil pipe and fittings offer plumbing engineers a high-performing DWV plumbing system for all buildings, from residential to commercial.

Are you looking for more insights on the value of cast iron pipe and fittings? Explore how cast iron starter fittings work for multistory construction projects where identical bathroom groups repeat floor after floor, such as in condominiums, apartments, hotels, and hospitals.