March 2024 Professional Engineer’s Perspective: Plumbing, What Is It?

In today’s world, plumbing infrastructure is critical to public health and sanitation. Plumbing originated during ancient civilizations, as public baths were being developed to serve large numbers of people who needed potable water and waste removal. As far back as 4000 BC in the area of Mesopotamia, clay sewer pipes were used to remove wastewater from sites and capture rainwater in wells.

But What Is Plumbing?

According to the Definition section in the Ohio Plumbing Code (IPC based), plumbing is defined as “the practice, materials, and fixtures utilized in the installation, maintenance, extension, and alteration of all piping, fixtures, plumbing appliances, and plumbing appurtenances, within or adjacent to any structure, in connection with sanitary drainage or storm drainage facilities; venting systems; and public or private water supply systems.” According to Wikipedia, plumbing is any system to convey fluids for a wide range of applications. Plumbing uses pipes, valves, fixtures, tanks, and other apparatuses to convey fluids. Waste removal and potable water delivery are among the most common uses, but plumbing is not limited to these applications. The word derives from the Latin for lead, plumbum, as the first effective pipes used in the Roman era were lead pipes.

Thus, plumbing is the basic term used for systems that provide potable water, collect and remove sanitary wastewater, and collect/direct rainwater to areas for future use with the intent of protecting public health. While this may be the basic definition, as plumbing engineers and designers, we know that today’s plumbing systems involve much more: gray- and black water systems, distribution of fuel gases and lubricants, medical gas systems, siphonic roof drainage, laboratory systems, and the management of water quality to ensure the water remains clean and potable, among many other plumbing/piping systems needed to serve the public’s needs.

Plumbing at the End of the Earth

While plumbing and the associated codes are utilized all over the world, their implementation and application vary widely. I say this after recent travels to the “end of the earth” at the southern tip of Argentina where the Pan-American Highway has its terminus point in the Puerto Madryn National Park. It is the furthest you can travel by land in the Americas. After visiting the “end of the world,” it seemed only logical that we continued to the South Pole region in Antarctica to visit the “bottom of the world.” It was a trip of a lifetime, allowing me to observe the differing styles of plumbing found in those parts of the world. While I think we can all agree that if it has a waste, drain it away, and if it smells, vent it and provide potable water to wash and drink, but it is also obvious that how that is accomplished differs greatly all over the world.

A fellow engineer asked if Argentina was similar to Brazil in their plumbing practices. He indicated that in Brazil they use what is known as “caixa sifonada” for a floor drain as well as the receptor for all other plumbing fixtures in the bathroom, except for the water closet. The caixa sifonada looks like this:

While we are talking about Latin America, the term itself is actually Portuguese in origin and translates as “siphoned box.” Note that there is no siphonic action actually taking place in the box or device. This device serves two purposes: It acts as a floor drain to collect overflows and runoff from the floor as well as a receiver for greywater waste from the lavatory, tub/shower, and bidet.

With that said, this is essentially a drum trap with multiple inlets being served by a single outlet. Drum traps were a type of plumbing trap used in residential-style applications before the advent of the modern P-trap. The drum trap is a cylindrical-shaped trap with a vertical drain outlet (just above the bottom of the unit) that, in this case, turns horizontally to connect with the vented drainage system. It holds a pool of water to create a “trap seal” that prevents sewer gases and odors from entering the space protected by the trap and contaminating the living space through the trap.

However, over time, drum traps have been found to be problematic in several ways. One of the primary issues is that they are prone to becoming clogged with hair, soap scum, and other substances. Because of their design and installation locations, drum traps are more challenging to clean than other types of traps.

Depending on the materials of construction, the drum trap can corrode over time, leading to leaks and damage to the surrounding plumbing system. In some cases, drum traps can become so corroded that they fail to create a proper seal, allowing sewer gases and odors to escape into the surrounding area.

At least in the Ohio Plumbing Code (OPC), which is based on the International Plumbing Code (IPC), drum traps are a prohibited type of trap except when used as a solids interceptor or serving a chemical waste system.

An additional concern is the amount of waste piping between the lavatory (maybe 10 feet), the tub/shower (maybe 8 feet), and the bidet (maybe 2 feet). The distances all are dependent on the room layout, but seem consistent with the room layout shown below:

Hotel Dazzler by Wyndham in Buenos Aires, Argentina. Note that there is no trap on the lavatory waste line.

The tub/shower was located to the right of the lavatory, as you faced the lavatory, and on the opposite wall from the water closet, bidet, and caixa sifonada.

This is the opposite wall from the lavatory with the bidet located near the foot of the tub/shower. The caixa sifonada is located between the water closet and the bidet.

The amount of waste piping allows ventilation through the drum trap and the other fixtures, which could introduce odors into the space, although no such odor was noted during our stay. But any piping is subject to a buildup of soap scum, biofilm, hair, etc. that could generate odor within those sections of piping.

So, in response to my fellow engineer, yes, it would appear that Argentina uses the same approach as Brazil.

About the Author

David D. Dexter, FNSPE, FASPE, CPD, CPI, LEED BD+C, PE, is a registered Professional Engineer, Certified Plumbing Inspector, and Certified Plans Examiner with more than 40 years of experience in the installation and design of plumbing systems. He specializes in plumbing, fire protection, and HVAC design as well as forensics related to mechanical system failures. Dave serves as Chair of ASPE’s Main Design Standards Committee, Chair of the Bylaws Committee, Co-Chair of the College of Fellows Selection Committee, and Co-Chair of the Professional Engineer Working Group. He also was the 2008–2009 President of the Engineering Foundation of Ohio, 2010–2011 President of the Ohio Society of Professional Engineers, and 2012–2014 Central Region Director for the National Society of Professional Engineers.

The opinions expressed in this article are those of the author and not the American Society of Plumbing Engineers.

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