Corrosive liquids can contain harmful chemicals that are detrimental to drain, waste and vent (DWV) piping systems that are not designed or rated for chemical use. These chemicals may create noxious or toxic fumes or interfere with sewage treatment processes. The International Plumbing Code (IPC) has clear provisions for addressing this challenge. In Section 803.1 of Chapter 8 (which covers indirect/special waste), the IPC states that chemical waste systems must be thoroughly diluted, neutralized or treated by passing through an approved dilution or neutralizing device before being discharged into a plumbing system. Furthermore, Chapter 7, Table 702.6, identifies the standards to which chemical waste drainage system pipe and fittings must adhere. Since the venting system is also exposed to vapors that can be detrimental to the piping system, the venting system must also be installed with rated piping.

Case Study: Improper handling of chemical waste in texas school remodel

Adhering to these IPC regulations will help you avoid potential risks and complications associated with corrosive chemicals and their disposal. As I've witnessed, having a 'set it and forget it' approach can lead to significant financial burdens.

Consider what happened at a private school in Texas when I was the City of Amarillo's chief plumbing/mechanical/irrigation inspector. When the school was constructed, it was outside the city limits and was not subject to any inspections. A few years later, it was annexed, and they applied for a permit to remodel the science lab wing of the building. This remodel included relocating some of the chemical waste lines.

During a rough-in inspection for the remodel, it was discovered that the contractor had tied onto an existing drainage piping system that was not rated for chemical waste. Consequently, the project failed the inspection because the installation did not meet the chemical waste requirements of the IPC. This real-life example underscores the potential consequences of non-compliance. Further investigation revealed that the entire under-slab chemical waste system was not installed with pipes rated for chemical waste.

Our first step was to obtain a copy of the plans from the design professional of record. In reviewing the plans, the design professional specified the proper piping for the chemical waste system. However, the plumbing contractor that installed the chemical waste system during the original construction of the school did not install it per the construction documents, creating a hazard.

Next, we (the building official, the assistant building official and I) connected with the plumbing contractor hired for the remodel, the school and the original design professional of record to explain why chemically rated pipes were necessary. We fully understood the costs involved in replacing their existing pipes and discussed how we could move forward with an alternative method of compliance. It was agreed upon that the existing non-rated chemical waste system could remain in place if it passed a yearly hydrostatic test. Our approach was that if the existing chemical waste system was in good working order, we saw no reason to make any changes.

Unfortunately, the hydrostatic test failed and provided evidence that the under-slab drainage system was leaking. The school then had to replace the under-slab chemical waste system with properly rated piping. This ensured that the chemical liquids and vapors would no longer pose a threat to the foundation system and the building occupants.

The importance of plan reviews and inspections

Scott McDonald, director of development services with the City of Denton, Texas, was the chief building official in Amarillo for this project. He remembers it well and says, “This project is a great example of the importance of proper plan reviews and inspections. Furthermore, by working with the school, the plumbing contractor and the design professional, we achieved compliance through communication and education, ensuring the health and life safety of the community we served. We should all strive to focus on compliance rather than enforcement.”

Building safety officials should be involved in the planning stage of new construction and remodeling projects, and plans should be strictly followed to safeguard against situations like these. Following a safety-focused plan can help you save time and money in the long run.

As an inspector, I always appreciated it when contractors came in from out of town and asked to speak with us. Those projects always yielded positive results because everyone, from the contractor to the building safety professional to the builder/developer, was on the same page from the start.

When working in an area with no building department, the best advice I can provide to building owners and design professionals is to contract with someone who is knowledgeable on the specific building code requirements associated with your project. Furthermore, the building owner or design professional of record should hire a special inspector to perform plan reviews and inspections.

Understanding local chemical waste handling regulations

Regulations vary considerably from municipality to municipality. Some places are regulated at the state level, while others allow each jurisdiction to adopt its own individual codes and amend them as desired. This creates unique challenges and differentiations among the jurisdictions that contractors should be familiar with before taking on a project. That is why it’s important to work closely with your local building department to understand the building codes that impact your project.

For example, some jurisdictions have determined that condensate (from air conditioning units or vent pipes), which has a high pH level and is therefore acidic by nature, must be neutralized before discharging into a plumbing system. In these jurisdictions, a neutralizing device needs to be installed, maintained and eventually replaced. However, most contractors don’t know this and may never encounter it unless they work in a jurisdiction that requires it, so it is essential for them to get this information upfront. Most jurisdictions publish their amendments online, but if not, the building department will be able to provide contractors with all the information needed to assist them in successful project completion.

Regardless, contractors should never hesitate to reach out to their local plumbing, mechanical, and fuel gas inspectors to ask about any codes or requirements that may be unique to their jurisdiction. As an inspector, I always appreciated it when contractors came in from out of town and asked to speak with us. Those projects always yielded positive results because everyone, from the contractor to the building safety professional to the builder/developer, was on the same page from the start. All expectations were understood, and potential points of confusion were avoided. Additional questions were asked and answered promptly because each party had already established a good relationship.

Every building safety professional will tell you that communication is critical, and they’re 100% right. The reality is that contractors will eventually encounter a challenge that isn’t well-defined or clearly communicated in a two-dimensional world. In those circumstances, the contractors who are most likely to succeed are those who are already in touch with their building department and those who are willing to reach out if they haven’t done so previously.