D-1 Sanitary Drain, Waste, and Vent Systems Introduction

The following terms will be used throughout this section. A complete list of terms for this section can be found in the Glossary.
Please also see the separate NPC Definitions for DWV Systems in Section D-1.2.

• acrylonitrile-butadiene-styrene (ABS) pipe: A type of plastic pipe that is lightweight, strong, and resistant to damage. It is often used in homes and buildings for carrying waste and venting air. However, because it can catch fire, it is usually only used in certain types of buildings. (Section D-1.4) 
• Applied Science Technologists and Technicians of BC (ASTTBC): The association for technology professionals and regulatory body that certifies wastewater professionals in BC.  The ASTTBC registers practitioners once they have obtained the proper training. (Section D-1.1)
• BC Plumbing Code (BCPC): The plumbing standard for British Columbia, historically based on the National Plumbing Code of Canada. (Section D-1.1)
• bell trap: A type of drain used in the past, often in floor drains. Installation is prohibited by the NPC because it can cause problems with draining. (Section D-1.10)
• certification mark: A special symbol or label on a product (such as ASME) that shows it has been tested and approved to meet safety and quality standards. It proves that the product is safe to use and works properly. Note about ASME certification marks: the ASME “H” or “U” stamp is used on pressure vessels, boilers, and piping systems to indicate compliance with ASME codes. In plumbing, ASME standards apply to products like pipes, fittings, and fixtures, but the products themselves often carry certification marks from testing organizations like CSA, NSF, or UL, which certify that they meet ASME standards. (Section D-1.1)
• chemical-dosing neutralization systems: Systems that use controlled injection of acid or base into a waste stream to neutralize chemicals. The chemicals react to form a salt and water mixture, which is then discharged. (Section D-1.11)
• cleanout: An access point installed in drainage and venting systems for cleaning and inspection services. (Section D-1.2; Section D-1.3; Section D-2.3)
• co-extruded dual-wall pipe: A pipe that has two layers, with a smooth inside and a stronger outside. The extra layer makes it more durable and better for certain drainage and sewer systems. (Section D-1.4)
• combustible piping: Pipes made from materials that can burn, such as ABS and PVC, which have specific installation restrictions. (Section D-1.4)
• drainage system: An assembly of pipes, fittings, fixtures, and traps used to convey sewage, clear-water waste, or stormwater to a public sewer or private sewage disposal system. It does not include subsoil drainage pipes. (Section D-1.1)
• DWV system: Stands for Drain, Waste, and Vent system, which removes wastewater and vent gases from a building, ensuring proper drainage and pressure balance. (Section D-1.3; Section D-2.3)
• Environmental Management Act: A law that helps protect the environment by making sure people and businesses follow rules about pollution, waste, and how they use natural resources. It helps keep the air, water, and land clean and safe for everyone. (Section D-1.1)
• fixture unit load: A way to measure how much water a plumbing fixture, like a sink or toilet, uses. It helps plumbers figure out how big the pipes need to be to handle the amount of water that flows through them. Each fixture has a specific number of fixture units based on how much water it uses. The higher the number of fixture units, the more water the fixture needs. (Section D-1.5)
• flame spread rating (FSR): A classification that indicates how quickly flames spread along a material’s surface, relevant for building code compliance. (Section D-1.4)
• forcemain: A pressurized sewer system that transports wastewater using pumps when gravity flow is insufficient. (Section D-1.4)
• grease interceptor: A device used to trap fats, oils, or grease from wastewater before it enters the drainage system, often used in kitchens, restaurants, or care facilities. (Section D-1.10)
• hydraulic load: The amount of water moving through a system, like pipes or drains, over a certain time. Imagine pouring water into a funnel—if you pour too much too fast, it overflows. In plumbing and wastewater systems, hydraulic load helps us understand how much water a system can handle before it gets too full or backs up. (Section D-1.5)
• indirect connections: Plumbing connections where a fixture or device is not directly connected but instead terminates above the flood level rim of a directly connected fixture, forming an air break. This type of connection is designed to prevent backflow. (Section D-1.10)
• limestone chip neutralization: A method where acidic waste is neutralized by mixing it with limestone chips (calcium carbonate). The process produces a chemical reaction that neutralizes the acid, and the mixture is then discharged. (Section D-1.11)
• municipal bylaws: Rules made by a city or town to help keep things safe and organized, like where buildings can be built and how plumbing systems should be set up. (Section D-1.1)
• National Plumbing Code (NPC): A model plumbing code developed by the National Research Council of Canada, updated every five years. (Section D-1.1)
• non-combustible piping: Pipes made from materials like cast iron and copper that do not burn and are often required in fire-rated construction. (Section D-1.4)
• p-trap: A U-shaped pipe that prevents sewer gases, odors, and pests from entering a building by maintaining a water seal. (Section D-1.3)
• S-trap: (Section D-1.10)
• sanitary building drain: A building drain that conducts sewage to a building sewer from the most upstream stack, branch, or fixture drain serving a water closet. (Section D-1.2; Section D-1.3)
• seismic restraint: The components and systems installed to protect mechanical systems, including piping, from seismic forces, ensuring that the system can withstand the stresses of an earthquake. (Section D-1.10)
• trap arm: The portion of a fixture drain between the trap weir and the vent pipe connection. (Section D-1.3)
• vent hierarchy: A system that classifies plumbing vents based on their role in the drainage system. As vents connect, their names change, determining their size and function. Smaller vents, like individual and branch vents, combine into larger ones, such as vent stacks and headers. This system ensures proper airflow and prevents sewer gas buildup. (Figure 22, Section D-1.3)