Definitions - First Step to Understanding the Code

Ask any licensed plumber and they will tell you that the first step in learning the code and studying for your exam is LEARNING THE DEFINITIONS.

That may sound really basic, and it is, but the Plumbing Code is a legal document and therefore very precise in scope and meaning. Even the simple words like SHALL or May have important meaning in the code. The section on definitions lists the definitions that pertain to the Plumbing industry, but definitions given in other codes (mechanical, fuel gas, building, etc.) are considered to be included by reference.

When in doubt – LOOK IT UP.

It is important to understand the meanings of technical and trade terms to understand the code. Many trade specific terms are not included in the definitions, but are assumed by experience. If you are not sure of a term look it up or ask your plumber or supervisor.

Some definitions are included below, but study your code book, and look at the definition chapters in other code books. You can view all of the NC State Code Books free online at: http://codes.iccsafe.org/North%20Carolina.html

BATTERY OF FIXTURES Any group of two or more similar adjacent fixtures which

discharge into a common horizontal waste or soil branch.

INDIVIDUAL VENT Vent piping from a single fixture to a branch vent or main vent.

BRANCH VENT Vent piping from a group of fixtures to the main vent pipe.

BUILDING DRAIN That part of the lowest piping of a drainage system that receives the discharge from soil, waste and other drainage pipes and extends 10 feet beyond the exterior walls of the building and conveys the drainage to the building sewer.

DEVELOPED LENGTH Length of piping measured along its center including fittings.

COMBINED BUILDING DRAIN A building drain that conveys both sewage and storm water or other drainage.

SANITARY BUILDING DRAIN A building drain that conveys sewage only.

BUILDING STORM DRAIN A building drain that conveys storm water or other drainage, but not sewage.

DRAINAGE SYSTEM Piping within a public or private premise that conveys sewage, rainwater or other liquid wastes to a point of disposal. A drainage system does not include the mains of a public sewer system or a private or public sewage treatment or disposal plant.

TRAP WEIR The highest point of water in a trap where it begins to flow down the horizontal drain piping.

GRAVITY DRAIN A drainage system that drains by gravity into the building sewer.

INDIRECT WASTE RECEPTOR A plumbing fixture designed specifically to collect

and dispose of liquid waste from other plumbing fixtures, plumbing equipment or

appliances which are required to discharge to the drainage system through an air gap such as floor sinks, mop receptors, service sinks, and standpipe or hub drains with integral air gaps.

LABELED Equipment, devices, fixtures or materials bearing the label of an approved agency.

PIPE SIZES For code purpose this is the nominal pipe sizes available commercially. When in the code, it is instructed to "increase by one pipe size." We should presume the pipe sizes that are available. 1/2, 3/4, 1, 1 1/4. 1 1/2 , 2, 2 1/2, 3, 4, 5, 6, 7, 8, 9, 10.

SCUPPER An opening in a wall or parapet that allows water to drain from a roof.

TOILET ROOM A room containing a water closet, and frequently, a lavatory, but not a bathtub, shower, spa or similar bathing fixture.

WATER SERVICE PIPE The piping from the water meter to the water distribution system of the building served. Water service pipe terminates 5 feet outside the foundation wall.

There are, of course, many more terms to learn. Read your code book. Google terms you are not sure of. Check the gas pipe and mechanical codes. The more comfortable you are with the common terms the easier it will be to understand the rest of the code. And if the inspector tells you that he is turning down your bathroom group because the developed length to the trap is too long and the branch tee is below the trap weir on your lavatory arm – you'll know what he's talking about.