Chapter 4 - Fixtures : Part 1

Chapter 4 of the North Carolina Plumbing Code begins to delve into the meat of the code. Type and placement of fixtures are generally within the scope of the architect and engineer on most projects, but you will need to know this stuff for the test. Plumbers are also expected to know these regulations on the job. If the engineer doesn't get the fixture count right it is the plumber who will have their inspection failed.

Review all drawings and specifications before you start work.

It is far more expensive to go back and add/change-out fixtures at the end of the job than to catch mistakes early on. Your first step, as the plumber, should be to review the drawings and specifications for compliance with local code. The engineer may be from out of state, or even outside the US.

It is the responsibility of the local plumber to step up and say, early on, that the system will not pass local code and changes need to be made.

This chapter of the code contains information on specific minimum requirements for fixtures and facilities in different types of structures and how to calculate occupancies and expected use. If you are one toilet short the local code official may catch the discrepancy on the initial rough – or they may not. But even if isn't caught until the final inspection it will still need to be added. That could be a major headache in a finished structure.

The chapter's first sentence gives us the scope: “This chapter shall govern the materials, design and installation of plumbing fixtures, faucets and fixture fittings in accordance with the type of occupancy, and shall provide the minimum number of fixtures for various types of occupancies.”

A long sentence. Let's break it down.

In this chapter we are told what the different types of occupancy are. Chart 403.1 breaks it down into 8 different categories which are further divided into occupancy types. For each we are given total fixtures, by type, which are required, based on how many people are expected to use the structure. This is given for male and female occupancy, which can have different ratios depending on structure and occupancy type.

Notice at the bottom of the chart are a long list of notes that provide adjustments to the chart for various situations.

This is a large chart, with a lot of what-ifs. You're not expected to memorize it all. That's why you have your code book handy on the job and when you take the test. The North Carolina Plumbing Code is filled with charts such as this. But you do need to be familiar with the information and know where to find the chart.

The chart is a quick reference.

The code text explains it all and goes into greater detail. If you have noticed the notes under the chart that are underlined, and other sections of code that are underlined, these are additions North Carolina has made to the International Plumbing Code – which our code is based on. These are often the gotchas that trip up out of state engineers who know the International Code very well, but may miss some small provision that North Carolina has changed.

In previous chapters we have seen entire sections of code that have been deleted or moved. This also keeps continuity with the International Code. In the North Carolina Statute, which governs the code, the International Code was adopted with North Carolina revisions. Most of the changes are small, but some change the entire intent of the original code. In all cases the North Carolina Code is the final word.

We must also note that types and occupancies not shown on table shall be determined by the local official.

Numbers and types can also be adjusted if it is shown that the occupancy will be different than the standard assumed in the chart. So an all girl school would not require the same ratio of male to female facilities as the “education” classification on the chart. We would need many more female and far less male facilities.

Prior to delving into the number and types, we are provided with some minimum material requirements for fixtures.

Section 401.2 describes prohibited types of water closets and prohibits trough urinals. I have never encountered a prohibited water closet. Manufacturers are well aware of the International Code standards and design their products accordingly. We saw in a previous chapter that all fixtures and material must comply with various “approved” standards.

Trough urinals were popular decades ago and may still exist in some older structures. These would fall under the code pertaining to existing structures as to whether they would need to be replaced. But they are definitely not allowed in new construction.

If you have never encountered a trough urinal, they are a single trough of varying length that can be used by multiple people – usually with a constant flow of water through the trough. They were outlawed years ago due to privacy and health concerns and also for their inefficiency.

Section 402 lists materials allowed and minimum quality of those materials. Again, manufacturers work to these standards and any major manufacturer's products should meet the minimums. But this could become an issue if off market or foreign goods are used. As said before, all fixtures and materials must meet approved standards as listed by ASTM, ASME, and others. When in doubt check with the local official before installation.

In my next post we will continue in Chapter 4 and drill down into a little more detail.