Through all of the discussions about a single plumbing code, the third code in the group, the PHCC-NA National Standard Plumbing Code (NSPC), seems to be the forgotten code. The NSPC, however, is alive and kicking. While the use of this code is the smallest land mass of the three, it is still the code for more than 15 million people.

I always think of the NSPC as having the fastest code-change cycle. By the time you receive the code change book, it is almost time for the hearing. Unlike the IPC and the UPC, there is only one hearing. The vote of the committee is final.

By the time you read this column, the final decisions will have been made for the NSPC cycle.

There were 139 code changes submitted to the NSPC. However, the majority of the code changes are what would be classified as nickel-and-dime, editorial-type changes. This is typical with all codes, as they constantly try to clarify code requirements.

Another large group of code changes are the updating of standards. There is no automatic process of updating the code to the latest standard. This results in many changes to simply modify the date of the standard.

Proposed Changes to NSPC

The big item again on the agenda is air admittance valves. The NSPC currently allows AAVs; however, the systems must be designed by a professional engineer. A plumbing contractor is not permitted to select an air admittance valve and simply install it.

The proposed change would allow individual and branch-type air admittance valves to be installed without a professional engineer designing the system. Stack-type air admittance valves would still require an engineer. The thought process is that, for other than one- and two-family dwellings, an engineer is involved in the design of the plumbing system. Hence, for stack applications, a plumbing engineer would be designing the system.

In the piping material section, there is a change proposed to add emphasis to the marking requirements for cast-iron soil pipe. This is in response to the import of Chinese cast-iron soil pipe. Domestic manufacturers are concerned that certain imported pipe is not being properly identified.

I found a series of changes to the code for the joining of cast iron to plastic pipe to be interesting. The changes relate to the pouring of molten lead in transition joints. For many years, it has been a practice of the profession to caulk a lead and oakum joint between a cast-iron hub and a plastic pipe.

The plastic industry has proposed a change that would prohibit this practice. They are suggesting a change to lead wool for the joints, not molten lead. The NSPC Committee proposed a change to only allow lead and oakum joints for solid wall plastic pipe, the concern being the cellular core products.

The lead is 600°F or hotter, and the temperature can impact plastic pipe. The question the committee will have to answer is, “Can you use molten lead for a solid wall pipe?”

The problem with using lead wool, as suggested by the plastics industry, is that it does not have the same holding power for the oakum as does a poured lead joint. The purpose of the lead is to hold the oakum in place when it first gets wet and expands.

Similar to the other plumbing codes, grease interceptors are a big issue for the NSPC. There are two proposals to completely rewrite the grease interceptor requirements. The proposed text follows the recommendations of the Plumbing and Drainage Institute (PDI). Sizing would be specified.

The new name of grease interceptor also would be added to the code. Type I hydromechanical interceptors would be your typical PDI in-place grease interceptor. GRD would apply to grease removal devices that are first hydromechanical interceptors. Type II gravity interceptors would be your large vaults installed outside, underground.

Dishwashers would be permitted to discharge to a grease interceptor under the major proposal, as well as food waste grinders. However, when a food waste grinder discharges to the grease interceptor, a solids interceptor would be required upstream of the grease interceptor.

In the storm drainage chapter, the NSPC Committee proposed changes to eliminate gutters and downspouts. The reason provided is that gutters and downspouts are installed by the sheet metal trade, not the plumbing trade. This argument gets back to the question of who the plumbing code is written for.

The proposal would acknowledge that gutters and downspouts could be used for storm drainage. However, there would be no requirements for the gutters and downspouts. If the gutters were improperly designed, their plumbing code would not address it. The language specifically refers to the gutters and downspouts as “other nonplumbing drainage.”

Also under the storm drainage chapter is a change to address storm water reuse. With the advent of green building design, this has become a major subject. The proposed change would allow storm water reuse to be used for nonpotable water applications. There are no specific nonpotable applications listed.

The system must be labeled “nonpotable water” throughout. Tank requirements are spelled out regarding overflow, refill and drain down. There also is a requirement for pumping.

The proposed water reuse section does include requirements for filtration and mold/bacteria prevention. While ultraviolet filtration systems and ozonator systems are listed, the text does not mandate either one of these systems.

While this code change is a start, it appears to need more work in clarifying the requirements for water reuse. As the proponent states, this is long overdue to address green building design. But any new requirements must have the proper mandatory language to protect public health and safety with water reuse.

This year’s cycle is considered a midterm change cycle. There is still one more code change cycle scheduled next year for the NSPC, before the next code edition is printed in 2009.