ASPE Position Statements





From time to time, the ASPE Board of Directors approves a position statement on a topic of interest in the plumbing engineering industry. The Society's currently approved position statements follow.


(Adopted October 30, 1999)
The American Society of Plumbing Engineers supports the creation and implementation of a single model plumbing code and its utilization, without significant modifications, by municipal, state, and other governmental agencies. For the future, ASPE endorses the evolution of a single model plumbing code into a cohesive world plumbing code.

Plumbing codes set the minimum standards to which plumbing systems are designed and installed. The proliferation of municipal, state, and other government codes increases the costs of engineering and installing plumbing systems.

Although plumbing code regulations vary, the engineering principles behind the design of plumbing systems are predictable and constant. A single, mandated model plumbing code would establish the proper minimum standards and requirements for the design and installation of plumbing systems, would eliminate inconsistencies among multiple and competing codes, and reduce the likelihood for errors and omissions.

As a benefi t to the plumbing industry and the public and to avoid the proliferation of additional competing model plumbing codes and organizations, ASPE strongly urges and challenges the current competing model plumbing code organizations to establish a single homogeneous model plumbing code.

(Adopted October 30, 1999)
The Board of Directors of the American Society of Plumbing Engineers (ASPE) does hereby resolve that there may be locations where an air-admittance valve can be installed safely when the strict guidelines for its use are followed. However, ASPE urges caution to the plumbing engineering community in the use of air-admittance valves until such time as additional data collection and research can be conducted on the proper limitations and use of these devices.

The American Society of Plumbing Engineers is committed to improving plumbing design and installations for the benefit and protection of the health, safety, and welfare of the public. To accomplish this, ASPE encourages the plumbing research needed to specify and determine the precise functions and operations of plumbing fixtures, materials, and systems to provide properly operating plumbing products and plumbing system designs.

ASPE acknowledges that various plumbing materials, products, and concepts have not always performed satisfactorily in appropriate installations, despite being approved by nationally recognized standards. Due to energy-conservation concerns, improved building construction materials and methods have resulted in reduced air leakage and less outside air being brought into occupied spaces, which, in turn, has required enhanced vigilance to prevent the introduction of noxious or toxic air, such as sewer gases, into an occupied space.

Opinion within the plumbing industry regarding the consistent and proper installation and workings of plumbing materials, products, and concepts has, at various times, been inconclusive and open to interpretation and disagreement. An example of such a product is the air-admittance valve.

Historically, atmospheric plumbing venting systems that compensate for either positive or negative pressure fluctuations in the drainage system have been used successfully for more than 50 years.

An air-admittance valve is a mechanical device and, therefore, may be subject to malfunctions. It is usually installed in semi-concealed locations (inside walls, in attics, or under counters) and is not designed to relieve excess pressure built up from within a plumbing drainage system.

The American Society of Plumbing Engineers recognizes that air-admittance valves have been installed in various installations throughout the United States and Europe and have apparently functioned properly and provided protection for the public from sewer gas entering into occupied spaces when the plumbing drainage and vent systems have been designed and installed in accordance with the codes and standards regulating air admittance valves.