Code Classroom Continued from page 22


ASME, is titled Sanitary Waste Valves for Use as an Alternate to Tubular P-Traps for Plumbing Drainage Systems. One company has been manufacturing these valves for use in the RV industry for many years and is now ready to introduce them to the plumbing industry. Because these devices are used in tubular brass traps, they are limited in size to 11/4-inch and 11/2-inch fixture drains only. They work to allow waste and air to flow down- stream through the device, and they prevent sewer gas from migrating back upstream and out of the fixture drain.


Sound-reducing plastic drainage pipes European manufacturers have been designing double-


and triple-wall polypropylene plastic drainage pipe fit- tings to minimize the noise associated with plastic sani- tary waste and vent piping. Plastic piping has often had a couple of disadvantages when compared to cast iron pipe. It has a very high rate of expansion, which must be accounted for with expansion joints in stacks and offsets in horizontal drains. Another issue with plastic drainage piping is noise. When waste is flowing in plastic piping you can hear it, because the piping is not very dense so, as the water splashes around in the pipe, it makes a waterfall or flowing water sound. This has always been a drawback in high-end construction, because no one wants to hear the flushing sounds. The development of higher density multiple layer fittings should reduce these noises but may not eliminate them. Cast iron piping is very dense and has always been a good material choice when noise is a concern. Look for this multi-wall plastic drainage piping tech-


nology to make its way into the U.S. market soon. Once again, there will need to be a standard for the product, and the performance criteria for the standard will need to be identified. Stay tuned.


Push-fit type pipe fittings Over the last several years, a push-on type pipe joining technology has evolved, and a standard has been devel- oped for push-fit fittings through the American Society of Sanitary Engineers (ASSE 1061 standard). Bill Chapin has done a great job chairing this working group. These types of fittings use tiny stainless steel teeth to


grab the pipe and hold onto it, and o-rings are used to make a pressure seal. The technology is new, and some models of these devices have a ring that allows you to lift the teeth so that the fitting can be removed from the pipe. These types of connections are being used on copper, CPVC, PEX and other pipe materials as approved by the manufacturers. I have heard that a joint with one of these fittings failed


when a plumber unfamiliar with the technology put a wrench on the fitting and tried to unscrew it. Apparently, the teeth were damaged, and the joint failed. Better edu- cation is required in the industry or identification of the fitting is required to minimize this type of failure. Push-fit or push-on type fittings have many advantages, and they will allow pipes to be repaired without the use of torches or epoxy cements.


Plumbing Engineer


PEX piping systems PEX piping systems are flexible plastic piping systems


made of cross-linked polyethylene plastic pipe material, which has a linear molecular construction. You might be familiar with this material if you have drunk from a poly- ethylene plastic beer cup. If you have ever crushed one of these cups or torn it, you noticed that, because of the lin- ear molecular arrangement, the cup tears in a linear form. Manufacturers have learned how to take multiple layers


of this material and weave it into an extrusion machine so that the different layers of the pipe are cross-linked. The resulting material is very strong and durable. It is a great product; however, with every new thing, there is a learn- ing curve. Some piping manufacturers have concentrated only on making the pipe and have relied on others for the fittings. They have recently experienced problems similar to those that plagued the manufacturers of polybutylene piping materials a couple of decades ago. The piping is fine but, in a few isolated incidents, the joints have expe- rienced failures. The joint failures have mostly been attributed to batch-


es of non-code compliant fittings. Some brass fittings came from Chinese importers and were apparently made with whatever scrap metals were handy and dumped into the furnace. It was mostly brass, but the Chinese foundries apparently did not have any quality control with reference to materials in the fittings. They had high levels of zinc and other materials. The zinc (or aluminum or other low quality materials) corroded when immersed in water, sac- rificing itself to the more noble brass material and leaving a very brittle sponge-like material under magnification. This brittleness is called a dezincification process. The dezincification may take several years. PEX piping is flexible, and it is not always restrained properly in residential applications. There have been com- plaints about noise associated with coils of the piping moving in the ceiling, causing bumping and sliding sounds. This occurs when the solenoid valves associated with dishwashers and clothes washers cause water ham- mer in the piping system; the pipe moves and bumps or makes a sliding sound when it comes into contact with drywall. The inherent movement associated with flows starting and stopping in the flexible PEX piping system has caused many joint failures, which result in water dam- age to the drywall. Caution must be used with these new pipe materials to


assure that the pipe is properly secured, that water ham- mer arrestors are installed and that fittings are stamped with the proper standard listed in the approved pipe fitting table in the codes. The fittings should be purchased from a reputable manufacturer. This should insure a very reli- able system.


One model plumbing code? A few years ago the two model plumbing and mechan-


ical code organizations ICC and IAPMO came together at a “One Code Summit” in Denver, Colorado, to discuss merging into one model code organization. They held meetings over a period of about a year and a half, and they


Continued on page 28 January 2011/Page 27


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88