Consulting-Specifying Engineer - March 2009 - (Page 19) Codes & Standards Using gray water efficiently Engineers may face roadblocks when designing gray water systems, but the technique is gaining traction. BY AMARA ROZGUS, Senior Editor ost engineers focus on lighting, HVAC, windows, and building siting when designing an efficient building. Often secondary on the list is designing a water-efficient building, which can be accomplished with various methods like no-water urinals, dual-flush M Building inspectors often have limited knowledge of gray water plumbing codes, a big barrier to plumbing engineers. water closets, and water reclamation, i.e., harvested rainwater and gray water. It’s sometimes referred to as graywater or grey water. Whatever you call it, it generally consists of reusing water originally used for hand-washing. What are the codes governing the use of reused water? That’s where the issue becomes, well … gray, and many engineers meet a roadblock in either materials funding or local building codes—or both. The 2009 International Plumbing Code Appendix C is the guideline provided to jurisdictions that adopt this plumbing code. Appendix O of the International Residential Code is quite similar, though only for residential dwellings. The first problem, funding, is the biggest push-back an engineer might receive from a building owner or management firm considering a whole-building gray water system. A whole-building system requires two sets of piping: one for fresh, potable water, and the other for gray water. A double-pipe system can double the materials cost. Plus, putting in place a cistern or other device to store the gray water ADDITIONAL READING 2009 International Plumbing Code: www .iccsafe.org Gray Water Policy Center, Oasis Design: http://oasisdesign.net /greywater More suggestions and links to local codes are online at www .csemag.com/graywater requires both space and money. Unless the gray water can be moved by gravity to the place it’s eventually used (such as for outdoor irrigation), pumps must be installed to move the water, especially if the water is being pumped to a multistory building for use in something like a cooling tower. Finally, many authorities having jurisdiction (AHJ) want the gray water treated before it’s reused with a tertiary treatment such as a filter, chemical treatment, or ozonation. Most authorities (and building residents) don’t want untreated—and possibly smelly or filmy—gray water sitting around in a storage tank for too long. Plumbing engineers unfamiliar with nontraditional plumbing designs, equipment, and code issues may run into trouble, possibly with the health department. Local health departments often voice their concern that the gray water might have a cross-connection with potable water, and even a connection to public water. AHJs typically don’t want the water sitting for more than 72 hours, and many have maximum amounts that can be stored at any time. To add to the cost, the gray water influent pipe and the drain to the jurisdiction’s sanitary sewers must be the same size and meet local code. Meeting with the locals Building inspectors often have limited knowledge of gray water plumbing codes, a big barrier to plumbing engineers. Water reuse is common and much-needed in the West, so gray water and rainwater use is more common. Engineers, Consulting-Specifying Engineer • MARCH 2009 19 http://www.iccsafe.org http://www.iccsafe.org http://oasisdesign.net/greywater http://oasisdesign.net/greywater http://www.csemag.com/graywater http://www.csemag.com/graywater Table of Contents for the Digital Edition of Consulting-Specifying Engineer - March 2009 Consulting-Specifying Engineer - March 2009 Contents Viewpoint News M/E Roundtable Codes & Standards Networked Controls for the 21st Century University Engineering a BIMStorm Fire and Life Safety in a High-Rise Snubbers: Protecting Medium-Voltage Transformers HVAC Special Report Case Study New Products Equipment Lifecycles Advertiser Index Green Space Pure Power Supplment Consulting-Specifying Engineer - March 2009 http://www.nxtbook.com/nxtbooks/reed/cse0410 http://www.nxtbook.com/nxtbooks/reed/cse0310 http://www.nxtbook.com/nxtbooks/reed/cse0210 http://www.nxtbook.com/nxtbooks/reed/cse0110 http://www.nxtbook.com/nxtbooks/reed/cse1209 http://www.nxtbook.com/nxtbooks/reed/cse1109 http://www.nxtbook.com/nxtbooks/reed/cse1009 http://www.nxtbook.com/nxtbooks/reed/cse0909 http://www.nxtbook.com/nxtbooks/reed/cse0809 http://www.nxtbook.com/nxtbooks/reed/cse0709 http://www.nxtbook.com/nxtbooks/reed/cse0609 http://www.nxtbook.com/nxtbooks/reed/cse0409_v2 http://www.nxtbook.com/nxtbooks/reed/cse0509 http://www.nxtbook.com/nxtbooks/reed/cse0409 http://www.nxtbook.com/nxtbooks/reed/cse0309 http://www.nxtbook.com/nxtbooks/reed/cse0209 http://www.nxtbook.com/nxtbooks/reed/cse0109 http://www.nxtbook.com/nxtbooks/reed/cse1208 http://www.nxtbook.com/nxtbooks/reed/cse1108 http://www.nxtbook.com/nxtbooks/reed/cse1008 http://www.nxtbook.com/nxtbooks/reed/cse0908 http://www.nxtbook.com/nxtbooks/reed/purepower_2008fall http://www.nxtbook.com/nxtbooks/reed/cse0808 http://www.nxtbook.com/nxtbooks/reed/cse0708 http://www.nxtbook.com/nxtbooks/reed/cse0608 http://www.nxtbook.com/nxtbooks/reed/purepower_2008summer http://www.nxtbook.com/nxtbooks/reed/cse-specifiersguide08 http://www.nxtbook.com/nxtbooks/reed/cse0508 http://www.nxtbook.com/nxtbooks/reed/cse0408 http://www.nxtbook.com/nxtbooks/reed/cse0308 http://www.nxtbook.com/nxtbooks/reed/cse0208 http://www.nxtbook.com/nxtbooks/reed/cse0108 http://www.nxtbook.com/nxtbooks/reed/cse1207 http://www.nxtbook.com/nxtbooks/reed/cse1107 http://www.nxtbook.com/nxtbooks/reed/cse1007 http://www.nxtbook.com/nxtbooks/reed/cse0907 http://www.nxtbook.com/nxtbooks/reed/cse0807 http://www.nxtbook.com/nxtbooks/reed/cse0707 http://www.nxtbook.com/nxtbooks/reed/cse-sg07 http://www.nxtbook.com/nxtbooks/reed/cse0607 http://www.nxtbook.com/nxtbooks/reed/cse0507 http://www.nxtbook.com/nxtbooks/reed/cse0207 http://www.nxtbookMEDIA.com
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