Hot Water Delivery Systems in the ICC Green Code ACEEE Hot Water Forum
Topics Introduction to the IgCC Hot water delivery in IPC and IECC Hot water delivery systems in the IgCC System design Recirculation Pipe insulation Additional water heating efficiency measures
Introduction to the IgCC
What is a Green Code Overlay? Works with existing codes, does not replace existing codes. IgCC is designed to work with ICC s family of codes. Adds broad-based sustainability to the life, health, & safety focus of the traditional codes. Does NOT trump the existing codes. Where a conflict exists, local codes, laws, and regulations take precedence
Scope Applies to traditional commercial AND high-rise residential buildings Residential portions of buildings (except high rise residential) covered by ICC-700 (NGBS) Applicable to new construction, alterations, and additions Provides criteria to measure compliance & drive green building into everyday practice
Subject Areas Energy efficiency Alternative energy sources Water efficiency Alternate water sources Materials and resource use Indoor environmental quality Global impact Site design and impact Operation and maintenance Existing buildings
Hot Water Delivery Systems in the IPC and IECC Setting the Foundation
Delivery Systems in the IPC Minimum Pipe Sizing Minimum size of 3/8 permitted to supply (IPC Table 604.5): Bidets Drinking fountains Lavatories Water closet flush tanks Volume reduction from 3/8 to ½ pipe ranges from 37% for Type M Copper to 46% for SDR9 PEX Reduced size flexible water connectors permitted between supply pipe and fixture.
Delivery Systems in the IPC Parallel Plumbing Further reductions in individual fixture supply lines permitted for parallel systems. Bathtubs, Kitchen sinks, Laundry, Showers, One-piece Water closets Developed length must be 60 or less and pressure at meter must be at least 35 psi Minimum size may be reduced by one pipe size from Table 604.5 Section 604.10 provides manifold sizing provisions for different nominal sizes, and 4 or 8 feet per second velocity.
IPC/IECC Requirements for Recirculating Systems
Hot Water Delivery Systems in the IgCC Raising the Bar
Piping System Types in the IgCC Circulating Everything Else Trunk and branch Central manifold Remote manifold Combinations Etc.
Efficient Hot Water Delivery Systems 13 Reduces water and energy waste by limiting the total volume in hot water pipes. 87 ounces between hot water source and outlet for most systems. 32 ounces from the loop for circulating systems. IgCC Table 702.8.2 provides volume values per length for most piping types. Includes: Pipe, fittings, valves, meters, manifolds
Basis for Volume Limits Rationale was to provide significant water savings while preserving a range of system design options and costs. In a word BALANCE. Flexibility needed to encompass various types of projects and uses. Recognizes that commercial installations vary widely and can include long runs. Lower volumes create a de facto requirement for recirculation in most commercial systems. Lower volume for recirculation systems reflects higher likelihood of use in commercial and also likely to be engineered
Volume Thresholds Compared 100 80 60 40 20 Nom. 64 Recirc. 64 Nom. 87 Recirc. 32 Nom. 32 Recirc. 16 0 WaterSense IGCC IAPMO Supplement
Basis for Volume Limits Core/Compact System: Feet of Copper Diameter Vol per ft Location of tubing Total Gal. Total Oz. 25 3/4" 0.0251 Water heater to remote manifold 0.6275 80.3 5 1/2" 0.0121 Manifold to fixture 0.0605 7.7 Total System Volume 0.688 88.1
Basis for Volume Limits Central Manifold Distribution System: Feet of PEX Diameter Gal. per ft Location of tubing Total Gal. Total Oz. 10 3/4" 0.0182 Water heater to manifold 0.182 23.3 30 1/2" 0.0092 Manifold to fixture 0.276 35.3 1.4 1-1/4" 0.1 14 port manifold 0.14 17.9 Total System Volume 0.598 76.5
Volume Verification IgCC requries that the volumes be verified by means of design calculations and/or measurements onsite. Discussion regarding bucket/stopwatch method Ultimately rejected over concerns about temperature transition profile. Would require that the volume threshold be increased compensate could create inaccuracies. http://img.diynetwork.com/diy/2004/06/ 11/wkh312_4fa_lead.jpg
Recirculating Pump Controls Permitted (IgCCC 608.2) TIMER-BASED OR THERMOSTATIC MOMENTARY CONTACT SWITCH MOTION SENSORS FLOW SWITCH DOOR SWITCH
608.8 (2) Requirements for Motion Sensor Controls Sensor(s) to make momentary contact when motion is sensed. After the signal is sent, the sensor must go into a lock out mode for not less than 5 minutes to prevent sending a signal to the electronic controls while the circulation loop is still hot.
Pipe Insulation Requirements Required for all service hot water pipes (IgCC 608.7) Exception for fixture connectors Exception for cases where pipe is completely surrounded by blown-in or sprayed insulation. T > D D (k = 0.22 to 0.28 BTU-in/h-ft 2 -F)
Summary IgCC is a commercial code overlay with performance and prescriptive tracks for energy compliance. IgCC is designed to work with other ICC codes like the IECC, IMC, IBC and IPC. Development is through ICC s consensus process. Dates to remember: Public Comment: March 15 May 14, 2010 Hearing: August 14-22, 2010 in Chicago Public Version #2 Release: November 3, 2010 Proposals Due for 2012 IgCC: January 3, 2011
Questions? Robert Guenther Director of Mechanical Programs ICC Plumbing Mechanical and Fuel Gas bguenther@iccsafe.org