COMPARING THE COMMERCIAL PROVISIONS OF THE 2015 IECC WITH THE CORRESPONDING PROVISIONS IN THE 2012 IECC FOR COMMERCIAL CONSTRUCTION IN TEXAS

Transcription

1 ESL-TR COMPARING THE COMMERCIAL PROVISIONS OF THE 2015 IECC WITH THE CORRESPONDING PROVISIONS IN THE 2012 IECC FOR COMMERCIAL CONSTRUCTION IN TEXAS A Reprt Jaya Mukhpadhyay, PhD Juan-Carls Baltazar, PhD, P.E. Shirley Ellis Jeff S. Haberl, PhD, P.E. Bahman Yazdani. P.E. Nvember 2014

2 ii Disclaimer This reprt is prvided by the Texas A&M Engineering Experiment Statin (TEES). The infrmatin prvided in this reprt is intended t be the best available infrmatin at the time f publicatin. TEES makes n claim r warranty, express r implied that the reprt r data herein is necessarily errr-free. Reference herein t any specific cmmercial prduct, prcess, r service by trade name, trademark, manufacturer, r therwise, des nt cnstitute r imply its endrsement, recmmendatin, r favring by the Energy Systems Labratry r any f its emplyees. The views and pinins f authrs expressed herein d nt necessarily state r reflect thse f the Texas A&M Engineering Experiment Statin r the Energy Systems Labratry.

3 iii Acknwledgements The Energy Systems Labratry (ESL) team wuld like t thank Prfessr Larry Degelman, Prfessr Emeritus at Texas A&M University fr his assistance in preparing this reprt.

4 iv EXECUTIVE SUMMARY The purpse f this analysis was t determine the stringency f cmmercial prvisins in the 2015 IECC when cmpared t the crrespnding prvisins in the 2012 IECC fr cmmercial buildings in Texas. In rder t perfrm the assessment, the mandatry, prescriptive and perfrmance cmmercial prvisins were cmpared. In rder t perfrm the assessment, this analysis cmpares the cmmercial prvisins in the 2012 IECC, and the 2015 IECC. A qualitative analysis was perfrmed cmparing all the sectins in Chapter 4[CE] f the 2012 IECC and Chapter 4 [CE] f the 2015 IECC. The analysis categrizes the impact f these changes in terms f stringency ver the 2012 cde. N attempt has been made t prvide a quantitative assessment using whle-building simulatin. Hence, certain prvisins in the 2015 cde culd nt be assessed and have been identified as such. When cmparing the requirements in Sectin C401 f the 2015 IECC with Sectin C401 f the 2012 IECC fr General requirements, it was cncluded: T demnstrate cmpliance with the first path prvided in the cde, it was nw required t cmply with the prvisins in the ASHRAE Standard Cmpliance fr existing buildings is nw prvided in Chapter 5[CE] f the 2015 IECC. When cmparing the requirements in Sectin C402 f the 2015 IECC with Sectin C402 f the 2012 IECC fr Building Envelpe Requirements, the 2015 cde demnstrated: Imprved specificatins fr paque building cmpnents. Imprved specificatins fr fenestratin. Expanded requirements t calculate U-factrs f walls with cld-frmed steel, aged rf reflectance and prvisins fr rms cntaining fuel burning appliances. When cmparing the requirements in Sectin C403 f the 2015 IECC with Sectin C403 f the 2012 IECC fr Building Mechanical Systems, the 2015 cde demnstrated: Imprved efficiency requirements fr HVAC equipment perfrmance. Added efficiency requirements fr air-cnditining units serving cmputer rms. Added specificatins fr cmmercial refrigeratin equipment. Elabrated and added prvisins fr HVAC system cntrls which include: requirement fr zne islatin; and requirement f ecnmizer fault detectin. Added specificatins fr ht water biler utdr temperature setback cntrl. Updated prvisins fr energy recvery ventilatin systems whse requirements are nw based n the number f hur s ventilatins systems perate. Intrduced specificatins fr kitchen exhaust systems. Updated requirements fr duct and plenum insulatin and sealing. Intrduced fan efficiency requirements. Updated prvisins fr air and water ecnmizers, which include added requirements fr the efficient peratin f these systems. Updated prvisins fr cmplex mechanical systems serving multiple znes, which include updated specificatins fr fan cntrls, heat rejectin equipment and ht gas bypass limitatins. When cmparing the requirements in Sectin C404 f the 2015 IECC with Sectin C404 f the 2012 IECC fr Service Water Heating, the 2015 cde demnstrated: Imprved specificatins fr certain categries f service ht water systems. Imprved specificatin fr insulatin f piping. Imprved specificatins fr energy cnsumptin f pls and permanent spas.

5 v Added infrmatin fr implementatin f efficient heated water supply piping, heated water circulating and temperature maintenance system, demand recirculatin cntrls, drain water heat recvery systems and energy requirements f prtable spas. Added cmmissining requirements fr ht water systems. When cmparing the requirements in Sectin C405 f the 2015 IECC with Sectin C405 f the 2012 IECC fr Electric Pwer and Lighting Systems, the 2015 cde demnstrated: Elabrate prvisins fr lighting cntrls, which include the added requirement f ccupant sensr cntrls. Elabrate prvisins fr daylight respnsive cntrls. Imprved specificatins fr permissible lighting pwer densities fr different building area types. Imprved specificatins fr nn-tradable cmpnents f exterir lighting. Added requirements fr electric transfrmers, electric mtrs as well as vertical and hrizntal transprtatin system and equipment. Sectin C406 fr Additinal Efficiency Package Optins has been updated in the 2015 IECC. Requirements f this sectin have been subdivided int the fllwing categries: mre efficient HVAC equipment perfrmance; reduced lighting pwer density; enhanced digital lighting cntrls; n-site renewable energy; dedicated utdr air system; and reduced energy use in service water system. Sectin C407 fr Ttal Building Perfrmance has been updated in the 2015 IECC. Nt many changes have been made in this sectin f the 2015 cde. Hwever, since this sectins f the cde references ther sectins which are mre stringent, it can be cncluded that cmpliance with this sectin is mre stringent. Sectin C408 fr System Cmmissining has been updated in the 2015 IECC. New requirements have been added fr lighting system functinal testing, which include: ccupant sensr cntrls, time cntrl switches, daylight respnsive cntrls and dcumentatin requirements fr lighting cntrls in cnstructin dcuments. It shuld be nted that several prvisins in the 2015 IECC culd nt be assessed qualitatively. A quantitative assessment is necessary t determine the stringency f these prvisins. These prvisins include: Intrducing the cmpnent perfrmance alternative in Sectin Increasing the maximum permissible area limits fr skylights with the additin f daylight respnsive cntrls in Sectin C and Sectin C respectively. Increasing specificatins fr SHGC and U-value fr skylights fr znes prvided with daylight respnsive cntrls in Sectin C Prvisins fr guidelines t calculate the adjustment factr fr water cled chillers in the case f chilled water temperature being different as described in Sectin C It is cncluded that the prvisins fr cmmercial buildings in the 2015 IECC are mre stringent than the crrespnding prvisins in the 2012 IECC. This reprt is rganized in the fllwing rder: Sectin 1: Prvides a brief verview f the task. Sectin 2: Describes the qualitative analysis that cmpares the cmmercial prvisins in the 2015 IECC and the 2009 IECC. Sectin 3: Prvides the cnclusins frm the study.

6 vi Table f Cntents 1. OVERVIEW QUALITATIVE ANALYSIS COMPARING THE COMMERCIAL PROVISIONS IN THE 2015 IECC AND 2012 IECC... 1 Cmparing the Prvisins in Sectin C401, fr General Requirements... 1 Cmparing the Prvisins in Sectin C402 Building Envelpe Requirements... 1 Cmparing the Prvisins in Sectin R403 Building Mechanical Systems... 4 Cmparing the Prvisins in Sectin C404 Service Water Heating Cmparing the Prvisins in Sectin C405 Electric Pwer and Lighting Systems Cmparing the Prvisins in Sectin C406 Additinal Efficiency Package Optins Cmparing the Prvisins in Sectin C407 Ttal Building Perfrmance Cmparing the Prvisins in Sectin C408 System Cmmissining CONCLUSIONS REFERENCES APPENDIX A APPENDIX B... 32

7 1 1. OVERVIEW The purpse f this analysis was t determine the stringency f residential prvisins in the 2015 IECC when cmpared t the crrespnding prvisins in the 2012 IECC fr cmmercial buildings in Texas. In rder t perfrm the assessment, the mandatry, prescriptive and perfrmance path prvisins were cmpared fr cmmercial buildings. 2. QUALITATIVE ANALYSIS COMPARING THE COMMERCIAL PROVISIONS IN THE 2015 IECC AND 2012 IECC A qualitative assessment was perfrmed cmparing all sectins f Chapter 4 (CE) f the 2015 IECC with the crrespnding sectins f Chapter 4 (CE) in the 2012 IECC. The findings and cmments are presented in the subsectins belw. The findings are als summarized in Appendix A f this reprt. In sectins where a discussin is required t prvide justificatin t the prpsed change in the 2015 IECC apprpriate references are made t the dcumentatin describing the prpsed changes t the cmmercial prvisins in the Internatinal Energy Cnservatin Cde (ICC 2013). N attempt was made t prvide a quantitative assessment f the cde. In additin, a study was perfrmed cmparing all sectins f the Chapter 4 (CE) f the 2015 IECC with the crrespnding sectins f Chapter 5 in 2009 IECC, which is the current Texas Building Energy Perfrmance Standard (TBEPS). The findings are summarized in Appendix B. Cmparing the Prvisins in Sectin C401 1, fr General Requirements Similar t the 2012 IECC, the 2015 IECC prvides three paths fr cmmercial buildings t demnstrate cmpliance. The descriptin f the cmpliance paths is prvided belw: T demnstrate cmpliance with the first path prvided in the 2015 cde, it was nw required t cmply with the prvisins in the ASHRAE Standard A preliminary qualitative and quantitative assessment f ASHRAE Standard has been perfrmed at the Pacific Nrthwest Natinal Labratry (Halversn et al. 2014a, 2014b). The reprts cnclude that the ASHRAE Standard is mre stringent than the ASHRAE Standard T demnstrate cmpliance with the prescriptive path prvided in the cde, in additin t the prescriptive requirements in Sectin C402, C403, C404 and C405, it is nw required t demnstrate cmpliance with any ne f the prvisins in Sectin C406 n additinal efficiency package ptins. Sectin C406 has been updated with mre stringent requirements in the 2015 IECC. Cmpliance requirements fr existing buildings have nw been relcated in Chapter 5[CE] f the 2015 IECC. The additins and mdificatins t the requirements in this sectin f the 2015 IECC pint t requirements that are mre stringent than thse in the 2012 IECC. Hence, the requirements in this sectin are mre stringent than the crrespnding requirements f the 2012 IECC. Cmparing the Prvisins in Sectin C402 Building Envelpe Requirements Accrding t Sectin C402.1 fr general requirements, the 2015 IECC prvides three ptins fr building thermal envelpe assemblies t cmply with the cde using prescriptive requirements. The paque building thermal envelpe assemblies are required t cmply with the R-value based methd, the U-, C- and F-factr based methd, r the cmpnent perfrmance alternative prvided in the cde. Changes and mdificatins in Sectin C402.1 have been described belw: 1 Sectins in this reprt refer t the rganizatin f infrmatin in the 2015 IECC.

8 2 Sectin C and C describe buildings that are exempt frm cmplying with the 2015 IECC. These sectins have been added t supprt and clarify descriptins and definitins elsewhere in the cde. The prvisins in these sectins have n impact n the stringency f the 2015 IECC ver the 2012 IECC. In Sectin C n insulatin cmpnent R-value-based methd, Table C has nw been updated with increase minimum R-value requirements fr mst building cmpnents. The prvisins in this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. Similarly in Sectin C n assembly U-factr, C-factr r F-factr based methds, Table C has been updated t reduce the maximum U-value requirements fr mst building cmpnents. In additin, Sectin C has been added in the 2015 cde t calculate the thermal resistance f cld-frmed steel. The prvisins in this sectin nw address a gap in the cde fr calculating U-factrs fr steel stud wall assemblies. The prvisins in this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C describing the cmpnent perfrmance alternative has been intrduced in the 2015 cde. The path intends t prvide significant additinal flexibility fr design teams, allwing trade-ffs fr U-values f varius building envelpe cmpnents withut requiring a full ttal building perfrmance cmputatin. A qualitative assessment cannt be used t assess the stringency f this sectin in the 2015 IECC ver the 2012 IECC. Sectin describing specific building thermal envelpe insulatin requirements has been mdified in the 2015 IECC. The mdificatins are presented in the paragraphs belw: Additinal language has been added t Sectin describing rf assembly, Sectin n thermal resistance f abve-grade walls, Sectin n slab-n-grade perimeter insulatin, and Sectin C n insulatin f radiant heating systems. The added descriptins clarify prvisins in the cde, which include: insulatin requirements f skylight curbs; characteristics f mass walls; requirements fr flr framing cavity insulatin t maintain permanent cntact with the underside f the subflr decking and structural slabs; and requirements fr prtecting slab-n-grade insulatin that extends away frm the building. The prvisins in these sectins increase the stringency f the 2015 IECC ver the 2012 IECC. Language has been mdified in Sectin C fr flrs. New exceptins have been added in the 2015 cde that allw fr an alternate psitin f flr framing cavity insulatin and prvisin f airspace between the insulatin applied t the underside f cncrete flr slabs. The additin f new exceptins decrease the stringency f the 2015 IECC ver the 2012 IECC. In additin, Sectin n multiple layers f cntinuus insulatin has been added in the 2015 IECC. The prvisins in this sectins describe the methd f installatin fr multiple layers f cntinuus insulatin, and specificatins insulatin f radiant heating systems. The prvisins in these sectins increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C402.3 n slar rf reflectance and thermal emittance has been mdified in the 2015 cde. The prvisins in this sectin require cmpliance fr minimum rf reflectance and emittance prvided in Table C The values fr initial reflectance have been mitted frm the Table in 2015 IECC. The sectin als lists certain specified types and prtins f rf fr which cmpliance is exempted. The prvisins f this sectin f the 2015 IECC are as stringent as thse in the 2012 IECC. Further mdificatins t this sectin are presented in the paragraph belw: Sectin C describing aged rf slar reflectance has been added in the 2015 cde t prvide an alternate cmpliance fr aged slar rf reflectance. The prvisins in this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C402.4 n fenestratin has been mdified in the 2015 IECC t include: requirements fr maximum permissible vertical fenestratin area; minimum skylight fenestratin area; prvisins fr

9 3 lighting cntrls; U-factrs and SHGC requirements. Mdificatins t this sectin are presented in the descriptins belw: Prvisins in Sectin n maximum area require the maximum fenestratin area t be 30% windw-t-wall area rati, which is as stringent as the prvisins in the 2012 IECC. Sectin C n increased vertical fenestratin area with daylight respnsive cntrls allws fr an increase in maximum windw-t-wall area rati t 40% f ttal rf area prvided certain cnditins are met and daylight respnse cntrls are installed. The added prvisins fr buildings three r mre stries abve grade in the 2015 IECC make this sectin less stringent than the crrespnding prvisins in the 2012 cde. Sectin C n increased skylight area with daylight respnsive cntrls, allw fr an increase in skylight area frm 3% t 4% f ttal rf area prvided certain cnditins are met and daylight respnse cntrls are installed. The prvisins in this sectin in the 2015 IECC are as stringent as the prvisins in the 2012 IECC. Sectin C n minimum skylight fenestratin area prvides minimum requirements fr skylights fr certain building types and area. The 2015 IECC prvides mre stringent requirements fr minimum flr area t qualify fr the prvisin f skylights. An added exceptin fr spaces nt requiring skylights prvides clarificatin t the cnditins such spaces must adhere t in rder t qualify as this exceptin. The prvisins in this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. - Sectin C describes requirements fr lighting cntrls in daylight znes under skylights. Remval f the exceptins in this sectin f the 2015 IECC increase the stringency f this cde ver the crrespnding sectin in the 2012 IECC. - Sectin C describe specificatins fr a haze factr fr skylights in certain situatins such as ffices and retail stres. The prvisins in this sectin d nt impact the stringency f the 2015 IECC ver the 2012 IECC. Sectin C prvides maximum U-factr and SHGC requirements. The sectin pints t Table C402.3 fr U-factr and SHGC specificatins in the cde. Table C402.3 prvides the requirements fr fenestratin in the 2015 cde, which is updated frm the table fr fenestratin requirements in the 2012 cde. The sectin n SHGC in the table has been expanded t prvide specificatins fr different rientatins and prjectin factrs. The prvisins in this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. - Sectin C n increased skylight SHGC nw relaxes the requirements f SHGC in skylights lcated abve daylight znes and prvided with daylight respnsive cntrls. The prvisins in this sectin d nt impact the stringency f the 2015 IECC ver the 2012 IECC. - Sectin n increased skylight U-factr utlines the requirements where exceptins may be prvided fr U-factrs fr cases where autmatic daylight cntrls are installed. The prvisins in this sectin d nt impact the stringency f the 2015 IECC ver the 2012 IECC. - Sectin C describes the prvisins fr dynamic glazing that have been mdified in the 2015 cde. The added requirement fr SHGC ratis in the 2015 IECC increase the stringency f this cde ver the crrespnding sectin in the 2012 IECC. - Sectin C n area-weighted U-factrs allws incrprating area-weighted averages fr U-values f fenestratin fr cmpliance. The prvisins in this sectin d nt impact the stringency f the 2015 IECC ver the 2012 IECC. Sectin C describes cmpliance fr paque drs. The sectin pints t relevant tables fr different types f paque drs. Since the tables referred by this sectin are as stringent as the crrespnding prvisins in the 2012 cde, the prvisins in this sectin d nt impact the stringency f the 2015 IECC ver the 2012 IECC. Sectin C402.5 n air leakage has been elabrated in the 2015 IECC. The mdificatins t this sectin are discussed in the paragraphs belw:

10 4 Sectin C n air barriers requires a prvisin f cntinuus air-barriers in mst climate znes. Althugh the prvisins in bth the cdes are similar, the remval f exceptins fr prvisin f air barriers in Climate Znes 1 and 3 increase the stringency f the 2015 IECC ver the 2012 IECC. - Sectin C n air-barrier cnstructin prvides guidelines fr air-barrier cnstructin in rder t ensure cmpliance with the cde. Air-barriers are nw required t cmply with list f requirements specified in the cde. The prvisins f this sectin f the 2015 IECC are as stringent as thse in the 2012 IECC. - Sectin C prvides cmpliance ptins fr air barriers. T cmply, air-barriers can meet the prvisins in Sectin C fr materials r Sectin C fr assemblies. The additin f masnry clay r shale materials and wall assemblies t be exempt frm testing renders the 2015 IECC less stringent than the 2012 IECC. Sectin C n air leakage f fenestratin prvides maximum air infiltratin rates fr fenestratin assemblies as utlined in Table C Maximum infiltratin values fr fenestratin cmpnents prvided in the 2015 cde have added prvisins fr high-speed drs hence increase the stringency f the 2015 IECC ver the 2012 IECC. Requirements have been added t Sectin C in the 2015 cde fr rms cntaining fuel burning appliances. These requirements address the safety issues assciated with such installatins. The prvisins in this sectin d nt impact the stringency f the 2015 IECC ver the 2012 IECC. Requirements have been rewrded in Sectin C fr drs and access pening t shafts, chutes, stairways and elevatr lbbies that clarify the sealing requirements fr such installatins. The prvisins in these sectins d nt impact the stringency f the 2015 IECC ver the 2012 IECC. Requirements have been rewrded in Sectin C fr air intakes, exhaust penings, stairways and shafts. The prvisins in this sectins d nt impact the stringency f the 2015 IECC ver the 2012 IECC. Sectin C n vestibules has been mdified t clarify exceptins fr drs with installed air curtains. The prvisins in these sectins increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C n recessed lighting has been rerganized in the 2015 cde in rder t clarify the prvisins in the cde. The prvisins in this sectin d nt impact the stringency f the 2015 IECC ver the 2012 IECC. Cmparing the Prvisins in Sectin R403 Building Mechanical Systems In Sectin C403.1 describing general prvisins fr building mechanical systems, new language has been added in the 2015 cde fr walk-in clers, walk-in freezers, refrigerated warehuse clers, and refrigerated freezers. The cntents f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin describes the mandatry prvisins applicable t all mechanical systems. The mdificatins t this sectin are discussed in the paragraphs belw: Sectin describing calculatin f heating and cling lads nw requires accunting fr reductin in lads n implementatin f energy recvery systems. The prvisins in this sectin d nt impact the stringency f the 2015 IECC ver the 2012 IECC. Sectin describing equipment sizing has been rerganized in the 2015 cde. The prvisins in this sectin d nt impact the stringency f the 2015 IECC ver the 2012 IECC. Current equipment has been updated with mre stringent efficiency requirements in Sectin describing HVAC equipment perfrmance requirements. In additin, new equipment requirements describing minimum efficiency air-cnditiners and cndensing units serving

11 5 cmputer rms has been added. The cntents f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. - The sectin refers t Tables (1) thrugh (10) fr equipment efficiencies. Infrmatin has been updated in Tables (1) thrugh (7) fr mre stringent specificatins. In additin, new infrmatin has been added t incrprate a greater variety f equipment. Table (9) has been added with efficiency specificatins fr units serving cmputer rms. Table (10) has been added with efficiency specificatins fr heat transfer equipment. - Sectin C n water cled centrifugal chilling packages has been updated frm the earlier cde. This sectin prvides guidelines t calculate the adjustment factr in the case f chilled water temperatures being different. The frmula is different than that specified in the 2012 cde. A qualitative analysis cannt be used t determine the stringency f the equatin prvided in this sectin. - Sectin n psitive displacement chilling packages prvides specificatins fr psitive displacement chilling packages in the case their perating cnditins d nt meet the specified requirements. This sectin pints t Table C (7), which has been updated in the 2015 IECC. The cntents f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C describing HVAC system cntrls mdifies the prvisins fr thermstatic cntrls, ff-hur cntrls, shut-ff dampers and snw and ice melt systems. New prvisins have been added fr setpint verlap restrictins fr znes having separate thermstat cntrls, zne islatin, freeze prtectin system cntrls and ecnmizer fault detectin diagnsis. - An exceptin has been added t Sectin C describing deadbands that allws applicatins requiring precisin in indr temperatures nt t have a deadband. The added exceptin f ccupancies r applicatins requiring precisin in indr temperature cntrl frm specificatins f deadbands cannt be challenged in terms f stringency as it addresses the health and safety f the ccupants. The prvisins in this sectin d nt impact the stringency f the 2015 IECC ver the 2012 IECC. Sectin C describing setpint verlap restrictins has been added fr znes that have separate heating and separate cling thermstatic cntrl. It is nw required t prvide a limit switch, mechanical stp r direct digital cntrl system with sftware prgramming t prevent the heating setpint t exceed the cling setpint and maintain a deadband. The prvisins f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. - Sectin C describing shutff dampers has been mdified t intrduce specificatins fr mtrized dampers that are prvided t cntrl the utdr air intakes, exhaust penings, stairway and shaft vents. Specificatins fr gravity dampers are als prvided in cases where the use f such dampers is permitted by the cde. The prvisins f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. - Sectin C describing zne islatin has nw been added t the 2015 IECC. The cde nw requires zne islatin f certain thermal znes. The cde nw als requires islatin devices installed in each f these znes. The cde nw als requires central systems and plants t prvide fr the peratin f islatin znes. The prvisins f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. - The text in Sectin C describing snw and ice melt system cntrls has been rerganized in the 2015 cde t prvide better clarity t the reader. The prvisins f this sectin d nt have an impact n the stringency f the 2015 IECC ver the 2012 IECC. - Sectin C describing freeze prtectin system cntrls intrduces specificatins fr freeze prtectin systems such as heat tracing f utdr pipes and heat exchangers. The prvisins f these sectins increase the stringency f the 2015 IECC ver the 2012 IECC.

12 6 - Requirements have been intrduced in Sectin C describing ecnmizer fault detectin and diagnstics that nw require the installatin f cntaminatin sensing devices and autmatic cntrls t stage r mdulate fan airflw rates r intermittently perate fans in respnse t these devices. The prvisins f these sectins increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin describing ht water biler utdr temperature setback cntrl has been intrduced in the cde t prvide requirements fr utdr temperature setback cntrls fr ht water bilers. The prvisins f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C describing ventilatin has been mdified t prvide fr parking garage ventilatin cntrls as described in Sectin C The prvisins in this sectin require the installatin f cntaminatin sensing devices and autmatic cntrls t stage r mdulate fan airflw rates r intermittently perate fans in respnse t these devices. The prvisins f these sectin increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C describing energy recvery ventilatin systems has been mdified in the 2015 cde. The sectin refers t Table C (1) and Table C (2) fr energy recvery requirements fr ventilatin systems. These tables has been added elabrating the energy recvery requirements fr different % f utdr air at full design airflw rate and climate znes. Additinal cnditins are added in the 2015 IECC that are exempt frm installing energy recvery systems. These include systems that exhaust txic, flammable, paint r crrsive fumes r dust and cmmercial kitchen hds that are used fr cllecting and remving grease vaprs and smke. The prvisins f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C describing kitchen exhaust systems has been intrduced in the 2015 cde. The cde nw prvides specificatins fr replacement air, cnditined supply air. The sectin als intrduces requirements fr kitchen hds that have airflw rates greater than 5,000 CFM. This sectin refers t Table C fr maximum exhaust flw rates fr different types f kitchen hds. The exhaust rates are als dependent n the usage f kitchen equipment. The prvisins f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C describing duct and plenum insulatin and sealing has been updated t prvide mre stringent requirements fr duct insulatin R-value. The prvisins f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. - In Sectin n duct cnstructin, Sectin C fr lw-pressure duct systems has been mdified t exclude certain types f lw pressure duct systems t be sealed as per specificatins prvided in this sectin. In Sectin C n high pressure duct systems, the cde tightens the air leakage rate requirements fr highpressure ducts frm 6 t 4. In additin, the equatin referenced by this sectin t calculate the rate f air leakage has been rewritten. The prvisins fr the 2015 cde discussed in the descriptins abve are as r mre stringent than the prvisins in the 2012 IECC. Sectin C describing mechanical system cmmissining and cmpletin requirements nw pint t sectin C408.2 describing mechanical systems and service water heating systems cmmissining and cmpletin requirements, which has been updated in the 2015 cde. The prvisins f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin describing air system design and cntrl has been mdified. - Sectin C describing allwable fan flr hrsepwer has been mdified in the 2015 cde t exclude fans exhausting air frm fume hds frm the exceptins that nt required t meet the allwable fan flr hrsepwer. The sectin refers t Table C (1) fr fan pwer definitins and Table C (2) fr fan pwer limitatins pressure drp adjustment. In Table C (2) infrmatin regarding equipment systems withut central heating r cling device and systems with central

13 7 electric heat has been added t get deductins fr fan pwer limitatin pressure drp adjustment. The prvisins f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. - Sectin C describing fan efficiency has been added t the cde. The sectin intrduces fan efficiency grade requirements fr mst fans. Certain fans are excluded frm these requirements. The prvisins fr the 2015 cde discussed in these sectins are as r mre stringent than the prvisins in the 2012 IECC. Sectin C describing refrigeratin equipment perfrmance has been added in the 2015 cde. The sectin prvides perfrmance requirements fr cmmercial refrigeratin equipment. The sectin refers t Table (1) fr minimum efficiency requirements fr cmmercial refrigeratin and Table (2) fr minimum efficiency requirements fr cmmercial refrigeratrs and freezers. The prvisins f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C describing walk-in clers, walk-in freezers, refrigerated warehuse clers and refrigerated warehuse freezers has been intrduced in the 2015 IECC. The sectin prvides several requirements fr clers and freezers that are nt site cnstructed r assembled t cmply with the cde. The prvisins f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C describing walk-in clers and walk-in freezers has been intrduced in the 2015 cde. The sectin prvides requirements fr clers and freezers that are site assembled r site cnstructed t cmply with the cde. The prvisins f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C describing refrigerated display cases has been intrduced in the 2015 cde. The sectin prvides requirements fr refrigerated cases that are site assembled r site cnstructed t cmply with the cde. The prvisins f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin describing ecnmizers has been rerganized by rearranging cmpnents frm different sectins in the 2012 IECC. Ecnmizer requirements have nw been relaxed frm cling system capacities 33, 000 Btu/hr as specified in the 2012 cde t 54, 000 Btu/hr specified in the 2015 cde. Certain exceptins have been added which allw passive chilled water cling systems r systems that include a heat recvery system. In additin, the sectin nw refers t Table C403.3 (1) fr minimum chilled water system cling capacity fr determining ecnmizer cling requirements. At first glance, the change fr requirement fr ecnmizers frm 33,000 Btu/h t 54,000 Btu/h wuld infer less stringency in the IECC2015 versin; hwever, the added level f detail in the requirements f IECC2015 may actually add t stringency in the larger size systems. Firstly, the Table C403.3(1) in IECC2015 cannt be cmpared t a crrespnding table in IECC While the IECC 2012 table sets a strict limit based n ttal system capacity, the IECC2015 table differentiates between water-cled and air-cled systems. Als the requirements are based n the Difference between the ttal chilled-water system capacity and the capacity f the cling units rather than the HVAC system capacity alne. Added t this is a list f arund 14 ther detailed requirements impsed n the system. Because f the added details, a qualitative analysis cannt be used t determine the stringency f the equatin prvided in this sectin. Hwever, is a mre clear guidance as t what requirements must be met n all the auxiliary equipment invlved in ecnmizer systems. Further mdificatins t this sectin are discussed in the paragraphs belw: Sectin describing integrated ecnmizers have been rewritten in the 2015 cde t clarify the integratin f ecnmizers with mechanical cling systems. This sectin nw pints t Table C fr DX cling stage requirements fr mdulating air-flw units. The prvisins f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin describing ecnmizer heating system has been re-wrded in the 2015 IECC. The prvisins in this sectin d nt impact the stringency f the 2015 IECC ver the 2012 IECC.

14 8 Sectin C describing air ecnmizers has been expanded in the 2015 cde t incrprate Sectin C n ecnmizer dampers. Accrding t this sub-sectin ecnmizer dampers are nw required t cmply with Sectin C n shutff dampers, which is mre stringent than the 2015 IECC. The prvisins f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin describing water ecnmizers have been updated in the 2015 cde. These include prvisins fr design capacity as prvided in Sectin C and maximum pressure drp as described in Sectin Sectin C prvides requirements f the design capacity f water ecnmizers. Exceptins describing systems that d nt require water ecnmizers have been added. The prvisins in this sectin makes the air ecnmizer requirements cnsistent with ANSI/ASHRAE/IES Standard The updated specificatins prvide exceptins fr cmputer rms allwing such spaces t avid water ecnmizers even if the lads cannt be met when the utdr temperatures are 50 F and less. Such spaces nly need the ecnmizer if they cannt meet the AC lad at 40 F r even 30 F. The prvisins f this sectin decrease the stringency f the 2015 IECC ver the 2012 IECC. Sectin C403.4 describing hydrnic and multiple-zne HVAC systems cntrls and equipment has been mdified in the 2015 cde t shw cnsistency with the crrespnding ASHRAE Standard The changes and mdificatins intrduced t this sectin are described in the paragraphs belw: Sectin C describing fan cntrl has been elabrated t prvide specificatins fr fan airflw cntrl, static pressure sensr lcatin and setpints fr direct digital cntrl. - Sectin C describing fan airflw cntrl nw elabrates n the fan cntrls based n methds implemented by DX and chilled water cling units and units that include airside ecnmizers t cntrl space temperature. The sectin nw pints t Table C fr apprpriate fan mtr sizes and mechanical cling capacity fr different system types. The prvisins fr the 2015 cde discussed in the descriptins abve are mre stringent than the prvisins in the 2012 IECC. - Sectin C describing static pressure sensr lcatin has been mdified in the 2015 cde. The cde nw requires the cntrller setpints t be n greater than 1.2 inch w.c. instead f /3 f the ttal design fan static pressure as required in the 2012 IECC. The prvisins fr the 2015 cde discussed in the descriptins abve are as r mre stringent than the prvisins in the 2012 IECC. - The requirements fr setpints fr direct digital cntrls in Sectin C have been elabrated. The direct digital cntrls are nw required t either have capabilities t mnitr the psitin f zne dampers r have an alternate methd f indicating the need fr static pressure that is capable f autmatically detecting any zne that excessively drives the reset lgic, generating an alarm t the system peratinal lcatin and allwing an peratr t readily remve ne r mre znes frm the reset algrithms. The prvisins fr the 2015 cde discussed in this sectin are mre stringent than the prvisins in the 2012 IECC. Sectin C n hydrnic systems cntrls has been elabrated t describe part-lad cntrls fr such system and biler turndwn ratis. - In Sectin C describing part-lad cntrls, althugh the capacity f the hydrnic systems eligible t include cntrls is relaxed frm 300,000 Btu/hr t 500,00 Btu/hr. The cmpliance requirements have been mdified that nw require capabilities t include resetting supply-water temperature, autmatic varying f fluid flw, autmatic varying f pump flw n chilled water systems and heat rejectin lps. The prvisins aim t match the requirement in the IECC with the crrespnding requirements prvided in the ASHRAE Standard The prvisins f this sectin decrease the stringency f the 2015 IECC ver the 2012 IECC. It shuld be nted that the initial capacities represent

15 9 small building sizes, which are generally nt served by hydrnic systems. Hence prviding part lad cntrls t systems serving such capacities wuld prvide small energy benefits relative t the added cntrl csts and benefits. - Sectin C describing biler turn dwn requires biler systems greater than 1,000,000 Btu/hr t cmply with turndwn ratis prvided in Table C The prvisins aim t match the requirement in the IECC with the crrespnding requirements prvided in the ASHRAE Standard The prvisins fr the 2015 cde discussed in this sectin are mre stringent than the prvisins in the 2012 IECC. Sectin C describing heat rejectin has been elabrated in the 2015 IECC. The sectin nw intrduces requirements fr fan speed cntrl, limitatins n centrifugal fan pen-circuit cling twers and requirements fr twer flw turndwn fr heat rejectin equipment such as air-cled cndensers, dry clers, pen circuit cling twers, clsed -circuit cling twers and evaprative cndensers in the cde. - Sectin describing fan speed cntrl elabrates the implementatin f fan speed cntrl f heat rejectin equipment. In Sectin C describing fan mtrs nt less than 7.5 hp, the cde prvides requirements fr fans greater than r equal t 7.5 hp t perate fans at lwer speeds in respnse t leaving fluid temperature r cndensing temperature / pressure f the heat rejectin device. The prvisins in this sectin d nt impact the stringency f the 2015 IECC ver the 2012 IECC. Sectin C describing multiple-cell heat rejectin equipment has been added t the 2015 cde. The sectin nw prvides specificatins t cntrl the variable speed fan drives installed in this equipment. The prvisins fr the 2015 cde discussed in this sectin are mre stringent than the prvisins in the 2012 IECC. - In Sectin C describing limitatins n centrifugal fan pen-circuit cling twers, the 2015 cde intrduces requirements fr pen-circuit cling-twers f certain capacity t meet the requirements fr axial fan pen circuit cling twers in Table C (8). The prvisins fr the 2015 cde discussed in this sectin are mre stringent than the prvisins in the 2012 IECC. - In Sectin C describing twer flw turndwn, the 2015 cde intrduces requirements fr cntrls fr pen-circuit cling-twers. The prvisins fr the 2015 cde discussed in this sectin are mre stringent than the prvisins in the 2012 IECC. Sectin C describing requirements fr cmplex mechanical systems serving multiple znes was mdified in the 2015 cde t include tw mre prvisins fr reducing primary air supply t each zne. The added prvisins include: any higher rate that can be demnstrated t reduce verall system annual energy use by ffsetting reheat/recl energy lsses thrugh a reductin in utdr air intake fr the system as apprved by the cde fficial; and the airflw rate required t cmply with applicable cdes r accreditatin standards such as pressure relatinships r minimum air changes. The prvisins fr the 2015 cde discussed in this sectin are mre stringent than the prvisins in the 2012 IECC. - Sectin describing fractinal hp fan mtrs has been added in the 2015 cde. The 2015 cde nw requires electrnically cmmutated mtrs r 70% mtr efficiency fr fans between 1/12 hp and 1hp. The sectin als allws the use f sheave adjustment instead f varying the mtr speed. The prvisins aim t match the requirement in the IECC with the crrespnding requirements prvided in the ASHRAE Standard The prvisins fr the 2015 cde discussed in this sectin are mre stringent than the prvisins in the 2012 IECC. Sectin describing ht gas bypass limitatins has been mdified in the 2015 cde. The 2015 cde nw sets limitatins t the use f ht gas bypass in terms f cntrl and capacity. Limitatins t the ht gas bypass is nw prvided in Table C The prvisins fr the 2015 cde discussed in this sectin are mre stringent than the prvisins in the 2012 IECC.

16 10 Sectin C403.5 describing refrigeratin systems has been intrduced in the 2015 IECC. The sectin prvides specificatins fr refrigeratin equipment that is served by remte cmpressrs and cndensers. Mdificatins t this sectin are discussed in the paragraphs belw: In Sectin C describing cndensers serving refrigeratin systems, remte cndensers serving the refrigerated display cases nw have t cmply with the specificatins fr saturated cndensing temperatures, cndenser fan pwer ratings, variable speed fan cntrl, and cndensing temperature setpint. The prvisins f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. In Sectin C describing cmpressrs systems, remte cmpressrs serving the refrigerated display cases nw have t cmply with requirements suctin grup cntrls, subcling and crankcase heater cntrl. The prvisins f this sectin increase the stringency f the 2015 IECC ver the 2012 IECC. Cmparing the Prvisins in Sectin C404 Service Water Heating Sectin C404.2 describing the service water heating equipment perfrmance efficiency has been mdified in the 2015 cde t include water-heating equipment intended fr space heating. The sectin refers t Table C404.2 fr minimum perfrmance f water heating equipment. The table has been updated t prvide mre stringent requirements fr electric water heaters > 12 kw, il strage water heaters > 105,000 Btu/h, and pl water heaters. The prvisins in these sectins increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C404.4 n pipe insulatin has been expanded t clarify insulatin requirements fr nncirculating systems. The sectin refers t Table C fr minimum pipe insulatin thickness fr different fluid temperatures and nminal pipe sizes. The sectin als lists certain exceptins which d nt require tubular pipe insulatin. The prvisins in this sectins increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C404.5 n efficient heated water supply piping was added in the 2015 cde. This sectin remedies the prblems f delivery f ht water t the pint f use by reducing the water vlume between the surce f heated water and the use. The sectin prvides maximum flw rates fr different nminal pipe sizes. The sectin als requires heated water supply pipes t cmply with Sectin C fr maximum allwable pipe length methd r Sectin C fr maximum allwable pipe vlume methd. The first methd (Sectin C ) requires n calculatin; it limits the water vlume in the pipes by limiting the pipe length. The secnd ptin (Sectin C ) requires a calculatin f vlume in the pipes, but prvides a table that translates the pipe length int a vlume and prvides quick ptins fr different pipe assumptins as prvided in Sectin C n water vlume determinatin. Table C has been intrduced in the 2015 cde t prvide maximum piping vlume and maximum piping lengths fr different nminal pipe sizes. The prvisins in this sectins increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C404.6 n heated water circulating and temperature maintenance system has been elabrated in the 2015 IECC t include specificatins fr circulatin systems in Sectin C , heat trace systems in Sectin C and cntrls fr ht water strage in Sectin C The prvisins in this sectins increase the stringency f the 2015 IECC ver the 2012 IECC. Specificatins fr demand recirculatin cntrls in Sectin and drain water heat recvery units in Sectin C404.8 have been intrduced in the 2015 cde. The prvisins in these sectins increase the stringency f the 2015 IECC ver the 2012 IECC.

17 11 Sectin C404.9 n energy cnsumptin f pls and permanent spas has been re-wrded in the 2015 cde. The prvisins in this sectin d nt impact the stringency f the 2015 IECC ver the 2012 IECC. The mdificatins t the sectin are presented in the paragraphs belw: In Sectin n heaters, the 2015 cde prvides clarificatin fr requirements f the On-Off switches fr heaters. In Sectin C n time switches, the 2015 cde is rewritten t prvide clarificatin fr the requirement f time switches. In Sectin C n cvers the 2015 cde is rewritten t prvide clarificatin fr the requirement f vapr-retardant cvers. Sectin C n energy cnsumptin f prtable spas has been intrduced in the 2015 cde t clarify cmpliance requirements fr electric-pwered prtable spas. The prvisins in this sectins increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C n service water heating system cmmissining and cmpletin requirements nw requires installed service water systems t be cmmissined. The sectin refers t Sectin C408.2 fr detailed requirements. The prvisins in this sectins increase the stringency f the 2015 IECC ver the 2012 IECC. Cmparing the Prvisins in Sectin C405 Electric Pwer and Lighting Systems Sectin C405.1 describing general prvisins fr electric pwer and lighting systems nw requires lighting fr dwelling units has t cmply with apprpriate sectins in the residential prvisins f the cde. In additin, prvisins fr refrigerated spaces are utlined in this sectin f the cde. The prvisin in this sectin increases the stringency f the 2015 IECC ver the 2012 IECC. Sectin C405.2 n lighting cntrls has been rearranged frm the 2012 editin f the cde. This sectin has been mdified t include a separate discussin n ccupant sensr cntrl and prvide an elabrate descriptin f daylighting cntrls. The mdified sectins are presented in the fllwing paragraphs: Sectin C n ccupant sensr cntrls nw makes it mandatry t install ccupancy sensrs fr certain types f spaces. The prvisin in this sectin increases the stringency f the 2015 IECC ver the 2012 IECC. - Sectin C n ccupant sensr cntrl functin and Sectin C n ccupant sensr cntrl functin in warehuses prvide specificatins fr lighting cntrls fr the spaces. The prvisins in these sectins increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin n time switch cntrls has been rerganized t describe ptins fr time switch cntrls in spaces where ccupancy sensrs are nt required. The additin f shp and labratry spaces t exceptins that d nt require time switches makes the prvisins f this sectin less stringent than thse in the 2012 IECC. - Sectin n time switch cntrl functin has been rewritten in the 2015 cde t cmbine prvisins fr ccupant verride and hliday scheduling int ne sectin. New prvisins have been added that nw require verride switches t have 7 day clcks and have prgram backup capabilities. The prvisin in this sectin increases the stringency f the 2015 IECC ver the 2012 IECC. - Sectin n light reductin cntrls has been rearranged in the 2015 cde. Sectin C n manual cntrls has been rearranged frm the 2012 cde. The prvisins in these sectins d nt impact the stringency f the 2015 IECC ver the 2012 IECC. In Sectin C n daylight respnsive cntrls, the 2015 cde nw prvides detailed requirements fr the installatin f daylight-respnsive cntrls. The sectin describes the space cnditins in which daylighting cntrls are t be installed. While the maximum size f zne

18 12 (i.e.2500 sqft) t be prvided by daylight cntrls has been remved in the 2015 cde, the level f detail n daylight cntrls that are described in a variety f space types and shapes far exceeds the specificatins in the 2012 IECC. It s likely that the individual daylighting cntrls culd be required in spaces far belw 2500 sqft. The prvisins in these sectins increase the stringency f the 2015 IECC ver the 2012 IECC. - Sectin C n daylight respnsive cntrl functin elabrates n the strategies that are t be implemented fr daylight cntrls. The requirements in this sectin t dim lights cntinuusly frm a full light utput t 15 percent f full light utput r lwer in ffice spaces, labratries and classrms increase the stringency f the 2015 IECC ver the 2012 IECC. - Sectin C n sidelight daylighting zne prvides detailed definitin f a sidelight daylight zne with apprpriate diagrams prvided in Figure (1), Figure (2) and Figure (3). Sectin C n tplight daylight zne prvides a detailed descriptin and definitin f a tplight daylight zne with apprpriate diagrams prvided in Figure C The prvisins in these sectins increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C n specific applicatins cntrls prvides specificatins fr applicatins such as display and accent lighting, display case lighting and lighting fr htel and mtel sleeping units. This sectin has added requirements fr htel and mtel sleeping units. The prvisins in these sectins increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin C n exterir lighting cntrls prvides elabrate descriptin f the cntrl strategies fr lighting f exterir applicatins. The sectin has been rerganized t describe cntrls fr varius types f exterir lighting. In additin, the sectin nw requires the ability t reduce exterir lighting levels fr designated perids f time fr certain types f lighting, which implies the apprpriate use f either time switches r mtin sensrs. The prvisins in these sectins increase the stringency f the 2015 IECC ver the 2012 IECC. Sectin describes interir lighting pwer requirements in the 2015 cde. Changes in this sectin are dcumented in the paragraphs belw: Sectin n ttal cnnected interir lighting pwer nw describes an equatin t calculate the ttal interir lighting pwer that has been rerganized frm the 2012 IECC. Changes have als been made t the exceptins fr lighting equipment that are nt t be included in calculating ttal cnnected lighting pwer. The exceptin fr sleeping units nw requires lighting in the units t cmply with crrespnding residential prvisins in the 2015 cde. In additin, mirrr lighting in dressing rms and lighting fr exit signs are nw included as part f the exceptins. The prvisins in these sectins d nt impact the stringency f the 2015 IECC ver the 2012 IECC. Sectin C describes the permissible allwances fr interir lighting pwer that are required fr cmpliance. Changes t this sectin are dcumented in paragraphs belw: - Sectin C describing the building area methd fr cmpliance refers t Table C (1), which has been updated with lwer permissible lighting pwer. The prvisins in this sectin increase the stringency f the 2015 IECC ver the 2009 IECC. - Sectin describing the space-by-space methd fr cmpliance has been intrduced t add flexibility fr a mre accurate assessment f lighting prvisins fr cmpliance. The sectin pints t Table C (2) which describes interir lighting pwer allwances fr space-by-space methds. This table has been updated with lwer permissible lighting pwer. The prvisins in these sectins increase the stringency f the 2015 IECC ver the 2012 IECC. When using space-by-space methd fr cmpliance additinal interir lighting pwer requirements are nw prvided in Sectin C The prvisins in these sectins d nt impact the stringency f the 2015 IECC ver the 2012 IECC.