Radiant Barrier Sheathing

Transcription

1 The Wood Producs Council is a Regisered Provider wih The American Insiue of Archiecs Coninuing Educaion Sysems (AIA/CES). Credi(s) earned on compleion of his program will be repored o AIA/CES for AIA members. Cerificaes of Compleion for boh AIA members and non-aia members are available upon reques. This program is regisered wih AIA/CES for coninuing professional educaion. As such, i does no include conen ha may be deemed or consrued o be an approval or endorsemen by he AIA of any maerial of consrucion or any mehod or manner of handling, using, disribuing, or dealing in any maerial or produc. Quesions relaed o specific maerials, mehods, and services will be addressed a he conclusion of his presenaion. Copyrigh Maerials This presenaion is proeced by US and Inernaional Copyrigh laws. Reproducion, disribuion, display and use of he presenaion wihou wrien permission of he speaker is prohibied. The Wood Producs Council 2012 Slide 2 of 35 Radian Barrier Sheahing Radian Barrier Sheahing LP Building Producs 414 Union Sree, Suie 2000 Nashville, TN www. LPcorp.com Course Number: LPTS01 Learning Unis: 1.00 LP Building Producs is a Regisered Provider wih The American Insiue of Archiecs Coninuing Educaion Sysems. Credi earned on compleion of his program will be repored o CES Records for AIA members. Cerificaes of Compleion for non-aia members are available upon reques. This program is regisered wih AIA/CES for coninuing professional regisraion. As such, i does no include conen ha may be deemed or consrued o be an approval or endorsemen by he AIA of any maerial or consrucion or any mehod or manner of handling, using, disribuing or dealing in any maerial or produc. Quesions relaed o specific maerials, mehods and services should be direced o he program insrucor. Tony Pugel, Ph.D Senior Process Technologis LP Building Producs Nashville TN (615) Tony.Pugel@LPcorp.com This presenaion is proeced by US and Inernaional copyrigh laws. Reproducion, disribuion, display and use of he presenaion wihou wrien permission of he speaker is prohibied. Slide 3 of 35

2 Learning Objecives Radian Barrier Sheahing A he end of his program, paricipans will: 1. Undersand forms of hea ransfer 2. Undersand how radian barriers affec hea ransfer hrough roof sysems 3. Undersand he benefis of a radian barrier sheahing in boh a heaing and cooling environmen 4. Undersand radian barrier sheahing applicaions and heir funcion, as well as key insallaion mehods Ouline Inroducion 1860 French scienis Pecle invesigaed he insulaing effec of meals in reducing radian hea ransfer Visual reflecance or color are no he deermining facors 1925 Firs paens on reflecive surfaces for building insulaion Radian barrier and reflecive insulaion inroduced for commercializaion 1960s NASA developed hin, mealized films for Apollo space program Radian barrier induced ino he Space Technology Hall of Fame Ouline

3 Hea Transfer Conducion Hea ransfer beween adjacen solids, liquids, or gases due o emperaure differences Convecion he ransfer of hea from one place o anoher by he movemen of fluids Radiaion The ransfer of hea hrough elecromagneic waves raveling hrough a vacuums or an air space Roof/Aic Examples of Hea Transfer Radiaion The roofing maerials are radianly heaed from he sun Conducion The roofing maerials conduc hea from he exerior o he inerior surfaces Convecion The inerior surface heas he aic air causing ho air o rise and exhaus hrough ridge or gable vens Slide 9 of 35 Slide 10 of 35 Ouline Imporan Conceps of Radian Hea Transfer Emissiviy + Refleciviy = 1 Emissiviy Refleciviy Solar Radiaion Slide 12 of 35

4 Radian Barrier Properies Radian Hea Gain Radian barriers are defined o have an emissiviy of 0.1 or less To work effecively, low emissiviy surfaces mus face an air space In summer, hea absorbed by roof componens is ransferred by infrared radiaion o he aic floor Sudies show an average of 93% of solar radiaed hea eners a building hrough he aic Slide 13 of 35 Ouline Radian Hea Gain in he Aic Aic hea gain is primarily governed by solar radiaion in summer, and more by conducion/convecion from he living space in winer. Airflow does no move radian energy, so increasing venilaion rae will no replace he efficiency gained by use of a radian barrier. Venilaion is sill imporan for conducion and convecion hea ransfer in he aic/roof. Slide 16 of 35

5 Summer Radian Hea Gain Residenial Energy Usage (EIA 2013 es.) Summer roof sheahing emperaures can reach 160 F wih aic emperaures exceeding 120 F Radian barrier roof sheahing blocks up o 97% of he radian hea from being ransmied ino he aic Oher, 15.5% Furnace/Boiler, 2.1% Compuers, 2.1% TV, 4.8% Dishwasher, 1.5% Washer, 0.5% Lighing, 8% Freezer, 1.2% Dryer, 3.3% Cooking, 2.8% Refrigeraion, 5.6% Heaing/Cooling, 38.5% Waer Heaing, 14.1% Slide 17 of 35 How radian barrier sheahing reduces energy coss Apply Radian Barrier Reduced energy coss Cooling Scenario Radian barrier reduces hea movemen from he roofing maerial o he aic space The aic space air emperaure is reduced and hea radiaed from he roof o aic floor is reduced from he aic floor o he living space is reduced Ducing and air handling equipmen in he aic are cooler Ouline

6 Radian Barrier Types 1. Foil, bubble insulaion, or mealized films usually made wih aluminum R a f e J O I S Roof Sheahing Aic Space Insulaion R a f e r J O I S Radian Barrier foil/film may be placed in a number of locaions in he aic Insallaions of Radian Barrier Types in Aics Living Space 2. Radian barrier sheahing - srucural sheahing (OSB or plywood) wih foil overlay R a f e r Radian Barrier Sheahing R a f e r Radian Barrier Sheahing is placed wih he foil facing he aic space 3. Inerior radiaion conrol coaings radiaion barrier pain R a f e r Aic Space Roof Sheahing Aic Space R a f e r Inerior Radiaion Conrol Coaings are sprayed ono he underside of he roof sheahing Horizonal and Rafer Mouned Radian Barriers If inerior aic gable walls are covered wih he radian barrier, roof-deck and rafer-mouned radian barriers provide equivalen ceiling hea gain reducions o horizonal insallaions Horizonal applicaion of a radian barrieron he aic floor is more likely o accumulae dus which increases he emissiviy of he surface The main feaure of he rafer mouned radian barrier is he reducion of radian hea flow ino he aic space Especially imporan for air condiioning and ducwork Ouline

7 Radian Barrier Sheahing OSB Sheahing Adhesive Aluminum Foil Sandard OSB roof sheahing (PS-2 Exposure 1) Mainains bond of foil o OSB during he lifeime of he sheahing ~ hickness foil wih adhesive and kraf paper backing Ouline Radian Barriers and Shingles Concern ha hea would mel or degrade composie shingles Sudies have demonsraed ha ho summer day peak shingle emperaures wih a radian barrier were only 2-5 F higher. Mos roofing manufacurers do no limi applicaions wih radian barrier sheahing. You should check wih your roofing maerial manufacurer abou your specific applicaion. Oher Consideraions wih Radian Barrier Sheahing Cell Phone Recepion As wih oher meal building componens, an already weak cell phone signal may be influenced by he presence of radian barriers in aics and walls Cell phone recepion issues should be addressed hrough he service provider Moisure condensaion on foil surface Normal daily cycle of cooling and heaing is no ypically a problem Air and moisure movemen from he living space o he aic space may resul in condensaion

8 Ouline Energy Savings Wih R-19 insulaion in he aic floor, radian barriers can reduce summer hea gain by 16-42% The insallaion of a radian barrier resuled in peak energy use reducion hree imes greaer han if aic insulaion was increased The value proposiion for radian barrier sheahing is ha i is an economical alernaive o increased mass insulaion because i addresses he predominan source (radiaion) of hea in aics Energy Savings Energy Savings are dependen upon: Climae Roof slope Venilaion rae Locaion of he air condiioning and heaing equipmen and ducwork Orienaion of he home Insulaion levels Window area and efficiency, number of occupans, ec. Lawrence-Berkeley Air Condiioning Aic Duc Sudy Compared aic and ceiling emperaures, duc emperaures and flows, and A/C elecriciy consumpion before and afer insalling a radian barrier on he roof sheahing New unoccupied home in Ausin, Texas The Home Living Area: 1520 f 2 Slab on Grade wih fla ceilings Roof pich: 6 in 12 Brown composie asphal shingles R-38 ceiling insulaion R-6 duc insulaion Boh air handler/duc sysem locaed in he aic Air infilraion measured

9 Air Condiioner Aic Duc Sudy A/C energy consumpion was 16% less 80% of decrease due o reduced radian hea gain by aic duc sysem Huningdon Engineering and Environmenal, Inc - Cenex Homes Sudy Houson The sudy: 20 o 30 emperaure measuremens were made in 7 similar mached pairs of houses in he Houson area one house in each pair had radian barrier roof sheahing and oher house had radiional sheahing Radian barrier homes had: reduced aic surface emperaure in he range of 17 o 29.9 F ambien aic air emperaure reducions were on he order of 12 F o 21 F A/C coil emperaure reducions in he range of 22 F o 27 F. Slide 33 of 35 Keneech Resource Recovery, Inc Ausin, Texas Evaluaed he annual energy use/cos for a home Savings provided payback for cos of produc in abou 2 years and an esimaed 40+% rae of ROI Savings due o a significan reducion in hea ransfer hrough he ducwork LP Building Producs Roaring River Energy Usage Sudy The sudy: In wo unoccupied idenical homes were moniored. Radian barrier roof sheahing versus convenional roof sheahing R-30 blown in fiberglass insulaion above he ceiling; R-11 insulaion in he walls; R-22 insulaion below he floors Heaed and cooled via idenical elecric hea pumps wih all ducwork locaed in he crawl space and he air handler locaed wihin he condiioned space Moniored for elecric energy consumpion emperaures and moniored a various locaions wihin he homes, he aic spaces and he oudoor emperaure

10 LP Building Producs Roaring River Energy Usage Sudy 14% summer monhly energy savings wih radian barrier sheahing 4% winer monhly energy savings wih radian barrier sheahing Florida Solar Energy Cener (FSEC) Sudies FSEC has published several repors on radian barrier echnology, including he effecs of: Ceiling insulaion level, horizonal versus roof/rafer insallaion dus accumulaion surface degradaion Florida Solar Energy Cener Sudy Resuls All oher hings being equal, he percenage reducion in ceiling hea ransfer for aic radian barrier sysems as compared o sandard aics should remain consan regardless of ceiling insulaion level. Hea gain of he aic is reduced a he plane of he roof mouned radian barrier, which is always above he insulaion, so he ne hea flow is reduced before i passes hrough he insulaion. Building Codes and Design Mos insulaing maerials are evaluaed individually using a conducive heaing procedure Uses ho air or a ho surface o generae hea flow hrough a maerial Radian barrier sheahing canno be evaluaed using his es mehod Because radian barriers require an air space hey mus be evaluaed as an assembly Aluminum is he only maerial exemped by FTC requiremens on insulaion when used for radian barrier

11 Ouline Building Codes and Design Some jurisdicions prescribe or allow he use of radian barriers in roofs o mee insulaion specificaions Ausin, Texas and oher municipaliies California (2013) Florida (2010) Honolulu Design using overall assembly R-value Includes air spaces wih reflecive maerials Use energy raing programs: see resources such as RESNET approved sofware Consul wih radian barrier sheahing manufacurer, consuling engineer, local code auhoriies, ec. o undersand requiremens Radian barriers are included in DOE Energy Sar Program Oak Ridge Naional Laboraory Energy Savings Calculaor Oak Ridge Naional Laboraories offers a simple energy savings calculaor on heir websie (Radian Barrier Fac Shee) Based on modeling program AicSim and EnergyPlus Calculaor only for aic applicaions in he cooling season

12 Radian Barrier Calculaor 1a. Selec Climae Zone or Ouline Radian Barrier Calculaor

13 Selecing a Radian Barrier Sheahing Mos OSB sheahing manufacurers make radian barrier sheahing panels Wood srucural panels may absorb moisure during consrucion Perforaions preven he aluminum overlay from acing as vapor barrier Proper perforaions reduce rapped moisure in he OSB subsrae and reduce re-drying ime Insallaion of Roof Radian Barrier Sheahing Aic sheahing insallaion Proec from moisure prior o and during insallaion. Keep he foil side clean. Place panels wih foil side facing down (oward aic space) on rafers, russes, and gable aic walls OSB surface sill placed up for safey Radian barrier sheahing has same nailing paerns as convenional sheahing Radian Barrier Sheahing Insallaion Radian Barrier Sheahing Insallaion Radian barrier should be placed face down, oward he inerior of he aic In a vauled ceiling configuraion, a 3/4" air space beween he aluminum layer and anoher surface is required Roofing Maerial Insulaion Radian Barrier Sheahing foil facing down ¾ minimum air gap

14 Gable End Insallaion Insallaion of Wall Radian Barrier Sheahing Radian barrier sheahing panels used on he gable ends of an aic are insalled in he same manner Aluminum face oward he aic space Foil surface should face ou, oward he exerior of he home Use furring srips o creae ¾ separaion beween he foil and he siding In ho climae zones, you may use only on souh and wes walls Proec radian barrier sheahing panels from moisure and rain before and during consrucion see insallaion direcions Ouline and References Summary Ceiling hea flow reducions due o radian barrier sheahing may: Reduce aic emperaure by up o 30 F in summer Produce summer cooling energy savings of up o 17% per monh Reduce monhly winer heaing cos by up o 5% Savings are dependen upon: Building design Climae Locaion and insulaion of ducs Localized condiions Radian barrier sheahing is a cos-efficien and insallaion-friendly produc for achieving energy savings

15 General References A Summary of Fify Years of Radian Barrier Research (RIMA-I websie, 2012) A Comprehensive Review of Radian Barrier Research Including Laboraory and Field Experimens ( ASHRAE Transacions, 2012) Radian Barrier Fac Shee (Oak Ridge Naional Laboraory, 2010) RIMA-I Handbook: Reflecive Insulaion, Radian Barriers, and Radiaion Conrol Coaings (RIMA-I Websie, 2002) Radian Barriers (DOE, 2012) Analysis in Suppor of he Radian Barrier Fac Shee 2010 Updae (ASHRAE, 2010) ASTM Sandard C1743: Sandard Pracice for Insallaion and Use of Radian Barrier Sysems in Residenial Building Consrucion (ASTM 2012) Quesions? This concludes The American Insiue of Archiecs Coninuing Educaion Sysems Course Tony Pugel LP Building Producs Tony.pugel@lpcorp.co m