The Guide to Radiant Barrier Insulation Total R-Value Calculations for Typical Building Applications Administered by ® Group January 2012 Insulation - The invisible energy saver By adding just 1% to your total building cost, you can install state of the art insulation. The result: • comfortable surroundings • saving money on energy costs • supporting a sustainable environment CORPORATE MEMBERS Contact our members for products and services that meet the requirements of quality, performance and safety as set by the Thermal Administered by Insulation Association of Southern Africa (TIASA). For a comprehensive list of Insulation Contractors, Distributors, Manufacturers, Suppliers & Specialists please visit: www.tiasa.org.za Offi ce: (011) 805 5002. THERMAL INSULATION ASSOCIATION OF SOUTHERN AFRICA P O Box 7861 1ST Floor, Block 4 HALFWAY HOUSE Construction Park 1685 2nd Road Midrand 1685 Tel: (011) 805-5002 Fax: (011) 805-5033 Administered by: e-mail: [email protected] web-site: www.aaamsa.co.za TIASA website: www.tiasa.org.za Acknowledgements TIASA, the TIASA Technical Committee and The Reflective foil / Radiant Barrier manufacturers of South Africa (as listed below) wishes to acknowledge the valuable assistance derived from the various publications listed below as well as the invaluable assistance and dedication by Mr. Alf Peyper in the development of this Guide to Radiant Barrier Insulation. Africa Thermal Insulations (Pty) Ltd Bhamuza (Pty) Ltd Nampak L&CP Sealed Air Africa American Society of Heating, Refrigerating & Air-Conditioning Engineers, Inc Fundamentals 1993/7 - 2001/5 (ASHRAE) National Building Research Institute of the Council for Scientific and Industrial Research. NBRI *DIS 16 -1960 DIS 61 -1958XBOU 2 -74 1987 X/BOU 2 - 8 1971 (Calc) CSIR Research Report No. 214 14-2-1957 Principles of Heating, Ventilating and Air - Conditioning HVAC Research at reference libraries of Universities - Wits & Tukkies 1960/70/80 Calculations: - Based on X/BOU 2-8-1971, 2-74-1987 - Thermal and Water Vapour Transmission ASHRAE 25-2005 (RSA values used). Dust:- NBRI and ASHRAE Reflectance Emittance 25-2005 & 3-10-2005 Effects of mean temperature rise ASHRAE 24-14-15-16-2005 & 22.6+16-1997 TIASA Thermal Insulation Handbook April 2001 (test methods - ASTM C158 & 177)) Poor Installation - Application ASHRAE 23 -15 & 24.3 - 2001 Moisture: - (Effects of) ASHRAE 23.5-6-2005, 24.5-2005 Facings ASHRAE 26.82001/5 Absorption - Exitance ASHRAE 3-9-2001 Resistance Attic Spaces ASHRAE 25.2-2005, 25.13-2001 Air Spaces Thermal Resistance ASHRAE 25.4-2005 Vapour Barriers ASHRAE 26.8 Results compare favorably with and are supportive of results published in Australia and America, most of which originated in South Africa (Lotz and van Straaten) DISCLAIMER All information, recommendation or advice contained in this AAAMSA Publication is given in good faith to the best of AAAMSA’s knowledge and based on current procedures in effect. Because actual use of AAAMSA Publications by the user is beyond the control of AAAMSA such use is within the exclusive responsibility of the user. AAAMSA cannot be held responsible for any loss incurred through incorrect or faulty use of its Publications. Great care has been taken to ensure that the information provided is correct. No responsibility will be accepted by AAAMSA for any errors and/or omissions, which may have inadvertently occurred. This Guide may be reproduced in whole or in part in any form or by any means provided the reproduction or transmission acknowledges the origin and copyright date. 3 TABLE OF CONTENTS Acknowledgement ............................................................................................................................................. 3 Background, Foreword & Scope....................................................................................................................... 5 Objective ............................................................................................................................................................ 6 1. National Building Regulation XA3 ............................................................................................................... 1.1 SANS 10400-XA Energy usage in buildings ......................................................................................... 7 1.2 SANS 204 Energy efficiency in buildings ............................................................................................. 8 2. Types of Reflective Foil Membranes/Radiant Barriers ............................................................................. 9 3. Terms & Definitions ...................................................................................................................................10 4. Introduction to Radiant Barriers ...............................................................................................................14 5. Fundamental principles of Radiant Heat Barriers / Reflective foils........................................................15 6. Moisture ......................................................................................................................................................17 7. The Effects of Mean Temperature Change on Conductance and Resistance ........................................18 8. Calculations ...............................................................................................................................................20 8.1 Methods and Values for Calculation of Heat Flow ...............................................................................20 8.2 Surface Coefficients and Resistance Values.......................................................................................20 8.3 Air Spaces, Coefficients, Thermal Conductances and Resistance Values ..........................................21 8.4 Thermal Resistance of Air Spaces ......................................................................................................21 9. Domestic Roof Applications .....................................................................................................................22 9.1 Combinations - Best Practice Reflective Foil & Bulk Insulation ..........................................................22 9.2 Application: Domestic Metal Sheet Clad Pitch 45o Roof - Reflective Membrane and Bulk Material .....23 9.3 Applications: Domestic Cement Tile and Metal roof ............................................................................24 9.4 Applications - Domestic Low Pitch 10o Metal Clad Roof ......................................................................26 9.5 Applications - Domestic Exposed Beam Cathedral Roof .....................................................................27 10. Industrial Roof Applications .....................................................................................................................28 10.1 Application: Industrial Best Practice - Roof System Material Combinations - Thermal ........................28 10.2 Application: Industrial Single Layer Double Sided Radiant Barrier/Reflective Foil Membrane ..............29 10.3 Application: Industrial Single Layer Double Sided Foil Membrane Introducing a Thermal Block ..........30 10.4 Application: Industrial Single Skin Roof Metal System With Two Double Foil Membranes ..................31 10.5 Comparisons: T1, T2, T3 With and Without Radiant Heat Barrier/Reflective Foils/Multiple Air Spaces32 10.6 Example of Typical Industrial Installation Procedure & Specification Guidance ..................................33 11. Wall Construction Comparisons ..............................................................................................................35 12. Apparent Typical Thermal Properties of Building and Insulation Materials .........................................36 4 BACKGROUND The recent publication of SANS 10400-XA Energy usage in buildings and SANS 204 Energy efficiency in buildings, with regard to Thermal Insulation products, obviated the need for a guide to be developed with specific reference to Reflective Foil Laminates/Radiant Barriers. As there is limited information available to consumers and professionals in South Africa, the objective in publishing this guide, is to disseminate knowledge about Reflective Foil Laminates/ Radiant Barriers and their contribution to achieving the performance requirements of SANS 204 in respect of energy efficient thermal insulation within the building envelope. Reflective Foil laminate/Radiant Barrier technology is vastly different to that of ordinary bulk insulation materials. The National Executive Committee of TIASA (Thermal Insulation Association of Southern Africa) agreed in February 2009, that due to the lack of knowledge and understanding of these materials in combination with airspaces, a guide to educate both Consumers and Professionals regarding its correct use and application, needed to be made available by the Reflective Foil Manufacturers in TIASA. FOREWORD The phenomenal progress and advances in technology combined with the unparalleled growth in the industrial sector globally, through the twenthieth century, is awe-inspiring. Opportunities of employment and improvement of quality of life further led to urbanization around the globe, resulting in an increased demand for housing, commercial and industrial buildings, as well as increased transportation, food production and worldwide travel for business and pleasure. Furthermore, providing for mans need,