ACI 122R-2014 Guide to Thermal Properties of Concrete and Masonry Systems (Incorporates Errata 4 22 2015).pdf

1、Guide to Thermal Properties of Concrete and Masonry SystemsReported by ACI/TMS Committee 122ACI/TMS 122R-14First PrintingDecember 2014ISBN: 978-0-87031-971-6This document is the intellectual property of ACI and the cosponsor, and both have copyright. All rights reserved. This material may not be rep

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3、 on the inside back cover of this document.Guide to Thermal Properties of Concrete and Masonry SystemsCopyright by the American Concrete Institute, Farmington Hills, MI. All rights reserved. This material may not be reproduced or copied, in whole or part, in any printed, mechanical, electronic, film

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12、 download, on CD-ROM, through electronic subscription, or reprint and may be obtained by contacting ACI.Most ACI standards and committee reports are gathered together in the annually revised ACI Manual of Concrete Practice (MCP).American Concrete Institute38800 Country Club DriveFarmington Hills, MI

13、 48331Phone: +1.248.848.3700Fax: +1.248.848.3701www.concrete.orgThis guide reports data on the thermal properties of concrete and masonry constituents, masonry units, and systems of mate-rials and products that form building components. This guide includes consideration of thermal inertia of concret

14、e and masonry, passive solar design, and procedures to limit condensation within assemblages.Keywords: aggregate; cement paste; concrete masonry unit; moisture; precast/prestressed concrete; specific heat; sustainability; thermal conduc-tivity; thermal diffusivity; thermal resistance.CONTENTSCHAPTER

15、 1INTRODUCTION, p. 21.1Introduction, p. 21.2Energy conservation with concrete and masonry, p. 21.3Building enclosure requirements, p. 2CHAPTER 2NOTATION AND DEFINITIONS, p. 22.1Notation, p. 22.2Definitions, p. 3CHAPTER 3THERMAL CONDUCTIVITY OF CONCRETE, AGGREGATE, AND CEMENT PASTE, p. 43.1Introducti

16、on, p. 43.2Thermal conductivity of concrete, p. 43.3Influence of moisture, p. 43.4Thermal conductivity of aggregates and cement paste, p. 53.5Thermal conductivity of concrete used in concrete masonry units, p. 53.6Thermal conductivity of two-phase systems, p. 73.7Sample thermal conductivity calculat

17、ions using cubic model, p. 73.8Practical thermal conductivity, p. 8CHAPTER 4CALCULATION METHODS FOR STEADY-STATE THERMAL RESISTANCE OF WALL SYSTEMS, p. 94.1Introduction, p. 94.2Thermal resistance of concrete masonry walls, p. 104.3Methods for calculating thermal resistance of concrete masonry units,

18、 p. 104.4Thermal resistance of other concrete wall systems, p. 13CHAPTER 5THERMAL INERTIA, p. 165.1Introduction, p. 165.2Factors affecting thermal inertia effect, p. 165.3Determining thermal inertia effects, p. 195.4Equivalent R-values for concrete and masonry walls, p. 21Stephen S. Szoke, ChairACI

19、122R-14Guide to Thermal Properties of Concrete and Masonry SystemsReported by ACI/TMS Committee 122Maribeth S. BradfieldTheodore W. BremnerDennis W. GraberThomas A. HolmJohn P. RiesJeffrey F. SpeckMartha G. VanGeem Consulting MemberW. Calvin McCallACI Committee Reports, Guides, and Commentaries are

20、intended for guidance in planning, designing, executing, and inspecting construction. This document is intended for the use of individuals who are competent to evaluate the significance and limitations of its content and recommendations and who will accept responsibility for the application of the m

21、aterial it contains. The American Concrete Institute disclaims any and all responsibility for the stated principles. The Institute shall not be liable for any loss or damage arising therefrom.Reference to this document shall not be made in contract documents. If items found in this document are desi

22、red by the Architect/Engineer to be a part of the contract documents, they shall be restated in mandatory language for incorporation by the Architect/Engineer.ACI 122R-14 supersedes ACI 122R-02 and was adopted and published December 2014Copyright 2014, American Concrete InstituteAll rights reserved

23、including rights of reproduction and use in any form or by any means, including the making of copies by any photo process, or by electronic or mechanical device, printed, written, or oral, or recording for sound or visual reproduc-tion or for use in any knowledge or retrieval system or device, unles

24、s permission in writing is obtained from the copyright proprietors.15.5Interior thermal inertia, p. 21CHAPTER 6THERMAL PROPERTIES FOR PASSIVE SOLAR DESIGN, p. 226.1Introduction, p. 226.2Thermal properties, p. 236.3Incorporating mass into passive solar designs, p. 236.4Summary, p. 24CHAPTER 7CONDENSA

25、TION CONTROL, p. 247.1Introduction, p. 247.2Prevention of condensation on wall surfaces under steady-state analysis, p. 257.3Prevention of condensation within wall construc-tions, p. 25CHAPTER 8REFERENCES, p. 26Authored documents, p. 27APPENDIX ATEST RESULTS AND CALCULATED THERMAL CONDUCTANCE OF OVE

26、N-DRIED CONCRETE MASONRY, p. 29CHAPTER 1INTRODUCTION1.1IntroductionTo reduce the use of nonrecoverable energy sources, authorities have adopted energy-conservation building codes and standards that apply to the design and construc-tion of buildings. The design of energy-conserving buildings requires

27、 an expanded understanding of the thermal proper-ties of the building envelope and the materials that comprise the envelope system.This guide provides thermal-property data and design techniques that are useful in designing concrete and masonry building envelopes and determining energy code compli-a

28、nce. The guide is intended for use by owners, architects, engineers, building inspectors, code-enforcement officials, and all those interested in the energy-efficient design of buildings containing concrete or masonry components.1.2Energy conservation with concrete and masonryDue to its inherent fun

29、ctionality and the availability of raw materials used in production, concrete and masonry are the worlds most widely used building materials. Many civiliza-tions have built structures with concrete and masonry walls that provide uniform and comfortable indoor temperatures despite all types of climat

30、ic conditions. Cathedrals composed of massive masonry walls produce an indoor climate with little temperature variation during the entire year despite the absence of a heating system. Even primitive housing in the desert areas of North America used thick masonry walls that resulted in acceptable int

31、erior temperatures despite high outside daytime temperatures.Housing systems have been developed featuring effi-cient load-bearing concrete or masonry wall systems that provide resistance to weather, temperature changes, fire, and noise. Many of these wall systems are made with light-weight concrete

32、 to enhance both static and dynamic thermal resistance.Numerous organizations have studied and reported on the steady-state and dynamic energy-conserving contribu-tions that concrete and concrete masonry walls can make to thermal efficiency in buildings (Peavy et al. 1973; Petersen and Barnett 1980;

33、 Petersen et al. 1981; U.S. Department of Energy 1989; ASHRAE 2009; ANSI/ASHRAE/IES 90.1; Childs et al. 1983; National Concrete Masonry Associa-tion 2010; Portland Cement Association 1981, 1982). This increased energy efficiency may permit reductions in the required size and operating costs of mecha

34、nical systems. This reduction in energy usage is not recognized by steady-state calculations (R-values and U-values). Improved calcu-lation methods are required to account for the dynamic, real-world performance of concrete and concrete masonry building elements.1.3Building enclosure requirementsIn

35、addition to structural requirements, a building envelope should be designed to control the flow of air, heat, sunlight, radiant energy, liquid water, and water vapor. It should also provide the many other attributes generally associated with enclosure materials, including fire protection, noise cont

36、rol, impact damage resistance, durability, aesthetic quality, and economy. Analysis of building enclosure materials should extend beyond heat-flow analysis to also account for their multifunctional purposes. The non-heat-flow subjects are beyond the scope of this guide, but this exclusion should not

37、 be taken as an indication that they are not crucial to the total overall performance of a building enclosure.CHAPTER 2NOTATION AND DEFINITIONS2.1Notationa = fractional areaagr= fractional grouted area of wallai= fractional area of insulationanp= fractional area of heat flow path for path number p o

38、f thermal layer number nas= fractional area of steelaungr= fractional ungrouted area of wallaw= fractional area of web of masonry unit determined using the dimensions of web in the same planes as the height and length of the masonry unitC = thermal conductance, Btu/(hft2F) (W/(m2K)cp= specific heat,

39、 Btu/(lbF) (J/kgK)fs = face shell thickness of concrete masonry unit, in. (mm)hc= heat capacity, Btu(ft3F) (J/(m3K)I = thermal inertia, Btu/(h1/2ft2F) (J/(m2Ks1/2)kc= thermal conductivity of concrete, Btu in./(hft2F) (W/(mK)kf= thermal conductivity of material placed in the cores of masonry units, B

40、tuin./(hft2F) (W/(mK)kp= thermal conductivity of cement paste, Btuin./(hft2F) (W/(mK)American Concrete Institute Copyrighted Material www.concrete.org2 GUIDE TO THERMAL PROPERTIES OF CONCRETE AND MASONRY SYSTEMS (ACI 122R-14)k = thermal conductivity, Btuin./(hft2F) (W/(mK)L = linear dimension, in. o

41、r ft (mm or m)La= actual length, in. (mm)Lb= width of concrete masonry unit, in. (mm)M = water-vapor permeance, permq = heat flow rate, Btu/h (W/K)qss= heat flow rate when steady-state conditions are achieved, Btu/h (W/K)qw= heat flow rate for conditions other than steady-state, Btu/h (W/K)R orR-val

42、ue = thermal resistance, (hft2F)/Btu (m2K)/W)Ri= thermal resistance of interior surface-air-film, equal to 0.68 (hft2F)/Btu (0.120 m2K/W) for nonre-flective, still air, vertical surfaces with horizontal heat flowRin= thermal resistance of insulation, (hft2F)/Btu (m2K)/W)Rnp= thermal resistance of he

43、at flow path number p of thermal layer number n, (hft2F)/Btu (m2K)/W)Ro= thermal resistance of exterior surface-air-film, equal to 0.17 (hft2F)/Btu for 15 mph wind (0.030 m2K/W for 6.7 m/s wind)Rs= thermal resistance of steel, (hft2F)/Btu (m2K)/W)RT= total thermal resistance of a construction assemb

44、ly including the thermal resistance of interior and exte-rior surface air-films, (hft2F)/Btu (m2K)/W)Rt= thermal resistance of the insulating layer, (hft2F)/Btu (m2K)/W)ti= indoor air temperature, F (C)to= outdoor air temperature, F (C)ts= saturation, or dew point temperature, F (C)U orU-value = ove

45、rall coefficient of thermal transmittance, Btu/(hft2F) (W/(m2K)Ugr= overall coefficient of thermal transmittance of fully grouted wall, Btu/(hft2F) (W/m2K)Uungr= overall coefficient of thermal transmittance of ungrouted wall, Btu/(hft2F) (W/m2K)V = volume, ft3(m3)Va= volume of compacted aggregate, f

46、t3(m3)Vc= volume of cement paste, ft3(m3)w = web thickness measured perpendicular to face of masonry unit, in (mm) = thermal diffusivity, (in.ft)/h (m2/s) = water-vapor permeability, grin./(hft2in.-Hg) (Hg/(smPa) = density, lb/ft3(kg/m3) specific property of a gas, liquid, or solid is a measure of t

47、he mass per unit volumem= moist density, lb/ft3(kg/m3) density of a material where moisture is presento= oven-dry density, lb/ft3(kg/m3)2.2DefinitionsACI provides a comprehensive list of definitions through an online resource, “ACI Concrete Terminology,” http:/www.concrete.org/Tools/ConcreteTerminol

48、ogy.aspx. Defi-nitions provided herein complement that resource.heat capacitymeasure of the amount of heat required to change by one degree a specified object.moist densitydensity of a material where moisture is present.overall coefficient of thermal transmittance, Uheat transfer of a construction a

49、ssembly is determined by combining the thermal resistance of the interior and exterior surface-air-films with the combined thermal resistance of the total construction materials.solar reflectancesurface property of a material deter -mined as the ratio of the reflected solar radiation, or electro-magnetic flux, to the incident solar radiation measured on a scale of 0.0 to 1.0: from not reflective at 0.0 to 100 per