THECONTROL OF MOISTUREMOVEMENT IN BUILDINGS USING THE DYNAYICB~ER ZONE Paul Pasqualini A thesis submitted in conformity with the requirements for the degree of Masters of Applied Science Department of Civil Engineering University of Toronto O Copyright by Paul Pasqualini 1999 National Libraiy Bibliothèque nationale 1*1 of Canada du Canada Acquisitions and Acquisitions et Bibliographic Services services bibliographiques 395 Wellington Street 395. rue Wdlingtm OttawaON K1AON4 OttawaON KlAW Canada Canada The author has granted a non- L'auteur a accordé une Licence non exclusive Licence dowing the exclusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loan, distriibute or seil reproduire, prêter, distxibuer ou copies of this thesis in rnicroform, vendre des copies de cette thèse sous paper or electronic formats. la fome de microfiche/nlm, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fkom it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. THECONTROL OF MOISTUREMOVEMENT IN BUILDINGS USINGTHE DYNAMICBUFFER ZONE MASTERSOF APPLIEDSCIEXCE, 1999 PAULPASQUALINI Department of Civil Engineering University of Toronto The performance and durability of building envelopes is significantly affected by their ability to control moisture movement. This is especially true for intentionally hurniditied buildings located in cold climates. Air esfiltration during winter months cm cause serious damage to the building envelope. inevitable flaw-s in conventional air barrier s>-stemsdue to workmanship and/or design deficiencies make the control of air Leakage a difficult task. The Dynamic Buffer Zone (DBZ) is an innovative air bamer system that can elirninate the potential deleterious effects of air exfiltration. The purpose of this research was to determine the influence of a DBZ systern on wall surtàce temperatures. This \vas achieved by constmcting and exposing a DBZ \val1 assembly to controiled temperature environrnents within a Iaboratory. The initial DBZ air temperature. the DBZ air flow rate and the DBZ cavity width were the key characteristics OF the system that il-ere investigated. The ssperimental results obtained indicate that the influence of the DBZ system on \vaIl surface temperatures is dependent on the tluid and therrnodynamic conditions of the DBZ air Liithin the cavity. For the conditions investigated. it was found that the DBZ system has a fairly insignifiant impact on wall surface temperatures. 1 should Iike to acknowledge the foliowing for their interest and assistance in the preparation of this thesis: Mr. Renzo Basset of the Department of Civil Engineering, University of Toronto, for his invaluable assistance with the computer contrai system and data acquisition, Mr. Peter DiLullo of Yolles Building Science Services, for providing the opportunity and the financial support to undertake this investigation, The Natural Sciences and Engineering Research Council of Canada, for their financial support, Dr. Kim Pressnail of the Department of Civil Engineering, University of Toronto, for his guidancet insight, and support throughout. List of Figures .......................................................................................................................... vi List of Tables ........................................................................................................................... ix 1.0 Introduction ..................................................................................................................... 1 2.0 Interaction of Moisture with Building Envelopes in Cold Regions ............................ 4 2.1 The Effects of Moisture on Masonry Walls .................................................................. 5 2.2 Condensation within the Building Envelope ...................~~~~.~~~..~~~.~~~~..~~..~...........~..~...~.7 2.2.1 Vapour Diffusion .................................................................................................. 7 2.2.2 Air leakage ............................................................................................................8 2.2.2.1 Pressure Sources ................... .. ...... ............................................................... 10 2.3 Quantity of Condensation due to Vapour Diffusion and Air leakage...... ................... 13 2.3.1 Vapour Diffusion .......................................................... 13 2.3 -2 Air Ieakage ............. .............................................................................................13 2.4 Limiting Condensation within the Building Envelope ............. .. ............................ 15 2.4.1 Vapour Retarder: Control of Vapow Diffkion .................................................. 16 2.4.2 Air Barrier: Control of Air Leakage ........................ ....................................... 16 3.0 The Dynamic Buffer Zone System.............................................................................. 19 20 3.1 Building Envelope Retrofit:.. Control of Heat, Moisture and Air Flow ................... ... 3.2 Dynamic BuEer Zone Pnnciple .................................................................................. 24 3 -3 Dynamic Insulation ..................................................................................................... 29 3.3.1 Overview ..................................................................... 30 3 -3-2 DBZ - A Dynarnic lnsulation System ................................................................ 31 4.0 DBZ Wall .Heat Triansfer Mechanisms .................................................................. 33 ** 4.1 Thermal Energy Transfer ... ........................................................ 33 4.1.1 Conduction .......................................................................................................... 33 4.1.2 Convection ........................................ ............. 34 4.1.3 Radiation ............................................................................................................. 36 4.2 DBZ Wall .Heat Transfer Mechanisms ................................................................... 37 4.3 Convection Heat Transfer Fundamentals .................................................................... 43 4.3.1 Forced Convection Basics ............... .................................................................... 43 4.3.1.1 Velocity Boundary Layer ........................................................................ 44 Thermal Boundary Layer ............................................................................................ 45 4.3.1 -3 Boundary Layer: Laminar or Turbulent Flow ................................................ 46 4.3.1.4 Convection Coefficients ......................... ... ............................................... 47 4.3.2 Interna1 Forced Convection Flow ....................................................................... 48 4.3 .2.1 Velocity Boundary Layer ................................................................................ 49 4.3.2.2 Thermai Boundary Layer ................................... ............................................. 51 4.3.3 Natural Convection ............................................................................................. 52 9 4.3 .3.1 Natural Convection O Enclosures ............................................. ....-. ..53 4.3.3.2 Combined effects of Naturai Convection and Radiation ................................ 55 4.3.4 Mixed Convection ........................... .-. ............ 56 5.0 Laboratory Research .................................................................................................... 59 5-1 Method ........................................................................................................................ 59 5.2 Apparatus .................................................................................................................... 64 5.2.1 TestingFacilityLayout ....................................................................................... 64 5.2.2 DBZTestWall ...............................................,-... ........................................... 65 5.2.2.1 Construction .................................................................................................. 66 5.2.2.2 Thermocouple Layout ..................................................................................... 68 5-23 DBZCavityAir................................................................................................... 70 5.2.3.1 Air Source ....................................................................................................... 70 5.2.3.2 DBZ Air Flow Control .................................................................................... 71 3 3 5 .2.3 -3 Temperature Control ....................................................................................... 71 5.2.3 -4 Air Distribution through Cavity .................................................................... 72 5.2.3 -5 Cavity Pressure Control .................................................................................. 75 5.2.4 Control of the Interior and Exterior Environment Temperatures .....-..-...