A thermal and moisture property database for common building and insulation materials.ABSTRACT An ASHRAE ASHRAE American Society of Heating, Refrigerating & Air Conditioning Engineers research project (RP-1018) that was conducted at the Institute for Research in Construction, National Research Council Canada, has resulted in a unique database on many hygrothermal properties of many common building and insulation materials that are currently used in North America North America, third largest continent (1990 est. pop. 365,000,000), c.9,400,000 sq mi (24,346,000 sq km), the northern of the two continents of the Western Hemisphere. . The properties that are determined include thermal conductivity thermal conductivity A measure of the ability of a material to transfer heat. Given two surfaces on either side of the material with a temperature difference between them, the thermal conductivity is the heat energy transferred per unit time and per unit , equilibrium moisture content The moisture content of wood below the fibre saturation point is a function of both relative humidity and temperature of surrounding air. The equilibrium moisture content is the moisture content at which the wood is neither gaining nor losing moisture; this however, is a dynamic , water vapor transmission characteristics, water absorption coefficient absorption coefficient n. 1. The milliliters of a gas at standard temperature and pressure that will saturate 100 milliters of liquid. 2. The amount of light absorbed in 1 atom or in 1 unit of thickness or mass of a given substance. , moisture diffusivity Dif`fu`siv´i`ty n. 1. Tendency to become diffused; tendency, as of heat, to become equalized by spreading through a conducting medium. , and airflow characteristics. The experimental and analytical procedures Analytical Procedures is one of financial audit skill which help an auditor understand the client's business and changes in the business, to identify potential risk areas and to plan other audit procedures. used in the research project are all based on either international standards or on well-documented and peer-reviewed approaches. The materials that have been investigated in the project include several wood-based products, such as oriented strand board Oriented strand board, or OSB, or waferboard, or Sterling board (UK), is an engineered wood product formed by layering strands (flakes) of wood in specific orientations. , plywood plywood, manufactured board composed of an odd number of thin sheets of wood glued together under pressure with grains of the successive layers at right angles. Laminated wood differs from plywood in that the grains of its sheets are parallel. , wood fiberboard fi·ber·board n. A building material composed of wood chips or plant fibers bonded together and compressed into rigid sheets. Noun 1. , and composite wood siding; masonry masonry: see brick; concrete; stonework; tile. masonry Craft of building in stone, brick, or block. By 4000 BC, Egypt had developed an elaborate cut-stone technique. products, such as clay brick, mortar, and aerated aer·ate tr.v. aer·at·ed, aer·at·ing, aer·ates 1. To supply with air or expose to the circulation of air: aerate soil. 2. concrete; five species of lumber lumber, term for timber that has been cut into boards for use as a building material. The major steps in producing lumber involve logging (the felling and preparation of timber for shipment to sawmills), sawing the logs into boards, grading the boards according to ; cladding The plastic or glass sheath that is fused to and surrounds the core of an optical fiber. The cladding's mirror-like coating keeps the light waves reflected inside the core. The cladding is covered with a protective outer jacket. See fiber optics glossary. products, such as stucco stucco (stŭk`ō), in architecture, a term loosely applied to various kinds of plasterwork, both exterior and interior. It now commonly refers to a plaster or cement used for the external coating of buildings, most frequently employed in , fiber cement board A cement board is a combination of cement and glass fibers formed into 4 foot by 8 foot sheets, 1/4 to 1/2 inch thick that are typically used as a tile backing board. Cement board can be nailed or screwed to wood or steel studs to create a substrate for vertical tile and attached , and the exterior coatings of EIFS EIFS Exterior Insulation and Finish System (construction) EIFS Extended Inter-Frame Space (IEEE 802.11) EIFS Economic Impact Forecast System EIFS Estonian Institute for Futures Studies systems; seven insulation products; six sheathing membranes; interior gypsum gypsum (jĭp`səm), mineral composed of calcium sulfate (calcium, sulfur, and oxygen) with two molecules of water, CaSO4·2H2O. It is the most common sulfate mineral, occurring in many places in a variety of forms. board, primer, and a latex latex, emulsion of a polymer (e.g., rubber) in water (see colloid). Natural latexes are produced by a number of plants, are usually white in color, and often contain, in addition to rubber, various gums, oils, and waxes. paint; and a natural stone, a cement-based sheathing board, and vinyl wallpaper. This paper lists the basic information on all materials that were investigated. It also summarizes the principles of the experimental procedures. Illustrative il·lus·tra·tive adj. Acting or serving as an illustration. il·lus  tra·tive·ly adv.Adj. 1. examples of the information that has been generated in the research project are presented. Results from statistical analyses are highlighted. INTRODUCTION With the advent of high-power personal computers, hygrothermal computer models have become powerful tools for building physicists and building practitioners alike. Significant advances were made during the past two decades in the development of hygrothermal models that are now useful in assessing the real-time responses of building envelope A building envelope is the separation between the interior and the exterior environments of a building. It serves as the outer shell to protect the indoor environment as well as to facilitate its climate control. assemblies to the variations in weather parameters and indoor environments. One major task in the International Energy Agency Annex an·nex tr.v. an·nexed, an·nex·ing, an·nex·es 1. To append or attach, especially to a larger or more significant thing. 2. 24 (Hens 1996) evaluated many hygrothermal models with diverse capabilities from European and Scandinavian countries Noun 1. Scandinavian country - any one of the countries occupying Scandinavia Scandinavian nation European country, European nation - any one of the countries occupying the European continent and North America. More recent developments are documented in an ASTM ASTM abbr. American Society for Testing and Materials manual (Trechsel 2001). All these models require a set of very reliable inputs to yield meaningful results. Among these inputs are the properties of the building materials Building materials used in the construction industry to create . These categories of materials and products are used by and construction project managers to specify the materials and methods used for . . The information on material properties available in the literature (Kumaran 1996; Trechsel 1994, 2001) is useful as a starting point Noun 1. starting point - earliest limiting point terminus a quo commencement, get-go, offset, outset, showtime, starting time, beginning, start, kickoff, first - the time at which something is supposed to begin; "they got an early start"; "she knew from the in the application of hygrothermal models, but it is not adequate for various reasons. Building materials evolve continuously and the properties may change significantly. Another problem is that none of these previous works address all relevant hygrothermal properties of all products either. Usually the information is assembled from various sources. Even some of the most well-planned works are incomplete and often become outdated (Tveit 1966; Hansen 1986; Burch et al. 1992; Richards et al. 1992). Hence the need for a systematic investigation of the properties of all current building materials was recognized and ASHRAE Research Project 1018 was formulated in this context. The original scope of the project was to "generate a set of reliable and representative data on the hygrothermal properties of 25 common building materials." The project is now complete and has resulted in detailed information on various hygrothermal properties of more than 35 building products. The properties that are determined include thermal conductivity, equilibrium moisture content, water vapor transmission characteristics, water absorption coefficient, moisture diffusivity, and airflow characteristics. The experimental and analytical procedures used in the research project are all based on either international standards or on well-documented and peer-reviewed approaches. This paper lists the basic information on all products that were investigated. It also summarizes the principles of the experimental procedures. Illustrative examples of the information that has been generated in the research project are presented. Results from statistical analyses, albeit rather limited by the available information, are highlighted. GENERAL DESCRIPTIONS OF THE BUILDING PRODUCTS Relevant information on all the products included in the project is given below. The information includes the physical details of the products, as these are available in the market, bulk densities, thickness, and, if available, details on the raw materials used in the manufacture. 1. Aerated Concrete: The test samples are taken from 1 x 1 x 1.5 ft blocks of the material. The bulk density is (460 [+ or -] 15) kg [m.sup.-3]. 2. Interior Gypsum Board: This product is available as 4 x 8 ft boards at a nominal thickness of 1/2 in. A paper layer is adhered to the major surfaces. Labels on the product say the following: Manufactured to exceed standards Can/CSA-A82.27 and ASTM C 36. The bulk density is (625 [+ or -] 7) kg [m.sup.-3]. 3. Oriented Strand Board-1: This product is available as 4 x 8 ft boards at a nominal thickness of 1/2 in. The strands of this product are manufactured from poplar Poplar, city, England Poplar, former metropolitan borough, SE England. See Tower Hamlets. poplar, in botany poplar: see willow. and aspen. The bulk density is (650 [+ or -] 30) kg [m.sup.-3]. 4. Oriented Strand Board-2: This product is available as 4 x 8 ft boards at a nominal thickness of 3/8 in. The strands of this product are manufactured from balsam balsam (bôl`səm), fragrant resin obtained from various trees. The true balsams are semisolid and insoluble in water, but they are soluble in alcohol and partly so in hydrocarbons. , poplar, and trembling aspen Trembling aspen is the popular name for either
5. Oriented Strand Board-3: This product is available as 4 x 8 ft boards at a nominal thickness of 7/16 in. The strands of this product are manufactured from birch, poplar, and aspen. The bulk density is (650 [+ or -] 30) kg [m.sup.-3]. 6. Plywood-1: This product is available as 4 x 8 ft boards at a nominal thickness of 3/4 in. It is certified See certification. as conforming to Canadian plywood manufacturing standard CSA (1) (Canadian Standards Association, Toronto, Ontario, www.csa.ca) A standards-defining organization founded in 1919. It is involved in many industries, including electronics, communications and information technology. O151, Canadian Softwood softwood Timber obtained from coniferous trees (mainly of the pine and fir families). With the exception of bald cypress, tamarack, and larch, softwood trees are evergreens. Plywood. The bulk density is (445 [+ or -] 5) kg [m.sup.-3]. 7. Plywood-2: This product is available as 4 x 8 ft boards at a nominal thickness of 1/2 in. It is certified as conforming to Canadian plywood manufacturing standard CSA O121, Douglas Fir Douglas fir: see pine. Douglas fir Any of about six species of coniferous evergreen timber trees (see conifer) that make up the genus Pseudotsuga, in the pine family, native to western North America and eastern Asia. Plywood. The bulk density is (470 [+ or -] 5) kg [m.sup.-3]. 8. Plywood-3: This product is available as 4 x 8 ft boards at a nominal thickness of 5/8 in. It is certified as conforming to Canadian plywood manufacturing standard CSA O121, Douglas Fir Plywood. The bulk density is (550 [+ or -] 5) kg [m.sup.-3]. 9. Wood fiber Board: This product is available as 4 x 8 ft boards at a nominal thickness of 7/16 in. Both major surfaces are coated black (bituminous bi·tu·mi·nous adj. 1. Like or containing bitumen. 2. Of or relating to bituminous coal. Adj. 1. bituminous - resembling or containing bitumen; "bituminous coal" ). The bulk density is (320 [+ or -] 10) kg [m.sup.-3]. 10. Eastern White Cedar white cedar In the lumber trade, the American arborvitae, some species of false cypress (genus Chamaecyparis) and McNab cypress, incense cedar (Calocedrus decurrens), and California juniper, all in the cypress family. : The specimens used for various tests are taken from 1 in. (nominal thickness) x 8 in. x 8 ft planks. The bulk density is (360 [+ or -] 20) kg [m.sup.-3]. 11. Western Red Cedar Western red cedar: see juniper, arborvitae. : The specimens used for various tests are taken from 1 in. (nominal thickness) x 8 in. x 8 ft planks. The bulk density is (350 [+ or -] 20) kg [m.sup.-3]. 12. Spruce spruce, any plant of the genus Picea, evergreen trees or shrubs of the family Pinaceae (pine family) widely distributed in the Northern Hemisphere. The needles are angular in cross section, rather than flattened as in the related hemlocks and firs. : The specimens used for various tests are taken from 1 in. (nominal thickness) x 8 in. x 8 ft planks. The bulk density is (400 [+ or -] 50) kg [m.sup.-3]. 13. Eastern White Pine: The specimens used for various tests are taken from 1 in. (nominal thickness) x 8 in. x 8 ft planks. The bulk density is (460 [+ or -] 60) kg [m.sup.-3]. 14. Southern Yellow Pine: The specimens used for various tests are taken from 1 in. (nominal thickness) x 8 in. x 8 ft planks. The bulk density is (500 [+ or -] 40) kg [m.sup.-3]. 15. Composite Wood Siding: This product is available as 4 x 8 ft boards at a nominal thickness of 7/16 in. The material is made out of high-density wood fiberboard, and one major surface is coated with a paint at a fraction of a millimeter thickness. The bulk density is (740 [+ or -] 30) kg [m.sup.-3]. 16. Clay Brick: The brick is manufactured in Canada and is identified as Charleston brick. Test specimens are prepared from a production batch of 72 x 78 x 250 mm bricks. The bricks are light reddish brown in color and referred to as "extruded clay brick." The bulk density is (1980 [+ or -] 30) kg [m.sup.-3]. 17. Mortar: The mortar is from a masonry cement masonry cement n. Cement used in the mortar of block and brick masonry. mortar mix, type N: 1 part by volume of masonry cement type N and 2 1/4 to 3 parts by volume of aggregate. The bulk density is (1600 [+ or -] 30) kg [m.sup.-3]. 18. Stucco: This is a regular Portland stucco mix. The bulk density is (1985 [+ or -] 30) kg [m.sup.-3]. 19. Fiber Cement: This product is available as 4 x 8 ft boards at a nominal thickness of 5/16 in. The bulk density is (1380 [+ or -] 40) kg [m.sup.-3]. 20. Cement Board: This product is available as 4 x 8 ft boards at a nominal thickness of 1/2 in. This is used as an exterior sheathing member in EIFS type walls. The bulk density is (1130 [+ or -] 50) kg [m.sup.-3]. 21. Limestone: This product is called Georgian Bay Georgian Bay, large northeastern extension of Lake Huron, S Ont., Canada, separated from Lake Huron by Manitoulin Island and by the Bruce Peninsula; Lucas Channel is its chief connection with Lake Huron. limestone, available as slabs of various sizes. The bulk density is (2500 [+ or -] 100) kg [m.sup.-3]. 22. Low-Density Glass Fiber Batt Insulation: Batt at a nominal thickness of 4 in. The bulk density is (11.5 [+ or -] 1.5) kg [m.sup.-3]. The fibers are held together using a binder binder: see combine. An earlier Microsoft Office workbook file that let users combine related documents from different Office applications. The documents could be viewed, saved, opened, e-mailed and printed as a group. . 23. Cellulose cellulose, chief constituent of the cell walls of plants. Chemically, it is a carbohydrate that is a high molecular weight polysaccharide. Raw cotton is composed of 91% pure cellulose; other important natural sources are flax, hemp, jute, straw, and wood. Fiber Insulation: All test specimens are prepared from samples blown from a commercial cellulose insulation The word cellulose comes from the French word for a living cellule and glucose, which is sugar. Insulation is the non conducting material used to separate the internal climate and sounds of a building from external climate and sounds. product according to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. the manufacturer's directions. The product is prepared from recycled newspaper as the starting material using a dry fiberization technology. The fire retardant fire retardant Public health A chemical used to resist combustion, which may contain polybrominated biphenyls and antimony oxide and fungicide fungicide (fŭn`jəsīd', fŭng`gə–), any substance used to destroy fungi. Some fungi are extremely damaging to crops (see diseases of plants), and others cause diseases in humans and other animals (see fungal infection). are also applied as dry raw materials during the production process. The applied density of the insulation is (30 [+ or -] 4) kg [m.sup.-3]. 24. Expanded Polystyrene polystyrene (pŏl'ēstī`rēn), widely used plastic; it is a polymer of styrene. Polystyrene is a colorless, transparent thermoplastic that softens slightly above 100°C; (212°F;) and becomes a viscous liquid at around 185°C; Insulation: This product meets CAN/ULC-S701-01 requirements for Type 1 expanded polystyrene insulation. The bulk density is (14.8 [+ or -] 0.2) kg [m.sup.-3]. 25. Extruded Polystyrene Insulation: A commercial product available as 4 x 4 ft boards at a nominal thickness of 4 in. The product meets CAN/CGSB/ONGC: 51.20-M87 and is type 4. The bulk density is (28.6 [+ or -] 0.2) kg [m.sup.-3]. 26. Sprayed Polyurethane Foam Noun 1. polyurethane foam - a foam made by adding water to polyurethane plastics polyfoam polyurethan, polyurethane - any of various polymers containing the urethane radical; a wide variety of synthetic forms are made and used as adhesives or plastics or Insulation: Test specimens are taken from a 4 ft x 4 ft sample prepared using a commercial product by spraying three passes at a total thickness of 6 in. The bulk density is (39 [+ or -] 2) kg [m.sup.-3]. 27. Polyisocyanurate Board Insulation: Test specimens are taken from a 4 ft x 8 ft board at a nominal thickness of 3 in. The facers were removed from both major surfaces before specimens were prepared for all tests. The bulk density is (26.5 [+ or -] 0.2) kg [m.sup.-3]. 28. Low-Density Sprayed Polyurethane Foam Insulation: Test specimens are taken from a 4 x 4 ft sample prepared using a commercial product sprayed at 8 to 10 ft height. The bulk density is 6.5 to 8.5 kg [m.sup.-3]. 29. #15 Felt: Mass per area is approximately 515 g [m.sup.-2]. The thickness is (0.72 [+ or -] 0.03) mm. 30. 10 Minute Paper: Mass per area is approximately 170 g [m.sup.-2]. The thickness is (0.20 [+ or -] 0.01) mm. 31. 30 Minute Paper: Mass per area is approximately 200 g [m.sup.-2]. The thickness is (0.22 [+ or -] 0.01) mm. 32. 60 Minute Paper: Mass per area is approximately 280 g [m.sup.-2]. The thickness is (0.34 [+ or -] 0.01) mm. 33. Spun Bonded Polyolefin: Mass per area is approximately 65 g [m.sup.-2]. The thickness is from 0.14 to 0.15 mm. 34. Spun Bonded Polyolefin with Crinkled Surface: Mass per area is approximately 67 g [m.sup.-2]. The thickness is about 0.1 mm. 35. Vinyl Wallpaper: Mass per area is approximately 170 g [m.sup.-2]. The thickness is (0.205 [+ or -] 0.008) mm. 36. Primer and Two Coats of a Latex Paint on Gypsum Board: Negligible thickness change for the gypsum board due to the coatings. 37. EIFS Base and Finish Coats: The base coat is polymer cement and the finish coat is latex acrylic. The combined thickness is approximately 4.5 mm and bulk density is approximately 1140 kg [m.sup.-3]. The properties reported include: * thermal conductivity, * sorption-desorption isotherms, * water vapor permeance Permeance The reciprocal of reluctance in a magnetic circuit. It is the analog of conductance (the reciprocal of resistance) in an electric circuit, and is given by (1) or permeability permeability /per·me·a·bil·i·ty/ (per?me-ah-bil´i-te) the property or state of being permeable. per·me·a·bil·i·ty n. 1. The property or condition of being permeable. 2. , * moisture diffusivity, * water absorption coefficient, * and air permeance or permeability. Attempts to measure liquid permeability directly were not successful, within the scope of the project. A method to evaluate this property from the information on desorption Desorption A process in which atomic and molecular species residing on the surface of a solid leave the surface and enter the surrounding gas or vacuum. isotherm isotherm, line drawn on a map of a particular region of the earth's surface connecting points of equal temperature; each point reflects one temperature reading or an average of several readings over a period of time. and moisture diffusivity was documented in one of the project reports and values given for many of the products investigated here (NRC NRC abbr. 1. National Research Council 2. Nuclear Regulatory Commission Noun 1. NRC - an independent federal agency created in 1974 to license and regulate nuclear power plants 2000). PRINCIPLES OF THE EXPERIMENTAL PROCEDURES Well-developed experimental procedures or international standard test procedures exist to determine the properties mentioned above. The principles of the experimental procedures that are used to determine the hygrothermal properties of building materials in the present investigation are given below. Heat capacity data that are listed in the final report (NRC 2002) are those taken from the International Energy Agency Annex 24 report (Kumaran 1996). Density data reported are the averages of the densities of many test specimens (conditioned to laboratory environment, approximately 21[degrees]C and 50% RH) for each material, calculated from direct measurements on the weight and on the geometric dimensions that are used to characterize each test specimen. Further details on each experimental procedure and data analyses may be found in the NRC Report No. B-1115.3 (NRC 1999). Thermal Conductivity of Dry Materials The heat conduction Heat conduction or thermal conduction is the spontaneous transfer of thermal energy through matter, from a region of higher temperature to a region of lower temperature, and hence acts to even out temperature differences. equation is used directly to determine the thermal conductivity of dry materials. Equipment that can maintain a known unidirectional The transfer or transmission of data in a channel in one direction only. steady-state heat flux (under known constant boundary temperatures) across a flat slab of known thickness is used for the measurements. The most commonly used equipment is the guarded hot plate apparatus or the heat flow meter flow meter Device that measures the velocity of a gas or liquid. It has applications in medicine as well as in chemical engineering, aeronautics, and meteorology. Examples include pitot tubes, venturi tubes, and rotameters (tapered graduated tubes with a float inside that is apparatus. ASTM Standards C 177, Standard Test Method for Steady-State Heat flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus, and C518, Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus, are widely used for this purpose. The latter is used in the present investigation. Similar standards are available from the International Standards Organization See ISO. and the European Union European Union (EU), name given since the ratification (Nov., 1993) of the Treaty of European Union, or Maastricht Treaty, to the European Community . In the ASTM standards, the heat conduction equation is written for practical applications as [lambda] = Q x l/(A x [DELTA]T), (1) where Q = heat flow rate across an area A, l = thickness of test specimen, and [DELTA]T = hot surface temperature--cold surface temperature. The thermal conductivity calculated according to Equation 1 is called apparent thermal conductivity. It is a function of the average temperature of the test specimen. Sorption/Desorption Isotherm For sorption sorption /sorp·tion/ (sorp´shun) the process or state of being sorbed; absorption or adsorption. sorp·tion n. Adsorption or absorption. measurements, the test specimen is dried at an appropriate drying temperature to constant mass. While maintaining a constant temperature, the dried specimen is placed consecutively in a series of test environments, with relative humidity relative humidity n. The ratio of the amount of water vapor in the air at a specific temperature to the maximum amount that the air could hold at that temperature, expressed as a percentage. increasing in stages, until equilibrium is reached in each environment. Equilibrium in each environment is confirmed by periodically weighing the specimen until constant mass is reached. From the measured mass changes, the equilibrium moisture content at each test condition can be calculated and the adsorption adsorption, adhesion of the molecules of liquids, gases, and dissolved substances to the surfaces of solids, as opposed to absorption, in which the molecules actually enter the absorbing medium (see adhesion and cohesion). isotherm drawn. The starting point for the desorption measurements is from an equilibrium condition very near 100% RH. While maintaining a constant temperature, the specimen is placed consecutively in a series of test environments, with relative humidity decreasing in stages, until equilibrium is reached in each environment. Equilibrium in each environment is confirmed by periodically weighing the specimen until constant mass is reached. Finally, the specimen is dried at the appropriate temperature to constant mass. From the measured mass changes, the equilibrium moisture content at each test condition can be calculated and the desorption isotherm drawn. A new CEN CEN - Conseil Européen pour la Normalisation. A body coordinating standardisation activities in the EEC and EFTA countries. standard (89 N 337 E) is under development for the determination of "hygroscopic hygroscopic /hy·gro·scop·ic/ (hi?gro-skop´ik) readily absorbing moisture. hy·gro·scop·ic adj. Readily absorbing moisture, as from the atmosphere. sorption curve." ASTM Standard C1498 addresses the same procedure. Desorption Isotherm above 95% RH from Pressure Plate Measurements The test specimens are saturated with water under vacuum. Those are then introduced in a pressure plate/ membrane apparatus that can maintain pressures up to 100 bar for several days. The plates/membrane in perfect hygric contact with the specimens extract water out of the pore pore (por) a small opening or empty space. alveolar pores openings between adjacent pulmonary alveoli that permit passage of air from one to another. structure until an equilibrium state is established. The equilibrium values for moisture content in the specimens and the corresponding pressures (measured as the excess over atmospheric pressure atmospheric pressure or barometric pressure Force per unit area exerted by the air above the surface of the Earth. Standard sea-level pressure, by definition, equals 1 atmosphere (atm), or 29.92 in. (760 mm) of mercury, 14.70 lbs per square in., or 101. ; the negative of this value is referred to as the "pore pressure" while the absolute value is the suction suction /suc·tion/ (suk´shun) aspiration of gas or fluid by mechanical means. post-tussive suction a sucking sound heard over a lung cavity just after a cough. ) are recorded. The equilibrium pressure [p.sub.h] can be converted to a relative humidity, [phi], using the following equation: ln [phi] = -[M/[rho]RT] [P.sub.h] (2) where M = the molar mass Molar mass, symbol M,[1] is the mass of one mole of a substance (chemical element or chemical compound).[2] It is a physical property which is characteristic of each pure substance. of water R = the ideal gas constant T = the thermodynamic ther·mo·dy·nam·ic adj. 1. Characteristic of or resulting from the conversion of heat into other forms of energy. 2. Of or relating to thermodynamics. temperature [rho] = the density of water A Nordtest technical report (Hansen 1998) briefly describes a procedure for pressure plate measurements and reports the results from an interlaboratory comparison. Measurements done by five laboratories on Baumberger sandstone sandstone, sedimentary rock formed by the cementing together of grains of sand. The usual cementing material in sandstone is calcium carbonate, iron oxides, or silica, and the hardness of sandstone varies according to the character of the cementing material; quartz and Sander sandstone are listed in the report. The results are statistically analyzed and comments are made on the difficulty of assigning uncertainties to the derived results. No standard procedure has yet been developed for the pressure plate measurements. Water Vapor Permeability/Permeance The vapor diffusion equation The diffusion equation is a partial differential equation which describes density fluctuations in a material undergoing diffusion. It is also used to describe processes exhibiting diffusive-like behaviour, for instance the 'diffusion' of alleles in a population in population is directly used to determine the water vapor permeability of building materials. The measurements are usually done under isothermal i·so·ther·mal adj. Of, relating to, or indicating equal or constant temperatures. isothermal, isothermic having the same temperature. conditions. A test specimen of known area and thickness separates two environments that differ in relative humidity (RH). Then the rate of vapor flow across the specimen, under steady-state conditions In telecommunication, the term steady-state condition has the following meanings:
n. Mathematics The set of conditions specified for behavior of the solution to a set of differential equations at the boundary of its domain. ), is gravimetrically determined. From these data, the water vapor permeability of the material is calculated as [[delta].sub.p] = [J.sub.v] x l/(A x [DELTA]p), (3) where [J.sub.v] = water vapor flow rate across an area A, l = thickness of the specimen, and [DELTA]p = difference in water vapor pressure vapor pressure, pressure exerted by a vapor that is in equilibrium with its liquid. A liquid standing in a sealed beaker is actually a dynamic system: some molecules of the liquid are evaporating to form vapor and some molecules of vapor are condensing to form liquid. across the specimen surfaces. Often, especially for membranes and composite materials composite material or composite, any material made from at least two discrete substances, such as concrete. Many materials are produced as composites, such as the fiberglass-reinforced plastics used for automobile bodies and boat hulls, but the , one calculates the water vapor permeance [[delta].sub.l] of a product at a given thickness from the above measurements as [[delta].sub.l] = [J.sub.v]/(A x [DELTA]p). (4) ASTM Standard E96, Test Methods for Water Vapor Transmission of Materials, prescribes two specific cases of this procedure--a dry cup method that gives the permeance or permeability at a mean RH of 25% and a wet cup method that gives the permeance or permeability at a mean RH of 75%. A new CEN standard (89 N 336 E) is being developed in the European Union based on an ISO (1) See ISO speed. (2) (International Organization for Standardization, Geneva, Switzerland, www.iso.ch) An organization that sets international standards, founded in 1946. The U.S. member body is ANSI. standard. More recently, a number of technical papers that deal with various technical aspects, limitations, and analyses of the experimental data of these procedures have appeared in the literature (Hansen and Lund 1990; Lackey et al. 1997; Kumaran 1998). Water Absorption Coefficient. One major surface of each test specimen is placed in contact with liquid water. The increase in mass as a result of moisture absorption is recorded as a function of time. Usually, during the initial part of the absorption process, a plot of the mass increase against the square root of time is linear. The slope of the line divided by the area of the surface in contact with water is the water absorption coefficient (Kumaran 1999). (1) CEN Standard 89 N 370 E on the determination of water absorption coefficients is now available. The use of a water absorption coefficient together with capillary capillary (kăp`əlĕr'ē), microscopic blood vessel, smallest unit of the circulatory system. Capillaries form a network of tiny tubes throughout the body, connecting arterioles (smallest arteries) and venules (smallest veins). saturation moisture content to derive information on an average moisture diffusivity for building products is explained in Kumaran (1999). Moisture Diffusivity. Moisture diffusivity [D.sub.w] defines the rate of movement of water [J.sub.l] within a material, induced by a water concentration gradient concentration gradient n. The graduated difference in concentration of a solute per unit distance through a solution. Noun 1. according to the following equation: [J.sub.l] = -[[rho].sup.0][D.sub.w] grad u (5) where [[rho].sup.0] = density of the dry material u = moisture content expressed as mass of water/dry mass of material In the experimental procedure, liquid water in contact with one surface of a test specimen is allowed to diffuse into the specimen. The distribution of moisture within the specimen is determined as a function of time at various intervals until the moving moisture front advances to half of the specimen. Gamma spectroscopy spectroscopy Branch of analysis devoted to identifying elements and compounds and elucidating atomic and molecular structure by measuring the radiant energy absorbed or emitted by a substance at characteristic wavelengths of the electromagnetic spectrum (including gamma ray, is used as the experimental technique. The data are analyzed using the Boltzmann transformation (Bruce and Klute 1956; Kumaran et al. 1989; Marchand and Kumaran 1994) to derive the moisture diffusivity as a function of moisture content. There is no standard test procedure for the determination of moisture diffusivity. There are many publications in the literature that describe the technical and experimental details (Marchand and Kumaran 1994; Descamps 1997; Pel 1995). Air Permeability/Permeance. Test specimens with known areas and thickness are positioned to separate two regions that differ in air pressure, and the airflow rate at a steady state and the pressure differential across the specimen are recorded. From these data, the air permeability [k.sub.a] is calculated as [k.sub.a] = [J.sub.a] x l/(A x [DELTA]p) (6) where [J.sub.a] = air flow rate across an area A, l = thickness of the specimen, and [DELTA]p = difference in air pressure across the specimen surfaces. Often, especially for membranes and composite materials, one calculates the air permeance [K.sub.a] of a product at a given thickness from the above measurements as [K.sub.a] = [J.sub.a]/(A x [DELTA]p). (7) ASTM Standard C 522, Standard Test Method for Airflow Resistance of Acoustical Materials, prescribes a method based on this principle. Bomberg and Kumaran (1986) have extended the method for general application to building materials. Comments on the Uncertainty of the Results From the description given above, it may be seen that the basic physical quantities that need to be measured in each of the test procedures are quantities such as mass, length, time, temperature, and voltage. At the Institute for Research in Construction, the instruments that are used to record these basic quantities are traceable to Canadian national standards. Mass can be measured within a milligram milligram /mil·li·gram/ (mg) (mil´i-gram) one thousandth (10-3) of a gram. mil·li·gram n. Abbr. mg A metric unit of mass equal to one thousandth (10-3) of a gram. , length within a fraction of a millimeter, time differences within a second, temperature within a few centi-Kelvin, and voltage within few micro-volt. Other physical quantities, such as relative humidity and air pressure, are maintained and measured within a few tenths of a percentage and these are also traceable to Canadian national standards. But the high precision that is attainable does not mean that the physical quantities measured are known within a few fractions of one percent. The basic inhomogeneity in·ho·mo·ge·ne·i·ty n. pl. in·ho·mo·ge·ne·i·ties 1. Lack of homogeneity. 2. Something that is not homogeneous or uniform. Noun 1. of all building products introduces uncertainties in the derived hygrothermal properties that are far greater than the uncertainties in the measurements of the basic physical quantities. The magnitude of these uncertainties depends on the building product under investigation. This aspect is clearly brought out in the final report of ASHRAE Research Project 1018. The measurements on one particular test specimen in a particular test method may yield the property for that specimen well within a percent. For example, the water vapor transmission for one test specimen can be determined well within a percent, as is evident from the project report. But when all the measurements on all test specimens used are combined to designate the water vapor permeability (or permeance) of the product, the uncertainty may be as large as 30% (see, for example, the results on aerated concrete in this paper). If the product is reasonably homogeneous, such as a building membrane, the uncertainty may be less that 10%. If results from more than one test laboratory are used to designate the property for a given product line, the uncertainty may still increase. Thus it is futile to say that such and such a test procedure can yield the corresponding material property within a given uncertainty. The result depends on the extent of inhomogeneity of the building product under investigation. Therefore, in the final report of the project, wherever possible, the uncertainty of each listed material property is individually assigned for each material. ILLUSTRATIVE EXAMPLES: PROPERTIES OF AERATED CONCRETE Illustrative examples are given below to show the details that have been reported in the final project report. Primary data, test conditions, uncertainties of measurements, and, wherever applicable, error analyses are documented in the report. Not all methods are applicable to all materials, and often not all properties are relevant to all materials. Aerated concrete is one of the products that has gone through the entire sets of measurements, so it serves as a good example to demonstrate the details of all experimental and analytical results. Thermal Conductivity Measurements are done according to ASTM Standard C518, and 30 x 30 cm specimens are used (Table 1). The temperatures of the plates are maintained within 0.02 [degrees]C for these measurements for a 12-hour period to confirm steady state. Note that the heat flow meter apparatus is built to measure the heat transmission characteristics of insulating materials, and for those materials the measurement uncertainties are within 2%. Aerated concrete is more conductive conductive having the quality of readily conducting electric current. conductive flooring flooring or floor covering made specially conductive to electrical current, usually by the inclusion of copper wiring that is earthed than traditional insulation, and the large heat fluxes measured may give measurement uncertainties as high as 5%. Sorption-Desorption Measurements (2) Either eight specimens, 40 mm x 40 mm x 20 mm each, or three specimens, 40 mm x 40 mm x 6 mm each, are used in these measurements; the numbers in parentheses See parenthesis. parentheses - See left parenthesis, right parenthesis. in Tables 2 and 3 indicate the experimental uncertainties. Water Vapor Transmission (WVT WVT Watervliet Arsenal (New York) WVT Wigner-Ville Transform WVT Wire Validation Testing WVT Wearable Virtual Table ) Rate Measurements (3) For each test condition, three circular specimens, each 15 cm in diameter, are used (see Tables 4 and 5). The average thickness of still air in the cups in both series is 11 mm. Derived Water Vapor Permeability (4) From the data listed in Tables 4 and 5, one can derive the dependence of the water vapor permeability on relative humidity for this aerated concrete (Kumaran 1998). An example is given in Table 6. The relation between WVT rate and chamber RH (Kumaran 1998) that is used for deriving the values in Table 6 is shown in Figure 1. A numeric numeric see numerical. numeric cluster see ten-key pad. summary of the analyses is listed below. The procedure used is based on CEN/TC 89/WG 10 N95, Determination of Water Absorption Coefficient, 1994-07-07. A commercial software package called TableCurve2 is used for the curve fit. The terminology below is from the package. The equation that represents the relation between x = chamber RH and y = WVT rate is (exponential 1. (mathematics) exponential - A function which raises some given constant (the "base") to the power of its argument. I.e. f x = b^x If no base is specified, e, the base of natural logarthims, is assumed. 2. ) y = a + b exp exp abbr. 1. exponent 2. exponential (-x/c) [r.sup.2], coefficient of determination Coefficient of determination A measure of the goodness of fit of the relationship between the dependent and independent variables in a regression analysis; for instance, the percentage of variation in the return of an asset explained by the market portfolio return. Also known as R-square. = 0.993 fit std error = 1.7E-07 F-value = 965.
90% Confidence
Parameter Value Std Error t-value Limits
a -7.41e-07 2.1e-07 -3.5 -1.12e-06 -3.69e-07
b 7.54e-07 1.9e-07 4.0 4.23e-07 1.08e-06
c -61.2 7.5 -8.1 -74.5 -47.9
From the above statistics, the estimated uncertainty in the derived value of the permeability may be up to 28%. [FIGURE 1 OMITTED] One may find another mathematical expression A group of characters or symbols representing a quantity or an operation. See arithmetic expression. to obtain a better fit to the experimental data than what is shown in Figure 1. For example, a cubic equation an equation in which the highest power of the unknown quantity is a cube. See also: Cubic (such as y = a + bx + c[x.sup.2] + d[x.sup.3]) apparently gives a better fit to the experimental data than that given by the exponential equation Noun 1. exponential equation - an equation involving exponential functions of a variable equation - a mathematical statement that two expressions are equal in Figure 1. However, the first derivative Noun 1. first derivative - the result of mathematical differentiation; the instantaneous change of one quantity relative to another; df(x)/dx derivative, derived function, differential, differential coefficient of this "apparently better fit" results in excursions that, in turn, result in a decrease in the vapor permeability with increasing relative humidity, through a certain range of RH values, below 50%RH. It is difficult to explain such a dependency. Therefore, in the final report of ASHRAE RP-1018, the behavior of the first derivative of the mathematical expression was also taken into account before the mathematical expression was chosen for the derivation derivation, in grammar: see inflection. of the dependency of water vapor permeability of each material on RH. The first derivative of the exponential equation in Figure 1 is free from any excursions. The users of the raw data in tables similar to Tables 4 and 5 have the freedom to choose any analytical expression In mathematics, an analytical expression (or expression in analytical form) is a mathematical expression, constructed using well-known operations that lend themselves readily to calculation. that best fits the experimental data, but they must be cautious about the behavior of the first derivative. Water Absorption Coefficient (5) Five test specimens, 5 cm x 5 cm x 5 cm each, were used in these measurements. Water is maintained at 22 ([+ or -] 1) [degrees]C. The numbers in parentheses in Table 7 give the standard deviations In statistics, the average amount a number varies from the average number in a series of numbers. (statistics) standard deviation - (SD) A measure of the range of values in a set of numbers. . Linear regression Linear regression A statistical technique for fitting a straight line to a set of data points. , using all the data from the first linear part of the absorption process for the five specimens, gives: Water absorption coefficient for the major surfaces = 0.036 [+ or -] 0.002 kg [m.sup.-2] [s.sup.-[1/2]]. Moisture Diffusivity Gamma ray gamma ray Penetrating very short-wavelength electromagnetic radiation, similar to an X-ray but of higher energy, that is emitted spontaneously by some radioactive substances (see gamma decay; radioactivity). method (Kumaran and Bomberg 1985) is used to measure the distribution of moisture in three test specimens, 5 cm x 23 cm x 2.4 cm each, during the moisture uptake through the edge. The principle of the methodology is described by Kumaran et al. (1989). Marchand and Kumaran (1994) reported the procedure used for the data reduction. The running average method that is described by Marchand and Kumaran (1994) gives the characteristic curve shown in Figure 2 for this aerated concrete. Several hundreds of data pairs obtained on the three test specimens, in 36 sets of measurements over a period of seven days are included in the analysis. The moisture diffusivity derived from the above characteristic curve is given in Table 8. The area enclosed en·close also in·close tr.v. en·closed, en·clos·ing, en·clos·es 1. To surround on all sides; close in. 2. To fence in so as to prevent common use: enclosed the pasture. by the characteristic curve in Figure 2 is ~0.033 kg [m.sup.-2] [s.sup.-[1/2]] and this value is very close to the water absorption coefficient = 0.036 kg [m.sup.-2] [s.sup.-[1/2]] that was directly determined. This should be the case, and the correspondence between the two shows the internal consistency In statistics and research, internal consistency is a measure based on the correlations between different items on the same test (or the same subscale on a larger test). It measures whether several items that propose to measure the same general construct produce similar scores. of the two methods. However, the uncertainty in the derived moisture diffusivity is estimated to be as high as 30% to 50%. [FIGURE 2 OMITTED] The diffusivity derived from moisture distribution data during a water uptake process may not quantitatively describe a drying process for all building materials. However, earlier work at the Institute for Research in Construction shows that for a cement-based sheathing board (NRC 2002, Appendix I) and for several OSB OSB abbr. Order of Saint Benedict test specimens under various boundary conditions (Maref et al. 2002) the drying process is reasonably well described using the diffusivity that has been derived from a water uptake process. For the present investigation, two series of drying experiments were conducted on this same aerated concrete. Both series of investigations suggest that the diffusivity determined from a "wetting process" describes the "drying process" with reasonable accuracy. Further details are given in the project's final report (NRC 2002, Appendix II). Air Permeability Bomberg and Kumaran (1986) have reported the principle of the method used in these measurements. Three circular test specimens (thickness of 20.29 mm, 20.56 mm, 20.34 mm), each approximately 15 cm in diameter, are used in these measurements. The measurements are conducted at a temperature = 22 ([+ or -]1)[degrees]C. All data obtained from two series of measurements on each specimen are shown in Figure 3. For the range of pressure differences between 25 Pa and 700 Pa, the flow rate linearly varies with the pressure difference for each test specimen. If each set is independently analyzed, the following three values are obtained for the air permeabilities: 4.2E-09 kg [m.sup.-1] [Pa.sup.-1] [s.sup.-1] with a linear correlation coefficient Correlation Coefficient A measure that determines the degree to which two variable's movements are associated. The correlation coefficient is calculated as: equal to 0.997, 3.0E-09 kg [m.sup.-1] [Pa.sup.-1] [s.sup.-1] with a linear correlation coefficient equal to 0.994, and 7.4E-09 kg [m.sup.-1] [Pa.sup.-1] [s.sup.-1] with a linear correlation coefficient equal to 0.991. [FIGURE 3 OMITTED] The mean of these three values is 4.9E-09 kg [m.sup.-1] [Pa.sup.-1] [s.sup.-1]. From the deviation of each test specimen from this mean value, within a confidence interval confidence interval, n a statistical device used to determine the range within which an acceptable datum would fall. Confidence intervals are usually expressed in percentages, typically 95% or 99%. of 95% (this was the default value that was used for each of the three linear regressions), one may assign (4.9 [+ or -] 2.6) E-09 kg [m.sup.-1] [Pa.sup.-1] [s.sup.-1] for the air permeability of this aerated concrete. OUTCOME OF ASHRAE RESEARCH PROJECT 1018 All applicable test procedures were applied to all the materials listed earlier. A summary of the information generated can be found in Table 9. A "yes" entry in any location in the table indicates the corresponding information has been generated and reported. A "no" entry indicates that the test method was not applicable. This may be due to lack of response or very slow response such that it was not practicable to generate the information. A vacant location indicates that the measurement was not planned in the project proposal. CONCLUDING REMARKS ASHRAE Research Project 1018 has now resulted in a set of information that building physicists were hoping to find readily available. These are documented in the project final report, "A Thermal and Moisture Transport Property Database for Common Building and Insulating Materials, Final Report from ASHRAE Research Project 1018-RP" (NRC 2002). Values for thermal conductivities In physics, thermal conductivity, k, is the intensive property of a material that indicates its ability to conduct heat. It is defined as the quantity of heat, Q, transmitted in time t through a thickness L , water vapor transmission properties, water absorption coefficients, moisture diffusivities from water uptake processes, and airflow characteristics of all materials, if applicable, are uniquely determined for each test specimen that has been investigated in the project. The same cannot be said about the equilibrium moisture contents. The responses shown by most materials were rather slow, and often equilibration equilibration /equi·li·bra·tion/ (e-kwil?i-bra´shun) the achievement of a balance between opposing elements or forces. occlusal equilibration took too long. The number of materials selected for the project for the equilibrium moisture content measurements was too high to be completed within the project's life. So these measurements were not done to the same detail as originally planned. Suction measurement using the pressure plate apparatus needs further investigation before it can be applied to all building materials. Depending on the starting point of saturation--vacuum saturation or capillary saturation through total submersion submersion the act of placing, or the condition of being under, the surface of a liquid. or capillary saturation on partial immersion--one may end up with slightly different equilibrium moisture content at each stage of the measurements. Efforts should be directed toward the development of an international standard to determine equilibrium moisture contents at very high relative humidities, close to saturation. Attempts to directly measure liquid permeabilities are continuing at the Institute for Research in Construction. The experiments to date have proven to be rather tedious and time consuming. No conclusive results are yet available. It is desirable to determine liquid permeabilities of building materials directly. Efforts should also be directed to develop a standard procedure for that purpose. ACKNOWLEDGMENTS The planning, attention, and dedication shown by Mr. John Lackey John Derran Lackey (born October 23, 1978, in Abilene, Texas) is a major league baseball starting pitcher from Abilene, Texas. He has played for the Los Angeles Angels of Anaheim his entire career. , Mrs. Nicole Normandin, Mr. Fitsum Tariku, and Mr. David van Reenen during the course of this work are largely responsible for the success of this project. They jointly performed all the measurements reported here. The only exceptions are some of the measurements on aerated concrete that are chosen as illustrative examples in this paper. Mr. Xiao-chuan Qiu performed some of those measurements under the supervision of either Mr. Lackey or Mrs. Normandin, while he was working at the Institute as a guest worker. Financial support from ASHRAE for this project is gratefully acknowledged. NOMENCLATURE nomenclature /no·men·cla·ture/ (no´men-kla?cher) a classified system of names, as of anatomical structures, organisms, etc. binomial nomenclature A = area, [m.sup.2] [D.sub.w] = moisture diffusivity, [m.sup.2][s.sup.-1] [J.sub.a] = airflow rate across an area, A, kg x [m.sup.-2][s.sup.-1] [J.sub.l] = liquid water flow rate across an area, A, kg x [m.sup.-2][s.sup.-1] [J.sub.v] = water vapor flow rate across an area, A, kg x [m.sup.-2][s.sup.-1] [k.sub.a] = air permeability, kg x [m.sup.-1][s.sup.-1][Pa.sup.-1] [K.sub.a] = air permeance, kg x [m.sup.-2][s.sup.-1][Pa.sup.-1] l = thickness, m M = molar mass, kg x mol[.sup.-1] p = air pressure or water vapor pressure, Pa [p.sub.h] = equilibrium air pressure, Pa Q = heat flow rate across an area, A, W x [m.sup.-2] R = ideal gas constant, J x [mol.sup.-1][K.sup.-1] T = temperature, K u = moisture content, kg x [kg.sup.-1] [[delta].sub.p] = water vapor permeability, kg x [m.sup.-1][s.sup.-1][Pa.sup.-1] [[delta].sub.l] = water vapor permeance for thickness, l, kg x [m.sup.-2][s.sup.-1][Pa.sup.-1] [DELTA] = difference in a physical quantity [lambda] = thermal conductivity, W x [m.sup.-1][K.sup.-1] [phi] = relative humidity, [-] [rho] = density, kg x [m.sup.-3] [[rho].sup.0] = density of dry material, kg x [m.sup.-3] REFERENCES Bomberg, M.T., and M.K. Kumaran. 1986. A test method to determine airflow resistance of exterior membranes and sheathings. Journal of Thermal Insulation The term thermal insulation can refer to materials used to reduce the rate of heat transfer, or the methods and processes used to reduce heat transfer. Heat is transferred from one material to another by conduction, convection and/or radiation. 9:224-35. Bruce, R.R., and A. Klute. 1956. The measurement of soil diffusivity. Soil Science Society of America The Soil Science Society of America (SSSA), is a scientific and professional society of soil scientists, principally in the U.S. but with a large number of non-U.S. members as well. Proceedings 20:251-57. Burch, D.M., W.C. Thomas, and A.H. Fanney. 1992. Water vapor permeability measurements of common building materials. ASHRAE Transactions 98(2):486-94. Descamps, F. 1997. Continuum and discrete modelling Discrete modelling is the discrete analogue of continuous modelling. In discrete modelling, discrete formulae are fit to data. A common method in this form of modelling is to use recurrence relations. of isothermal water and air transfer in porous porous /por·ous/ (por´us) penetrated by pores and open spaces. po·rous adj. 1. Full of or having pores. 2. Admitting the passage of gas or liquid through pores. media. PhD thesis, Katholieke University-Leuven, pp. 57-107. Hansen, M.H. 1998. Retention curves measured using pressure plate and pressure membrane. Nordtest Technical Report 367, Danish Building Research Institute, p. 63. Hansen, K.K. 1986. Sorption isotherms A sorption isotherm is a stochastic model of the sorption behaviour of a chemical entity which depicts the partitioning between sorbed phase and dissolved phase. See also
Hansen, K.K., and H.B. Lund. 1990. Cup method for determination of water vapor transmission properties of building materials. Sources of uncertainty in the method. Proceedings of the 2nd Symposium, Building Physics in Nordic Countries, pp. 291-98. Hens, H. 1996. Heat, air and moisture transport. Final report, Vol 1, Task 1: Modelling. International Energy Agency Annex 24, Laboratorium Bouwfysica, Katholieke University-Leuven, Belgium. Kumaran, M.K. 1996. Heat, air and moisture transport. Final report, Vol 3, Task 3: Material properties. International Energy Agency Annex 24, Laboratorium Bouwfysica, Katholieke University--Leuven, Belgium. Kumaran, M.K. 1998. An alternative procedure for the analysis of data from the cup measurements for determination of water vapor transmission properties. Journal of Testing and Evaluation 26:575-81. Kumaran, M.K. 1999. Moisture diffusivity of building materials from water absorption measurements. Journal of Thermal Envelope and Building Science 22:349-55. Kumaran, M.K., and M.T. Bomberg. 1985. A gamma-spectrometer for determination of density distribution and moisture distribution in building materials. Moisture and Humidity: Measurements and Control in Science and Industry: Proceedings of International Symposium, pp. 485-90. Kumaran, M.K., G.P. Mitalas, R. Kohonen, and T. Ojanen. 1989. Moisture transport coefficient of pine from gamma ray measurements. Collected Papers in Heat Transfer, ASME ASME - American Society of Mechanical Engineers Heat Transfer Division 123:179-83. Lackey, J.C., R.G. Marchand, and M.K. Kumaran. 1997. A logical extension of ASTM Standard E96 to determine the dependence of water vapor transmission on relative humidity. In ASTM STP STP or standard temperature and pressure, standard conditions for measurement of the properties of matter. The standard temperature is the freezing point of pure water, 0°C; or 273.15°K;. 1320, Insulation Materials: Testing and Applications, R.S. Graves and R.R. Zarr, eds., vol. 3, pp. 456-70. West Conshohocken, PA: American Society for Testing and Materials. Marchand, R.G., and M.K. Kumaran. 1994. Moisture diffusivity of cellulose insulation. Journal of Thermal Insulation and Building Envelopes 17:362-37. Maref, W., M.K. Kumaran, M.A. Lacasse, M.C. Swinton, and D. van Reenen. 2002. Laboratory measurement and benchmarking of an advanced hygrothermal model. Proceedings of the 12th International Heat Transfer Conference, Grenoble, France, pp. 117-22. NRC. 1999. A thermal and moisture transport property database for common building and insulating materials--1018-RP. NRC Canada Client Report to ASHRAE, No. B-1115.3. National Research Council Canada, Ottawa. NRC. 2000. Thermal and moisture transport property database for common building and insulating materials--1018-RP. NRC Canada Client Report to ASHRAE, No. B-1115.9. National Research Council Canada, Ottawa. NRC. 2002. A thermal and moisture transport property database for common building and insulating materials, Final Report from ASHRAE Research Project RP-1018. NRC Canada Client Report, No. B-1115.13. National Research Council Canada, Ottawa. Pel, L. 1995. Moisture transport in porous building materials. PhD thesis, Eindhoven University of Technology The Eindhoven University of Technology (in Dutch: Technische Universiteit Eindhoven or TU/e, and formerly Technische Hogeschool Eindhoven or THE) is a university of technology located in Eindhoven, the Netherlands. , The Netherlands, pp. 47-80. Richards, R.F., D.M. Burch, and W.C. Thomas. 1992. Water vapor sorption measurements of common building materials. ASHRAE Transactions 98(2):475-85. Tveit, A. 1966. Measurements of moisture sorption and moisture permeability of porous materials. Report 45, Norwegian Building Research Institute, Oslo. Trechsel, H. R., ed. 1994. Manual on Moisture Control in Buildings. ASTM Manual Series: MNL MNL Manual MNL Miller Nichols Library MNL Maatschappij der Nederlandse Letterkunde MNL Monday Night Live (call-in sports show) MNL Media Net Link, Inc. 18:35-53. Philadelphia: American Society for Testing and Materials. Trechsel, H.R., ed. 2001. Moisture Analysis Moisture analysis covers a variety of methods for measuring moisture content in both high level and trace amounts in solids, liquids, or gases. Moisture in percentage amounts is monitored as a specification in commercial food production. and Condensation Control in Building Envelopes. ASTM Manual Series: MNL 40:29-65, 161-183. Philadelphia: American Society for Testing and Materials. Mavinkal K. Kumaran, PhD Mavinkal K. Kumaran is a principal research officer in the Heat and Moisture Performance of Envelopes group, Institute for Research in Construction, National Research Council Canada, Ottawa, Ontario. (1). When this method was applied to membranes, the membranes were put in perfect hygric contact with a substrate such as OSB. (2). In the hygroscopic range, the measurements are done using the proposed procedure for ASTM Standard C1498, which in turn is based on CEN 89 N 337 E "Hygroscopic Sorption Curve"; at the higher range, the pressure plate method is used. Details of the pressure plate method are given in Hansen (1998), page 63. (3). Measurements are done as described in Lackey et al. (1997). (4). The analysis is done as for plywood as described in Kumaran (1998). (5). The procedure used is based on CEN/TC 89/WG 10 N95, Determination of Water Absorption Coefficient, 1994-07-07.
Table 1. Thermal Conductivity of Aerated Concrete
Specimen Hot Surface Cold Surface
Thickness Temperature Temperature Conductivity
mm [degrees]C [degrees]C W [m.sup.-1] [K.sup.-1]
24.24 31.51 9.75 0.121
24.24 11.45 -2.44 0.119
Table 2. Sorption Data for Aerated Concrete
Moisture Content, kg
RH, % Temperature, [degrees]C [kg.sup.-1]
100, vacuum saturation Lab at 22 (1) 1.720(0.01), eight
specimens
88.1 (1) 23.0 (0.1) 0.050 (0.002), three
specimens
71.5 (1) 23.0 (0.1) 0.021 (0.001), three
specimens
0.6 (1) 23.0 (0.1) 0.011 (0.001), three
specimens
Table 3. Desorption Data for Aerated Concrete
RH, % Temperature, [degrees] C Moisture Content, kg [kg.sup.-1]
99.99 (0.01) Lab at 22 (1) 0.92 (0.13), eight specimens
99.98 (0.01) Lab at 22 (1) 0.81 (0.09), eight specimens
99.96 (0.01) Lab at 22 (1) 0.77 (0.07), eight specimens
99.93(0.01) Lab at 22 (1) 0.75 (0.06), eight specimens
99.85 (0.01) Lab at 22 (1) 0.72 (0.05), eight specimens
99.78(0.01) Lab at 22 (1) 0.70 (0.05), eight specimens
99.71 (0.01) Lab at 22 (1) 0.68 (0.04), eight specimens
99.47 (0.01) Lab at 22 (1) 0.64 (0.04), eight specimens
99.34(0.01) Lab at 22 (1) 0.61 (0.02), eight specimens
99.19(0.01) Lab at 22 (1) 0.57 (0.02), eight specimens
98.97(0.01) Lab at 22 (1) 0.54 (0.02), eight specimens
88.1 (1) 23.0 (0.1) 0.063 (0.001), three specimens
71.5 (1) 23.0 (0.1) 0.022 (0.001), three specimens
50.6 (1) 23.0 (0.1) 0.011 (0.001), three specimens
Table 4. Dry Cup Measurements on Aerated Concrete Specimens*
WVT Rate
Specimen Thickness Chamber RH Chamber Temperature kg [m.sup.-2]
mm % [degrees]C [s.sup.-1]
20.11 50.6 (1) 22.9 (0.1) 1.09E-06 (5.5E-09)
20.56 50.6 (1) 22.9 (0.1) 1.14E-06 (5.6E-09)
20.44 50.6 (1) 22.9 (0.1) 1.03E-06 (4.0E-09)
20.11 71.5 (1) 22.7 (0.1) 1.69E-06 (6.0E-09)
20.56 71.5 (1) 22.7 (0.1) 1.79E-06 (3.3E-09)
20.44 71.5 (1) 22.7 (0.1) 1.63E-06 (5.3E-09)
20.11 88.1 (1) 23.3 (0.1) 2.18E-06 (6.5E-09)
20.56 88.1 (1) 23.3 (0.1) 2.30E-06 (4.4E-09)
20.44 88.1 (1) 23.3 (0.1) 2.23E-06 (5.6E-09)
* The numbers in parentheses indicate the experimental uncertainties for
RH and temperature and standard errors for WVT rate, obtained from
statistical analyses of the data at a steady state.
Table 5. Wet Cup Measurements on Aerated Concrete Specimens*
WVT Rate
Specimen Thickness Chamber RH Chamber Temperature kg [m.sup.-2]
mm % [degrees]C [s.sup.-1]
20.29 71.7 (1) 22.7 (0.1) 1.30E-06 (1.7E-08)
20.34 71.7 (1) 22.7 (0.1) 1.40E-06 (1.4E-08)
20.11 71.7 (1) 22.7 (0.1) 1.49E-06 (1.5E-08)
20.29 87.8 (1) 23.2 (0.1) 1.13E-06 (1.5E-08)
20.34 87.8 (1) 23.2 (0.1) 9.60E-07 (1.0E.08)
20.11 87.8 (1) 23.2 (0.1) 9.69E-07 (1.0E.08)
* The numbers in parentheses indicate the experimental uncertainties for
RH and temperature and standard errors for WVT rate, obtained from
statistical analyses of the data at a steady state.
Table 6. Dependence of Water Vapor Permeability of Aerated Concrete on
Relative Humidity
Permeability, kg [m.sup.-1] Permeability, kg [m.sup.-1]
RH, % [s.sup.-1] [Pa.sup.-1] RH, % [s.sup.-1] [Pa.sup.-1]
10 1.12E-11 60 2.76E-11
20 1.33E-11 70 3.34E-11
30 1.59E-11 80 4.07E-11
40 1.91E-11 90 5.00E-11
50 2.29E-11 100 6.21E-11
Table 7. Water Absorption Data for Aerated Concrete
Square Root of time, Water Absorption
[s.sup.1/2] kg [m.sup.-2]
7.75 0.93 (0.13)
13.42 1.24 (0.17)
17.32 1.41 (0.21)
24.49 1.73 (0.25)
30.00 1.96 (0.29)
38.73 2.29 (0.34)
45.83 2.55 (0.37)
54.77 2.87 (0.44)
64.81 3.20 (0.47)
73.48 3.48 (0.53)
81.24 3.71 (0.56)
91.65 4.05 (0.62)
101.00 4.31 (0.69)
Table 8. The Dependence of Moisture Diffusivity of Aerated Concrete on
Moisture Content
Diffusivity
Moisture Content Diffusivity Moisture Content [m.sup.2]
kg [kg.sup.-1] [m.sup.2] [s.sup.-1] kg [kg.sup.-1] [s.sup.-1]
0.087 8.72E-09 0.326 3.44E-09
0.109 5.47E-09 0.348 3.64E-09
0.130 4.32E-09 0.370 3.91E-09
0.152 3.76E-09 0.391 4.29E-09
0.174 3.44E-09 0.413 4.81E-09
0.196 3.26E-09 0.435 5.56E-09
0.217 3.16E-09 0.457 6.71E-09
0.239 3.12E-09 0.478 8.71E-09
0.261 3.13E-09 0.500 1.30E-08
0.283 3.19E-09 0.522 2.89E-08
0.304 3.29E-09 0.543 5.15E-08
Table 9. Matrix Showing Available Information from ASHRAE RP-1018
Vapor
Thermal Permeability/ Sorption/
Material Conductivity Permeance Desorption
Clay Brick Yes Yes Yes
Aerated Concrete Yes Yes Yes
Mortar Yes Yes Yes
Stucco Yes Yes Yes
EIFS (Base & Finish No Yes No
Coat)
Composite Wood Siding Yes Yes Yes
Limestone Yes Yes Yes
OSB-1 Yes Yes Yes
OSB-2 Yes Yes Yes
OSB-3 Yes Yes Yes
Plywood-1 Yes Yes Yes
Plywood-2 Yes Yes Yes
Plywood-3 Yes Yes Yes
Woodfiber Board Yes Yes Yes
Fibercement Board Yes Yes Yes
Cementitious Board Yes Yes Yes
Spun Bonded Yes
Polyolefin-1
Spun Bonded Yes
Polyolefin-2
#15 Felt Yes
10 min Paper Yes
30 min Paper Yes
60 min Paper Yes
Glassfiber Batts Yes Yes Yes
Cellulose Fiber Yes Yes Yes
Expanded Polystyrene Yes Yes Yes
Extruded Polystyrene Yes Yes Yes
Spray Polyurethane Yes Yes Yes
Polyisocyanurate Yes Yes Yes
Low-Density Foam Yes Yes Yes
Spruce Yes Yes Yes
Eastern White Pine Yes Yes Yes
Southern Yellow Pine Yes Yes Yes
Eastern White Cedar Yes Yes Yes
Western Red Cedar Yes Yes Yes
Interior Gypsum Yes Yes Yes
Vinyl Wall paper Yes
Primer Yes
Paint Yes
Air
Moisture Permeability/ Absorption
Material Suction Diffusivity Permeance Coefficient
Clay Brick Yes Yes Yes Yes
Aerated Concrete Yes Yes Yes Yes
Mortar Yes Yes Yes Yes
Stucco Yes Yes Yes Yes
EIFS (Base & Finish No No Yes No
Coat)
Composite Wood Siding No Yes Yes Yes
Limestone Yes No Yes Yes
OSB-1 Yes Yes Yes Yes
OSB-2 Yes Yes Yes Yes
OSB-3 Yes Yes Yes Yes
Plywood-1 Yes Yes Yes Yes
Plywood-2 Yes Yes Yes Yes
Plywood-3 Yes Yes Yes Yes
Woodfiber Board Yes Yes Yes Yes
Fibercement Board Yes Yes Yes Yes
Cementitious Board Yes Yes Yes Yes
Spun Bonded Yes Yes
Polyolefin-1
Spun Bonded Yes Yes
Polyolefin-2
#15 Felt Yes Yes
10 min Paper Yes Yes
30 min Paper Yes Yes
60 min Paper Yes Yes
Glassfiber Batts Yes
Cellulose Fiber Yes Yes
Expanded Polystyrene Yes
Extruded Polystyrene Yes
Spray Polyurethane Yes
Polyisocyanurate Yes
Low-Density Foam Yes
Spruce Yes Yes Yes Yes
Eastern White Pine Yes Yes Yes Yes
Southern Yellow Pine Yes Yes Yes Yes
Eastern White Cedar Yes Yes Yes Yes
Western Red Cedar Yes Yes Yes Yes
Interior Gypsum No Yes Yes Yes
Vinyl Wall paper Yes Yes
Primer Yes Yes
Paint Yes Yes
|
|
||||||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion