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moisture vapor permeability of roofing materials /membrane

moisture vapor permeability of roofing materials /membrane
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moisture vapor permeability of roofing materials /membrane - 1

Intelligent Measurement of Water Vapor Transmission Rate of Exterior Building Materials Abstract With increasing focus on energy efficient and sustainable building envelopes, the need to define the heat-air-moisture transport (hygrothermal) properties of building materials accurately cannot be overemphasized. New techniques have been evolving and being examined for this purpose. The Modified Cup Method is one such technique to determine the water vapour transmission properties of building materials. This paper uses C360M Water Vapor Transmission Rate Test System to test the water vapor transmission rate of an exterior wall coating, and introduces the test principle, test instrument specifications, application scope, and test procedure, in hope to provide a reference for further studies on water vapor permeability of building materials. Keywords: water vapor transmission rate, water vapor permeability Tester, water vapor transmission rate test system, cup method, gravimetric method, coatings, building materials, moisture permeability Good waterproof is a basic property of exterior wall coatings for buildings. When there is a humidity difference between the two sides of the wall, water vapor will permeate through the wall from high humidity side to low humidity side, resulting in the moisture transfer in the wall. In addition, if the permeability of building materials is poor, the rain or snow water leak into the interior of the wall through the cracks, while the moisture in the wall cannot permeate outward, it will lead to the increase of water content in the wall, erode the wall and the insulation layer structure, and affect the durability, safety and insulation function of the wall. At the same time, water vapor in the wall may condense and freeze which will affect the strength of the material and cause a certain extrusion effect on the material, resulting in wall hollowing, shedding, cracking, mildew and other quality problems. Therefore, the external wall coating should be able to discharge the water vapor in the wall in time. Test sample

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moisture vapor permeability of roofing materials /membrane - 2

We take an exterior bu n uilding coatin as test sa ng ample in this study. The tests were done s e follo owing the pr rocedure out tlined in AS STM E96 – Standard Te Methods for Water Vapor est V Tran nsmission of Materials. The instrumen we used is Labthink newly launch C360M Water T nt n hed W Vapo Transmissi Rate Test System. or ion t Figure 1 C3 360M Water V Vapor Transm mission Rate Test System Sum mmary of Te Methods est The method described in ASTM E96 is cup metho also name as gravime d n od, ed metric method. The wate vapor trans er smission can be determin by calcula ned ating the...

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moisture vapor permeability of roofing materials /membrane - 3

unifo form thicknes and be fre of wrinkle creases or other visib imperfect ss ee es, o ble tions. Identify the fy perm meating direct tion of the test and mark t permeatin direction on the test spe the ng o ecimen. Gene erally the w water vapor p permeates from the outside in. e (2) Then m mount the spe ecimen in sp pecific order and the test specimen sh hould be flat and t clam mped within t test dish. The test dish should be ke in horizon level and add water to 2/3 the h ept ntal d of th whole test dish. Do not splash water drop on the screws. The test dish and the O-ring sh he r t hould...

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moisture vapor permeability of roofing materials /membrane - 4

(5) View the e test results and reports . If necessary y, repeat the above proce edures to per rform anot ther round of f tests. Test Results t The average water vapor rate of the co e r oatings tested in this pape is 137.8 g/( d er (m2 24h) from six m samp ples. Con nclusion Water vapor transmission rate is an important pe r erformance in ndex of exter rior building wall coat tings. We use an intellig ed gent way to d determine the water vapor transmissio of the sam e r on mples. d n he utomatically carried out by the instrume in c y ent The weighing and permeation process of th test are...

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moisture vapor permeability of roofing materials /membrane - 5

the end of the test based on it. It does not need the frequent intervention by the test operator, avoids human interference, improves the efficiency and reduce labor intensity. The test temperature, humidity and air velocity in the test chamber can be adjusted and controlled automatically, the accuracy and stability of the test is high. Labthink Instruments Co., Ltd, is dedicated to providing customers with packaging testing solutions and helping the manufacturers to reach their goals of quality and safety assurance through improvement of packaging testing techniques and development of...

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