Document GKYmZNO5QzpdVYwBZbn5yxdON

American Society of Heating and Ventilating Engineers Guide, 1936 A complete study of all of the factors involved in air movement through I : building constructions would be very complex. Some of the complicating factors are: the variations in wind velocity and direction; the exposure of i the building with respect to air leakage openings and with respect to I adjoining buildings; the variations in outside temperatures as influencing | Jthe chimney effect; the relative area and resistance of openings on the windward and leeward sides and on the lower floors and on the upper S floors; the influence of a planned air supply and the related outlet vents- I and the variation from the average of individual building units. A study | of infiltration points to the need for care in the obtaining of good building | construction, or unnecessarily large heat losses will result. :! Chapter 6--Air Leakage AIR LEAKAGE THROUGH WALLS | Table 1 gives data on infiltration through brick and frame walls. The I brick walls listed in this table are walls which show poor workmanship | and which are constructed of porous brick and lime mortar. For good 1 workmanship, the leakage through hard brick walls with cement-lime f : mortar does not exceed one-third the values given. These tests indicate I : that plastering reduces the leakage by about 96 per cent; a heavy coat of | , cold water paint, 50 per cent; and 3 coats of oil paint carefully applied, 5 28 per cent. The infiltration through walls ranges from 6 to 25 per cent | ; of that through windows and doors in a 10-story office building, with | s imperfect sealing of plaster at the baseboards of the rooms. With perfect J : sealing the range is from 0.5 to 2.7 per cent or a practically negligible j qseuaalinntgitya,twthh.eich.bain.sdeibcoaaterds.. t.heI.ti.mw.pilol.rtbaencneotoefd-gIo-roodmw-otarkb-ml-ean1s, htihpaitn proper the m- Iff ; filtration through properly plastered walls can be neglected. Fa : Table 1. Infiltration through Walls Expressed in cubic feet Per square foot per hour* Type of Wall 5 8Hin. Brick Wall \ {plastered."! 1.75 0.017 Wind Velocity, Miles per Hour 10 is , 20 25 30 4.20 7.85 12.2 18.6 22.9 0.037 0.066 0.107 0.161. 0.236 \ t s 13 in. Brick Wall------- 1.44 3.92 7.48 1116 16.3 21.2 0.005 0.013 0.025 0.043 0.067 0*197 t. Frame Wall, with lath and piaster*1 0.03 0.07 0.13 0.18 0.23 ! 0.26 The values given in this table are 20 per cent less than test values to allow for building up of pressure in rooms and are based on test data reported in the papers listed p. 140. bWall construction: Bevel siding painted or cedar shingles, sheathing, building paper, wood lath and 3 coats gypsum plaster. 132 ). Fig. 1. Infiltration through Various Types of Shingle Construction The value of building paper when applied between sheathing and shingles is indicated by Fig. 1, which represents the effect on outside construction only, without lath and plaster. The effectiveness of plaster properly applied is no justification for the use of low grade building paper or of the poor construction of the wall containing it. Not only is it difficult to secure and maintain the full effectiveness of the plaster but also it is highly desirable to have two points of high resistance to air flow with an air space between them. a: $ ? iHfiLTffAirott m C.F.H. PER Sp. Ft. or WALL Fig. 2. Infiltration through Single Surface Walls Used in Farm and Other Shelter Buildings