Abstract: In many cases snow loads constitute the largest design load for the roof system. A careful assessment of the snow load is required, therefore, to avoid both unnecessary construction costs and undue risk of failure.
Abstract: Some of the more important properties of bitumens are examined in this Digest. Particular mention is made of the adhesive, waterproofing and flow characteristics that control the use to which bitumens are placed in construction. An outline is also given of the various bitumens and the manner in which they are used.
Abstract: Solar heat gain can be substantially reduced by orienting a building so that there is a minimum of glass in the east and west facades. Solar heat gain through south facing windows can be controlled during the summer by outside shades or by tilting; if they are double glazed such windows do not increase the energy requirements for heating in the southern part of Canada. Heat gain in the east or west facades can be reduced by using double glazing. Finally blinds can be used to reduce solar heating.
Abstract: It is only recently that scientific studies have been undertaken to explain the mechanisms of rain penetration. Through better understanding of these mechanisms it should be possible to design and construct walls from which the problem is virtually eliminated.
Abstract:Walls and roofs designed today often incorporate details that have a lower resistance to heat flow than the main construction. In general, these details are thermally weak because high-conductivity structural elements project partly or wholly through materials of lower conductivity; in this Digest they are referred to as "thermal bridges". To provide a basis for recognizing and minimizing the problems presented by thermal bridges, this Digest deals with a few examples and illustrates factors that influence their thermal performance.
Abstract: It is recognized that factors other than flammability of lining materials -- ventilation, the nature and distribution of the contents and geometry of a compartment -- can materially affect the development of a fire. When these are equal, however, fire will develop more rapidly in the compartment having the more flammable lining. The selection of materials for the interior linings of buildings is therefore an important consideration; it affects not only the safety of property but also the safety of the occupants. The hazard exists, as well, for those in other areas who may be trapped by a rapidly spreading fire.
Subject: flame spread; fire compartments; flame spread ratings; building codes : Flame spread
Canadian Building Digest; no. CBD-45, ISSN: 0008-3097, Publication date: 1963-09
Abstract: Interior surface temperatures at the edges of sealed double- glazing units are lower than those of many conventional double window arrangements, and the building humidities that can be carried without excessive condensation on these surfaces are correspondingly lower. They must be sealed initially with dry air between the panes, and in spite of the stresses imposed by service conditions must retain the seal over their required service life. Units can fail by either breakage or condensation and the scumming that results from excessive moisture gain. On the other hand, sealed glazing units have advantages in the elimination of storm sash, reduction of surfaces that need cleaning to two, and prevention of condensation between panes. These may often outweigh the potential problems in their use.
Abstract: The maximum temperature of the outer surface of any building depends mainly on its colour and orientation. The colour and proximity of neighbouring surfaces also have a significant effect on surface temperature. Analysis has shown that dark roof surfaces may reach temperatures of the order of 230 degrees F in summer and fall a few degrees below the minimum air temperature in winter. It is important, therefore, to be sure that any proposed roofing system with a dark surface can operate satisfactorily at temperatures varying between -50 and 230 degrees F. If a light coloured surface is used to reduce the maximum temperature it is important to be sure that the surface will retain a low value of short-wave absorptivity over its entire service life. The maximum temperature for a wall surface is between 140 and 190 degrees F, depending on colour and proximity to reflecting surfaces. If external shading devices are used they should have a dark surface that will absorb the radiation incident on them rather than reflect it onto adjacent wall or window surfaces. It is important, however, not to darken the colour of an outer surface until it has been established that its new shade will not cause the temperature of the wall materials to exceed their allowable values.
Abstract: Durable walls can be achieved by judicious selection of materials to suit the environment, by modification of the environment to suit the materials available, or by a combination of both. Such manipulation, however, requires an understanding of the pertinent properties of materials and the phenomena that operate within walls.