| 摘要 |
<p>A building component with a passage right through it is of of plaster and, at one open end, has a surrounding depression or seating, the outer face of which is parallel to the outer face, of the component. This seating continues into the internal cavity. At the opposite open end there is a peripheral strip or spigot, the inner face of which is in continuous alignment with the internal passage. The pref. density is 0.9-1.3 kg/dm3, the pref. compressive strength 60-160 kp/cm2, and the pref. bending tensile strength 20-60 kg/cm2. For use as a building block for forming a ventilation duct for multi-storey blocks of flats or other residential buildings, esp. for forced ventilation of kitchens and sanitary rooms. The components can be mounted one upon another like building blocks to form the duct and, because of their smooth external face, require no further rendering but can immediately be painted or wall-papered.</p> |
