170 POWER-HOUSE DESIGN 



before using. Fresh or quick-setting cement may heat enough 

 while setting to cause expansion and distortion of large castings. A 

 record of the grout and room temperature should be taken as a check. 



Floors. No combustible material of any kind should, if pos- 

 sible, be used in the construction of a power-house. As the sub- 

 structure of the building is generally built of concrete it is but 

 natural that the floors should also be of concrete. A dark color is 

 preferable so as to render drops of oil inconspicuous. Tile or mosaic 

 floors are possibly the best floor finish for a generating room. It is 

 smooth, easy to keep clean and has a very handsome apperance 

 if made to conform with the general interior finish of the station. 



Walls. The walls may be either of reinforced concrete con- 

 struction or of brick with a steel skeleton framework. Where 

 future extensions are contemplated a false wall is provided on one 

 end of the building. The interior should be kept as light as pos- 

 sible, and it is therefore advisable to apply a smooth surface of 

 cement plaster and whitewash or paint the same. For more 

 important stations the walls may be faced with pressed brick and 

 up from the floor to about 10 feet with enameled brick. Where 

 the extra expense is warranted, the walls may be entirely lined 

 with enameled brick and a wainscoting of contrasting color, 

 preferably olive-green. 



Roof. The roof of the building should always be supported 

 on the steel trusses, carried on the side of the walls or on the 

 steel columns. The slope should not be excessive, 2 inches per 

 foot being sufficient with gravel covering. This construction 

 requires less material, and is advantageous when the transmission 

 wires are to enter the station through roof entrance bushings, 

 or where the lightning arrester horns are to be installed on the roof. 



The roof covering may simply consist of boards covered with 

 roofing paper, tar and gravel. Reinforced concrete is some- 

 times used in place of boards so as to make an absolutely fireproof 

 construction. Roofs covered with red tile are often used and 

 present a very pleasing appearance. Corrugated iron roofs are, 

 however, objectionable due to the liability of moisture condensing 

 on the inner surface and dripping into the station. They may 

 also cause the station to be extremely hot in the summer unless an 

 insulating lining is provided below the roof trusses to keep out the 

 heat. This, however, is objectionable and corrugated iron roofs 

 are therefore seldom used for power-houses. For tile or metal 



