HEAVY TIMBER 



early part of the nineteenth century, but no great prominence 

 was given to this particular type of structure until the owners 

 of a large number of these mills formed an organization about 

 the year 1835 for the mutual protection of their property from 

 damage by fire. The outgrowth of this primary organization 

 was the formation of the Associated Factory Mutual Fire In- 

 surance Companies. 



The results of the combined interests of the factory owners 

 were shown in the recommendation of a standard type of mill 

 building which had proved its value not only through per- 

 manence, but also by its fire-resisting qualities. City building 

 ordinances at the present time model their requirements for 

 buildings of the mill construction type largely upon the orig- 

 inal suggestions of these mutual insurance companies. 



An instance of the durability of timber in properly built 

 mill construction buildings is shown in the Warner mill in 

 Newburyport, Mass. In this building heavy timber girders 

 45 feet long and spanning three bays have carried their load 

 since the early 50's without signs of failure, and are said to 

 be in as good condition today as when installed. While girders 

 of this length are not common at the present time and shorter 

 lengths are used for the same purpose, this instance shows the 

 dependence which may be put in mill construction when prop- 

 erly selected timber of a high quality is used. 



What Mill The marked success of early heavy timber 



Construction structures of the mill construction type led to 

 Means Today the popular use of this form of construction 

 in practically all kinds of large buildings. As 

 its use developed, new problems arose which made necessary 

 a departure from the original designs. This variation to suit 

 the case in hand finally resulted in three general classes of 

 framing, each commonly referred to by builders as mill con- 

 struction. These classes have certain basic points in common, 

 such as heavy timber, brick, stone, or concrete walls; stairways 

 and elevators enclosed in fireproof shafts or towers ; floors with 

 no openings or with all openings protected by fireproof covers ; 

 each floor or room isolated by means of automatic fireproof 

 doors or fire walls; windows protected by shutters or by the 

 use of wire glass ; sprinkler equipment, etc. 



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