NATURAL HISTORY BUILDING 83 



Pipe connections and radiators. — The hot water distribution pipe, 

 8 inches in diameter where it leaves the heaters, passes through a 

 flue at the west end of the east wing directly to the attic. It there 

 branches in three directions, one branch supplying the entire south 

 side of the building, another the north side of the east wing, and the 

 third the remainder of the building. To decrease the friction in the 

 pipes they are greatly increased in size on reaching the attic. Con- 

 nected with these mains are 130 drops located in pier chases of the 

 outer and court walls, these pipes being mostly 1| inches in diameter, 

 although a few are only 1| inches. 



There are four radiators on each drop, one for each of the four 

 stories, except in the east wing where there are only three, the ground 

 story being otherwise heated. ^Vlierever possible radiators have been 

 placed under or at the base of the windows, with two connections to 

 the drop, both at the same end of the radiator. To compel the passage 

 of water through the radiators the connections to the drops have 

 been made as large as, and in some cases larger than, the drops them- 

 selves, and long turned fittings have been used, joined in such a way 

 as to secure the least possible friction to the flow of water to the 

 radiators. The radiators are furnished with Norwall packless radia- 

 tor valves of the globe pattern. 



The drops are connected to hot water mains in the tunnels under 

 the ground floor in a manner similar to the connections in the attic. 

 These mains, which return the water to the circulating pumps, are 

 run along the ceiling of the tunnels and brought together into a 10- 

 inch main near the pumps. To allow for expansion of the mains, 

 loops are located both in the attic and in the tunnels, thus obviating 

 the use of expansion joints. The drops are provided with valves in 

 the same places, and also with drain cocks in the tunnels so that any 

 drop can be separately drained without disturbing the system. The 

 attic valves are of the lock shield type opening by means of a key, 

 which prevents their being tampered with. The mains in the attic 

 and tunnels are likewise supplied with valves so disposed that differ- 

 ent sections of the building can be cut out of service, an arrangement 

 found necessary for the proper adjustment and convenient operation 

 of the entire heating s3^stem. 



The radiators used in the new building are of the Peerless type; 

 they range in height from 22 to 38 inches, and are two and three 

 columns. Their length varies according to location, and some of 

 those in the main exhibition halls, where they occupy the full width 

 of the window surface, consist of as many as 50 sections. The total 

 number installed is about 465, furnishing approximately 70,000 

 square feet of direct and 3,000 square feet of indirect radiation 

 surface. 



Heating of ground stoiy of east wing. — For heating the ground 

 story of the east wing, in which the mechanical plant is located, the 



