located in the basement of the Bourne Addition 

 Building about 60 feet west of the old engine room 

 and connected to it by means of a pipe passage, as 

 indicated on the accompanying plan. 



These boilers are equipped with superheaters 

 and a balanced draft system, the blower of which is 

 located north of boiler No. 5, as shown. 



From this blower, indicated by the number 8 

 on the boiler-room plan, is run the main balanced 

 draft duct (marked 10) at the rear of the boilers, 

 with a number of branch ducts extending to the 

 bridge wall of each boiler, as indicated by the dotted 

 lines. The advantages of this balanced draft system 

 are described in detail farther on ; incidentally, it helps 

 to keep down the temperature of the boiler room, 

 which is one of the coolest in the city. 



There is an overhead smoke breeching at the 

 rear of the boilers, marked 6 on the plan, extend- 

 ing to the steel smokestack, marked 7, located in 

 the northwest corner of the building. An air space 

 has been left around the stack, between it and the 

 surrounding brickwork, from the basement to the 

 roof, for ventilating the boiler room. 



Above the roof the stack has been carried over 

 to the north and combined with that of the City 

 Investing Building, an unusual procedure, never 

 before attempted, as far as the writer knows. The 

 results have been very satisfactory. 



There are installed in the new boiler room two 

 feed pumps; a feed- water meter; a blow-off tank 

 located in a sump, with electrical drain pump; an 

 overhead coal trolley with scales; a ventilating blower, 

 and underground vacuum ash conveyer pipes. 



These, marked 21 on the plan, consist of a main, 

 extra-heavy wrought iron pipe, with branches ex- 

 tending to a series of cast iron boxes, with remov- 

 able strainer covers. There are three of these 

 located in the floor just in front of each boiler, so 

 that the ashes may be raked directly into them; and 

 one between each pair of boilers, for drawing off the 

 soot at the side clean-out doors. 



The new boiler room is connected to the engine 

 room by means of a 12- inch high-pressure steam main, 

 extending from the rear of the boilers through the pipe 

 gallery to the engine room, along the westerly wall 

 of the latter (where the connections to the new engines 

 are taken off), thence to the front of the building and 

 back to the boiler room, thus making a complete 

 circuit. 



This main is marked 22 on the plan. 



Parallel to the 12-inch main over the boilers is 

 located a 6-inch auxiliary main. This is likewise 

 run through the pipe gallery to the engine room and 



branches to the pumps, compressors, heating main 

 and various minor appurtenances. 



After the new boiler plant had been placed in com- 

 mission the old boilers were removed, thereby making 

 room for one of the new engines and generators and 

 the new pumping plant. At the same time the 

 erection of an extension at the rear of the Bourne 

 Building afforded opportunity for installing another 

 of the new engine-generator units. In this manner 

 the old units were gradually replaced. 



The new power plant consists of five units com- 

 posed of three simple and two compound Ball & 

 Wood engines, coupled with Diehl generators, ag- 

 gregating 1,400 kilowatts' capacity. A detailed de- 

 scription of them will be found in succeeding pages. 

 They occupy the entire space of what was originally 

 the Bourne Building engine and boiler room, with a 

 rear extension. Four of them are placed in a straight 

 line, leaving a large open space in front of the main 

 switch board, as will be seen by referring to the plan. 

 Opposite the switch board is placed the steam-gauge 

 board. A generous amount of space is left around 

 each unit; as a result the building has one of the most 

 imposing engine rooms in the city. 



The engine and generator foundations are built 

 of armored concrete, designed, with considerable 

 ingenuity, so as to avoid the old grillage foundations 

 under the columns of the Bourne Building. 



The leads from the generators to the switch 

 board consist of lead armored cables in underground 

 iron conduits. 



Each steam connection from the 12-inch main to 

 the engines is equipped with a steam separator to 

 insure the delivery of dry steam. These separators 

 are described in detail farther on. A 10-inch and an 

 18-inch exhaust main are run under the engine-room 

 floor, east of the engines, with an underground con- 

 nection to each. These two mains are combined 

 into a 20-inch pipe marked 26 on the plan, from 

 which a branch was passed through the feed-water 

 heater, located in the pump room, east of the engine 

 room. In this heater a portion of the exhaust 

 steam is utilized for heating the boiler feed water, 

 which is pumped through it from the suction tanks 

 to the boilers by the boiler-feed pumps. 



The 20-inch exhaust main is run in the form of a 

 loop around the feed-water heater, as shown on the 

 plan. From this loop are taken the principal heating 

 mains. Should, for any reason, the supply of ex- 

 haust steam become inadequate for heating purposes, 

 live steam may be injected into the exhaust loop 

 through a 6-inch high-pressure steam connection, after 

 reducing the steam pressure from 160 pounds down to 

 81] 



