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Generating Station in New York City, a pioneer installation promoted and designed by Thomas A. Edison in the last decade of the 19th century. For lighting installations particularly, the cyclic variations of alternating current at frequencies of 25 cycles each second or less were perceptible to human sight and resulted in ocular irritations attributable to lamp flicker.

In the decade following the completion in 1910 of the Capitol Power Plant, the arguments of the proponents for the use of 60-cycle alternating current electricity for both lighting and power utilizations prevailed. Thereafter the use of directcurrent electricity, except for specialized applications, and 25-cycle alternatingcurrent electricity diminished rapidly. By 1950 the use of 60-cycle alternatingcurrent for conventional lighting and power applications was almost universal. At that time the direct-current and 25-cycle alternating-current systems still being utilized on Capitol Hill were, in effect, a curiosity because of their antiquity.

The previously described progress in the electrical industry ultimately was instrumental in the enactment of Public Law 413 by the 81st Congress. Under the provisions of that act, generation of electrical energy was totally discontinued at the Capitol Power Plant in September 1951 and since that time the plant has served only as a source of steam for heating and other domestic uses, and for refrigeration used in conjunction with the air cooling of the Capitol, the Legislative Office Buildings, the Library Buildings and the Supreme Court Building. Since 1951 electrical energy has been purchased from the local electric utility company and its use has increased from approximately 40 million kilowatt hours to approximately 115 million kilowatt hours annually. Also under the authority of Public Law 413, the electrical systems in all buildings and facilities under the jurisdiction of the Architect of the Capitol were converted from 25-cycle alternating current and direct current to 60-cycle alternating current.

As part of the program authorized by Public Law 413, eight of the sixteen old boilers in the Capitol Power Plant were replaced by three modern steam generators having an hourly capability for producing 220,000 pounds of steamper-hour with two of the three new steam generators in operation, and the third in stand-by readiness. Also the six obsolete and inadequate reciprocating refrigeration machines having a total capability equivalent to the heat-absorbing capacity of 4800 tons of ice melting in 24 hours were replaced by four centrifugal refrigeration machines rated 2200 tons each, or the equivalent of 8800 tons of ice melting in 24 hours. The construction of new machine foundations was the only general construction work associated with this replacement of machinery.

Subsidiary work accomplished under Public Law 413 included the construction of a 4-cell cooling tower on the grounds of the Capitol Power Plant to supplant the function of the old river pump house, the installation of a 13,000-volt/ 4160-volt outdoor metalclad electrical substation also on the grounds of the Capitol Power Plant and designed to receive and transform electrical energy purchased from the local utility company to supply the expanded needs of the new machinery in the Capitol Power Plant, and the complete revamping of the electrical distribution systems within the confines of the Capitol Power Plant building for the utilization of the 60-cycle alternating current energy purchased from the local utility company.

Additional supporting work accomplished under the provisions of Public Law 413 included the construction of a reinforced concrete walk-through tunnel. 10 feet 6 inches wide by 11 feet high, with walls of a minimum thickness of 14 inches, containing steam lines, condensate return lines, and chilled water lines was constructed during the period 1952-1954 from the Power Plant to the old Senate Office Building. This tunnel, located principally on North Carolina Avenue, Second Street and Constitution Avenue, was placed in service during the calendar year 1954, at which time the use of the section of old tunnel under First Street between Independence Avenue and Constitution Avenue was discontinued. This so-called "East" tunnel was built to serve the new Senate Office Building, the Supreme Court Building, and the two Library Buildings. The Capitol, the Cannon Building and the Longworth Building continued to be served with steam for heating and chilled water for air-conditioning by the “West" distribution system completed in 1938.

All of the facilities constructed and installed under Public Law 413 were designed to provide the steam and air-conditioning requirements of the United States Capitol prior to the Extension of its East Front, the two existing House Office Buildings, the old Senate Office Building, the Annex to the Library of Congress, the Supreme Court Building, a contemplated New Senate Office Building, and future House Office Building anticipated to be much smaller in physical size than the Rayburn Building subsequently conceived, and the eventual mod. ernization of the obsolete heating facilities in the Main Building of the Library of Congress. The new designs developed under Public Law 413 also provided for the continuation of steam service only for the heating of the Government Printing Office, the City Post Office and the Botanic Garden as had been the practice in the past. By an act of Congress approved subsequent to the enactment of Public Law 413, the Folger Shakespeare Library was connected to the Capitol Power Plant's steam distribution system through a branch connection originating in the Annex to the Library of Congress. The terms of this act provided for monthly payments to the Federal Treasury for the steam consumed by that building for heating and for the generation of domestic hot water service.

As previously mentioned, the electrical distribution systems in all of the buildings under the jurisdiction of the Architect of the Capitol were converted from 25-cycle alternating current and direct current energy to 60-cycle alternating current energy under the provisions of Public Law 413. On January 11, 1963, the last of the five A.C./D.C. motor-generator sets in the Dynamo Room in the Capitol was permanently shut-down and the old equipment in this room was dismantled and removed from the Building. These operations concluded the changes and improvements authorized by Public Law 413.

When the accomplishment of the Extension of the East Front of the Capitol, the authorization of an additional House Office Building of much larger proportions than originally contemplated, the imminent construction of the Senate and House Subway Transportation Systems, the foreseeable extension of the New Senate Office Building and the unavoidable improvements needed in the Main Building of the Library of Congress, the Architect of the Capitol prudently initiated in 1957 a restudy of the present and future needs of the Capitol Power Plant. This restudy culminated in the circumstances described in Part IV of this report.



INTRODUCTION In 1957 the Architect of the Capitol inaugurated a study of the present and future needs of the Capitol Power Plant in anticipation of foreseeable new steam and refrigeration loads to be imposed on that facility. This study was made for and under the direction of the Architect of the Capitol by Guy B. Panero, Consulting Engineer of New York City under Contract No. ACpp-553 dated October 15, 1957. At that time six new construction projects were contemplated or in progress, Damely, the East Front Extension of the United States Capitol, the Rayburn House Office Building, the Cafeteria in the courtyard of the Longworth Building, the Garage in the courtyard of the Cannon Building, the New Senate Subway Transportation System and the House Subway Transportation System. The long overdue replacement of the antiquated heating system in the Main Building of the Library of Congress and the urgent need for a combination heating and cooling system in that building also was anticipated and provided for in the appraisal of the Power Plant's future responsibilities. The new facilities for heating and cooling the Main Building of the Library of Congress were approved by the 87th Congress on August 10, 1961 and the work has been accomplished under the provisions of Public Law 87-130.

Based on the Consulting Engineer's findings and conclusions as set forth in a comprehensive report dated March 15, 1958, the Architect of the Capitol recommended to the 85th Congress a major expansion in the steam generating and refrigeration facilities at the Capitol Power Plant, including necessary additions and improvements in the underground steam and chilled water distribution systems associated with the Power Plant's services. Public Law 85–895, 85th Congress, HR 12883, approved September 2, 1958 provided $6,500,000 for the further expansion of the Capitol Power Plant and for modifications to its steam and chilled water distribution systems.

More detailed information concerning the scope of this project, work accomplished to date, unfinished work and matters of administrative interest are included in the succeeding sections of this report. Section A

The expansion program outlined in Public Law 85–895 did not include any new building construction, or major alterations to existing buildings. However, it did

provide for inside plant installations consisting of four oil-fired steam generators complete with fuel firing equipment, two 1100-ton refrigeration machines, two 2200-ton refrigeration machines, one chilled water circulating pump, feedwater treatment equipment and an additional 208Y/120-volt switchgear assembly.

After completion of the changes and improvements described in Part III of this report, there remained in the north boiler room eight of the obsolete coal-fired boilers complete with underfeed stokers, ash hoppers and smoke breechings. In the turbine room there still remained two 2,000 KW and two 6,250 KW steam turbine-driven electric generators idled in 1951, complete with con. densing equipment, piping and miscellaneous auxiliary equipment. Obsolete 25-cycle transformers, circuit breakers and miscellaneous switchboard equipment, also idle since 1951, occupied usable floor space in an electrical bay on the North side of the turbine room.

As a prerequisite to the installation of new steam generators, refrigeration machines, chilled water pump, feedwater treatment equipment and additional electrical apparatus authorized by the new expansion project, it was necessary to remove from the north boiler room and the turbine room all of the obsolete equipment mentioned in the preceding paragraph. This work was accomplished as part of the obligations included in Contract No. ACpp-577 (See Section "E") completed on April 11, 1960.

Space available in the west end of the refrigeration apparatus room had previously been prepared and left vacant for the future installation of two additional refrigeration machines.

It was also planned to dispose of the pumps, motors and switchgear in the abandoned river pump house, and to demolish the building and its underpinnings. By arrangements concluded in 1909, this facility had been constructed at the direction of the House Office Building Commission on a waterfront site under the jurisdiction of the Government of the District of Columbia, a circumstance that resulted in the negotiations hereinafter described.

In a letter from Tom Miller Marine Towing and Salvage, Inc., dated June 21, 1961, this company indicated its desire to lease the river pump house property, to remove all of its machinery and make all necessary repairs to insure the existence of a safe structure. This organization also proposed to remove the large water intake pipes between the pump house and the shore line, and to seal the open manhole in the sea wall with a grating; all without expense to the Government provided a mutually satisfactory leasehold could be negotiated.

In letter of June 27, 1961 addressed to the Commissioners of the District of Columbia, the Commissioners were apprised by the Architect of the Capitol of the Miller request and, at the same time, the Commissioners were informed that neither the Architect of the Capitol or the House Office Building Commission had any legal authority to lease the existing property to anyone for any purpose whatsoever, or to authorize its use for any purpose other than that approved by the Congress, An immediate response from the Secretary, Board of Commissioners, District of Columbia indicated a desire on the part of the Commissioners that the pumping station be conveyed to the District. A formal document of conveyance signed by the Chairman of the House Office Building Commission and the Architect of the Capitol, issued on July 10, 1961, officially transferred the river pump house, its installations and environs to the Government of the District of Columbia.

The new construction work and plant installations accomplished or in progress under the Expansion of Facilities Project as of March 28, 1967 are described in Section B of this report. A total of 27 personal service, supply and construction contracts, as listed in Sections E and F, have been awarded and all but three contracts have been completed.

All of this work was accomplished over a period of 8 years without interrupting the seasonal services supplied by the Capitol Power Plant. For this reason most of the work had to be performed in carefully planned and rigidly timed increments, necessarily of relatively short duration individually, to avoid untenable interruptions in the steam or chilled water services. New installations and modifications to existing installations associated with the generation and distribution of steam for heating had to be accomplished during non-heating seasons, and those associated with the supply of chilled water for air-conditioning had to be accomplished during non-cooling seasons.

The complexity of the project was further increased by the need for correlating the Power Plant work with the building construction and modernization programs simultaneously in progress elsewhere on Capitol Hill to insure the

Power Plant's timely readiness to supply the new demands created by the completion of such new construction and modernization programs.

Additional atuhorized work as listed in Section is in the planning stage. This work includes (1) the installation of the new water treatment plant already under contract for manufacture by the American Water Softener Company, (2) modifications and extensions to the existing steam distribution systems, and (3) reinsulation of the chilled water lines in the tunnel on South Capitol Street. Section B

New Construction and installations.-As of March 28, 1967 approximately 85% of the work authorized by Public Law 85–895 has been completed or placed under contract. The items of work for which plans must still be developed are described in Section of Part IV of this report. A complete listing of contracts awarded to date is included in Section E. Sections D and F include facets of the project which are of administrative interest. The following paragraphs describe the work that has been completed or placed under contract.

Two 1100-ton refrigeration machines complete with geared drives and 1250 horsepower electric motors have been installed in the previously vacant spaces at the west end of the refrigeration apparatus room constructed in 1936–38. Additionally, two 2200-ton refrigeration machines complete with geared drives and 2500 horsepower electric motors have been installed in the east end of the turbine room built in 1906-10, in a space vacated by two of the obsolete steam-turbine-driven, 27-gcle, electric generating units. The two 1100-ton machines were accepted for use by the Government on September 17, 1960, and the two 2200-ton machines were accepted for use by the Government on August 18, 1965. All of these machines have served useful purposes during recent cooling seasons.

As an adjunct to the installation of the aforementioned refrigeration machines, a 3-cell cooling tower having a capacity equivalent to the condensing requirements of three 2200-ton refrigeration machines was constructed in the southeast corner of the Capitol Power Plant grounds, adjacent to the 4-cell tower mentioned in Part III of the report. This installation was accepted for use by the Government on June 6, 1963.

One additional chilled water pump of 9800 gpm capacity and having hydraulic characteristics identical with those of the three existing chilled water pumps was installed in the southeast corner of the turbine room and accepted for use by the Government on July 1, 1964, thus providing a total pumping capacity of 39,200 gallons-per-minute at an imposed head of 245 feet of water.

The installation of a dual piping system consisting of one chilled water supply main and one return main, from a point exterior to the southeast corner of the Old Senate Office Building to the Senate Terrace of the Capitol Building was completed in March 1963. This new section of chilled water piping established a physical connection between the previously separated east and west distribution systems, thus providing a complete loop circuit from and to the Capitol Power Plant. In other words, the chilled water distribution system now is continuous from a point starting at the east end of the refrigeration apparatus room in the Capitol Power Plant and following a sub-surfaced route along North Carolina Avenue to Second Street, S.E., thence along Second Street in a northerly direction to Constitution Avenue, N.E., thence along Constitution Avenue in a westerly direction to the north end of the Old Senate Subway Tunnel, through the Old Senate Subway Tunnel to a point of about 150 feet north of the north facade of the Senate Wing of the Capitol where the pipes penetrate the subway tunnel wall and eontinue on a sub-surfaced route in the Capitol Grounds to Room ST-36 in the west Senate Terrace, thence exposed through the Senate and House Terraces of the Capitol to the Rotunda of the Cannon Building via the House Pedestrian Tunnel, under New Jersey Avenue to the basement of the Longworth Building and then south under South Capitol Street to a point at the westerly end of the refrigeration apparatus room in the Power Plant. The availability of the previously described loop circuit has made possible a successful redistribution of the chilled water supply to all buildings connected to the system, a compelling requirement brought about by the construction of the Rayburn Building.

A new railroad siding has been constructed on the Virginia Avenue side of the Capitol Power Plant Grounds and this installation became operational on Xovember 16, 1964. Prior to the installation of the new siding, the old siding was removed from service and demolished. The new track system was designed to accommodate storage for eight 70-ton coal cars, while 8 additional cars of like capacity can be delivered to or removed from the Plant grounds. The new railroad siding has substantially expedited the coal-handling process and has eliminated the frequent car derailments and other hazards experienced with the old track system. A by-product of this improvement has been the release of an acre of plant property for future plant expansion, an area that was not previously available because of the unique layout of the old track system.

Four oil-fired steam generators, each having a capacity to produce 50,000 pounds of steam every hour, were accepted for use by the Government on March 3, 1966. The addition of these oil-fired steam generators increased the installed steam generating capacity of the Power Plant from 330,000 pounds per hour to 530,000 pounds per hour. Additionally, the capability of dual-fuel-plant operation provides the Government with security during emergencies arising from strikes or other stoppages in the oil, coal or transportation industries.

The completed oil storage facility for the Power Plant includes two 10,000gallon underground steel tanks connected by a concrete tunnel to an underground concrete storage tank with sufficient capacity to store 200,000 gallons of fuel oil. The concrete storage tank is situated at the extreme southwest corner of the Power Plant grounds. This site was selected to minimize truck delivery interferences with other Power Plant operations. The two 10,000-gallon steel tanks were ready for use by the Government on May 12, 1965 and the underground concrete storage tank was accepted for use on April 29, 1966.

The antiquated coal-handling system placed in operation in 1910 and designed to alternately deliver coal from the storage yard or track hopper to the coal bunkers within the plant was removed from service in the spring of 1965. It was immediately demolished and replaced by a modern system of hoppers, inclined belt conveyors, oil-fired car-thawing devices and a mechanical car shaker. This integrated system was accepted for use on December 28, 1965. The new coalhandling system is capable of delivering variable quantities of coal up to approximately 200 tons maximium each hour from either a track hopper where coal is dumped from the cars, or from a coal yard hopper in the storage yard. Consequently the coal can be conveyed from the track hopper to the bunkers, from the track hopper to the storage yard, or from the storage yard to the bunkers through separate systems of inclined conveyor belts.

In the fall of 1966 a contract was awarded for accomplishing modifications and extensions to that portion of the west steam distribution system located under South Capitol Street, and extending from Canal Street to Independence Avenue. Work on this site now is in progress.

On March 22, 1967 contract No. ACpp-747 was awarded for the manufacture and delivery of a new water treatment plant to be installed in the east side of the north boiler rooms. Completion of this installatiotn is scheduled for January 1968. Section C Unfinished authorized work.

(1) Water Treatment Plant As mentioned in Section B hereof, a contract for manufacturing and delivering the water treatment plant equipment was awarded on March 22, 1967. An installation contract including general construction work, piping systems and installation of the manufactured equipment on order now is being prepared for issue to prospective bidders on or about July 1, 1967. It is expected that the new water treatment plant will be ready for tests in January 1968.

(2) Steam Distribution System Additional modifications and extensions to existing steam distributions, including new steam service facilities and connections to the Capitol Building, via the west front grounds, are contemplated. Also some modifications to the piping systems serving the Government Printing Office and the City Post Office are to be accomplished under the provisions of Public Law 85-895.

The proposed new steam piping systems contemplated for installation in the west front grounds of the Capitol are closely related to the proposed reconstruction of the West Front of the Capitol. In fact it would be decidedly advantageous to have the work of both projects proceed cojointly to avoid unnecessary disturbance and expense. For this reason development of final plans for the new steam systems in the west grounds of the Capitol has been temporarily deferred pending final action by the Congress on the West Front Extension Project. Plans for the modifications to be made in the Government Printing Office tunnel are in the process of development.

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