Evening star. [volume] (Washington, D.C.) 1854-1972, 1891-10-28

The conduit duct system which admits of
drawing in and taking out wires and cables as
circumstances require. is, in the opinion Of the
board. unquestionably the cheapest and most
practicable system thus far developed, all
things considered. For general mimic
IF t nIns CLAW psonPSs tine the duraP5y
Of its material and special applicability to the
service in Washington in view of the few i'm
| pedimen,s. taken in connection with lie COM
parative cheapness and capacity. lead the board
to the conclusion that OF those conduits having
had reasonably successful test Of several
years, il best meets the requirements of a sys-
TEN specially suitable to the District Of
Columbia
QUESTIONS DISCUSSED.
The report then discusses the question,
"What shall be provided for in a conduit sys-
TEN for District wiring" The answer the re-
port says. depends upon the following condi-
tons; ia) Shall the several franchised
Companies now operating wires be al
lowed or required to extend them in
their own separate conduits? o. If
the companies extend their conduits shall the
telegraph companies doing business in Wash
inStOn be required to build conduits for oil
their wires! (c) shall each of these corpora
lions in the conduits already constructed
and iii all future conduits as provided,
De required, as Is the case OF
Philadelphia and in many large cities OF Eu-
rope, to provide not less than one duct on each
line OF a conduit for the free and exclusive use
OF the public In addition to such other obilga-
tons as may be deemed proper. If these ques-
tons we're answered In the affirmative, the
board says the requirements of the District
Tor conduits would be limited to the iire-alarm
and police-sigual service. The board, however,
thinks the public interests will be best sub
served upon a negative basis.
DISTRICT TO CONTROL The coSDUIIs.
'In other words" the report says, 1--WE
would recommend that all future conduits
shall be built, owned and controlled by the
District, believing in the broad theory
that the public thoroughfares and grounds
are and should be the exclusive
public property, and that the
business necessarily conducted for public pur-
poses upon these thoroughfares. should be
owned and controlled by the public. This is
not an untried theory. Years of actual
trial has demonstrated the practicability
OF public water supply system
under municipal ownership. In the United
States As per cent of the water works and fully
80 per cent of the investment In water works
plants are owned and controlled by municipal
corporations. Without exception municipal
ownership in these cases has brought about a
material Improvement in the water supply and
a reduction in the water rates" The report
refers also to the municipal ownership OF gas
and electric ligh: plants. After giving various
arguments for and against such municipal
ownership the board remarks that
the conservatism of public interest
in favor of economy points to the
municipal ownership of underground
plants upon the public domain. 1t Is sufficiently
apparent. they think. that under pubic owner
ship the extent of interference in the tearing
up of streets will be reduced to a minimum.
The report says:
believing, we have endeavored to show.
that the interests of the District will be best
subserved by public ownership of all future
condults, We have prepared a general plan of
condults within the District. anticipating, as
We think, the requirements for the future ex-
tension of the present service and the under
of the telegraph companies and the District
police and FIRE alarm department.
THE PLANS.
These plans provide conduits with a mini
mum capacity of four duets tc a maximum
of sixteen duets. For purposes of uniformity
and economy recommend the ioca-
tlOE Of signaling and alarm stations,
far as practicable, at the southeast corner
Of the intersections, within reason
able distances apart. These stations
can and should be combined with an electric
light pole OF approved artistic pattern. SO as to
economic both space and a void useless xpend-
ltu-e- The plans aud estimates are based upon
the rectangular Titrifed glazed clay conduit
which has been heretofore referred
to and has been found from suffi-
ciant trial in the District to meet
all the requirements. 1t is not as cheap as the
crcosuted conduit systems in in Ihiladel-
phia or brooklyn, but, if encased, as provided
III concrete. its construction will be of per-
manent character without liability
to partial combustion by electric leakage
in accidental cases or injury to the cable. On
the other hand its cost will be less than iron or
other material and its relative capacity of
ducts greater.
The details of construction have been only
outlined for general estimates as they will vary
with every block and relative position to the
gas. water and special electric service pipes
and conduits.
The important. features in the construction
OF this system are: First, a permanent AMI uni
form base of concrete g inches is a fair thick
ness: second the careful laying and alignment
OF the sections SO to insure true lines
and continuous ducts: third, the proper bedding
and Incaslng of each tier of sections in a
uniform layer of small stone or gravel concrete:
fourth, the proper construction of the man
holes with good coating of cement mortar or
concrete from the base up to the top, to
render them mpermeable both to moisture
and gas as far practicable: fifth
the efficient ventilation of the manholes
through lamp connections: sixth. provisions
for tight. close-fitting covers and plug or valve
sewer connections to manholes in the lower
section of the city liable to overflow or subject
TO back water, and ventilated covers with open
trapped sewer connections for manholes in the
upper section Of the city.
ESTIMATE AND COST.
The following is an approximate estimate
of the length and cost of the conduits and man
holes comprising the system:
$500 lineal feet or Al 81 miles duct
80. 100 lineal feet or 9.49 miles duct
eondui; 1O5,2lO
1860 lineal feet or 3.33 miles II duct
eondait :.....-.:............ $500
Loo lineal feet or 10 miles 16 duct
CoAuuit neutrality-suspicious.. 4t.400
S445,640
30. 600 lineal feet or Sc. Sc miles. allow
gag 10 per cent for contingencies and
supervision NEUTRALITY-SUSPICIOUS.. 44564
$500 204
Total length of ducts SIT 6s- 100 miles. Cost
rer mile. - ,5i3.
Considering that after construction it will
take several years to nil all the ducts and the
cost OF maintenance and supervision, We re-
CART that cents per lineal foot per year for
each duct used as a reasonable rental for the
first lew years
The estimates contemplate manholes on an
average of 800 feet apart. Local conditions
viii make this a variable factor.
The cost of manholes also varies with the
size of coEduits, ranging from $40 to $40
each. The figures given will in the aggregate
be found sufficiently accurate for purposes of
legislative determination
Accurate and exact details will necessarily
huy, To be preDarel unier the snpsrv;s;nn IL