alley sections which is charged to the general city fund. The city used
275,498,112 gallons of water, costing $28,416.65 including $8,800 for
hydrant rental. The average rate of assessment per foot front is about
.017¢. In some cities where water is unavailable outside of city limits,
or available only for a short time, oil has been used to meet the
demands for dust prevention. What seems to be the best is some non-
volatile oil that will quickly penetrate the wearing surface of the road
incorporating itself with the fine particles so that it forms a dense,
smooth, waterproof coating, or else renders the surface dressing so
heavy that wind will not hold it in suspension in the air. In addition
to this its non-volatile character gives it lasting qualities.
The Milwaukee Bureau of Municipal Research believes that “The service at
its best is of no value as it does not clean but only allays dust on the
street where in its wet condition it requires a further process of
cleaning by the squeegee or flusher and White Wings. If the city had a
sufficient amount of modern equipment to clean streets more frequently,
the valueless method of sprinkling could be eliminated and an enormous
expense saved.”
In some cities street railway companies are required to sprinkle between
their tracks and for certain distances on either side of the track. The
legal question has several times arisen, whether a Municipal corporation
has authority to enact an ordinance to compel railway companies to
sprinkle in this way and also whether the particular ordinance in
question is reasonable, or so unreasonable as to be void. Generally
speaking it has been decided that such an ordinance must be specific,
not burdensome, and confined to the company’s tracks, though in one case
in Massachusetts, under the statutory powers conferred upon municipal
authority, an ordinance requiring sprinkling from curb to curb was
sustained. Courts have held that an ordinance providing that “each and
every Company or Corporation operating street car lines within the
limits of the city of ——— shall water their tracks so as to effectually
keep the dust on the same laid,” and provides a penalty for its
violation, is neither indefinite nor wanting in uniformity.
The question of sprinkling streets before sweeping has been discussed
repeatedly. Following are the methods used in some cities:
_New York._—Sprinkling before machines. No sprinkling before hand
sweeping.
_Chicago._—Sprinkling before sweeping. The Chicago Code of 1911
requires that street car companies shall keep well sprinkled with
water in a manner satisfactory to the Commissioner of Public
Works, all streets on which they maintain and operate their
tracks. They are required to sprinkle such streets twice each day.
By another section such street car companies shall clean such
portions of streets as lie between the two outermost rails of such
tracks and also every additional service as may be prescribed in
any railway ordinance relating to or affecting any street.
_Philadelphia._—The proposals and specifications for the cleaning of
streets, roads, alleys, inlets and markets for 1915, contained the
following provision: In addition to the cleaning by blockmen
required under these specifications, all streets must be
periodically cleaned by machines, the number of weekly cleanings
being given in the classification of streets, the remaining
machine work shall be done with machine brooms immediately
preceded by sprinklers.
_St. Louis._—Sprinkling before sweeping is very rarely done, except
in the case of certain large sweeping machines used by the city.
_Baltimore._—Sprinkles before sweeping.
_Pittsburgh._—Principal thoroughfares including all streets in
business district cleaned by machine sweepers. Water cart precedes
sweeping machine. The cart must never be more than one block ahead
of the sweeper.
_Washington._—Superintendent of street cleaning gives his opinion
that much more effective sweeping can be done without sprinkling
and in hand patrol work where dirt is not allowed to collect in
any considerable quantity is not necessary. In machine sweeping,
however, he finds it necessary to sprinkle with a small amount of
water. In cold weather sprinkling is omitted; but at such times
many complaints are received on account of dust.
_Minneapolis._—In general the orders of the street district
commissioners are to sprinkle the streets before sweeping.
Street Cleaning Methods
Four methods are used in American cities for street cleaning, hand
sweeping, machine sweeping, flushing by machine and hose and
squeegeeing.
All experts advocate the sweeping of streets by hand, commonly called
the patrol system. The implements used in patrol cleaning are broom, pan
scraper, squeegees, can carrier and cans. The broom is usually one which
has a 4 × 18 inch block, filled with split bamboo, rattan, hickory,
steel wire or black African bass. The block is usually fitted with a
steel scraper. The pan scraper is constructed like a dust pan, turned up
sides and back. It is about 36 inches wide by 15 inches deep. The
squeegee is a board about 36 inches wide fitted with a rubber strip
which extends below the lower edge of the board. Brooms, pan scrapers
and squeegees have handles about 66 inches long. The cans are made to
hold about three cubic feet of dirt and taper 19 inches in diameter at
the top to 17 inches at the bottom. The can carrier has two large wheels
and two small, and a platform upon which the can or cans rest.
A new carrier has been devised which carries two cans and is so balanced
that the two cans are more easily manipulated than the one. Some cities
are now substituting canvas bags for cans.
Whinery says that when street surfaces are of such character as to admit
it, hand sweeping is the most effective method.
J. W. Paxton says that hand cleaning work is capable of better
distribution than any other method, because more attention can be given
to dirtier areas by increasing the number of men who only clean the
portions of the street which are dirty and work on those portions until
they are clean. There is a fine scum which is not apparent when the
pavements are dry but rises up in a thin sheet of mud when moist, making
the pavements very slippery. This and fine dust cannot be removed by
hand cleaners, but by washing about twice a week in addition to hand
cleaning, these troubles can be eliminated.
Very believes that this method of cleaning is fairly effective but is a
dust raiser and the ability of the man to cover areas is very limited,
especially since the automobile has come into such general use, as it
interferes with the sweeper and his work. He says that there are hand
machine brooms built on the principle of the carpet sweeper which are
not dust raisers and which as a matter of fact do much more effective
work. The pan scraper is only valuable to remove manure and mud and
coarse litter, and its use should be limited to the time necessary for
such work, and the broom used for dust removal.
The area a sweeper can clean depends upon the existence of local
conditions. A test was made in New York City for one week and it was
found that the area one sweeper was able to clean in a day of eight
hours varied from 2,212 square yards to 16,075 square yards, with an
average over the whole city of 5,745 square yards. The efficiency
division of the Civil Service Commission of Chicago reports: “From an
analysis of the findings of the time and motion studies of street
cleaners the following table has been deduced, upon which are based the
relative difficulty of cleaning different pavements under varying
conditions and the standard and equivalent areas to be cleaned by one
man in one eight-hour day.”
┌────────────────┬────────────┬────────────┐
│ Pavement │ Condition │Square Yards│
├────────────────┼────────────┼────────────┤
│Asphalt │Good │ 21,500 │
│Asphalt │Fair │ 19,300 │
│Asphalt │Bad │ 17,200 │
│Creosote Blocks │Good │ 21,500 │
│Brick │Good │ 16,000 │
│Brick │Fair │ 14,400 │
│Brick │Poor │ 12,800 │
│Granite │Good │ 13,400 │
│Granite │Fair │ 12,100 │
│Granite │Poor │ 10,700 │
└────────────────┴────────────┴────────────┘
In Philadelphia, which cleans its streets by contract, block men are
assigned to sections designated by the chief. The area to be covered
depends upon the character and amount of traffic. The duties of block
men consist in patrolling the areas, gathering all papers and refuse and
sweeping dirt as fast as it accumulates, and putting it into dust proof
bags ready for loading into special wagons and hauling to a dumping
station. The equipment used in hand patrol work consists of hand
machines, bag carrier, burlap sacks, push brooms, hand scrapers, special
cans and shovels. The dirt collected is placed in sacks and left at
convenient points to be collected by special wagons and taken to the
dump in sacks, these being returned by the drivers. Sacks are used in
preference to cans because of the weight, bulk and noisiness of the
latter.
Machine Sweeping
Machine sweeping and cleaning is almost universally condemned, although
this method is used in many cities. The machine broom is preceded by a
sprinkling cart to loosen the filth and in a measure to prevent the dust
rising. This is seldom effected. A broom is found to cover about 40,000
square yards per eight hours. The material is swept into windrows at the
side and finally delivered to a windrow in the gutter, where it is
picked up. The efficiency of the rotary broom system is considerably
reduced because the sweepers meet continual obstructions in busy streets
and when operating over paved streets the brooms remove the coarser
fragments of dirt only and leave the finer particles on the pavement.
Where the rotary broom is preceded by a street sprinkler, the dust forms
into mud and clings to the surface of the pavement, and where the
pavement is rough the mud is forced into the joints between paving
blocks. As the street becomes dry, the dirt pulverizes and appears again
as a dust nuisance. In all but one instance machine sweepers have been
dispensed with in Chicago. South Water Street, the heavy wholesale fruit
district of the city, is badly congested during the day, which makes it
impossible effectively to clean this district by the “block” system.
This street becomes very dirty during the day and is covered with a
thick layer of dirt and débris at night. In this instance, the broom
machines appear to be effective and give fairly good results in the
cleaning of this coarse material.
The Chicago Commission believes that the mixing of calcium chloride with
the water which is sprinkled in the different sections of the city would
greatly add to the effectiveness of street cleaning and eliminating the
perils of dust.
According to Very horse drawn brooms of the rotary style are not as
effective as the hand broom.
Whinery says, “Sweeping by power sweepers at intervals of one or more
days, while less expensive is far less effective and satisfactory than
hand sweeping, though if properly done and supplemented by sprinkling
with water or oil at intervals sufficiently near together to prevent
dust flying it serves a good purpose.”
J. W. Paxton is of the opinion that the machine broom raises so much
dust that heavy sprinkling is required. The fine dust mixed with water
produces mud which is smeared on the street by the broom and when this
becomes dry it turns to dust again. The broom sweeps only the coarser
particles and many of these are thrown over the broom by centrifugal
force to the pavement again.
In Philadelphia, machine broom cleaning is done in batteries of two or
three, preceded by sprinklers, the number of brooms in each battery
depending upon the width and character of the streets to be cleaned. The
average gang consists of two machine brooms and one sprinkler, and four
to seven broomers and a sufficient supply of wagons to remove the
refuse, the number depending upon the haul to the dump and season of
year, together with amount and character of traffic.
An investigation made by the Milwaukee Bureau of Municipal Research into
the cost of rotary broom service brought out the following facts: In
industrial and outlying residential section and upon streets adjacent to
wharfs, where pavements are constructed of brick, sandstone, limestone
or granite, the rotary brooms are usually used. The process is done
nightly and to prevent dust, a sprinkler is used in advance of broom.
The following analysis of the cost of operation has been made by the
Bureau:
Cost of machine $250.00
Depreciation of 10 per cent. on machine $25.00
Interest at 4½ per cent. 11.25
—————— ———————
$36.25
Minor repairs and replacements
6 brooms at 50 lbs. bamboo $20.00
ea. at 8¢. per lb 24.00
48 hrs. labor @ 24¢ hr 12.00 56.00
—————— ———————
$92.25
150 days operation $0.615
2 sweepers at $2 per day ea. 4.00
Team and driver per day 5.00
Grease, etc. 0.05
——————
$ 9.665
Average yards cleaned, 40,000
Average cost per 1,000 sq. yds., 24.1
Combined with sprinkler
Sprinkler, team per day $5.00
Water 0.90 5.90
——————
40,000 sq. yds. sprinkled, cost per 1,000 sq. 14.7
yds
Broom cost per 1,000 sq. yds 24.1
———————
Combined cost per 1,000 sq. yds 38.8
The assessment per front foot on a street 30 ft. wide and cleaned 50
times a season would be 3.2¢.
Pick-up Machines
To improve on machine sweeping various types of motor pick-up machines
have been invented. Most of them have proved of no value. Some, however,
are being used by cities with good results on dry, smooth pavement in
good repair. Most experts question whether vacuum cleaning will ever be
able to remove effectively mud or wet dust. Some experts, however,
believe that these pick-up machines will solve the problem of cleaning
macadam pavements, as it is the only method that can be employed without
serious results. These machines will travel at a rate of four miles an
hour, which exceeds the speed attained by any horsepower sweeper.
The experience of Oakland, Cal., with this method of cleaning is
interesting. Adjacent to the congested district a suction sweeper had
been used for several years. The district had been swept from three to
six times a week, by contract, to the satisfaction of the city
officials. The department reports that the cost was rather high in
comparison with that for rotary sweeping, but that the results were more
satisfactory. It cost the city 35¢. per 1,000 square yards to clean with
the suction sweeper and 26¢. per 1,000 square yards with the rotary
brooms. It had been generally assumed that the patrol system was the
most expensive until the Street Commissioner readjusted the routes
according to area and traffic. He then found that hand sweeping could be
done on streets not swept by rotary brooms at the same cost or not to
exceed a ten per cent. increase. He found also that it could be done for
much less than cleaning by suction machines. The city has, therefore,
entirely superseded this method of cleaning at an estimated annual
saving of $3,000 and with much better results.
Pomona, California, found that moisture upon the surface of a pavement
or in any form of refuse cannot be lifted by a suction sweeper. Instead
it is in effect smeared over the surface of the street. In all cases
where the street is dry and the surface of the pavement is reasonably
dry the city has found the machine very positive in its operation.
Los Angeles, California, is thoroughly testing the vacuum method of
street cleaning following a report by the Efficiency Commission, which
has estimated a saving of $65,071 a year if the streets are swept with
vacuum cleaners instead of flushed. The report says that supplementary
observations and calculations show that the cost of flushing under
present conditions is 24.06¢. per 1,000 square yards, and the cost of
vacuum cleaning 10.96 cents per 1,000 square yards. These figures
include the cost of supervision, maintenance of equipment, workman’s
compensation, gutter cleaning and water at cost of production. The cost
of operating one of these machines is given by the Milwaukee Bureau of
Municipal Research, as follows:
Purchase price $4,000
Depreciation 50 per cent. $2,000
Interest 4½ per cent. 180
——————
$2,180
Repairs (estimated) 25
Replacement of brooms, 30 @ $6 ea. 180
Labor making brooms 60
——————
Yearly cost $2,445
150 days operation, cost per day $16.30
1 Chauffeur $3.00
2 sweepers 4.00
1½ time 2.50
Gasoline and oil 1.25
Water .12 $10.87 10.87
————— ——————
$27.17
From personal observation it was calculated this machine can operate at
a speed of four miles per hour and perform work at about 75 per cent.
efficiency, or at a cost of 21.4¢. per 1,000 square yards.
The assessment per front foot based on a street 30 feet wide and cleaned
50 times a season would be 1.77 cents.
Raymond W. Parlin, Deputy Commissioner Street Cleaning, New York City,
says: “So definite are the needs of the cities for results better than
those produced by sweeping that it may be safely prophesied that
sweeping in the future will cease to be a primary method of cleaning a
modern city and will become an auxiliary to other more efficient methods
or used where only rough cleaning is desired.”
Cleaning by Flushing
All authorities agree that whatever method for primary cleaning is
adopted, it is important that the street surface be frequently washed by
the use of hose, horse drawn flushers, flushing cars, or power
squeegees. Reports from cities show that flushing is replacing machine
sweeping and that the automobile flusher is becoming popular. The Chief
of the Atlanta Sanitary Department favors doing away with sweeping
machine and cleaning the streets entirely with flushing machines. He
says that sweeping machines are out of date and that flushers are the
ideal machines.
The squeegee is a vehicle having a tank and a revolving rubber roller,
which washes the pavement as the vehicle moves along the street and the
water from the tank is sprinkled in front of the roller. Hose flushing
is used in cities having graded streets and sufficient water supply.
Street flushers have pressure tanks which depend for their pressure
either upon the pressure from the water mains or upon the pressure
obtained from a pump operated by a gasoline engine. The latter plan
gives the better results.
Whinery is of the opinion that on well paved streets the most efficient
and satisfactory method so far devised with the apparatus now available
is hand cleaning by the patrol system by day, followed with hose or
flushing wagons or scrubbing squeegees during the night. While this is
somewhat more expensive than plain machine sweeping he thinks that no
other method yet devised will produce equally clean streets at a lower
cost.
Gustave H. Hanna says: “The use of flushers has proven not only the
cheapest but the most satisfactory method of street cleaning that our
experience in Cleveland has been able to develop. Statistics of the
department show an average cost of 15.3 cents per square of 10,000
square feet for flushing to which must be added practically 9 cents for
pick-up work, a total of some 24 cents per square as against 42 cents
for work with White Wings. The White Wings are too convenient and
necessary an adjunct to be wholly displaced under any consideration.
Down town streets must be swept continually during the day and the hand
sweeper with his small cart can also work to advantage in gutters of
residential streets collecting dirt that has either been flushed or
blown to the curb; but so far as our experience goes, the lessening of
cleaning cost by cheaper methods means simply the extension of the use
of flushers at every practical point.
“There is an argument of sanitation in favor of flushing. Hand sweeping
causes a certain amount of dust and mechanical sweeping usually causes
still more. I am opposed to the use of simple sprinkling as a means of
laying dust. Ammonia and other products leach out of damp manure and
form a scum on the surface that is nearly impossible to remove, and
makes pavement slippery and foul smelling.
“Water should also be applied with force enough to carry the refuse to
gutter where it should be properly collected with broom and shovel and
removed. In Philadelphia flushing machines are used only on poorly paved
streets and block pavement. High pressure flushing machines are usually
operated similarly.”
Very reports that objection is made to flushing because materials are
washed into sewers. The same objection, he says, might be made to hand
sweeping, as many sweepers are like housemaids and sweep the dust into
the catch basins to make work easy. The material need not reach the
sewers if the operator knows his business. Many fear that the action of
water when used in flushing will wear away the pavement surface or the
joint materials. His answer is that it should, if such a class of
pavement or of jointing is allowed to be laid, to expose the paving
contractor.
The Chicago Civil Service Commission says that personal inquiry and
analysis of reports from cities using flushing machines seem to indicate
that the use of flushing machines on rough and smooth pavement and the
use of squeegees on smoother permanent pavements have given more
effective cleaning than the ordinary block or gang cleaning where it is
practicable to make the substitution.
The Milwaukee Bureau of Municipal Research, in its investigation of
street cleaning in that city, says the contention of some is that
flushing is detrimental to pavement as it removes grout, but such has
not been proven in Milwaukee. The one fact that remains uncontradicted
is that they clean the streets of every particle of débris and leave the
thoroughfares in a sanitary condition; a matter of most vital
importance.
In Milwaukee night work is confined to two territories comprising the
heavy traffic and commercial territories and each alternating night the
streets are flushed. This requires the use of four machines and they
operate in a staggered double formation, cleaning the entire area
without a return movement. When intersecting streets are encountered,
the two rear machines perform the work and then return to the original
function. A great deal more territory is thus covered than if machines
were paired and each allotted a given area. Day work is performed in
like manner except that the remaining four machines are assigned to
outlying districts and confined thereto. The following is the cost of
operating machine flushers as computed by the Bureau:
Cost of machine $1,500.00
Fixed charges.
Depreciation of 10% on (wagon & tank) $100.00
Depreciation of 25% on engine 125.00
Interest at 4½% 67.50
——————— $292.50
Maintenance
Painting (each season) 20.00
Hose and coupling, each season 15.00 35.00 $327.50
——————— ———————
150 days operation—cost per day $2.18
———————
In recommending the flushing process the Milwaukee Bureau says that
sprinkling will be greatly reduced, the slippery surface of
thoroughfares due to this valueless method will no longer exist, and
that a cleaner and more sanitary condition will be the result.
The experience of Scranton, Pa., with flushers is that in going over the
streets but once satisfactory results are not obtained. The director of
public works says that this has also been found in other cities he has
visited where flushers are used. He has concluded that the only
practical and efficient way to clean streets is by the use of automobile
flushers, one to about one and a half minutes ahead of the other, the
first flusher dampening the horse droppings and other material that may
stick to the pavement, thus loosening them, and the second flusher
sweeping them into the gutter.
Birmingham, Alabama, reports that its experience has been that a great
saving and better results are obtained by substituting street flushers
for sprinklers and brooms.