Posted on Jan 16, 2008 under Uncategorized |
If two fires occur simultaneously in a town or fire district of
10 ooo people the hourly consumption for fire purposes alone
will be at the rate of 173 gallons per person per day. In
general for each fire district the maximum available hourly
supply for both fire purposes and domestic use should be at a
rate from three to four times as great as that of the mean
daily consumption.
The pressure under which the water is delivered in the
streets is an important factor in all questions relating to fires.
If the pressure be very high fire engines may not be needed,
as the hose may be attached directly to the hydrants. If the
pressure be very low it may not be possible to secure an
effective fire service even with the use of engines, since a low
pressure is always accompanied by a small discharge. In the
houses a very high pressure greatly increases the waste of
water, while of course a very low pressure furnishes an insuffi-
cient supply. Pressures over 100 pounds per square inch are
high, and pressures less than 30 pounds per square inch are
low.
Posted on Jan 13, 2008 under Uncategorized |
When plans are to be made for a gravity supply there are
two important preliminary questions to be discussed: first,
what amount of water can be obtained; second, what storage
capacity is needed for the supply of the town. The first
question involves the preparation of maps of the neighboring
watersheds, the collection of rainfall and run-off data, and
certain reservoir estimates. The second question involves the
considerations of consumption and pressure presented in the
last article and more detailed estimates of storage capacity.
The combination of the results of these two inquiries enables
a decision to be made as to whether or not a given watershed
will furnish a sufficient supply for the town.
Posted on Nov 20, 2007 under Uncategorized |
On Mondays, when every household is at work on the
weekly washing, the consumption may be put at from 20 to
40 per cent higher than the mean for the week. Accordingly,
on the basis of 100 gallons per person as the daily mean for
the year, the Monday consumption during very cold or very
hot weather may be taken as from 140 to 170 gallons per
person per day.
Posted on Nov 16, 2007 under Uncategorized |
A small city generally uses less water per person than a
large one; but the mean for American cities having 50000
population is over 100 gallons per person per day. A manu-
facturing town has a high rate of consumption, and the same
is true for a city with asphalt streets, since much water is used
in washing them. In towns without factories and having a
population of less than 10000 the mean daily consumption
will generally be between 60 and 100 gallons per person per
day.
The daily consumption during July and August is from 15
to 20 per cent greater than the mean for the year, as in these
months much water is used for sprinkling streets and lawns.
In the northern part of the United States the daily consump-
tion during January and February may be also 15 or 20 per
cent higher than the mean, owing to the large amount that
is wasted in order to prevent freezing of the pipes. If 100
gallons per person is the daily mean for the year the daily
mean during these four months may be as high as 120 gallons
per person.
Posted on Nov 16, 2007 under Uncategorized |
The mean daily consumption per person in Philadelphia
was 68 gallons in 1880 and 132 gallons in 1890; in Chicago,
112 gallons in 1880 and 127 gallons in 1890; in St. Louis, 72
gallons in 1880 and 78 gallons in 1890; in Detroit, 130 gallons
in 1880 and 155 gallons in 1890. In general the consumption
of water shows a gradual increase in all the cities of the
United States, but according to reliable estimates nearly one-
half this is waste. This is demonstrated by the use of the