Page 285 - Facility Piping Systems Handbook for Industrial, Commercial, and Healthcare Facilities

SITE UTILITY SYSTEMS

SITE UTILITY SYSTEMS 6.7

T = Dimension from centerline of pipe to grade

FIGURE 6.6 Shape factor.

The following example will illustrate the use of Eq. (6.1):
K = 10 −4 fpm

H = 6ft
C = 053. (from Fig. 6.5)
T = 25 ft (This is the dimension by examining the borings from grade to the impervious
layer under the water table. L = 20 ft.
Therefore:

Q = 1 × 0 0001 6 0 53 0 0000053. × × . = . cfs/ft of pipee
60

To this figure, add 25 percent additional flow if the height of a wet period occurred in the
immediate past and 50 percent additional flow if the height of the dry season is occurring at
present. These figures are the author’s estimate for a reasonable allowance. It is important
to check with local building officials for confirmation based on their experience.
There is always the possibility of groundwater being polluted. Before groundwater is
discharged into the public sewer, samples of the water should be taken. Acceptable sam-
pling and testing procedures must be used. The key terms used are sampling for priority
pollutants and contaminants of concern. After the tests are run, a full assessment by the
local, state, and federal authorities must be made to determine both the extent of any con-
tamination and the ultimate method of disposal.

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