Page 60 - Urban water supply handbook

URBAN WATER INFRASTRUCTURE: A HISTORICAL PERSPECTIVE

URBAN WATER INFRASTRUCTURE 1.59

up to the vicenaria, or 20-pipe, the
diameter in each unit increasing by
the addition of individual quarter-
digits, as in the senaria, or 6-pipe,
which has a diameter of six-fourths,
and the septenaria, or 7-pipe, which
has seven, and so on by similar
increases, up to the vicenaria.

Frontinus defined 25 pipe sizes with
the first being the quinaria.
Frontinus (39):

The quinaria pipe: diameter, 1 digit
1
plus /4; circumference, 3 digits plus
3
11 /12 plus /288 [3.9272 digits]; capac-
ity, 1 quinaria.
The quinaria has an inner diameter of
2.31 cm, a circumference of 7.27 cm,
2
and a cross-sectional area of 4.2 cm .
FIGURE 1.46 Brick tower on which sec-
ondary castella (lead storage tanks) were The quinaria was used as the unit for
3
mounted on top of the tower. Lead pipes were rate of flow (41.5 m /day) (Hauck,
used for the flow of water to and from the lead 1988).
tanks and were placed in the vertical recessed
portion shown in the tower. The exiting lead
pipes (calices) branched off to supply individ- Lead Pipes. The use of lead pipes was
ual customers and also supplied the public the most common method of conveying
fountain shown at the base of the tower. water from the castella to the public
(Photo by Larry W. Mays and copyright by
Larry W. Mays) fountains and private houses through-
out the Roman Empire. It is interesting
to note that the Latin word for lead
workers was plumbarii, which found its way into the English as plumbers and into
French as plombiers. Lead pipes were recognized as a health hazard by the
Romans, and Vitruvius warned against their use. However, because of the calcium
carbonate buildup inside the pipes and the fact that water was moving continu-
ously in the pipes indicates that the Romans most likely did not contract lead poi-
soning from the lead pipes in their water supply systems (Hodge, 1992). Lead had
many advantages including: (1) it was cheap, (2) it was readily available in large
quantities, (3) it was easy to handle and malleable enough to form sheets, (4) it had
a low melting temperature so it was easy to cast and to solder, (5) it was flexible
enough for pipes to be bent around obstructions, and (6) it was strong enough to
handle water pressures developed in the water supply systems.
Both Vitruvius and Frontinus discussed the process of making lead pipes.
First, the lead was melted and poured out from a melting pot onto a flat surface.

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