TECHNICAL
83
Basic theory of fluid
mechanics for plumbing
Artists must understand the medium and the materials they
work with so work of value can be produced. The same applies
to plumbers — their medium being water. In this, the first of a
series of articles that will run exclusively in Plumbing Africa,
we take a closer look at water.
By Chris Kyle
Now here’s the difference: if the artist produces
poor work, it is of little consequence. A poor painting
won’t ruin a building or an environment; it can
simply be removed and replaced with something
more appealing, whereas the plumbing services in a
building, once installed, are to a considerable extent
permanent and cannot easily be changed without
huge inconvenience and cost.
Plumbers are professionals who are entrusted to
ensure the nation’s health and safety when it comes to
sanitation, as well as the preservation of humankind’s
most critical resource: water. This responsibility in
anyone’s book is a very onerous one that should not be
taken lightly.
and one oxygen atom; thus, its symbol is H 2 O. Water
molecules are so small that about twenty thousand,
million, million, million water molecules are present in an
average drop of water.
Water molecules bond together through a process of
‘hydrogen bonding’. This bonding is relatively weak by
comparison to that of other bonds, whereby it is strong
enough to stick together but is easily parted when an
object is placed into a mass of water.
Oxygen
The more we know about the medium, materials, and
principles we work with and their characteristics, the
better we will be able to offer safe, compliant, and
sustainable solutions while also increasing our ability to
solve problems.
Remember that many aspects of engineering and
physics are based on natural phenomena — that what
happens in the natural environment. Plumbing is a
division of engineering.
We’ll begin with the absolute basics.
Practical applications of the theories are boxed in italics.
WHAT IS WATER?
Water is a transparent, tasteless, odourless, and almost
colourless fluid.
Chemical composition
The water molecule is made of two hydrogen atoms
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Hydrogen
A water molecule.
States
Water can exist in three states; that is:
1. Gas: Water vapour — an invisible gas. Water
changes from liquid to gas (boils) in the ambient
atmosphere at sea level at approximately 100°C
or when pressure is dropped below the
vapour pressure.
2. Liquid: As a rule of thumb, water remains liquid
between 1°C and 99°C and will flow from a
high- to low-pressure area.
3. Solid: Water becomes ice at 0°C.
About the author
Chris Kyle is a qualified
commercial pilot and flying
instructor, accredited CETA
trainer and assessor, CPD
course writer and presenter
to the architectural fraternity,
and professional plumbing
industry licensed plumber.
Chris has plotted his course
in the building industry from
his early days as national
specifications manager for
Cobra Watertech, to where
he is today as the general
manager of Calafrica.
August 2018 Volume 24 I Number 6