Plumbing Africa August 2018 - Page 85

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 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