Page 159 - The City and Guilds Textbook: Plumbing Book 1 for the Level 3 Apprenticeship (9189), Level 2 Technical Certificate (8202) and Level 2 Diploma (6035)

SCIENTIFIC PRINCIPLES CHAPTER 3

CHAPTER 3

INTRODUCTION

Plumbing contains a lot of science. The laws of physics and chemistry are involved in one form or another in
almost everything that we do, from the installation of cold water systems and hot water systems to central
heating and drainage. It is the science behind these laws that gives us the theory to enable us to design and
install these systems correctly and efficiently. In this chapter, we will be investigating some of the laws of
physics and chemistry that we use in our day-to-day activities.

By the end of this chapter, you will have knowledge and understanding of the following:
l units of measurement used in the plumbing and heating industry
l properties of materials
l the relationship between energy, heat and power
l the principles of force and pressure, and their application in the plumbing and heating industry
l the mechanical principles in the plumbing and heating industry
l the principles of electricity in the plumbing and heating industry.

Before we begin, it is important that we familiarise ourselves with the SI units of
measurement so that we can use these as reference points during this chapter.

1 UNITS OF MEASUREMENT USED

IN THE PLUMBING AND HEATING

INDUSTRY: THE SI SYSTEM

The SI system of measurement is a universal, unified, self-consistent system of KEY TERM
measurement units based on the m/k/s (metre/kilogram/second) system. We Derived units: combinations
will use these measurement units as reference points throughout this chapter. of the seven base units by
The international system is commonly referred to throughout the world as SI a system of multiplication
after the initials of ‘Systeme International Unite’. The units can be categorised and division calculations.
into two main groups: There are 21 derived units
of measurement, some of
1 base units which have special names
2 derived units. and symbols.

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