HOW TO MEASURE THE
ENERGY USED TO FIRE CLAY
BRICKS
A PRACTICAL GUIDE FOR BRICKMAKERS, FIELD-WORKERS
AND RESEARCHERS
Introduction
In 1996 ITDG (now known as Practical Action) undertook a project working with small-scale
brickmakers in Peru, Ecuador and Zimbabwe. The idea is to disseminate appropriate, energy
efficient principles and practices. But what is an energy efficient brick firing technology? How
do you measure it? And how do you compare it with technologies used in other places?
Data on energy use in brickmaking has generally been collected and presented in a random
fashion. It's often of very little use when trying to evaluate and compare processes. For
example, a report may state 'brickmakers use four sacks of coal to fire a thousand bricks.'
Fine, but what does this tell us about the energy used? We don't know the mass of a sack of
coal. We don't know its calorific value. And we don't know anything about the bricks. What
type of soil are they made from, and how much heat is needed for vitrification - the formation
of the ceramic bond? How wet were they going to the kiln - how much fuel was used simply to
dry them? What is their mass? (Bigger, heavier bricks obviously take more energy to fire.) And
how well burned are they? In short, we know next to nothing useful.
This technical brief
details a way of
gathering and
presenting information
on brick firing. If the
method is followed, it
will allow not only the
energy use of a
particular kiln to be
calculated, but also
the efficiency to be
compared to others
world-wide. There are
Figure 1: Brickmaker lighting a kiln
with a liquid fuel burner. Photo:
Practical Action.
difficulties involved in
establishing a
methodology. For
example, some
scientific knowledge is implicit. Also, facilities around the
world and the resources available to those monitoring brick
firing will be different. As far as possible, the method
presented here minimises costs and the need for specialist
services.
Figure 2: Firing bricks using
wood as a fuel. Photo:
Practical Action.
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