6. Purge - Why Do We Purge

• City and Guilds
• Further Education (Key Stage 5)

Purge - Why Do We Purge

This lesson is intended to be a supplement and revision aid. 

It is to be used together with your in-class lesson notes and gas book.

Completion of this lesson adds to your Guided Learning Hours.

Guided Learning Hours - 3 Hours

Introduction Video

The purging video is a bit of an old one and the sound isnt great but it explains why we purge.

It is an introduction to an important and quite complex part of your course.

I've popped in a few questions just to highlight some important details.

Don't expect to understand it all until you've been taught it in class and have actually carried out a purge in the workshop.

To ensure that all the air has been purged from a system we multiply the size of the system pipework by...

1. 10
2. 1.5
3. 2
4. The size of the meter

When calculating the pipework volume (pv) we add 10% to the total capacity. WHy do we do this?

1. To allow for elbows and tees
2. To allow for any mistakes in our calculations
3. To allow for expansion due to heat
4. To allow for expansion due to cold

Write down 3 things you learned in this lesson.

Have students enter three things they learned in this lesson. With this they can indicate their own learning efficiency of this lesson.

Write down 2 things you want to know more about.

Here, students enter two things they would like to know more about. This not only increases involvement, but also gives them more ownership.

Ask 1 question about something you haven't quite understood yet.

The students indicate here (in question form) with which part of the material they still have difficulty. For the teacher, this not only provides insight into the extent to which the students understand/master the material, but also a good starting point for the next lesson.