## The Gas Laws in Action

### Bord Gáis Networks

Chemistry
Physics
Technology
The Gas Laws describe how the volume, temperature and pressure of a mass of gas are related. The design and safe operation of the natural gas network involves the practical application of these laws.

Contains the full lesson along with a supporting toolkit, including teachers’ notes.

### Lesson excerpt

Part of Our Lives
We are all aware that gas is widely used as a fuel in our homes and in industry. We may not be aware that the gas we use comes from sources hundreds of kilometres away and is transported by Bord Gáis Networks to our homes and businesses through a network of pipelines. This network is an effective and efficient method of moving gas from source to user. However, the engineers who design and manage the network could not do so without a sound knowledge of the famous Gas Laws. In this lesson, we will look at these laws and see how they affect the operation of the Bord Gáis network as it carries gas from Scotland to users in all parts of Ireland.

Overview of the Network
The gas network is efficient because the gas can be compressed and transported at high pressure and this is more economical than liquefying the gas and transporting it by tanker. The network consists of high pressure underground steel pipelines that bring gas to cities and towns throughout the country and low pressure polyethylene pipelines within urban centres.

Onshore terminals at Gormanston, Co. Meath and Loughshinny, Co. Dublin receive the gas from Scotland through two undersea pipelines called Interconnector 1 and Interconnector 2. The gas pressure in these pipelines is about 150 bar (15 MPa). This is reduced to 85 bar before the gas is introduced into the Bord Gáis network. This high pressure gas moves through the main network until it reaches the local networks, where the pressure is reduced to 4 bar (400 kPa). Pressure units are explained in the panel below.

### True or False?

1. Steel pipelines are used for high pressure networks, whereas polyethylene is used for the low pressure local network. true
2. Bord Gáis on-shore locations are sited in Co. Wicklow. false
3. Boyle’s Law states that P1V1 = P2V2. false
4. In the Bord Gáis network the term PRS means Private Regeneration Station. false
5. When most real gas expands freely, the temperature decreases. true
6. The bar is a unit of temperature. false
7. Bord Gáis also provides electricity to customers. true
8. The gas pressure in the undersea pipes is about 10 bar. false
9. The unit of pressure is the newton. false
10. Charles’ Law states that V1/T1 = V2/T2. true