Pipes and fittings

1.Read and translate the text

Half-hard tempered copper tubing is the most popu­lar material for the pipework. It is lightweight, solders well and can be bent by hand using a bending spring. This is essential to avoid crimping the walls of the pipe, which reduces the diameter of the pipe.

The standard sizes are:

15 mm (0.5 in); 22 mm (0.75 in); 28 mm (1 in)

In metric systems the pipe is measured by its outside diameter.

You can use two different joints to connect copper pipes to fittings:

1. compression joints;

2. capillary joints.

(b)

Figure 18.7 Two types of joint for copper pipes: (a) compression joints; (b) capillary joints.

The compression joints in Figure 18.7 are the easiest connections to make. One end of a fitting is threaded at the bend or tee. The end of the pipe that fits into the bend or tee has a nut and ferrule. You push the nut of the pipe into the threaded end of the fitting. This pushes the ferrule into its mouth. When you tighten the nut then the ferrule is com­pressed. This makes a watertight joint. This method is also good for tap, valve and cylinder connec­tions.

The capillary joints in Figure 18.7 are less popular because you need to use a blowlamp to soften the solder that joins the pipes. Capillary joints also need a compression joint at the connec­tion to a tap or fitting. You make a capillary joint by pushing one end of a pipe into the end of a bend or tee with a ring of solder in a groove. You then move a blowlamp over the pipe to soften the solder. When solder appears at the edge of the joint you should allow the completed joint to cool. You can remake the joint by reheating.

Iron pipes require a different method to join them. You need to cut a thread in the end of the iron pipe after it has been cut to the correct length.

Bends and tees are usually already grooved to receive threaded pipes. You cover the threaded end with a jointing compound and bind it with hemp or tape wound in the direction of the thread. To complete it, you tighten the fitting on the threaded pipe.

Check your understanding

• Water for domestic buildings is mainly used for drinking, cooking and washing.

• The pressure in the main supply comes from gravity or pumping.

• Water for drinking and cooking may come di­rectly from the main supply.

• Water used for other purposes can be stored in a tank.

• Overflow pipes are fitted to storage tanks to avoid damage to the interior of the building.

• You use hot water mainly for washing and cleaning.

Water can be heated by:

1. electric boilers or immersion heaters;

2. solid fuel boilers;

3. gas or oil boilers;

4. solar power collectors.

• A hot water installation must have a vent or expansion pipe to relieve pressure in the pipework if the system overheats.

• The cold water storage tank must be higher than the hot water cylinder to provide the pressure to push the water out of the taps.

• Boilers use primary circuits to heat water.

• Immersion heaters use an element in the tank to heat the water.

A passive solar system uses thermal syphonage to heat water.

• An active solar system needs a pump to circulate water from the collector to the stooge cylinder.

REVISION EXERCISES AND QUESTIONS

1. What are three sources of water?

2. What does a water treatment plant do?

3. What are the purposes of:

stored water

mains water?

4. What do the following parts of a plumbing system do:

a stop cock

a ball valve?

5. What are the main differences between active solar water heating systems and passive solar water heating systems?

6. What are two methods for joining copper water pipes?