Above-ground drainage

1 . Memorise the following technical words:

bottle trap – бутыльчатый сифон

clamping ring – обжимное кольцо

collar – патрубок

compression joint – соединение обжатием,

female ring – кольцо с внутренней резьбой; охватывающее кольцо

male – с наружной резьбой

O-ring – уплотнительное кольцо, уплотнительный сальник

outlet – выпускное отверстие

plumbing – прокладка водопроводных и канализационных труб(в здании)

push fit – заталкивание, забивание

rubber washer – резиновая прокладка

sanitary appliances – санитарно-техническое оборудование

sanitary fitting – санузел

seal – водяная завеса, изолирующий слой, водяной затвор

soil pipe – канализационная труба

soil stack – канализационный стояк

tight seal – герметичное уплотнение

uPVC – непластифицированный полихлорвинил

“U”trap – U-образный сифон, двухколенчатый сифон

waste pipe – сливная труба (от санузлов к канализационной трубе)

WC pan – унитаз

welded joint – сварной шов, соединение сваркой

2.Read and translate the text:

The purpose of this section is to describe how waste water goes from the sanitary fittings to the underground drainage connections.

Above-ground drainage is installed after the roof is put on the building to protect the fittings from the weather. The pipework runs along the surface of the walls so that it is accessible for cleaning and clearing.

Above-ground drainage is connected by one of these two methods:

1. The 100 mm outlets for WCs are connected by branch pipes to vertical pipes, called soil stacks, that connect to the drains. inside or outside the building. The underground drains have sockets that fit spigots on the soil pipes. The water seal or trap formed in a WC pan ensures that gases and smells from the drain do not enter the building.

2. Other sanitary fittings such as baths, basins, showers and sinks have smaller outlets, which cannot be directly connected to the drains. They are connected to the underground drains by one of these methods:

- wastes flow through above-ground pipes and discharge over or flow into trapped gullies at the top end of the drains;

- wastes flow from above-ground pipes into the soil stack that carries the WC waste.

The pipework to sanitary fittings The soil and waste pipes that carry the discharge from sanitary fittings are usually made from unplasticised PVC (uPVC). UPVC pipes come in a range of sizes to suit the plumbing requirements. Typical diameters are - 32 mm; 38 mm; 50 mm; 75 mm; 100 mm. (Figure 5.)

You can choose from four types of joint for uPVC pipes:

1. push fit with rubber ‘O’ rings for pipes with larger diameters (75-100 mm);

2. spigot and socket joints;

3. welded joints, which are spigot and socket con­nections that are welded firmly together with a solvent;

4. compression joints, which are used for smaller- diameter pipes like the traps on the waste pipes for baths and basins. A compression joint is a male collar which screws onto a female ring. This compresses a rubber washer to form a tight seal.

Figure 5. Standard joints for uPVC pipes: (a) push fit joint with an 'O' ring; <b) spigot and socket joint; (c) welded joint; (d) compression joint.

The purpose of traps. All sanitary fittings have traps, which are either built in or separate. The trap is a water seal be­tween the drain and the sanitary fitting to keep out gases and smells, which are unpleasant and un­healthy.

The traps for sanitary fittings are usually the standard sizes.

It is important to ensure that the trap fittings connected to the internal pipework maintain a secure seal. When water is discharged from a sanitary fitting by flushing a toilet or draining a basin, then some of the water should stay in the trap to maintain the seal.

Traps and sanitary fittings. Traps are usually made from uPVC. They attach to the waste fittings of sanitary appliances and match the diameter of the pipe joints.

Two types of traps are in common use:

1. the bottle trap, which is shaped like a bottle. The lower part, containing the trap, unscrews for easy cleaning;

2. the ‘U’ trap, which is formed by bending a pipe into a ‘U’ shape.

Ventilating the indoor drainage system. An indoor drainage system needs to be ventilated to prevent gases from the sewer entering the building. You ventilate the system by extending the drain that takes the waste from the WC, called a soil vent pipe, above the level of the roof. The soil vent pipe may run up an external or internal wall.

The soil vent pipe allows the gases to escape safely into the atmosphere. The top of the pipe should have a wire cage to prevent birds entering and blocking it.

3.Answer the questions:

1. What does above-ground drainage consist of? 2. Where is above-ground drainage connected to the underground drainage? 3. What is the function of a trap? 4. How is an indoor drainage system ventilated?

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