Read and summarize the text below.

 

Text 6 B

Wastewater Systems

 

Older wastewater systems use cast-iron pipes for all pipes three inches and above, and often for two-inch pipes. Smaller pipes were generally lead at first, then copper. The cast-iron pipes were usually joined by inserting the straight (spigot) end of one into the flared (hub) end of the other. Most joints of smaller pipes into the drain pipes would involve brass ferrules, over which the smaller pipe would be pressed, then molten lead wiped around the joint to effect a seal.

Cast-iron pipe is still used, but it is used without the hub system, "no-hub bands" being used to join the straight ends of two pieces. These are rubber collars which include a hose clamp to effect a liquid and gas-tight seal. Cast-iron is still commonly used in commercial and industrial DW systems due to its durability and is often required by building code due to its non-combustibility. All cast iron soil pipe systems are notoriously difficult to work on, with reasons including weight, cost, corrosion of threaded joints, and requirement for specialized tools like pipe cutters and pipe threaders.

Copper and brass domestic waste (DW) systems were popular from about 1950 to 1970, depending on local building codes. They may be heralded as a precursor to modern plastic DW pipes, since they were a lot lighter and easier to work with than cast iron, lead, or clay, all of which had been used previously. Being non-combustible, copper and brass remain the soil pipes of choice in many places where building codes require non-combustible drains and may often be found in new apartment buildings and hotels.

Fittings are soldered into place as with potable copper supplies. In DW applications, copper and brass are subject to acidic corrosion and therefore have a finite lifespan.

Today, most residential wastewater plumbing systems use schedule 40 PVC (polyvinyl chloride). This is joined using fittings that the pipe fits into with a close tolerance; the joint being sealed with a glue after a solvent cleaner (or primer) is used.

ABS (acrylonitrile bytadiene styrene) is a thick-walled black plastic pipe mainly used for repairing old systems that used ABS, but it remains popular due to concerns over toxic outgassing when PVC burns.

In commercial applications, acid resistant waste piping systems may be required. These can be made from polypropylene, polyethylene, tempered glass, stainless steel, high silca ductile iron, or fiber re-inforced polymer. The material is selected based on the type of waste to be conveyed. Acid neutralization tanks are often required to protect non-acid resistant sewers. Also, interceptors may be required to keep oil, grease, sand, plaster, lint or hair from clogging waste piping.

 

Notes on the text:

 

threader - резьбонарезной станок; винторезный станок; болторезный станок

precursor - предшественник

lifespan - продолжительность жизни

polyvinyl chloride = PVC - поливинилхлорид

acrylonitrile bytadiene styrene = ABS – акрилонитрил бутадиен стирол

polypropylene - полипропилен

tempered glass - закалённое стекло

12. Read and translate the information below:

 

Figuring Out Your Drain-Waste-Vent Lines

 

If you have to make plumbing repairs around your home, it helps to understand your drain-waste-vent system (DWV). The fat pipes in your house make up the DWV, carrying wastewater to a city sewer line or your private sewer treatment facility (called a septic tank and field).

The drainpipes collect the water from sinks, showers, tubs, and appliances.

The waste pipes remove water and material from the toilet.

The vent pipes remove or exhaust sewer gases and allow air to enter the system so that the wastewater flows freely.

The drainpipes are made of cast iron, galvanized pipe, copper, or plastic. Local building codes that regulate the materials used in the DWV system have changed over the years, so most older homes have a combination of materials.

A typical bathroom sink is a good example of how all these components work together. You probably haven’t spent much time observing the pipes beneath your vanity, but take a look and this is what you’ll see:

Water runs down the sink drain into a p-trap (so called because it’s shaped like the letter), which fills up with water to prevent sewer gases and odors from getting into the house through the pipe. This water gets refreshed whenever more water runs through it.

A drainpipe attached to the p-trap goes into an opening in the wall.

Behind the wall (where you can’t see), a vent line and drainpipe lead to a soil stack, which is the control center of the wastewater system. Drain pipes take the wastewater to the soil stack; through the stack, sewer gases are carried up to the roof through vent lines.

All the faucets and water appliances in a house use this same system of drains, pipes, and vents. All the waste lines have a cleanout, which is a Y-shaped fitting that’s accessible so that you can clean out any serious obstructions within the system.

13. Read and translate the text below:

 

Text 6 C