General Water Distribution

32問 • 2年前

問題一覧

The water service pipe is an underground pipe that is typically called a ______. It extends from the underground street main that is part of a district or city water system and delivers pressurized potable water to a building plumbing system.

LATERAL

In the conventional rigid-pipe distribution configuration, the hot and cold water distribution pipes are installed ______ to one another as they convey hot and cold water to risers and branch pipes.

PARALLEL

A ___________________________________consists of a plastic or metal plumbing manifold and flexible plastic piping. The manifold serves as a common location from which all the plumbing fixtures are supplied.

HOMERUN OR MANIFOLD DISTRIBUTION CONFIGURATION

Two basic types of water supply distribution systems are used in buildings: the ________ (or upflow) system and the _________ (or downflow) systems.

UPFEED, DOWNFEED

• Fluid (gas or liquid) molecules tend to seek equilibrium (a stability of forces). When forces acting on a fluid are unequal, molecules in the fluid move in the direction of the resultant forces. • Therefore, an elementary property of any fluid at rest (not flowing) is that the force exerted on any molecule within the fluid is the same in all directions.

HYDROSTATIC PRESSURE

This pressure loss or pressure drop in a plumbing system is from friction loss as the water moves through the system and pressure loss as water is forced to a higher elevation (e.g., from the basement to an upper story).

WATER PRESSURE

• If pipe diameters are small, cost is low but noise, erosion (from high velocities), and pumping costs (from high-pressure losses) are high. • In contrast, large diameter pipes reduce noise erosion and pumping costs, but result in high installation costs. An intermediate pipe diameter is desirable.

WATER VELOCITY

____________ is a physical phenomenon that occurs in a liquid when it experiences a drastic drop in pressure that causes the liquid to vaporize into small vapor bubbles.

CAVITATION

__________ is a problem because the liquid being vaporized expands greatly; for example, 1 ft3 (or 1m3) of water at room temperature becomes 1600 ft3 (or 1600 m3) of vapor at the same temperature.

VAPORIZATION

As the low pressure returns to normal pressure levels, these bubbles implode as the vapor changes phase back to a liquid and thus drastically decreases its volume.

CAVITATION

___________is an unsatisfactory connection or arrangement of piping that can cause non-potable water to enter the potable water system. each day—half of these from garden hoses.

CROSS-CONNECTIONS

What does AWWA means?

AMERICAN WATER WORKS ASSOCIATION

•__________is a type of cross-connection that occurs when contaminated water or someother liquid or substance unintentionally flows backwards into distribution pipes containing potable water. •Simply, it is water flowing in the opposite direction from normal flow.

BACKFLOW

In a plumbing supply system, the sudden closing of a valve will cause fast-flowing water to stop quickly, resulting in a large increase in pressure that is known as ___________.

WATER HAMMER

__________ are 15 in to 5 ft long pipes or pipe-like devices. They are installed vertically above the fixture water connection and are concealed in the wall.

AIR CHAMBERS

______________ are patented devices that absorb hydraulic shock. Such devices, when installed, must be accessible for maintenance.

WATER HAMMER ARRESTORS

No matter what type of piping material is used in the water system, some expansion in the pipe will occur.

THERMAL EXPANSION

As water flows through a pipe, its _________ (thickness) decreases with temperature decrease.

VISCOSITY

A phase change from liquid (water) to solid (ice) results in about a 10% increase in volume.

FREEZING

Liquid water expands above 39°F (4°C). Expansion is about 4.37% from 40°F (4.4°C) to 212°F (100°C). This volumetric change from expansion (ΔV) equates to about 0.0254% per °F (0.0457% per °C).

EXPANDING WATER

As pipes in a plumbing system are used, their inner walls become increasingly rough. The effects of aging in a plumbing system are related to piping material, quality of water (e.g., hard versus soft), and water temperature. Buildup from calcium deposits (especially in high-temperature hard water) and corrosion (especially in ferrous pipe materials) reduces the inside opening in the pipe, which restricts flow.

AGING

__________is applied to the outer walls of piping to reduce heat loss from the pipe or prevent condensation on the outside pipe walls. ex: foam & covered fiberglass insulation

PIPE INSULATION

The water supply system should be tested for leaks before it is covered with finish materials to determine if it is watertight.

TESTING

______ not only waste money and water, they can cause damage to walls, flooring, ceilings, furniture, and electrical systems. Leaking pipes also create an environment for mold and mildew to thrive.

LEAKS

A ________potable water that is heated to at least 120°F.

HOT WATER

__________ is an appliance or system that heats water for domestic or building service hot water use.

WATER HEATER

Consists of a storage tank and a heating medium. Typically, storage tank sizes include 30, 40, 50, 60, 65, 75, 80, 100, and 120-gal (120- to 400-L) capacity. (TYPE OF WATER HEATER)

STORAGE TANK WATER HEATERS

Sometimes called tankless water heaters or demand water heaters, supply hot water on demand. They do not rely on a standby storage in a tank to artificially boost their capacity. (TYPE OF WATER HEATER)

INSTANTANEOUS WATER HEATERS

Consist of a separate storage tank that stores water heated by a heat exchanger. The heat exchanger may be a separate unit that is heated by steam or hot water from a boiler or may be contained in a boiler

CIRCULATING WATER HEATERS

A building’s space heating boiler can also be used to heat water. Two types of water heaters that use this system are _________ and ___________. (TYPES OF WATER HEATERS)

TANKSLESS COIL, INDIRECT WATEE HEATERS

Extract energy from outdoor air and use it to produce hot water very efficiently. (TYPE OF WATER HEATER)

HEAT PUMP WATER HEATERS

Typically includes collectors mounted on the roof or in a clear area of the yard, a separate storage tank near the conventional heater in the home, connecting pipes, and an electronic controller.

SOLAR WATER HEATERS

WORLD BANK AND IMF (FROM WEB)

Honey Joy T. Dallego · 21問 · 2年前

WORLD BANK AND IMF (FROM WEB)