Unit 2

90 سوال • 2026-11-11

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The term piping refers to:

all of the above

The most common material(s) used in manufacture of piping is (are):

All of the above

The advantage of tubing over pipe is:

both a and b are correct

The advantage of pipe over tubing is:

Pipe thickness

Which is true when comparing piping and tubing

all of the above

Copper tubing is standardized on the basis of use into standard:

Wall thickness schedules

The most common connections are:

all of the above

What are the four requirements for correctly making up a flange joint?

Thoroughly clean, accurate align, use proper gasket, and tighten bolts in proper order

The difference between brazing and soldering is:

The solder flow temperature

Which functions do pipe fittings perform?

All of the above

The gate valve is not designed for throttling, however:

It has a relative low pressure drop across it

The globe valve is designed for throttling, however:

It has a relatively high pressure drop

Which valve is quick acting, and indicates open or closed by its handle?

Ball valve

Which valve uses a disc, and has a 90° rotation?

Butterfly valve

Which valve may have to be lubricated to assist movement (opening or closing)?

Plug valve

What valve is designed to allow flow in only one direction?

Check valve

A valve installed to reduce high pressure steam entering a building is:

Pressure reducing valve

A valve designed to relieve pressure in the event of overpressurization is the:

Pressure relief valve

A normally open valve is a two-way valve:

That is open without any force applied to it

A three-way valve can be:

any of the above

A site-specific FDNY permit is required for:

all of the above

A hot work program authorization:

Must be signed, issued by responsible person and available for inspection

Hot work consist of:

Welding, brazing, soldering

Usually it is the ______ that causes the fire:

thousands of sparks and slag

While hot work is performed:

Sprinkler system protection must not be shut off or impaired

A fire watch for torch operations should be conducted by fire guard:

In any building, when torch operation is conducted by person with permit

Acetylene valves shall:

Not be opened more than 1 ½ turns

Fuel gas or oxygen containers stored must be separated from any combustible material by a minimum distance of:

20 feet

________ will react chemically with acetylene and may cause explosion.

copper

The C of F holder is:

Both b and c are correct

A domestic water distribution system must deliver water:

all of the above

An upfeed system:

Is pumped upward through vertical piping to the highest point of the building

A downfeed system:

Both a and b are correct

Pressure loss in pipes is due to:

All of the above

Which is the best description of back pressure?

Increase in pressure in the downstream piping system

With the exception of water closets or other fixtures with integral traps built into the fixture body, every plumbing fixture connected directly to a sanitary drainage system must have a(n):

Separate water seal trap

A flushometer is a flush valve that:

provides a mean of opening water supply so it can discharge a predetermined volume of water

(A) type(s) of flushometer(s) may be:

all of the above

Two __________ chambers are used to operate the flushometer. How these __________ chambers are __________ will determine which type flushometer is used.

Pressure, pressure, separated

All flushometers rely on __________ in upper and lower chambers to allow water to flow.

changes in pressure

Problem(s) that lead to failure in water systems is (are):

all of the above

Scale buildup reduces heat transfer, increases energy cost and could lead to system shutdown. A scale buildup of 1/32 of an inch can:

Decrease heat transfer by 68%

Reduction of scale formation can be accomplished by:

All of the above

Factor(s) that may contribute to corrosion is (are):

All of the above

_____ is the solid material that accumulates and can cause _____.

Sludge, fouling

With the temperature of water in a cooling system up to 160°F:

every increase of 25 to 50°F causes corrosion to double

Condensers that are not cleaned by punching tubes may require _____.

Acid-based cleaner

The procedure for cleaning a water cooled condenser is:

Shut down system, close isolation valves, drain and clean

Open-loop systems are susceptible to:

Microbiological contamination

Typical treatment for controlling microbiological growth include:

biocides

What do all steam systems have in common?

all of the above

Most commercial buildings in NYC will use:

Utility steam

As steam travels through the distribution system, heat is lost resulting in:

condensate

Advantage(s) of steam systems is (are):

all of the above

Convectors can use what type(s) of convection.

natural and forced

When steam (fin tube) coils are used:

The interior of the space can be heated

What is the result of air in the system?

all of the above

The vacuum pump performs (a) major function(s) such as:

all of the above

The horizontal steam supply pipes between the supply and the heating units are called the ________, and the vertical pipes to the various floors are called ________.

Mains, risers

Before starting the steam system:

All of the above

What is the function of a steam trap?

To remove condensate and air from system

Steam traps may discharge:

Both continuously and intermittently

Type(s) of steam trap(s) is (are):

All of the above

What type of steam trap continuously vents air, is durable and least susceptible to malfunction due to dirt or scale that enters the trap?

Inverted bucket

What type of steam trap is designed to remove condensate continuously and is capable of handling large quantities of condensate?

Float and thermostatic

What type of steam trap allows rapid purging of air at startup?

Both bimetallic thermostatic and bimetal thermostatic

A disc steam trap is also called a(n):

Both a kinetic steam trap and a thermodynamic steam trap

A fixed orifice steam trap is not designed for:

Varying load conditions

A normal operating steam trap will be about:

10°F to 20°F cooler at the outlet

An infrared pyrometer is used to:

Measure temperature when steam traps are not easily accessible

What does a hot water heating system require?

A circulating pump

Advantages of hot water systems over steam systems may be:

All of the above

Air removal is important. Where would air collect in a hot water system?

high spots

Most systems will use a(n) ______ on convectors.

Automatic air vent

What is used to remove entrained air from the water which is installed on the horizontal pipe?

Air separator

Continued circulation that may cause overheating of a zone is prevented by:

Flow control valves

What is used to correct hydronic imbalance:

Balancing valve

An expansion tank is needed because:

All of the above

What replaces the boiler in a hot water system:

Steam, hot water converter

A positive pressure should be maintained to:

avoid cavitation and drawing in air

A warm air heating system consists of:

All of the above

Advantage(s) of forced warm air heating systems over steam or hot water radiators or convectors is (are):

all of the above

In commercial facilities primary heat is often supplied by:

warm air

What is perimeter heating?

Heat supplied along walls near the floor level under the windows

Ventilation is need for:

All of the above

Humidification is needed for:

Human comfort, prevention of static electricity and wood shrinkage

A blower is driven by a V-belt with a __________.

Fixed pulley mounted on the blower shaft

Adjusting the adjustable pulley can:

Vary blower speed, change volume of air

The alignment is checked by using a(n) __________.

Straight edge or thin steel wire

A good rule of thumb for determination of proper V-belt tension is that for each foot of distance between pulleys, the belt should have about ___ inch in vertical movement midway between the pulleys.

3/4 inch