Underground Utilities

Question 1

What type of piping reduces in cross sectio by folding for insertion?

Answer 1

Thermo Formed Pipe

Question 2

When should in-line replacement by considered (ILR)?

Answer 2

When the capacity of a pipeline is found to be inadequate

Question 3

Three main categories for trenchless construction methods:

Answer 3

1. Horizontal Earth Boring
2. Pipe Jacking
3. Utility Tunneling

Question 4

The steeper the slope of a gravity pipe the ___

Answer 4

higher the possibility that pipe segments deteriorate

Question 5

Depending on the size of the pipe and the nature of the lining being applied, the recycled content for DI pipe can exceed ____%

Answer 5

90%

Question 6

Steel building LEED Credit: use materials with recycled content such that the sum of post-consumer recycled content plus one-half of the post industrial content constitutes?

Answer 6

5% of the total value of the materials in the project.

Question 7

List Pipe Weld Positions:

Answer 7

1g horizontal rolled position
2g vertical position
5g horizontal fixed position
6g inclined position - 45 degrees

Question 8

What is PBT?

Answer 8

Polybutylene is a flexible (grey or black) plastic pipe which is attached with barbed fittings and secured in place with a copper clamp

Question 9

Galvanized CSP can provide a service lift of?

Answer 9

50 years

Question 10

What is HOBAS Pipe?

Answer 10

HOBAS is a manufacturer of glass fiber reinforced plastic

Question 11

How many miles of interstate and instrastate transmission NG piplines are there?

Answer 11

300,000 miles of NG pipeline

Question 12

Why does the slope of a gravity pipe have an impact on the condition of the pipe?

Answer 12

The steeper the slope the higher the possibility that pipe segments will deterorate.

Question 13

What is a sonde and what test system is it used with?

Answer 13

Specially constructed electrode used with the FELL test - Frequency location - pinpoint blockages or pipeline defects when used with video inspection systems

Question 14

What type of paints use varnish as a vehicle?

Answer 14

1. Resing Based Paints
2. Oil Based Paints
3. Enamels

Question 15

Vinyl alkyd resin is used to control corrosion on what surface?

Answer 15

Steel

Question 16

What is the millimeter thickness for a single coat polymer on underground applications?

Answer 16

40 to 250 mm

Question 17

What are the burn temperatures for a:

1. Propane/Air Flame
2. Propane/ Oxygen Flame
3. Acetylene/Oxygen Flame

Answer 17

1. 2,000 C (3,630 F)
2. 2,500 C (4,350 F)
3. 3,500 C (6,330 F)
   * T(F) = T(C)*1.8 + 32

Question 18

What is the most common method of mechanized brazing?

Answer 18

Torch brazing

Question 19

What is a semi-automatic or automatic arc welding process that requires a continuously fed consumable tubular electrode containing a fluz and a constant voltage?

Answer 19

FCAW = Flux-cored arc welding

Question 20

When not welding, Arc welding involves open circuit voltages of?

Answer 20

20 - 100 volts

Question 21

What is vacuum aluminum brazing?

Answer 21

A high purity process and, inlike drip-brazing, there are no residual salts left on the surfaces or trapped within the recess features of the components to be brazed.

Question 22

A three-carbon alkane with the molecular formula C3H8 is?

Answer 22

Propane

Question 23

What is a high vapor pressure, unsuitable for vacuum brazing?

Answer 23

Maganese

Question 24

What is the difference between MIG & TIG Welding?

Answer 24

MIG = wire feed- metal inert gas - GMAW = Gas Metal Arc Welding

TIG = heli-arc - tungsten inert gas - GTAW = Gas Tungsten Arc Welding

Question 25

Water hydrants - connecting a line to main should be no less than?

Answer 25

6” per AWWA Manual M-17

Question 26

A water hydrant should have what size and type of pit to prevent freezing?

Answer 26

2 x 2 x 2’ coarse gravel drainage pit to a depth of 6” above the hydrant openings.

Question 27

Average cure time for thrust blocks?

Answer 27

At least 2,000 psi at 28 days and with a minimum cure time of 5 days

Question 28

What is the flush velocity and pressure test of ductile iron water lines?

Answer 28

Flush velocity at 3 FPS | P-test at 1.5 times the stated working pressure for at least 2 hours

Question 29

What are the three methods of chlorine cleaning piping?

Answer 29

1. Continuous feed 2. Tablet 3. Slug AWW C51 25mg/L feee chlorine and retained at least 24 hours and tested - 1fps

Question 30

Ductile iron service tap requirements?

Answer 30

For 6” and larger DI pipe -> 1” direct taps located at 10 or 2. Taps staggered around circumference at least 12 inch apart. Do not drill in a straight line. -> dissimilar metals at connections - 3’ clear distance of dielectric tape

Question 31

Temperature growth of DI pipe?

Answer 31

100F, 20’ length at 0.15 inches.

Question 32

Wall penetration recommendation?

Answer 32

Locate flexible joint about 18” from wall:

Question 33

Cover requirements for a NG main and pipeline?

Answer 33

Main -> not less than 24” | Pipeline -> 24” - 36”

Question 34

Clearance between NG mains and pipelines and other underground structures?

Answer 34

Main -> 6” | Pipeline -> 2”

Question 35

Spacing between valves for NG pipeline dependent on location class?

Answer 35

Class 1 = 20 miles Class 2 = 15 miles Class 3 = 10 miles Class 4 = 5 miles

Question 36

Class location definitions for NG pipeline?

Answer 36

Class 1 = 10 homes are fewer Class 2 = more than 10 but fewer than 46 homes Class 3 = 46 or more homes Class 4 = high rises/ urban

Question 37

Formula guideline for maximum width of trench for concrete pipe?

Answer 37

1.25D + 1 foot

Question 38

How should you lay concrete pipe?

Answer 38

the bell end typically should point upstream and the spigot or tongue should point downstream

Question 39

Minimum Flattened Polyethylene Tube Widths for Push-on Joint* pipe?

Answer 39

Approximately 1.25OD + 12”

Question 40

What are the three devices used for compaction and the type of soil they compact best?

Answer 40

The steel wheeled roller is best suited for compacting coarse aggre- gate such as slag, coarse gravel and graded rock aggregates. The sheepsfoot roller is best for co- hesive clays or silts, but is not suitable for use on granular soils. Specially designed rubber tired roll- ers, which provide both static weight and kneading action, are applicable to many soils from clays to sand.

Question 41

To perform the infiltration test on concrete pipe, the water table should be at least what height over the crown of the pipe?

Answer 41

2 feet

Question 42

What is the minimum thickness of the base course, aggregate size and layer thickness for a culvert?

Answer 42

3” minimum base layer with 2” layers and 1-1/2” sized aggregate

Question 43

How should boxes be placed?

Answer 43

start at the outlet end of the line of box sections. The bell end should point upstream and the spigot or tongue should point downstream.