Nevada A-19A Pipelines and Conduits for Water Contractor Examination

According to the DIPRA Installation Guide for Ductile Iron Pipe, what hydrostatic test is recommended for a newly installed water main?

• AAt least 1.5 times the stated working pressure at the lowest elevation of the test sectio…
• BEqual to the stated working pressure at the highest elevation, held for 30 minutes
• CTwice the stated working pressure at mid-length, held for 24 hours
• D50 psi above atmospheric pressure at any hydrant, held for 15 minutes

What minimum flushing velocity does DIPRA, citing ANSI/AWWA C651, use when sizing openings to flush a new water main?

• A1.0 foot per second
• B2.0 feet per second
• C3.0 feet per second
• D5.0 feet per second

How is a ductile-iron push-on joint assembled?

• AThe gasket is seated in the bell groove and the beveled plain end is pushed into the bell…
• BThe gasket is glued to the spigot and the bell is heated until the joint fuses
• CA lead-and-oakum pour is packed into the bell after the pipe is stabbed
• DThe joint is threaded and made up with pipe dope and a chain wrench

Why does DIPRA require bell holes at each ductile-iron joint?

• ATo store extra polyethylene film and unused gaskets next to the joint
• BSo the entire pipe can hang free of the trench bottom until the hydrostatic test is finis…
• CTo create a sump that collects groundwater away from the pipe barrel
• DSo the joint can be assembled and the pipe barrel can rest evenly on the trench bottom

When pipe laying stops for the day, what should be done with the open end of a water main?

• ALeave it open so air can circulate and dry the cement-mortar lining
• BClose it with a watertight plug that can be vented before removal
• CStuff rags in the bell and cover the trench with plywood only
• DCap it with polyethylene film taped to the coating

What is the primary purpose of polyethylene encasement on ductile-iron water pipe?

• ATo make the joint completely airtight and watertight
• BTo increase the pipe's internal working-pressure rating by one pressure class
• CTo isolate the pipe from corrosive soils as described in ANSI/AWWA C105
• DTo replace the need for bedding and haunching around the barrel

How should unused synthetic-rubber push-on and mechanical-joint gaskets be stored on a water-main job?

• AIn a cool location out of direct sunlight, with no contact with petroleum products
• BSoaked in diesel fuel so they stay flexible in desert heat
• CStacked on the hot asphalt berm so they warm before installation
• DHung on the excavator boom where they can air-dry after rain

In normal open-cut installation, which end of a ductile-iron pipe is pushed into the pipe already in the trench?

• AThe bell end is pushed into the previously laid spigot
• BThe spigot (plain end) is installed into the previously laid bell
• CEither end may be used interchangeably with no extra bell-hole work
• DThe flanged end is bolted to the previously laid mechanical joint

Before a length of ductile-iron pipe is lowered into the trench, what inspection does DIPRA require?

• AOnly a hydrostatic shop-test stamp check on the bell face
• BOnly a coating-thickness reading at mid-barrel
• CInspection for damage plus a check of the interior for dirt and foreign objects
• DA magnetic-particle test of every joint after the gasket is seated

Why must sand, dirt, ice, and excess coating be removed from the bell gasket recess and the plain end before jointing?

• ATo reduce the pipe's outside diameter so it fits a smaller casing
• BTo prevent gasket displacement and leaking joints
• CTo allow the cement-mortar lining to bond to the adjoining length
• DTo meet the 1-mil asphaltic-coating thickness in ANSI/AWWA C151

What earth cover does DIPRA generally describe as desirable for water mains to cushion traffic shock where frost is not the governing factor?

• A6 to 8 inches of select sand only
• B12 inches of flowable fill only
• CAbout 2.5 to 3 feet of cover
• DA minimum of 8 feet of cover in every climate

Unbalanced hydrostatic thrust in a pressure water main must be restrained at which locations?

• AOnly at mid-span of long straight runs of push-on pipe
• BOnly at air-release valves on constant-grade tangents
• COnly where the pipe is polyethylene-encased
• DAt bends, tees, reducers, dead ends, and hydrants

How should bundled ductile-iron pipe be unloaded from a truck?

• ARoll the pipe off the side onto a pile of old tires
• BCut the straps with an axe while workers stand beside the load
• CUse a forklift or crane; never roll the pipe off the carrier or drop it onto cushions
• DPush the pipe off with the backhoe bucket after removing the chocks

Damaged cement-mortar lining on ductile-iron pipe may be patched in the field in accordance with which standard?

• AANSI/AWWA C104/A21.4
• BANSI/AWWA C105/A21.5
• CANSI/AWWA C111/A21.11
• DANSI/AWWA C151/A21.51

The AWWA C651 tablet method is intended to produce about what average chlorine dose in a new main?

• A2 mg/L
• B10 mg/L
• C25 mg/L
• D200 mg/L

Unless otherwise specified, the standard asphaltic coating furnished on ductile-iron pipe is about 1 mil thick. What is its primary purpose?

• ATo serve as the sole long-term corrosion barrier in aggressive soils
• BTo minimize atmospheric oxidation for aesthetic reasons
• CTo replace polyethylene encasement on every buried installation
• DTo increase the pipe wall thickness used in ANSI/AWWA C150 design

Using the contractor formula gallons = 0.0408 × D² × L (D in inches, L in feet), how much water is needed to fill 500 feet of 8-inch water main?

• A653 gallons
• B1,040 gallons
• C1,306 gallons
• D2,611 gallons

Using gallons = 0.0408 × D² × L, how much water fills 800 feet of 12-inch water main?

• A2,350 gallons
• B3,133 gallons
• C4,700 gallons
• D5,875 gallons

Using gallons = 0.0408 × D² × L, how many gallons are required to fill 250 feet of 6-inch water main?

• A184 gallons
• B245 gallons
• C367 gallons
• D612 gallons

What range of bolt torque does DIPRA Table 4 specify for 4-inch through 24-inch mechanical joints?

• A45 to 60 foot-pounds
• B75 to 90 foot-pounds
• C100 to 120 foot-pounds
• D120 to 150 foot-pounds

What DIPRA bolt-torque range applies to a 3-inch mechanical joint?

• A45 to 60 foot-pounds
• B75 to 90 foot-pounds
• C100 to 120 foot-pounds
• D150 to 180 foot-pounds

For full-length 3- through 12-inch push-on ductile-iron pipe, what maximum joint deflection does DIPRA Table 5 list?

• A1 degree
• B3 degrees
• C5 degrees
• D12 degrees

For 14-inch and larger full-length push-on ductile-iron pipe, what maximum deflection does DIPRA Table 5 show unless the manufacturer allows more?

• A1 degree
• B3 degrees
• C5 degrees
• D8 degrees

When a push-on or mechanical-joint water main must be deflected, when is the deflection made?

• ABy stabbing the plain end into an already-deflected bell
• BAfter the joint is assembled in a straight line, then swinging the pipe
• CBy tightening only the bolts on the inside of the curve
• DBy cutting a wedge off the spigot so the joint closes on a bias

ANSI/AWWA C150 Type 4 laying condition for ductile-iron pipe is best described as which of the following?

• AFlat-bottom trench with loose backfill only and no bedding
• BPipe hung from trench shields with no soil support under the barrel
• CConcrete cradle from the invert to the springline, uncompacted above
• DPipe bedded in sand, gravel, or crushed stone to 1/8 of the diameter (4-inch minimum), wi…

Under ANSI/AWWA C150 Type 5 laying condition, to about what Standard Proctor density is granular or select material compacted to the top of the pipe?

• A70 percent of AASHTO T-99
• B80 percent of AASHTO T-99
• C90 percent of AASHTO T-99
• D100 percent of AASHTO T-180 Modified Proctor

What is ANSI/AWWA C150 Type 3 laying condition for ductile-iron pipe?

• APipe bedded in a 4-inch minimum of loose soil, with backfill lightly consolidated to the…
• BPipe on piles with no soil bedding
• CPipe bedded to the crown in 3,000 psi concrete
• DFlat-bottom trench and loose backfill only

When a ductile-iron water main up to 24 inches is laid in rock, how far must rock be kept from the bottom and sides of the pipe?

• ARock may touch the barrel if the bells are padded
• BNot closer than 3 inches
• CNot closer than 6 inches
• DNot closer than 18 inches

For 30-inch and larger ductile-iron pipe laid in rock, what minimum clearance from rock does DIPRA require at the bottom and sides?

• A3 inches
• B6 inches
• C9 inches
• D24 inches

After the AWWA C651 continuous-feed method fills a main with water chlorinated to about 25 mg/L, what free-chlorine residual must remain after the 24-hour hold?

• AA residual is not required if the water still smells of chlorine
• BNot less than 2 mg/L
• CNot less than 10 mg/L
• DNot less than 50 mg/L

Which statement correctly describes the AWWA C651 slug method of disinfecting a water main?

• AA 25 mg/L dose is held for 24 hours with no flushing beforehand
• BA slug of about 100 mg/L free chlorine is moved through the main so interior surfaces see…
• CA 200 mg/L spray is applied to the interior and the main is placed in service after 30 mi…
• DPotable water with the system's normal residual is held for 1 hour

If the water temperature is below 41°F (5°C), how long must chlorinated water remain in the main under the AWWA C651 tablet method?

• AAt least 8 hours
• BAt least 12 hours
• CAt least 24 hours
• DAt least 48 hours

When calcium hypochlorite granules are used as a precaution during laying, DIPRA/C651 place them at the beginning of the main and at what interval along the line?

• AEvery 50 feet
• BEvery 100 feet
• CEvery 500 feet
• DOnly at the downstream hydrant

During filling for a hydrostatic test, how should air be removed from the water main?

• ABy applying test pressure immediately so air dissolves into the water
• BBy filling slowly and leaving vents open at high points until water flows steadily
• CBy leaving a hydrant cracked 1/4 turn for the entire two-hour hold
• DBy pumping compressed air in at the low point to push water to the vents

When should a newly laid ductile-iron water main normally be hydrostatically tested?

• ABefore any backfill is placed, with every joint fully exposed
• BAfter backfilling, except when the engineer requires an exposed-joint test and the barrel…
• COnly after the main has been in service for 30 days
• DOnly on the polyethylene-encased portions of the line

Why are flanged joints seldom used on buried ductile-iron water mains?

• AFlanges cannot be manufactured in sizes above 6 inches
• BFlanged joints are not rated for potable water
• CThe rigid flanged joint is not recommended where heavy settlement or vibration is likely
• DFlanged bolts cannot be torqued underground for legal reasons

A standard mechanical joint on ductile-iron pipe provides which thrust performance?

• AIt is a fully restrained joint that replaces thrust blocks at all fittings
• BIt is not a restrained joint and offers no practical resistance to joint separation from…
• CIt restrains thrust only when the bolts are painted after assembly
• DIt restrains thrust if the gland is installed backward

ANSI/AWWA C105 Method A polyethylene encasement uses which installation pattern?

• AOne length of polyethylene tube per length of pipe, overlapped at the joints
• BA single continuous tube pulled over the entire project from a reel
• CPaint-on polyethylene mastic in place of film
• DFilm applied only under the bells, leaving the barrels bare

Which statement about polyethylene encasement is consistent with DIPRA guidance?

• AIt must be heat-sealed so that it is completely airtight and watertight
• BIt should keep soil and bedding off the pipe but is not intended to be completely airtigh…
• CIt may be left torn if the tear is below the springline
• DIt replaces the need to inspect and repair damaged shop coating

When a fire hydrant is restrained with a concrete thrust block, which practice does DIPRA require?

• APour the block against undisturbed soil, rest the hydrant on a concrete pad, and keep the…
• BPour the block against loose backfill so it can flex with the hydrant
• CCover the drain port with concrete so groundwater cannot enter the barrel
• DOmit the pad and hang the hydrant from the tee with the valve box

How should a valve box be set over a buried water-main valve?

• ASo truck-traffic loads transfer directly through the box onto the valve and pipe
• BGrouted tightly to the pipe so the vault and the main act as one structure
• CResting above the valve so traffic load is not transferred to the valve or the pipe
• DOmitted whenever the valve has a 2-inch operating nut

When ductile-iron pipe is installed inside a casing, how much larger should the casing be, and how is the carrier pipe kept off the casing?

• AThe casing should be the same ID as the carrier OD, and the pipes may be in metal-to-meta…
• BThe casing should be 6 to 8 inches larger than the outside diameter of the bells, with in…
• CThe casing should be 24 inches larger than the barrel, with no spacers
• DThe casing should be two nominal sizes smaller so the carrier is a tight interference fit

When ductile-iron pipe is cut in the field for a valve or fitting, what must be done to a cut end that will enter a push-on bell?

• ALeave the cut square and sharp so it bites the gasket
• BThread the cut end and make up a mechanical joint gland
• CWeld a new factory bevel onto the cut end
• DGrind the cut smooth and bevel the end the same as a factory plain end

A 540-foot water main will be laid with 18-foot nominal ductile-iron pipe and no specials. How many full lengths are required?

• A18 lengths
• B27 lengths
• C30 lengths
• D36 lengths

In soils contaminated with hydrocarbons, which gasket material does DIPRA identify as the most resistant to permeation?

• AStandard SBR (styrene-butadiene) rubber
• BNatural gum rubber
• CFluorocarbon rubber
• DLeather and oakum

Per ANSI/AWWA C600 as cited by DIPRA, what maximum particle size is allowed in gravel bedding or backfill immediately adjacent to ductile-iron pipe?

• A3/8 inch
• B2 inches
• C6 inches
• D8 inches