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100+ Free Arizona ROC A-12/CR-80 Sewers, Drains and Pipe Laying Practice Questions

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2026 Statistics

Key Facts: Arizona ROC A-12/CR-80 Sewers, Drains and Pipe Laying Exam

80

Official Exam Questions

PSI Candidate Information Bulletin

210 min

Exam Time Limit

PSI Services

70%

Passing Score (56/80)

AZ Registrar of Contractors

$66

Trade Exam Fee

PSI Test Delivery

2 ft

OSHA Spoil Pile Setback

OSHA 1926.651(j)(2)

25 ft

Max Egress Travel Distance

OSHA 1926.651(c)(2)

The Arizona ROC A-12 / CR-80 trade exam contains 80 scored multiple-choice questions administered by PSI Services over 210 minutes with a 70% passing threshold. Local practice MCQs serve as an English-language study adaptation of trade standards, OSHA trench safety rules, and pipe hydraulics.

Sample Arizona ROC A-12/CR-80 Sewers, Drains and Pipe Laying Practice Questions

Try these sample questions to test your Arizona ROC A-12/CR-80 Sewers, Drains and Pipe Laying exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1A contractor is laying a 400-foot run of 8-inch gravity sewer pipe between two manholes. If the invert elevation at the upstream manhole is 100.00 feet and the downstream invert is 98.00 feet, what is the slope percentage of the sewer line?
A.0.25%
B.0.50%
C.1.00%
D.2.00%
Explanation: The slope is calculated as total drop divided by horizontal length. Drop = 100.00 ft - 98.00 ft = 2.00 ft. Slope = 2.00 / 400 = 0.005, which corresponds to 0.50%.
2Per standard gravity sanitary sewer design guidelines (such as Ten States Standards and UPC), what minimum flow velocity must be maintained when flowing full to prevent solid waste settlement?
A.3.5 feet per second (fps)
B.2.0 feet per second (fps)
C.5.0 feet per second (fps)
D.8.0 feet per second (fps)
Explanation: A minimum mean velocity of 2.0 feet per second (fps) is required in gravity sewer mains to maintain self-cleansing action and prevent the deposition of organic solids and grit.
3The invert elevation at Upstream Manhole A is 105.50 feet. A 10-inch PVC sewer main extends 250 feet to Downstream Manhole B at a slope of 1.00%. What is the invert elevation at Manhole B?
A.108.00 feet
B.104.50 feet
C.102.50 feet
D.103.00 feet
Explanation: Total vertical drop = Length × Slope = 250 ft × 0.0100 = 2.50 ft. Downstream Invert = Upstream Invert - Drop = 105.50 ft - 2.50 ft = 103.00 ft.
4When performing a low-pressure air test on a newly installed plastic gravity sewer line according to UNI-B-6 / ASTM F1417 standards, what is the standard test pressure drop monitored after stabilization?
A.From 3.5 psig down to 2.5 psig
B.From 5.0 psig down to 0.0 psig
C.From 4.0 psig down to 1.0 psig
D.From 10.0 psig down to 5.0 psig
Explanation: ASTM F1417 low-pressure air testing specifies pressurizing the line to approximately 4.0 psig, allowing temperature stabilization, and timing the pressure drop from 3.5 psig to 2.5 psig (a 1.0 psig drop).
5What is the maximum allowable internal vertical deflection limit for flexible thermoplastic sewer pipe (such as PVC SDR 35) when tested with a rigid mandrel after backfilling?
A.3.0%
B.7.5%
C.5.0%
D.10.0%
Explanation: Standard municipal and ASTM specifications limit post-installation flexible sewer pipe deflection to a maximum of 5.0% of the base internal diameter to ensure structural integrity and joint seal tightness.
6According to standard sewer design codes, an external drop manhole assembly is required when the vertical elevation difference between the incoming sewer invert and the outgoing sewer invert exceeds:
A.5.0 feet (60 inches)
B.3.5 feet (42 inches)
C.2.0 feet (24 inches)
D.6.0 feet (72 inches)
Explanation: When an incoming sewer enters a manhole more than 2.0 feet (24 inches) above the manhole invert channel, a drop manhole connection (internal or external drop pipe) must be provided to prevent erosion and splashing.
7In Manning's equation for storm drain capacity, how does replacing corrugated metal pipe (n = 0.024) with smooth-interior high-density polyethylene (n = 0.012) affect flow capacity at the same slope and diameter?
A.Flow capacity doubles (increases by 100%)
B.Flow capacity remains unchanged
C.Flow capacity increases by 50%
D.Flow capacity decreases by 50%
Explanation: In Manning's equation, Q = (1.486 / n) x A x R^(2/3) x S^(1/2), discharge is inversely proportional to the roughness coefficient n. Halving n from 0.024 to 0.012 therefore doubles the flow the pipe can carry at the same slope and diameter, which is why a smooth-wall pipe can often be one size smaller than corrugated metal for the same duty.
8Under ASTM D2321 for flexible sewer pipe embedment, which soil class consists of angular, crushed stone (such as 1/4 inch to 1-1/2 inch washed rock) providing maximum pipe support with minimal compaction effort?
A.Class IV
B.Class III
C.Class I
D.Class II
Explanation: ASTM D2321 classifies angular, crushed stone or rock mixtures as Class I embedment material, offering high stiffness and self-compacting properties for pipe haunching and bedding.
9What primary advantage does Vitrified Clay Pipe (VCP) possess when installed in municipal industrial sanitary sewer mains exposed to biogenic sulfuric acid corrosion?
A.Complete chemical inertness to the sulfuric acid produced by hydrogen sulfide (H2S) corrosion
B.High tensile flexibility to absorb ground movement
C.Extremely light weight allowing manual placement without cranes
D.Solvent-weld joints eliminating elastomeric gaskets
Explanation: Vitrified clay pipe is chemically inert and completely immune to hydrogen sulfide (H2S) and biogenic sulfuric acid attack, making it ideal for aggressive sanitary sewer environments.
10A sewer plan lists the rim elevation of Manhole MH-10 as 1,250.00 feet. The depth from the top of the manhole rim to the pipe invert is 8.50 feet. What is the invert elevation of MH-10?
A.1,241.00 feet
B.1,242.00 feet
C.1,258.50 feet
D.1,241.50 feet
Explanation: Invert Elevation = Rim Elevation - Invert Depth = 1,250.00 ft - 8.50 ft = 1,241.50 ft.

About the Arizona ROC A-12/CR-80 Sewers, Drains and Pipe Laying Exam

The Arizona ROC A-12 (CR-80) Sewers, Drains and Pipe Laying trade examination evaluates candidates on the technical, legal, and safety standards required to construct, alter, or repair underground pipelines for sewers, storm drains, water mains, fuel gas, and septic systems. The computer-based test is open-book, allowing candidates to bring approved code books and reference texts into the PSI test center.

Assessment

80 multiple-choice questions covering Sewers & Storm Drains (25%), Excavation & Backfilling (25%), Water Piping (12.5%), Gas Piping (12.5%), General Piping (6.25%), Septic Systems (6.25%), Safety (6.25%), and Welding (6.25%).

Time Limit

210 minutes

Passing Score

70%

Exam Fee

$66 (Arizona Registrar of Contractors / PSI Services LLC)

Arizona ROC A-12/CR-80 Sewers, Drains and Pipe Laying Exam Content Outline

25%

Sewers and Storm Drain Systems

Sewer main installation, gravity sewer hydraulics, invert elevations, drop manholes, PVC (SDR 35/C900), Ductile Iron Pipe (DIP), Reinforced Concrete Pipe (RCP), Vitrified Clay Pipe (VCP), trenchless pipe bursting, storm drain culverts, headwalls, catch basins, low-pressure air testing (UNI-B-6), and mandrel deflection testing.

25%

Excavation and Backfilling

OSHA 1926 Subpart P trenching rules, soil classification (Type A, B, C), unconfined compressive strength testing, sloping, benching, hydraulic shoring, trench boxes, pipe bedding, backfill placement, lift thickness, Standard and Modified Proctor compaction density testing, spoil pile setback, and ladder egress.

12.5%

Water Piping

Water main installation standards (AWWA C600/C900), ductile iron pipe classes, HDPE pipe fusion, concrete thrust blocks, mega-lugs, hydrostatic pressure testing formulas, disinfection & chlorination (AWWA C651 continuous feed/slug methods), gate valves, fire hydrants, and backflow prevention.

12.5%

Gas Piping

Underground polyethylene (PE) and steel fuel gas distribution lines, NFPA 54 / IFGC standards, 18 AWG insulated tracer wire, yellow caution warning tape, sacrificial anode cathodic protection, butt fusion, pressure testing minimums, line purging, and depth of cover requirements.

6.25%

General Piping

Pipe sizing, Schedule 40/80 and SDR ratings, Hazen-Williams friction loss calculations, expansion joints, pipe hangers and supports, fitting layout (bends, tees, wyes), solvent welding, mechanical couplings, and material thermal expansion.

6.25%

Septic Systems

ADEQ Title 18 Chapter 9 onsite wastewater regulations, septic tank volume sizing based on daily design flow, two-compartment baffles, effluent filters, percolation rate (MPI) testing, leach field absorption trench sizing, distribution boxes, and environmental setback distances.

6.25%

Safety

OSHA 1926 Subpart P, Arizona 811 (Blue Stake) utility locate protocols (2-working-day notice, 24-inch tolerance zone), confined space entry in sewer structures (OSHA Subpart AA testing for O2, H2S, flammable gases), mechanical ventilation, fall protection, and personal protective equipment.

6.25%

Welding

Steel pipe joint welding per AWS D1.1 / API 1104, weld joint bevel prep, SMAW stick welding (E6010 root pass, E7018 fill/cap), GTAW, plastic pipe fusion welding (HDPE heating temperature 400°F-450°F, heat/cool cycle parameters), non-destructive testing (NDT), and welder qualification.

How to Pass the Arizona ROC A-12/CR-80 Sewers, Drains and Pipe Laying Exam

What You Need to Know

  • Passing score: 70%
  • Assessment: 80 multiple-choice questions covering Sewers & Storm Drains (25%), Excavation & Backfilling (25%), Water Piping (12.5%), Gas Piping (12.5%), General Piping (6.25%), Septic Systems (6.25%), Safety (6.25%), and Welding (6.25%).
  • Time limit: 210 minutes
  • Exam fee: $66

Keys to Passing

  • Work through all 100 available questions
  • Review every answer and explanation
  • Track weak areas and revisit them
  • Use our AI tutor for tough concepts

Arizona ROC A-12/CR-80 Sewers, Drains and Pipe Laying Study Tips from Top Performers

1Memorize OSHA 1926 Subpart P soil strength thresholds, allowable sloping angles, benching rules, and trench box clearance limits.
2Practice gravity sewer fall and slope calculations: Slope = Fall / Distance, and Invert Elevation = Surface Elevation - Invert Depth.
3Understand water main hydrostatic testing procedures (AWWA C600) and chlorination dosage methods (AWWA C651).
4Learn underground PE gas line tracer wire specifications (18 AWG insulated copper) and warning tape positioning.
5Review ADEQ Title 18 Chapter 9 septic tank sizing rules, percolation rate calculations (MPI), and separation setback distances.

Frequently Asked Questions

What work is covered under the Arizona ROC A-12 / CR-80 license classification?

The A-12 (General Engineering Dual) / CR-80 (Commercial) classification permits the installation, alteration, and repair of underground pipelines for sewers, storm drains, water mains, fuel gas piping, septic systems, irrigation lines, manholes, catch basins, and associated trenching, backfilling, and pipe welding.

How many questions are on the official AZ ROC A-12 exam and what is the passing score?

The official PSI trade exam contains 80 scored multiple-choice questions. Candidates are allowed 210 minutes (3.5 hours) and must achieve a score of at least 70% (56 correct answers) to pass.

Is the Arizona ROC A-12 trade examination open-book?

Yes. The exam is open-book. Candidates may bring approved reference materials into the PSI testing center, including standard plumbing/piping codes (UPC/IPC), OSHA 1926 standards, AWWA standards, and pipe installation handbooks.

What are the OSHA trenching and soil classification rules tested on the exam?

The exam heavily tests OSHA 1926 Subpart P: Type A soil (unconfined compressive strength ≥ 1.5 tsf, max slope 3/4:1), Type B soil (0.5 to 1.5 tsf, max slope 1:1), and Type C soil (≤ 0.5 tsf, max slope 1-1/2:1). Spoil piles must be kept at least 2 feet from trench edges, and ladders must be placed within 25 feet of lateral travel in trenches 4 feet or deeper.

Do I need to take a separate exam for Arizona statutes and rules?

Yes. In addition to the A-12 / CR-80 trade examination, license applicants must pass the Arizona Registrar of Contractors Statutes and Rules Examination (SRE).