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100+ Free AZ ROC A General Engineering (Commercial) Practice Questions

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2026 Statistics

Key Facts: AZ ROC A General Engineering (Commercial) Exam

109

Scored Exam Questions

PSI Arizona ROC Bulletin

240 min

Time Limit (4 Hours)

PSI Arizona ROC Bulletin

70%

Passing Score (77/109)

PSI Arizona ROC Bulletin

$66

PSI Exam Fee

PSI Arizona ROC Bulletin

Open Book

Exam Delivery Format

PSI Services LLC

14

Blueprint Content Domains

PSI Arizona ROC Bulletin

Arizona ROC A General Engineering (Commercial) trade exam via PSI: 109 scored questions, 240 minutes, 70% pass standard (77 correct), fee $66. Open-book trade examination covering heavy civil, underground utilities, paving, safety, electrical transmission, and solar installations. The practice question bank is an English-language MCQ study adaptation.

Sample AZ ROC A General Engineering (Commercial) Practice Questions

Try these sample questions to test your AZ ROC A General Engineering (Commercial) exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1An 8-inch SDR-35 PVC gravity sewer pipe is being installed using Manning's roughness coefficient n = 0.013. According to MAG standards and standard civil engineering practice, what is the minimum pipe slope required to maintain a self-cleansing velocity of 2.0 feet per second when flowing full?
A.0.40%
B.0.20%
C.0.80%
D.1.20%
Explanation: According to Manning's equation for circular pipes, an 8-inch sewer pipe requires a minimum slope of 0.0040 ft/ft (0.40%) to achieve the standard self-cleansing velocity of 2.0 ft/s when flowing full or half full.
2During low-pressure air testing of a 500-foot section of 10-inch PVC gravity sewer line, the pressure is pressurized to 4.0 psig and allowed to stabilize. Per MAG / UNI-B-6 standards, what is the minimum duration required for the pressure to drop from 3.5 psig to 2.5 psig?
A.2 minutes 15 seconds
B.5 minutes 50 seconds
C.8 minutes 30 seconds
D.12 minutes 00 seconds
Explanation: Per UNI-B-6 low-pressure air testing standards adopted by MAG Section 615, for 500 feet of 10-inch pipe, the calculated minimum test holding time for a 1.0 psig drop (3.5 to 2.5 psig) is approximately 5 minutes and 50 seconds.
3A sanitary sewer manhole has an incoming sewer lateral whose invert elevation is 30 inches above the manhole main invert channel. According to standard Arizona municipal specifications and MAG details, what structure must be installed?
A.A standard bench fill without modification
B.A 90-degree long-radius elbow inside the cone
C.An outside drop pipe connection assembly
D.An inline backwater check valve
Explanation: When an incoming sewer invert is 24 inches or more above the manhole bottom invert channel, an outside (or approved inside) drop manhole assembly must be installed to prevent sewage splashing and structural erosion.
4To verify structural stability after backfilling a 12-inch ASTM D3034 SDR-35 PVC sewer pipe, a rigid mandrel deflection test is conducted 30 days post-installation. What is the maximum allowable initial pipe deflection percentage allowed by MAG Section 615?
A.7.5%
B.10.0%
C.2.5%
D.5.0%
Explanation: MAG Section 615 specifies that flexible thermoplastic sewer pipes must not exceed 5.0% maximum deflection when tested with a rigid 9-arm mandrel 30 days after backfill completion.
5When installing a gravity sanitary sewer line beneath a commercial roadway subject to heavy traffic loading, what is the standard requirement for trench pipe bedding and initial backfill zone?
A.Granular aggregate bedding compacted to 95% relative density extending from 4 inches below pipe to 12 inches above pipe crown
B.Native uncompacted excavated soil placed directly under pipe
C.Flowable lean concrete backfill surrounding the pipe up to subgrade elevation
D.Clean washed river sand without compaction
Explanation: Standard MAG bedding details require Class B granular bedding (such as crushed aggregate or ABC) placed 4 to 6 inches below the barrel and compacted to 95% density up to 12 inches above the crown of the pipe to support traffic loads.
6A sewer main runs from Station 10+00 to Station 12+50 on a uniform downward slope of 0.40%. If the invert elevation at Station 10+00 is 1,245.50 feet, what is the invert elevation at Station 12+50?
A.1,246.50 feet
B.1,244.50 feet
C.1,243.50 feet
D.1,245.10 feet
Explanation: The distance between Station 10+00 and 12+50 is 250 feet. Total fall = 250 ft x 0.0040 = 1.00 foot. Invert elevation at 12+50 = 1,245.50 - 1.00 = 1,244.50 feet.
7In a sewage force main system pumping wastewater to a high-elevation treatment facility, what appurtenance must be installed at all high points along the pipeline profile?
A.Pressure reducing valve (PRV)
B.Backwater check valve
C.Combination air release and vacuum breaker valve
D.Orifice plate flow meter
Explanation: Combination air release and vacuum breaker valves are required at high points on sewage force mains to discharge accumulated gas pockets during operation and admit air during draining to prevent pipeline collapse.
8According to ASTM C1244 standards for negative air pressure (vacuum) testing of precast concrete sewer manholes, a vacuum of 10 inches of Hg is drawn. For a 48-inch diameter manhole 10 feet deep, what is the minimum required test duration for the vacuum to drop no lower than 9 inches of Hg?
A.120 seconds
B.180 seconds
C.300 seconds
D.60 seconds
Explanation: Per ASTM C1244 Table 1, a 48-inch diameter precast concrete manhole up to 10 feet deep must maintain the vacuum drop from 10 in. Hg to 9 in. Hg for at least 60 seconds to pass.
9Per Arizona Department of Environmental Quality (ADEQ) engineering regulations (AAC R18-5-502), what is the minimum horizontal separation required between a parallel potable water main and a sanitary sewer main?
A.10 feet
B.6 feet
C.3 feet
D.15 feet
Explanation: ADEQ rules require a minimum horizontal separation of 10 feet between parallel potable water lines and sanitary sewer pipelines to prevent contamination in case of pipeline failure.
10A newly installed 12-inch C900 PVC potable water main operating at a design pressure of 100 psi must undergo hydrostatic pressure testing per AWWA standards. What is the required test pressure and minimum duration?
A.100 psi for 1 hour
B.150 psi for 2 hours
C.200 psi for 24 hours
D.125 psi for 30 minutes
Explanation: AWWA standards require hydrostatic pressure testing at 1.5 times the working pressure (or 150 psi minimum, whichever is greater) evaluated at the lowest point of the section, held for a minimum of 2 hours.

About the AZ ROC A General Engineering (Commercial) Exam

The Arizona ROC Class A General Engineering (Commercial) trade examination covers heavy civil construction, utility infrastructure, earthwork, structural steel, piling, paving, electrical transmission, traffic control, and renewable energy installations (solar thermal and PV). Administered as a 4-hour (240 minutes), 109-scored-question open-book computer examination by PSI Services LLC, candidates must achieve a passing score of 70% (77 correct out of 109). This study bank provides 100 realistic practice questions adapted into English-language multiple-choice format aligned proportionally to the official PSI candidate bulletin subject outline.

Questions

109 scored questions

Time Limit

240 minutes

Passing Score

70%

Exam Fee

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

AZ ROC A General Engineering (Commercial) Exam Content Outline

15%

Sewers

Gravity sewer lines, manholes, cleanouts, pipe materials, slope calculations, and hydrostatic/low-pressure air testing (10 official items).

15%

Water Piping

Water mains, pressure testing, disinfection procedures, thrust block design, backflow prevention, and AWWA standards (5 official items).

15%

Gas Piping

Fuel gas transmission and distribution piping, NFPA 54/IFGC, ASME B31.8, purging, cathodic protection, and pressure testing (6 official items).

15%

Paving

Asphalt concrete mix design, subgrade compaction, tack/prime coats, lift thickness, nuclear density testing, and surface finishing (10 official items).

15%

Excavation, Compaction, and Grading

OSHA trenching, soil classification, mass haul calculations, volume swell/shrinkage, compaction equipment, and Proctor density (12 official items).

15%

Safety

OSHA 1926 construction safety standards, fall protection, crane clearances, PPE, HAZCOM, and confined space entry (10 official items).

15%

Steel

Structural steel erection, column anchorage, joist bridging, welding standards (AWS D1.1), and high-strength bolting (3 official items).

15%

Piles

Driven piles, drilled shafts/caissons, bentonite slurry properties, pile driving formulas, load testing, and integrity testing (6 official items).

15%

Concrete

ACI mix design, slump testing, air entrainment, hot/cold weather placement, formwork design, and rebar clearance (10 official items).

15%

Traffic Control

MUTCD temporary traffic control, taper lengths, channelizing devices, advance warning sign placement, and flagging standards (6 official items).

15%

Electrical Transmission Lines

Overhead transmission lines, conductor sag, tower/pole guy anchoring, NESC clearances, underground distribution, and grounding (11 official items).

15%

Storm Water Runoff

SWPPP ADEQ permits, erosion control, retention/detention basin design, Rational Method hydrology, and culvert hydraulics (9 official items).

15%

Solar Thermal

Commercial solar thermal collectors, heat transfer fluid glycol loops, solar fraction, expansion tanks, and stagnation protection (8 official items).

15%

Photovoltaic Systems

Commercial/utility PV arrays, NEC 690/705, string sizing, OCPD calculations, rapid shutdown, and inverter grounding (3 official items).

How to Pass the AZ ROC A General Engineering (Commercial) Exam

What You Need to Know

  • Passing score: 70%
  • Exam length: 109 questions
  • Time limit: 240 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

AZ ROC A General Engineering (Commercial) Study Tips from Top Performers

1Organize approved references (OSHA 1926, MUTCD, ACI 318, AWWA standards, NESC, NEC) with permanent tab dividers matching the 14 exam blueprint categories.
2Master earthwork calculations including bank cubic yards, loose cubic yards, compaction shrinkage, and slope ratio formulas.
3Practice MUTCD taper length calculations (L = W x S for speeds 45 mph and above; L = W x S^2 / 60 for lower speeds) and channelizing device spacing rules.
4Review OSHA excavation safety standards thoroughly, including Type A, B, and C soil slope requirements and trench shield regulations.
5Work through worked examples on electrical conductor sag, solar PV string cold-temperature voltage sizing, and hydraulic pipe flow calculations.

Frequently Asked Questions

What is the format and length of the AZ ROC A General Engineering (Commercial) exam?

The official trade exam administered by PSI contains 109 scored multiple-choice questions with a 240-minute (4-hour) time limit. A score of 70% (77 correct answers) or higher is required to pass.

Is the AZ ROC A General Engineering trade examination open-book?

Yes, PSI trade exams in Arizona are open-book. Candidates may bring approved reference books listed in the official PSI candidate information bulletin. Notes must be permanently bound or tabbed using permanent index tabs.

What topics carry the highest weight on the AZ ROC A exam?

Excavation, Compaction, and Grading (12 questions), Electrical Transmission Lines (11 questions), Sewers (10 questions), Paving (10 questions), Concrete (10 questions), and Safety (10 questions) together represent over 55% of the total examination content.

How much does the AZ ROC A exam cost and how do I schedule it?

The PSI trade examination fee is $66 per attempt. Candidates schedule their exam directly through PSI Services LLC at test-takers.psiexams.com after submitting their eligibility paperwork if required.

Is a separate Business Management exam required for Arizona ROC license applicants?

Yes. In addition to passing the A General Engineering trade exam, license applicants must also pass the Arizona ROC Statutes and Rules exam (AZ SREC / Business Management exam) unless granted a waiver by the Registrar.