PracticeVideosBlogFlashcardsEspañol
All Practice Exams

Free Practice Questions for Iran Nezam Mechanical Supervision Exam

Exam-style questions and explanations by OpenExamPrep.

✓ No registration✓ No credit card
100+ Questions
100% Free

Loading practice questions...

Same family resources

Explore More Iran Construction Engineering Org (IRCEO / Nezam Mohandesi)

Continue into nearby exams from the same family. Each card keeps practice questions, study guides, flashcards, videos, and articles in one place.

Iran Construction Engineering Org — Civil Design & Calculation

Practice Questions

Iran Construction Engineering Org — Civil Execution

Practice Questions

Iran Construction Engineering Org — Civil Supervision

Practice Questions

Iran Construction Engineering Org — Electrical Design

Practice Questions

Iran Construction Engineering Org — Electrical Supervision

Practice Questions

Iran Construction Engineering Org — Mechanical Design

Practice Questions
Exam Review

Key Facts: Iran Nezam Mechanical Supervision Exam Exam

60 Questions

Total Questions

INBR / MRUD

150 minutes

Time Limit

INBR

50 / 100

Passing Threshold (clause 6-4, 1405 instruction)

INBR

3 wrong = 1 right

Negative Marking Rule

INBR

Open-Book

Exam Delivery Mode

INBR

Grade 3

Initial License Grade Awarded

IRCEO

The Iran Nezam Mechanical Supervision examination is a 150-minute open-book paper of 60 four-option multiple-choice questions, held nationwide under the Office of National Building Regulations. It assesses a mechanical engineer's supervisory duties, plumbing and gas piping pressure testing, HVAC equipment installation inspections, and jobsite safety. Negative marking applies and the pass threshold is 50 out of 100. The official paper is in Persian; OpenExamPrep provides independent English-language practice questions for the same topics.

Sample Iran Nezam Mechanical Supervision Exam Practice Questions

Try these sample questions to review concepts for the Iran Nezam Mechanical Supervision Exam exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Under INBR Topic 17, newly installed low-pressure (1/4 psi) building gas piping must pass a leak-tightness test (آزمایش نشتی) after the strength test. What test pressure and minimum holding duration must the supervising engineer witness for that leak test?
A.10 psi (0.7 bar) held for a minimum of 24 hours with no pressure drop
B.30 psi (2.0 bar) held for a minimum of 15 minutes
C.10 psi (0.7 bar) held for a minimum of 1 hour
D.50 psi (3.5 bar) held for a minimum of 2 hours
Explanation: Topic 17 splits the verification into two tests. The strength test (آزمایش مقاومت) is carried out at about 2 bar (30 psi) for one hour to prove the pipe and joints can withstand pressure. The leak test (آزمایش نشتی) then follows at 0.7 bar (10 psi) and must be held for a full 24 hours with no detectable pressure drop, with temperature correction applied because ambient swings alone move the gauge. The long duration is what makes the test sensitive enough to reveal a slow weep that a short test would miss, and the network must remain fully exposed throughout.
2When inspecting the calibrated pressure gauge used for the 10 psi pneumatic strength test of building gas piping under INBR Topic 17, which gauge specification is mandatory?
A.A gauge with a dial range of 0 to 100 psi so it can be reused for hydrostatic testing
B.A gauge with a dial range where the test pressure falls within the middle third of the scale (such as 0 to 15 or 0 to 20 psi) and minimum dial diameter of 75 mm
C.Any digital automotive tire pressure gauge with a resolution of 0.5 psi
D.A water manometer with a maximum height of 500 mm
Explanation: INBR Topic 17 requires that pressure gauges used for pneumatic testing be calibrated, certified, and sized such that the test pressure falls within the middle third of the gauge's full scale (e.g., 0-15 psi or 0-20 psi for a 10 psi test). The dial diameter must be at least 75 mm to ensure clear, unambiguous readability by the inspector.
3Under INBR Topic 17, which medium is strictly prohibited for use in the pneumatic pressure testing of building natural gas piping?
A.Pure oxygen
B.Compressed atmospheric air
C.Dry nitrogen gas
D.Carbon dioxide gas
Explanation: INBR Topic 17 strictly prohibits the use of pure oxygen or any flammable gas as a testing medium due to the catastrophic risk of violent fire and explosion when pressurized oxygen contacts hydrocarbons, pipe oils, or trace grease. Only clean compressed air or inert gases (such as nitrogen) are permitted.
4During the final leak detection check of all accessible gas pipe joints under test pressure, which method must the supervising engineer insist upon according to INBR Topic 17?
A.Passing an open lighter flame slowly around each threaded and welded joint
B.Applying a certified commercial foaming bubble solution or mild soap-and-water mixture to every joint
C.Listening closely for hissing sounds while the room is kept silent
D.Spraying aerosol lubricating oil on joints and looking for discoloration
Explanation: INBR Topic 17 specifies that leak detection on gas piping joints during pneumatic testing must be performed using an approved foaming soap bubble solution or a certified electronic combustible gas leak detector. Using an open flame is strictly hazardous and legally prohibited.
5When performing visual inspection of circumferential butt welds on black steel natural gas piping under INBR Topic 17, which defect requires immediate rejection of the weld?
A.A uniform weld reinforcement crown height of 1.5 mm above the base metal
B.Any visible crack, lack of penetration at the root, or undercut exceeding code limits
C.A light surface heat discoloration adjacent to the heat-affected zone
D.A weld width that is 3 mm wider than the original bevel groove
Explanation: Under INBR Topic 17 and Iranian national gas welding standards (API 1104 / ASME B31.8 references), any weld exhibiting cracks, incomplete root penetration, lack of side fusion, or excessive undercut is defective and must be rejected and ground out or cut out and re-welded.
6Which material and application rule is mandatory for threaded joint sealants on low-pressure natural gas piping under INBR Topic 17?
A.White thin plumbing PTFE tape applied across both male and female internal threads
B.Approved gas-rated yellow Teflon tape or certified gas pipe paste applied only to external male threads, leaving the first two threads bare
C.Cotton fiber hemp soaked in red lead paint applied heavily to the inside of female fittings
D.Standard silicone bathroom caulk applied to the joint exterior after assembly
Explanation: INBR Topic 17 mandates the use of approved joint sealants specifically rated for natural gas (such as yellow gas PTFE tape or specialized non-hardening gas pipe dope). The sealant must be applied exclusively to the external male threads, leaving the first two leading threads clean to prevent shredding sealant particles from entering the gas stream and clogging appliance orifices.
7For underground steel gas piping or gas pipe embedded in floor masonry, what external corrosion protection system must the supervising mechanical engineer verify under INBR Topic 17?
A.A single coat of oil-based red primer paint
B.Cold-applied synthetic primer followed by two layers of anti-corrosion polyken tape wrapped with a minimum 50% overlap
C.Wrapping the bare pipe in dry corrugated cardboard before pouring concrete
D.No protection is necessary if seamless Schedule 40 black steel pipe is used
Explanation: Under INBR Topic 17, buried or masonry-embedded steel gas piping must be thoroughly wire-brushed, coated with an approved cold-applied synthetic primer, and wrapped spirally with approved anti-corrosion tape (e.g., Polyken tape) maintaining a minimum 50% overlap, ensuring zero air pockets and complete dielectric insulation.
8Prior to backfilling an underground steel gas pipe wrapped with anti-corrosion tape, which testing method is used by the supervisor to detect microscopic pinholes or voids (holidays) in the coating?
A.A high-voltage electric holiday detector spark tester passed over the entire wrapped surface
B.Soaking the wrapped pipe with kerosene to observe dark spots
C.A visual inspection with a magnifying glass under direct sunlight
D.Pressurizing the annular space between tape and pipe with water
Explanation: INBR Topic 17 and NIGC standards require wrapped underground steel gas pipes to be inspected using a high-voltage spark tester (holiday detector) calibrated to the tape thickness. Any pinhole, tear, or void in the dielectric wrap creates a spark breakdown that sounds an audible alarm, identifying flaws for patching before trench backfill.
9What is the mandatory surface identification requirement for exposed indoor natural gas piping under INBR Topic 17?
A.Pipes must be painted entirely in gloss safety yellow (or banded with yellow markers indicating gas flow direction at regular intervals)
B.Pipes must be painted bright red to indicate hazard
C.Pipes must remain unpainted bare steel so weld seams remain visible
D.Pipes must be painted the same color as the adjacent walls to blend into the interior decor
Explanation: INBR Topic 17 stipulates that exposed internal gas piping must be painted safety yellow (or marked with approved yellow identification tape/bands with flow direction arrows at intervals not exceeding 2 meters and near wall penetrations) to ensure immediate visual recognition by emergency responders and occupants.
10When a gas pipe penetrates an interior concrete foundation wall or concrete floor slab, what sleeve specification must the supervising engineer enforce under INBR Topic 17?
A.The pipe may be cast directly into solid concrete without any sleeve to ensure structural rigidity
B.The pipe must pass through a metallic or rigid PVC sleeve at least one nominal size larger than the pipe, sealed with pliable non-hardening mastic, and extending at least 20 mm above the finished floor
C.A wooden sleeve filled with expandable gypsum plaster
D.A rubber hose slipped over the pipe with no annular sealing
Explanation: INBR Topic 17 mandates that gas pipes traversing floors or walls must be installed inside a protective sleeve (steel or rigid plastic) sized at least one commercial diameter larger than the carrier pipe. For floors, the sleeve must extend at least 20 mm above finished floor level to prevent water ingress, with the annular space packed with non-hardening, moisture-proof sealant (such as bituminous mastic).

About the Iran Nezam Mechanical Supervision Exam Exam

The Iran Nezam Mechanical Supervision exam is the official licensure assessment administered by the Ministry of Roads and Urban Development for mechanical engineers seeking the supervision (Nezarat) practicing grade in the Construction Engineering Organization of Iran. Supervising mechanical engineers verify that building HVAC installations, plumbing and drainage systems, natural gas distribution networks, fire suppression systems, and mechanical safety mechanisms strictly comply with approved engineering drawings and the Iranian National Building Regulations (INBR).

Exam sponsor: Office of National Building Regulations and Building Control (inbr.ir), Ministry of Roads and Urban Development; delivered nationwide by the National Organization for Educational Testing (Sazman-e Sanjesh) educational services company. The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Assessment

60 four-option multiple-choice questions covering natural gas supervision (Topic 17), plumbing testing (Topic 16), HVAC inspection (Topic 14), supervisory procedures (Topic 2), and fire protection/safety (Topics 3, 12)

Time Limit

150 minutes

Passing Score

50 out of 100 (50%) — clause 6-4 of the official 1405 registration instruction, calculated after the negative-marking deduction

Exam / Certification Fees

Set per sitting and shown in the inbr.ir registration cart; the official 1405 registration instruction does not publish a fixed amount

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

25%

Natural Gas Piping & Flue Inspection (INBR Topic 17)

Pneumatic strength and tightness testing of gas piping, pipe joint welding and threading inspection, primer and anti-corrosion wrap, yellow identification paint, pipe sleeve penetration details, combustion air openings, and chimney flue clearances and draft tests

25%

Plumbing & Drainage Testing (INBR Topic 16)

Hydrostatic testing of potable water supply piping (minimum 10 bar or 1.5 times working pressure), gravity drainage water testing (3 m head) and air/smoke testing, drain pipe slope verification, cleanout locations and access clearances, trap seal depths, backflow prevention assemblies, and sanitary fixture mounting

20%

HVAC Equipment & Duct Inspection (INBR Topic 14)

Mounting of chillers, boilers, and cooling towers, vibration isolation springs and pads, expansion tank connection and relief piping, sheet metal duct gauges and support hanger spacing, flexible duct connectors, fire and smoke dampers, fusible link ratings, duct inspection doors, and air and hydronic water balancing

15%

Supervisory Procedures & Legal Duties (INBR Topics 1 & 2)

Statutory duties under INBR Topic 2 and Article 34 of the Construction Engineering Law, mandatory stage inspection reports, defect notifications, formal municipal stop-work notices, technical coordination with civil and electrical supervisors, and civil and criminal liability of the supervising engineer

15%

Fire Suppression & Jobsite Safety (INBR Topics 3 & 12)

Automatic fire sprinkler installation inspection, sprinkler head clearance from ceilings and obstacles, hydrostatic testing of fire piping (200 psi / 14 bar for 2 hours), Siamese fire department connection checks, standpipe hose valves, boiler room explosion venting, pressure relief valve discharge piping, and confined space safety

Preparing for the Iran Nezam Mechanical Supervision Exam Exam

What You Need to Know

  • Passing score: 50 out of 100 (50%) — clause 6-4 of the official 1405 registration instruction, calculated after the negative-marking deduction
  • Assessment: 60 four-option multiple-choice questions covering natural gas supervision (Topic 17), plumbing testing (Topic 16), HVAC inspection (Topic 14), supervisory procedures (Topic 2), and fire protection/safety (Topics 3, 12)
  • Time limit: 150 minutes
  • Exam / certification fees: Set per sitting and shown in the inbr.ir registration cart; the official 1405 registration instruction does not publish a fixed amount Official sources

Using Our Practice Resources

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

Iran Nezam Mechanical Supervision Exam: Suggested Study Strategy

1Master the pressure test parameters: 10 bar (or 1.5x working pressure) for potable water (Topic 16), 3 m water head for drainage (Topic 16), 10 psi / 30 psi pneumatic test for gas piping (Topic 17), and 200 psi / 14 bar for 2 hours for fire sprinklers (Topic 3).
2Memorize critical dimensional rules such as trap seal depth (50-100 mm), cleanout clearance requirements, chimney slope (minimum 2% upward toward outlet), combustion air ventilation openings (1 cm² per 30 kcal/hr or direct fresh air), and duct sheet metal thickness tables.
3Thoroughly review supervisory legal duties under INBR Topic 2: stage report submission deadlines, non-conformance notices, municipal stop-work requests, and joint coordination with civil, electrical, and architectural supervisors.
4Tabulate and index INBR Topics 14, 16, and 17 with colored sticky tabs for rapid retrieval during the timed open-book exam.
5Practice negative-marking discipline: leave questions blank if you cannot narrow down options, to avoid forfeiting 1/3 point per guess.

Frequently Asked Questions

What is the format of the Iran Nezam Mechanical Supervision exam?

The examination consists of 60 four-option multiple-choice questions to be completed in 150 minutes. Under clause 6-2 of the official registration instruction, the test is held open book (کتاب‌باز), allowing candidates to consult INBR volumes, technical charts, and personal reference binders. Negative marking applies: three incorrect answers cancel one correct answer. The official paper is in Persian.

What passing score is required for the Mechanical Supervision exam?

Clause 6-4 of the official registration instruction establishes the passing threshold at 50 out of 100 (50%). Because of the negative marking rule (1/3 point deducted per wrong answer), candidates must achieve a net score of at least 50%. A passing score remains valid for up to 3 years toward obtaining the Grade 3 (Payeh 3) practicing license from the provincial Construction Engineering Organization.

What are the eligibility requirements for this exam?

Candidates must hold an accredited Bachelor's, Master's, or Ph.D. degree in Mechanical Engineering recognized by the Ministry of Science, Research and Technology. A mandatory minimum post-graduation practical experience period is required: 3 years for Bachelor's holders, 2 years for Master's holders, and 1 year for Ph.D. graduates, along with provincial Nezam membership and military completion or exemption for males.

Which National Building Regulations (INBR) are covered in the mechanical supervision syllabus?

The core topics include Topic 14 (Mechanical Installations / HVAC), Topic 16 (Sanitary and Plumbing Installations), Topic 17 (Natural Gas Piping for Buildings), Topic 3 (Fire Protection and Life Safety), Topic 12 (Jobsite Safety and Worker Health), Topic 19 (Energy Conservation in Buildings), Topic 2 (Administrative Systems and Supervisory Duties), Topic 22 (Care and Maintenance of Building Systems), and Publication 128 (General Technical Specifications for Mechanical Installations).

What are the key inspection stages for a supervising mechanical engineer on a building project?

The supervising mechanical engineer must inspect and file mandatory reports at key milestones: underground drainage piping before backfilling; rough-in plumbing and gas piping prior to concealment/wall closing (including pneumatic and hydrostatic pressure tests); HVAC ductwork and damper installation before ceiling closure; boiler room and central plant equipment mounting and venting; fire protection system hydrostatic testing; and final commissioning, balancing, and fixture testing before occupancy certification.