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An ASSE 6020 inspector reviewing a Level 1 medical oxygen source must confirm the source has at least:

A primary supply and a reserve only

A single primary supply

A primary supply and a backup compressor

A primary, secondary, and reserve supply

to track

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2026 Statistics

Key Facts: ASSE 6020 Exam

100

Written Exam Questions

ASSE Series 6000

70%

Typical Passing Score

ASSE 6020 administrators

24 hrs

Minimum Training

ASSE 6020 standard

2 years

Required Experience

ASSE 6020 eligibility

3 years

Certification Validity

ASSE recertification policy

4 hours

Exam Time Limit

ASSE 6020 administrators

ASSE 6020 candidates must complete a minimum 24-hour medical gas inspector course, document 2 years of practical inspection/design/verification experience (or hold ASSE 6010), and pass a 100-question written exam (typically 70% pass, some administrators 75-80%). Certification is valid for 3 years. Effective preparation focuses on the inspector's role under NFPA 99 Chapter 5, in-progress brazing inspection, source equipment and alarm checks, witnessing installer pressure and cross-connection tests, and final AHJ acceptance documentation.

Sample ASSE 6020 Practice Questions

Try these sample questions to test your ASSE 6020 exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which code is the primary U.S. standard that an ASSE 6020 Medical Gas Inspector enforces during inspection of new medical gas piping systems?

A.NFPA 70 National Electrical Code

B.NFPA 99 Health Care Facilities Code

C.NFPA 54 National Fuel Gas Code

D.ASME B31.9 Building Services Piping

Explanation: NFPA 99, Health Care Facilities Code, Chapter 5 (Gas and Vacuum Systems) is the primary U.S. standard enforced by the ASSE 6020 inspector. It governs materials, brazing, source equipment, alarms, testing, and acceptance for medical gas systems.

2What is the primary role of an ASSE 6020 Medical Gas Inspector?

A.Braze copper tubing under nitrogen purge

B.Perform the independent final verification before clinical service

C.Review installation work and witness acceptance testing on behalf of the AHJ

D.Maintain source equipment and replace filters

Explanation: The ASSE 6020 inspector reviews installation work and witnesses acceptance testing on behalf of the Authority Having Jurisdiction (AHJ). The inspector does not braze, does not perform independent verification (that is the ASSE 6030 verifier), and does not maintain in-service systems (that is ASSE 6040).

3Per NFPA 99, who must perform the final verification of a medical gas system before it is placed in clinical service?

A.The ASSE 6010 installer who brazed the system

B.The ASSE 6020 inspector

C.An ASSE 6030 verifier independent of the installing contractor

D.The hospital's ASSE 6040 maintenance staff

Explanation: NFPA 99 requires final verification by an ASSE 6030 verifier who is independent of the installing contractor on the project. The 6020 inspector witnesses and documents the 6030 verifier's tests but does not perform them.

4Which ASTM specification covers seamless copper tube cleaned, capped, and labeled specifically for medical gas service?

A.ASTM B819

B.ASTM B280

C.ASTM B88

D.ASTM A53

Explanation: ASTM B819 specifies seamless copper tube for medical gas and medical vacuum service. The tube is cleaned to oxygen-service levels, capped, and stamped OXY, MED, OXY/MED, or ACR/MED. ASSE 6020 inspectors verify the tube markings on every project.

5During an in-progress brazing inspection, the inspector observes no purge gas flowing through the copper tube while joints are being brazed. The correct response is to:

A.Accept the work because purging is optional for joints under 1 inch

B.Reject the work and require oxygen-free nitrogen purge during brazing

C.Accept the work if the brazer uses cadmium-free filler

D.Allow the work to continue and verify by visual inspection only

Explanation: NFPA 99 requires oxygen-free nitrogen (nitrogen NF) purging during medical gas brazing to prevent copper oxide scale from forming inside the tube. Without purge, scale flakes off into the gas stream over time. The inspector must reject and require purging.

6Which standard qualifies a brazer for medical gas piping joints?

A.AWS D1.1 Structural Welding Code

B.ASME Boiler and Pressure Vessel Code, Section IX

C.API 1104 Pipeline Welding

D.ISO 9606 Welder Qualification

Explanation: ASME Section IX is the standard used to qualify brazers and brazing procedures for medical gas piping per NFPA 99. The inspector should review the brazer's current ASME IX qualification record before accepting in-progress work.

7Which brazing filler metal family is acceptable for joining copper-to-copper medical gas piping joints?

A.BAg cadmium-bearing silver alloys

B.BCuP copper-phosphorus alloys

C.Tin-lead 50/50 solder

D.Aluminum-silicon brazing alloys

Explanation: BCuP copper-phosphorus filler metals (AWS A5.8) are acceptable for copper-to-copper medical gas joints. They are self-fluxing on copper. Cadmium-bearing alloys are prohibited because they produce toxic fumes; soft solders are never permitted on medical gas.

8When the installer brazes copper tube to a bronze valve body, which brazing filler metal must be used?

A.BCuP copper-phosphorus alloy

B.Cadmium-free BAg silver brazing alloy with flux

C.Cadmium-bearing BAg silver brazing alloy

D.Tin-antimony 95/5 solder

Explanation: BCuP alloys form brittle phosphides when brazed to ferrous or bronze base metals. NFPA 99 requires a cadmium-free BAg silver brazing alloy with appropriate flux for copper-to-dissimilar metal medical gas joints. Cadmium-bearing silver is prohibited.

9Why are cadmium-bearing brazing alloys prohibited for medical gas piping?

A.They are too expensive for hospital projects

B.They produce toxic cadmium oxide fumes during brazing

C.They cannot wet copper effectively

D.They are incompatible with nitrogen purge

Explanation: Cadmium-bearing silver brazing alloys release toxic cadmium oxide fumes when heated, posing severe health risks to the brazer and others nearby. NFPA 99 and OSHA effectively require cadmium-free BAg alloys for medical gas brazing.

10Per NFPA 99 / CGA C-9, what is the correct identification color for medical oxygen piping?

A.Yellow

B.Green

C.Blue

D.Black

Explanation: Under CGA C-9 and NFPA 99 labeling, medical oxygen is identified by green. Inspectors verify pipe labels and station outlet colors during the final inspection.

About the ASSE 6020 Exam

ASSE 6020 is the national certification for Medical Gas Systems Inspectors who review and witness the installation, brazing, and acceptance testing of medical gas and vacuum systems in U.S. health care facilities per NFPA 99 Chapter 5. Inspectors verify that ASSE 6010 installers used approved materials (ASTM B819 copper), qualified brazers (ASME Section IX), correct filler metals (BCuP for copper-to-copper, cadmium-free BAg for dissimilar metals), oxygen-free nitrogen purge, proper source equipment, alarms, valves, DISS outlets, identification, and that the independent ASSE 6030 verification was successfully completed before clinical service.

Assessment

100-question written multiple-choice exam (often open-book NFPA 99)

Time Limit

Up to 4 hours

Passing Score

70% (some administrators 75-80%)

Exam Fee

$200-450 USD (ASSE International (delivered by approved third-party agencies))

ASSE 6020 Exam Content Outline

20%

NFPA 99 Chapter 5 and Inspection Authority

AHJ role, inspector responsibilities, code adoption, Level 1/2/3 system categories, and acceptance criteria.

15%

Piping Materials and Documentation Review

ASTM B819 medical gas tube, oxygen-service cleanliness, approved drawings, submittal review, and bill of materials verification.

20%

In-Progress Brazing Inspection

Witnessing nitrogen purge at 5-15 SCFH, brazer qualification per ASME Section IX, BCuP vs cadmium-free BAg filler selection, joint visual inspection, and brazing logs.

15%

Source Equipment, Alarms, and Outlets Inspection

Bulk oxygen siting per NFPA 55, manifold sizing, medical air compressor intake location, vacuum exhaust, master/area/local alarms, DISS outlets, and labeling.

15%

Final Inspection and Verification Witnessing

Witnessing installer initial pressure test (1.5x working), cross-connection test, particulate purge, 24-hour standing pressure test, and the independent ASSE 6030 verification before patient use.

15%

Documentation, Permits, and Acceptance

Permit review, as-built drawings, brazer/installer credentialing, verifier reports, certificates of compliance, and AHJ acceptance sign-off.

How to Pass the ASSE 6020 Exam

What You Need to Know

Passing score: 70% (some administrators 75-80%)
Assessment: 100-question written multiple-choice exam (often open-book NFPA 99)
Time limit: Up to 4 hours
Exam fee: $200-450 USD

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

ASSE 6020 Study Tips from Top Performers

1Memorize the inspector's role under NFPA 99: review submittals, witness in-progress brazing, witness final tests, document AHJ acceptance — the exam tests what you witness, not what you do with a torch.

2Learn the CGA C-9 gas colors cold: oxygen green, nitrous oxide blue, medical air yellow, medical vacuum white, nitrogen black, CO2 gray, helium brown — wrong color = automatic rejection.

3Drill the verification test sequence the inspector witnesses: (1) initial pressure 1.5x working with oil-free dry nitrogen, (2) cross-connection, (3) particulate purge, (4) 24-hour standing pressure, (5) independent ASSE 6030 source/outlet/purity tests.

4Know which brazing filler must be used where: BCuP for copper-to-copper (self-fluxing), cadmium-free BAg with flux for copper-to-dissimilar metal, NEVER cadmium-bearing silver alloy.

5Memorize key inspector numbers: 100 questions, 70% pass (typical), 24 hours minimum training, 2 years experience, 3-year cert cycle, 1.5x working pressure for initial test.

6Remember independence: the ASSE 6030 verifier cannot be employed by the installing contractor on the same project — this is the most-tested independence rule.

7When in doubt, the inspector rejects and documents. The exam rewards the cautious answer that protects patients over the answer that accepts substandard work.

Frequently Asked Questions

What does an ASSE 6020 Medical Gas Inspector do?

An ASSE 6020 inspector reviews and witnesses the installation, brazing, and acceptance testing of medical gas and vacuum systems in U.S. health care facilities per NFPA 99 Chapter 5. The inspector reviews submittals and approved drawings, witnesses in-progress brazing (nitrogen purge, qualified brazer, correct filler metal), inspects source equipment, alarms, and DISS outlets, witnesses the installer's pressure and cross-connection tests, witnesses the independent ASSE 6030 verification, and signs off AHJ acceptance documentation before the system is placed in clinical service.

What are the prerequisites to sit for the ASSE 6020 exam?

ASSE 6020 candidates must complete a minimum 24-hour medical gas inspector course delivered by an ASSE 6050-certified instructor AND have 2 years of documented practical experience. Eligibility also requires being employed as a plumbing/mechanical inspector or AHJ administrator, OR being regularly engaged in design/inspection/verification of medical gas systems, OR holding ASSE 6010 installer certification.

How many questions are on the ASSE 6020 exam and what is the passing score?

The ASSE 6020 exam is a 100-question written multiple-choice test, typically open-book with NFPA 99 referenced. The passing score is set by the ASSE-approved third-party administrator: most use 70%, some require 75% or 80%. Candidates have up to 4 hours to complete the exam.

What is the difference between ASSE 6010, 6020, 6030, and 6040?

ASSE 6010 is the Installer (brazes the piping). ASSE 6020 is the Inspector (reviews installation work and signs off AHJ acceptance). ASSE 6030 is the independent Verifier (performs final verification testing required by NFPA 99 before clinical service). ASSE 6040 is the Maintenance Personnel certification for staff who service systems already in service. NFPA 99 requires the 6030 verifier to be independent of the installation contractor on the same project.

Does an ASSE 6020 inspector perform the final verification testing?

No. NFPA 99 requires the final verification to be performed by an independent ASSE 6030 verifier who is not employed by the installing contractor. The ASSE 6020 inspector witnesses the 6030 verification, reviews the verifier's report, and signs off AHJ acceptance. The inspector does not run the cross-connection, particulate, or purity tests personally.

How long is ASSE 6020 certification valid?

ASSE 6020 certification is valid for 3 years. Recertification requires completing ASSE-approved continuing education in medical gas inspection and re-examining as required by the administrator. Inspectors should also keep a current copy of NFPA 99 as the code is revised approximately every 3 years.

100+ Free ASSE 6020 Practice Questions

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