6.10 - Quick Reference

Module: Safety Leak Detection Shipping and Safe Disposal
Covers: Sections 6.1–6.9
Regulatory and technical verification date: August 10, 2026
Use: Rapid review before the Module 6 practice questions and later Core/Universal certification review

1. Personal Protective Equipment and Refrigerant Exposure

Basic PPE

SDS Sections to Remember

Exposure Response

Refrigerant exposure
→ stop the exposure
→ move to a safe location
→ follow the refrigerant SDS
→ obtain medical attention when required

For frozen / frostbitten tissue:

• Do not rub the injured area.
• Do not flush frozen tissue with water.
• Do not remove clothing frozen to tissue.
• Obtain prompt medical attention.

For eye exposure:

Eye tissue frozen
→ immediate medical attention

Eye tissue not frozen
→ flush thoroughly with water for at least 15 minutes
→ follow SDS / medical guidance

High-Priority Reminder

Class A refrigerant
≠ harmless

Lower-toxicity refrigerants can still cause:

• Frostbite.
• Oxygen displacement.
• Cardiac effects.
• High-pressure injury.
• Thermal-decomposition exposure.

2. Respiratory and Confined-Space Hazards

Oxygen Displacement

A refrigerant release can displace breathable air.

More refrigerant vapor
→ less available oxygen
→ asphyxiation risk

OSHA defines an oxygen-deficient atmosphere as:

O₂ < 19.5% by volume

A normal oxygen reading does not automatically prove that refrigerant concentration is below every toxic or exposure limit.

Refrigerant Accumulation

Many common refrigerant vapors are denser than air and can create higher concentrations in:

• Floor-level areas.
• Pits.
• Trenches.
• Below-grade spaces.

However:

not every refrigerant is heavier than air

and real releases mix with room air.

Use the specific refrigerant SDS and actual ventilation/room conditions.

Cardiac and Central-Nervous-System Effects

High refrigerant exposure can contribute to:

• Dizziness.
• Confusion.
• Loss of coordination.
• Loss of consciousness.
• Cardiac sensitization / arrhythmia risk.

Do not remain in a contaminated space simply because no strong odor is present.

Safe Response

Suspected dangerous release
→ evacuate
→ ventilate
→ evaluate atmosphere
→ re-enter only when authorized and safe

Respiratory Protection

• Air-purifying respirators do not supply oxygen.
• Unknown or potentially immediately dangerous to life or health (IDLH) atmospheres require appropriate atmosphere-supplying respiratory protection under a respiratory-protection program.
• Self-contained breathing apparatus (SCBA) may be required for applicable emergency/IDLH conditions.
• Do not make an unplanned rescue entry into an oxygen-deficient or unknown atmosphere.

Confined-Space Reminder

Machinery room
≠ automatically an OSHA confined space

A pit, vault, tank, or other space may separately meet the confined-space definition.

3. Fire Explosion and Thermal-Decomposition Hazards

Test-Gas Rule

USE
→ dry nitrogen

DO NOT USE
→ oxygen
→ compressed air

Why Oxygen Is Prohibited

Oxygen is a strong oxidizer.

A refrigeration system can contain:

• Refrigeration oil.
• Organic materials.
• Refrigerant residue.
• Other combustible substances.

Oxygen under pressure can greatly increase fire or explosion risk.

Why Compressed Air Is Prohibited

Compressed air contains:

• Oxygen.
• Moisture.
• Possible compressor oil or contamination.

It can also create an unsafe refrigerant-air mixture.

Open Flame and Hot Surface Hazards

Do not expose refrigerant to:

• Open flame.
• Torch flame.
• Welding arc or hot work without proper controls.
• Extremely hot surfaces.

High temperatures can decompose refrigerants into hazardous products.

Possible decomposition products depend on the refrigerant chemistry and can include:

• Hydrogen fluoride (HF) for fluorinated compounds.
• Hydrogen chloride (HCl) for chlorine-containing compounds.
• Carbonyl fluoride or related carbonyl halides for some fluorinated compounds.
• Phosgene under some chlorine-containing halocarbon decomposition conditions.

Phosgene is not a universal decomposition product of every refrigerant.

Flammable-Refrigerant Reminder

A2L
≠ nonflammable

For flammable refrigerants:

• Control ignition sources.
• Use compatible/approved service equipment.
• Follow manufacturer ventilation instructions.
• Follow current code and listing requirements.

4. Refrigerant Safety Classifications

ASHRAE Safety-Group Matrix

Decode the Safety Group

LETTER
→ toxicity

NUMBER / NUMBER-LETTER
→ flammability

Toxicity Classes

A
→ lower toxicity

B
→ higher toxicity

Do not translate these as:

A = nontoxic
B = deadly

Flammability Classes

1
→ no flame propagation under specified test conditions

2L
→ lower flammability with low burning velocity

2
→ lower flammability

3
→ higher flammability

The familiar 2L low-burning-velocity criterion is:

≤ 10 cm/s

within the Standard 34 classification framework.

Representative Examples

Do Not Confuse

Safety group
≠ ODP
≠ GWP
≠ refrigerant pressure category
≠ Section 608 certification type

Current-Source Reminder

Older sources may show superseded classifications.

For field decisions:

latest applicable Standard 34 + published addenda
→ current safety classification

5. Nitrogen Pressure Testing

Correct Generic Setup

Dry nitrogen cylinder
→ pressure regulator
→ downstream relief valve
→ service hose
→ manifold center / service port
→ refrigeration system

For the standard manifold concept:

BLUE hose
→ low-side service connection

RED hose
→ high-side service connection

YELLOW / center hose
→ regulated nitrogen source

Actual valve positions and connection points depend on the manufacturer test procedure.

Required Safety Elements

Test-Pressure Rule

Manufacturer-specified test pressure
+
weakest exposed component rating
→ allowable test pressure

There is no universal EPA nitrogen test pressure for every system.

Safe Pressure-Test Sequence

Identify system and test section
→ recover refrigerant as required
→ inspect test equipment
→ connect with valves closed
→ configure system valves
→ purge service line as appropriate
→ pressurize slowly
→ stop at specified pressure
→ isolate nitrogen supply
→ record pressure + temperature
→ leak check
→ repair / retest if needed
→ depressurize safely

Standing-Test Reminder

At test pressure
→ close / isolate nitrogen supply
→ observe system pressure

Leaving the nitrogen source feeding the system can mask a leak.

Temperature Effect

Temperature decreases
→ test-gas pressure can decrease

Temperature increases
→ test-gas pressure can increase

Do not treat every pressure change as automatic proof of leakage.

Brazing Purge Versus Pressure Test

Do not seal a brazing purge circuit at pressure as though it were a standing pressure test.

6. Leak Detection Methods

Leak-Method Comparison

Main EPA Leak-Inspection Distinction

Leak inspection
→ must detect AND determine location

Methods such as:

• Pressure decay.
• Vacuum decay.
• Pressure checks.
• Sight-glass observations.
• Receiver-level observations.
• Charging-chart indications.

may indicate a problem but do not locate the leak by themselves.

Practical Search Sequence

For a charged system with a compatible detector:

Visual inspection
→ electronic detector survey
→ bubble solution / other pinpoint method
→ repair
→ verify

For a recovered system:

Dry nitrogen pressure test
→ bubble and/or ultrasonic location method
→ repair
→ retest

Open-Drive Compressor

Open-drive compressor
→ rotating shaft passes through housing
→ inspect shaft seal as a possible leak location

7. Machinery-Room Safety

Safety-Layer Sequence

DETECT
→ ALARM
→ VENTILATE
→ CONTROL
→ RESTRICT ACCESS
→ VERIFY BEFORE RE-ENTRY

Main Functions

Detector Placement

Detector placement depends on:

• Refrigerant properties.
• Expected leak location.
• Airflow.
• Equipment arrangement.
• Room geometry.
• Current code/standard.
• Detector manufacturer instructions.

Do not use one universal detector height for every refrigerant.

Alarm and Ventilation

Detector
→ senses

Alarm
→ warns

Ventilation
→ removes / dilutes contaminated air

Do not treat these as the same function.

Emergency Shutdown

Equipment shutdown
≠ leak guaranteed to stop
≠ atmosphere proven safe

Stored refrigerant can continue escaping after electrical machinery stops.

Current-Code Reminder

Do not memorize one old universal:

• Alarm ppm value.
• Sensor mounting height.
• Ventilation cfm value.
• Ventilation formula.

Actual requirements depend on:

adopted code
+
current referenced standards / addenda
+
refrigerant
+
equipment listing
+
manufacturer instructions
+
AHJ requirements

8. Cylinder Shipping and Transportation

EPA Exam-Level Shipping Concept

EPA’s current Section 608 topic framework expects recognition of:

Refrigerant identification
+
applicable DOT classification label / tag

DOT Hazard Communication

Do not assume every refrigerant has the same DOT classification.

ASHRAE Versus DOT

ASHRAE A1 / A2L / A3 / B2L
≠
DOT transportation division

They are different classification systems.

Marking Label Placard Shipping Paper

Shipping Paper Basic Description

When required, the basic description generally includes:

Identification number
→ proper shipping name
→ hazard class/division
→ packing group, when assigned

Not every Class 2 gas is assigned a packing group.

Service-Vehicle Securement

Cylinder
→ restrained against shifting
→ restrained against overturning
→ restrained against ejection

Preferred normal HVAC handling:

upright
+
securely restrained
+
valve protected

The general federal Class 2 highway rule can permit securely restrained upright or horizontal cylinders in applicable situations.

Therefore:

upright
→ preferred normal HVAC practice

but:

upright
≠ universal federal orientation rule for every Class 2 shipment

Heat

Temperature increases
→ cylinder pressure increases

Protect cylinders from:

• Open flame.
• Torch heat.
• Vehicle exhaust heat.
• Other excessive heat exposure.

The DOT 55°C / 131°F value appearing in cylinder filling/pressure criteria is not a recommended storage temperature.

Materials of Trade

A materials-of-trade exception can reduce some HMR requirements for qualifying business transportation.

It is not an automatic HVAC exemption.

Check the current rule for:

• Material eligibility.
• Quantity.
• Packaging.
• Marking.
• Securement.
• Other conditions.

9. Safe Disposal Requirements

First Disposal Decision

How does the appliance normally enter disposal?

Equipment Normally Dismantled On-Site

Examples:

• Central residential A/C.
• Retail food refrigeration.
• Chillers.
• Industrial-process refrigeration.

General path:

Recover refrigerant under applicable Section 608 service-practice rule
→ verify required recovery endpoint
→ dismantle / remove
→ scrap / recycle / dispose

Equipment Entering the Waste Stream Intact

Examples:

• Household refrigerator/freezer.
• Window A/C.
• Other small appliance.
• MVAC.
• MVAC-like appliance.

The final processor must:

recover remaining refrigerant

or:

verify proper prior recovery

Final-Processor Verification

A signed statement includes:

Name of person who recovered refrigerant
+
Address of person who recovered refrigerant
+
Date refrigerant was recovered

A qualifying supplier contract can also be used where the current rule permits it.

Sticker Trap

"Refrigerant removed" sticker
→ useful internal information
→ NOT sufficient EPA verification by itself

Leaked-Out Exception

If all refrigerant escaped before delivery due to:

• System failure.
• Accident.
• Other unavoidable occurrence.

and recovery is impossible, the final processor obtains the applicable signed leaked-out statement.

Deliberate line cutting / intentional venting
→ does NOT qualify

Disposal Certification Exception

For disposal recovery from:

• Small appliances.
• MVACs.
• MVAC-like appliances.

the person performing that disposal recovery has a technician-certification exception.

But:

certification exception
≠ recovery exception

and:

certification exception
≠ recovery-equipment performance exception

Two Different Three-Year Record Rules

Do not confuse these two rules.

Disposable Refrigerant Cylinders

A disposable refrigerant cylinder:

≠ refrigeration appliance
≠ refillable recovery cylinder

Common one-way cylinders such as DOT-39 cylinders are nonrefillable.

Future Part 84 Disposable-Cylinder Rule

Under the current rule:

January 1, 2028
→ main compliance date for the Part 84 disposable-cylinder heel-management requirement

The current rule contains an alternative pathway involving a certified technician evacuating a qualifying covered disposable cylinder to:

15 in. Hg vacuum

with the required certification statement.

Important:

15 in. Hg
→ specific future Part 84 disposable-cylinder pathway
→ NOT a Section 608 appliance evacuation level

The January 1, 2028 date is still a future compliance date.

10. High-Priority Numbers and Conditions

Numbers in this table must always be read together with their stated conditions.

11. High-Priority Safety Decision Rules

Refrigerant Contact

Liquid refrigerant on skin / eyes
→ cold-injury risk
→ appropriate first response + SDS + medical guidance

Refrigerant Release

Unknown or dangerous room atmosphere
→ evacuate
→ ventilate
→ verify atmosphere
→ re-enter only when authorized and safe

Pressure Testing

Dry nitrogen
→ regulator
→ downstream relief protection
→ manufacturer test-pressure limit

Leak Detection

Pressure / vacuum decay
→ may indicate a problem
→ does not locate the leak

Flammable Refrigerant

A2L / A2 / A3 / B2L / B2 / B3
→ ignition-source control matters
→ use compatible tools and procedures

Machinery-Room Alarm

Alarm active
→ do not enter casually
→ follow emergency procedure

Cylinder Transportation

Identify
→ inspect
→ close/protect valves
→ mark/label
→ document when required
→ secure
→ protect from heat

Appliance Disposal

End of useful life
→ recover refrigerant
or
→ verify proper prior recovery
→ then final disposal

12. Frequently Confused Concepts

13. Module 6 Examination Checklist

Before taking the Module 6 practice questions, confirm that you can answer each item without notes.

PPE and Exposure

• Why can liquid refrigerant cause frostbite?
• Which SDS section contains first-aid information?
• Which SDS section contains PPE/exposure-control information?
• Why does a face shield not automatically replace primary eye protection?
• What should not be done to frozen tissue?

Respiratory Safety

• What oxygen concentration is considered oxygen-deficient?
• Why can refrigerant accumulate in low areas?
• Why is “all refrigerants are heavier than air” incorrect?
• Why does an air-purifying respirator not solve oxygen deficiency?
• When can SCBA / atmosphere-supplying protection become necessary?

Fire and Decomposition

• Why are oxygen and compressed air prohibited for leak-test pressurization?
• Why are open flames and hot surfaces hazardous around refrigerant?
• Why is phosgene not a universal refrigerant decomposition product?
• Why does A2L still require ignition-source control?

Safety Classification

• What does the letter in A2L represent?
• What does 2L represent?
• What is the difference between A1, A2L, A2, and A3?
• Why can an older refrigerant classification be wrong today?

Nitrogen Testing

• What is the correct nitrogen component sequence?
• Where is the downstream relief valve located?
• What controls maximum test pressure?
• Why should pressure be raised gradually?
• Why is the nitrogen source isolated for a standing test?
• Why must temperature be considered?

Leak Detection

• Why is an oil trace only a clue?
• Which methods can pinpoint a leak?
• Why does pressure decay not locate a leak?
• Why does vacuum rise have multiple possible causes?
• Why must an electronic detector match the refrigerant?
• What special leak location should be checked on an open-drive compressor?

Machinery Room

• What are the functions of detector, alarm, ventilation, and shutdown?
• Why should alarm indication be available before entry?
• Why is there no universal detector height or alarm ppm?
• Why does shutdown not prove the leak has stopped?
• Why is a machinery room not automatically a confined space?

Shipping

• What must be identified on a refrigerant cylinder?
• What is the difference among marking, label, placard, and shipping paper?
• What do DOT Divisions 2.1 and 2.2 represent?
• How should cylinders be secured in normal HVAC service?
• Why must cylinders be protected from heat?
• Why is a materials-of-trade exception not a blanket HVAC exemption?

Disposal

• What is the difference between on-site dismantling and intact waste-stream disposal?
• What two choices does the final processor have?
• What three items belong in the signed prior-recovery statement?
• Why is a sticker alone insufficient?
• What qualifies for the leaked-out statement?
• What are the two separate three-year record rules?
• What does the disposal certification exception not remove?
• Why is the January 1, 2028 disposable-cylinder rule kept separate from Section 608 appliance recovery?

14. Final Memory Map

PPE
→ protect eyes / hands / body
→ use SDS and manufacturer guidance

RELEASE
→ evacuate
→ ventilate
→ verify atmosphere

FIRE / PRESSURE
→ no oxygen
→ no compressed air
→ control ignition

SAFETY CLASS
→ letter = toxicity
→ number = flammability

NITROGEN TEST
→ cylinder
→ regulator
→ downstream relief
→ manifold
→ system

LEAK SEARCH
→ indication is not always location
→ use a location-capable method

MACHINERY ROOM
→ detect
→ alarm
→ ventilate
→ control
→ restrict access
→ verify

SHIPPING
→ identify
→ mark / label
→ document if required
→ secure
→ protect

DISPOSAL
→ recover
or
→ verify prior recovery
→ keep required records

References

Current Regulatory and Safety Sources Used in Sections 6.1–6.9

1. U.S. Environmental Protection Agency, Test Topics — Section 608 Technician Certification, current Core safety, leak-detection, nitrogen, cylinder, and shipping topics. Accessed August 10, 2026.

2. U.S. Environmental Protection Agency, Stationary Refrigeration Safe Disposal Requirements, current safe-disposal responsibilities and verification guidance. Accessed August 10, 2026.

3. Electronic Code of Federal Regulations, 40 CFR §82.155 — Safe Disposal of Appliances, current final-processor verification, supplier-notification, leaked-out statement, and recordkeeping requirements. Checked August 10, 2026.

4. Electronic Code of Federal Regulations, 40 CFR §82.156 — Proper Evacuation of Refrigerant from Appliances, current disposal recovery and technician recordkeeping requirements. Checked August 10, 2026.

5. Electronic Code of Federal Regulations, 40 CFR Part 84, Subpart C, current HFC/substitute management framework, including leak-repair and future disposable-cylinder requirements discussed in Sections 6.6 and 6.9. Checked August 10, 2026.

6. Occupational Safety and Health Administration, 29 CFR 1910.134 — Respiratory Protection, current respiratory-protection framework. Accessed August 10, 2026.

7. Occupational Safety and Health Administration, 29 CFR 1910.146 — Permit-Required Confined Spaces, current confined-space and hazardous-atmosphere definitions. Accessed August 10, 2026.

8. ASHRAE, ANSI/ASHRAE Standard 34-2024 — Designation and Safety Classification of Refrigerants, together with applicable published addenda and current public refrigerant-designation information used in Section 6.4.

9. ASHRAE, ANSI/ASHRAE Standard 15-2024 — Safety Standard for Refrigeration Systems, together with applicable published addenda used in Section 6.7.

10. Electronic Code of Federal Regulations, 49 CFR Parts 171–180 — Hazardous Materials Regulations, current DOT/PHMSA transportation framework used in Section 6.8.

Project Section Cross-References

11. Section 6.1 - Personal Protective Equipment and Refrigerant Exposure.

12. Section 6.2 - Respiratory and Confined-Space Hazards.

13. Section 6.3 - Fire Explosion and Decomposition Hazards.

14. Section 6.4 - Refrigerant Safety Classifications.

15. Section 6.5 - Nitrogen Pressure Testing.

16. Section 6.6 - Leak Detection Methods.

17. Section 6.7 - Machinery-Room Safety.

18. Section 6.8 - Cylinder Shipping and Transportation.

19. Section 6.9 - Safe Disposal Requirements.