10.2 - High-Priority Numbers and Thresholds

Module: Universal Review and Mock Examinations
Covers: High-priority numerical values from Core, Type I, Type II, and Type III
Current regulatory verification date: August 14, 2026
Provider-policy verification date: August 14, 2026
Primary current authorities: 40 CFR Part 82, Subpart F; 40 CFR Part 84, Subpart C where explicitly identified; current U.S. EPA Section 608 guidance; current SkillCat examination guidance where explicitly identified
Course role: Organizes the numerical values most likely to be confused during Universal examination preparation by concept and controlling condition, rather than as an isolated list of numbers

Learning Objectives

After completing this section, a student should be able to:

1. Associate each high-priority number with the rule, procedure, or definition it controls.
2. Distinguish charge thresholds used for small appliances, system-dependent recovery equipment, evacuation tables, and leak-repair programs.
3. Recall the Type I recovery percentages and the conditions that determine which percentage applies.
4. Select the correct Type II or Type III evacuation endpoint from the current EPA table.
5. Distinguish the 80% recovery-cylinder training limit from the Type I 80% refrigerant-recovery requirement.
6. Distinguish current Section 608 ozone-depleting-refrigerant leak-repair thresholds from the separate AIM Act HFC leak-repair program.
7. Recall the major record-retention periods used in Section 608 compliance.
8. Recognize Type III examination-preparation values that are not universal equipment design ratings.
9. Distinguish EPA regulatory values from certifying-provider examination rules.
10. Use a compact numerical decision process during Universal practice examinations.

Introduction

Numbers are difficult to memorize when they are learned without context.

For example:

15 lb

means little by itself.

A useful memory statement is:

FULL CHARGE >15 lb
→ ordinary system-dependent recovery equipment prohibited
→ unless permanently attached as a pump-out unit

The same principle applies to every number in this section.

For Universal preparation, memorize each number as a five-part package:

NUMBER
+
CONCEPT
+
CONDITION
+
UNIT
+
CURRENT / EXAM / PROVIDER STATUS

A number that is remembered without its condition is a common source of incorrect answers.

1. Master Charge-Threshold Map

Several important EPA 608 numbers are expressed in pounds of refrigerant. They control different rules.

The Four Most Important Charge Numbers

5 lb
→ SMALL APPLIANCE

15 lb
→ SYSTEM-DEPENDENT RECOVERY-EQUIPMENT LIMIT

50 lb
→ SECTION 608 ODS LEAK-REPAIR APPLICABILITY

200 lb
→ CERTAIN TYPE II EVACUATION-TABLE ROWS

Exam trap: 15 lb, 50 lb, and 200 lb are not three versions of the same rule.

2. Small-Appliance Charge Limit

The current small-appliance definition uses:

≤5 lb refrigerant

but the charge limit is only one part of the definition.

A small appliance must be:

FULLY MANUFACTURED AT A FACTORY
+
FACTORY CHARGED
+
HERMETICALLY SEALED AT A FACTORY
+
≤5 lb REFRIGERANT

Do Not Memorize

≤5 lb
→ automatically Type I

Memorize

ALL FOUR SMALL-APPLIANCE CONDITIONS
→ Type I

A field-connected split system with a 4-lb charge is not converted into a Type I small appliance merely because its charge is less than 5 lb.

3. System-Dependent Recovery-Equipment Charge Limit

Current federal regulations use:

>15 lb FULL CHARGE
→ ordinary system-dependent recovery equipment prohibited

The exception is:

PERMANENTLY ATTACHED PUMP-OUT UNIT

Important

The rule uses:

FULL CHARGE

not:

amount currently remaining after a leak

Example:

Full charge = 20 lb
Current remaining refrigerant = 8 lb

The appliance is still a greater-than-15-lb full-charge appliance for this rule.

4. Refrigerant Pressure-Classification Numbers

These values determine whether a refrigerant falls into the low-, medium-, high-, or very-high-pressure appliance category.

Memory Ladder

45
→ LOW / MEDIUM boundary

170
→ MEDIUM / HIGH boundary

355
→ HIGH / VERY-HIGH pressure criterion

All three pressure values are:

psia
at
104°F

Exam trap: Do not replace psia with psig.

5. Major-Repair Numerical Condition

Removal of a compressor, condenser, evaporator, or auxiliary heat-exchange coil is already major maintenance, service, or repair.

The numerical part of the current definition is:

OPENING >4 in² OF FLOW AREA
+
OPEN >15 min
→ MAJOR

Both numerical conditions must be present for this part of the definition.

6. Recovery-Equipment Date That Changes Requirements

One date appears repeatedly:

NOVEMBER 15, 1993

This date belongs to the:

RECOVERY / RECYCLING EQUIPMENT

not the appliance.

Exam Trap

Incorrect:

Appliance built before November 15, 1993
→ use old recovery requirement

Correct:

Recovery/recycling equipment manufactured or imported before November 15, 1993
→ use pre-1993 requirement where applicable

7. Type I Recovery Percentages

Current Type I Requirements

Memory Pattern

POST-1993
+
COMPRESSOR WORKS
→ 90%

POST-1993
+
COMPRESSOR FAILED
→ 80%

PRE-1993 EQUIPMENT
→ 80%

ALTERNATIVE
→ 4 in. Hg vacuum

High-Risk Confusion

80% Type I refrigerant recovery
≠
80% recovery-cylinder fill

The same percentage appears in two different concepts.

8. Current Type II and Type III Evacuation Levels

For appliances other than small appliances, MVACs, and MVAC-like appliances, current 40 CFR § 82.156 Table 1 uses the following values.

Current Table 1

Post-1993 Type II Pattern

The highest-priority column for modern recovery equipment is:

VERY HIGH
→ 0 in. Hg vacuum

HIGH <200 lb
→ 0 in. Hg vacuum

HIGH ≥200 lb
→ 10 in. Hg vacuum

MEDIUM <200 lb
→ 10 in. Hg vacuum

MEDIUM ≥200 lb
→ 15 in. Hg vacuum

Type III Pattern

LOW PRESSURE
→ 25 mm Hg absolute

The low-pressure value:

• Does not change at 200 lb.
• Does not change between the pre-1993 and post-1993 recovery-equipment columns.

Critical Unit Warning

25 mm Hg absolute
≠
25 in. Hg vacuum

9. Current Special Opening and Oil-Change Pressure Values

Current service-practice exceptions use several values near atmospheric pressure.

Do Not Confuse

0 psig
→ atmospheric gauge pressure

with:

0 psia
→ perfect vacuum

They are not the same condition.

10. Recovery-Cylinder Fill

EPA test topics emphasize the danger of filling recovery cylinders more than:

80%

For this course, the standard weight-based training calculation is:

$$W_{\text{refrigerant,max}}=0.80\cdot WC$$

where:

• $W_{\text{refrigerant,max}}$ = maximum refrigerant weight for the standard 80% training calculation.
• $WC$ = cylinder water capacity by weight.

The maximum gross scale weight is:

$$W_{\text{gross,max}}=TW+0.80\cdot WC$$

where:

• $TW$ = tare weight.
• $WC$ = water capacity by weight.

Cylinder Number Table

Important Limitation

The 80% training calculation does not authorize exceeding a lower:

• Cylinder-manufacturer limit.
• DOT filling-density limit.
• Refrigerant-specific limit.

If a lower limit applies:

LOWER LIMIT CONTROLS

Exam Trap

80% of WC

not:

80% of TW

11. Type III Examination-Preparation Pressure and Temperature Values

Several traditional Type III examination values remain important for test preparation. These values must be kept separate from current Table 1 evacuation levels and from actual equipment-specific relief-device ratings.

Type III Exam-Preparation Values

The 10 / 15 / 130 Memory Group

10 psig
→ LOW-PRESSURE LEAK-TEST EXAM MAXIMUM

10 psig
→ LOW-PRESSURE RECOVERY-UNIT CUTOUT

15 psig
→ LOW-PRESSURE RECOVERY-VESSEL RUPTURE DISC

130°F
→ TYPE III OIL HEATING

The first two use the same numerical value for different equipment and procedures.

Critical Warning

Do not convert:

15 psig recovery-vessel rupture-disc exam value

into:

all low-pressure chillers have a 15-psig rupture disc

Actual chiller relief protection is equipment-specific.

12. Current Section 608 ODS Leak-Repair Thresholds

The current Section 608 leak-repair program in 40 CFR § 82.157 applies to qualifying appliances with:

FULL CHARGE ≥50 lb

and:

CLASS I OR CLASS II REFRIGERANT
OR
A BLEND CONTAINING CLASS I / CLASS II REFRIGERANT

Appliances containing solely substitute refrigerants are not covered by current § 82.157.

Current Section 608 Leak-Rate Triggers

Current Section 608 Leak-Repair Timing Numbers

Current Leak-Inspection Charge Boundary

For applicable appliances exceeding the leak rate:

13. Historical Section 608 Leak Rates

Older EPA 608 study material may contain:

35%

and:

15%

These are historical values and must not replace the current § 82.157 trigger rates.

Current Versus Historical

Exam Strategy

When a question explicitly asks for the current Section 608 leak-repair trigger:

IPR → 30%
COMMERCIAL → 20%
COMFORT / OTHER → 10%

Do not select 35% or 15% merely because they appear in an older study guide.

14. Separate Current AIM Act HFC Leak-Repair Numbers

Beginning January 1, 2026, 40 CFR Part 84 contains a separate leak-repair program for qualifying appliances containing regulated HFCs or qualifying substitutes.

This is not the same program as Section 608 § 82.157.

Applicability

The current rule excludes:

• Appliances containing solely ozone-depleting refrigerant.
• Refrigerant-containing appliances in the residential and light-commercial air-conditioning and heat-pump subsector.

Current AIM Act Leak-Rate Triggers

Why This Is Easy to Confuse

The trigger percentages are similar to the current Section 608 table, but the applicability thresholds differ:

SECTION 608 §82.157
→ 50 lb or more
→ ODS-containing refrigerant

AIM ACT §84.106
→ 15 lb or more
→ qualifying HFC / substitute
→ separate exclusions

Universal-exam preparation note: Traditional EPA Section 608 questions focus on Section 608 concepts. This AIM Act section is retained because the project requires current field-regulatory awareness and because current HFC service compliance should not be incorrectly described using the ODS-only § 82.157 applicability rule.

15. Record-Retention Periods

Recordkeeping questions often use the same number:

3 YEARS

but the starting point differs.

High-Priority Record Table

Disposal Range

The disposal-record requirement is:

>5 lb
AND
<50 lb

This means:

• Exactly 5 lb does not satisfy the >5 lb condition.
• Exactly 50 lb does not satisfy the <50 lb condition.

Memory Aid

3 YEARS
→ common Section 608 record-retention number

but always ask:

3 years FROM WHEN?

16. SkillCat Provider-Specific Examination Numbers

The following values are provider policy, not EPA regulatory thresholds.

SkillCat is listed by EPA as an approved Section 608 technician certification program offering online testing.

Current SkillCat Help-Center Exam Structure

Current SkillCat Attempt / Review Numbers

Passing-Score Wording Requires Caution

Current SkillCat public pages are not perfectly consistent.

The SkillCat Help Center currently states:

70% overall on each exam

while other current SkillCat 2026 guidance describes passing as:

18 correct out of 25
in each required section

Therefore:

Follow the scoring rule and examination agreement displayed in the current SkillCat application at the time of testing.

Do not assume that an older screenshot, blog post, or course note overrides the current in-app instructions.

Project Readiness Standard

This project’s preparation target remains:

≥22 / 25
in EACH section
on TWO separate closed-book attempts

That is:

$$\frac{22}{25}\cdot 100=88\%$$

This is a project readiness target, not an EPA or SkillCat passing rule.

17. The Most Dangerous Number Collisions

Collision 1 — 5 lb

5 lb
→ small-appliance charge limit

but:

>5 lb and <50 lb
→ disposal-record range

Collision 2 — 15 lb

>15 lb
→ ordinary system-dependent recovery equipment prohibited

but separately:

≥15 lb
→ AIM Act §84.106 full-charge applicability threshold

and separately:

15 psig
→ traditional low-pressure recovery-vessel rupture-disc exam value

The unit changes from:

lb

to:

psig

Collision 3 — 50 lb

≥50 lb
→ current Section 608 ODS leak-repair applicability

and:

<50 lb
→ upper boundary of the technician disposal-record range

Collision 4 — 80%

80%
→ Type I refrigerant recovery under specified conditions

and separately:

80%
→ recovery-cylinder overfill / training calculation concept

Collision 5 — 10

10 in. Hg vacuum
→ several post-1993 Type II Table 1 rows

10%
→ current comfort-cooling / other leak-rate trigger

10 psig
→ Type III leak-test exam maximum

10 psig
→ traditional Type III recovery-unit cutout

10 days
→ current Section 608 follow-up verification timing

The number is useless unless the unit and concept are attached.

Collision 6 — 15

15 in. Hg vacuum
→ post-1993 medium-pressure ≥200-lb Table 1 endpoint

15 lb
→ system-dependent recovery threshold

15 psig
→ recovery-vessel rupture-disc exam value

15 min
→ part of the major-repair opening definition

Collision 7 — 25

25 mm Hg absolute
→ Type III normal Table 1 endpoint

25 questions
→ minimum core / technical-group question count in Section 608 certification exams and common provider section structure

Never answer only from the number.

18. High-Priority Numbers by Concept

Appliance Classification

5 lb
→ small-appliance maximum charge

45 / 170 / 355 psia @ 104°F
→ pressure-category boundaries

Recovery Equipment

November 15, 1993
→ recovery-equipment date boundary

>15 lb full charge
→ ordinary system-dependent equipment prohibited

Type I

80% / 90%
→ refrigerant recovery

4 in. Hg vacuum
→ alternative Type I endpoint

Type II

200 lb
→ evacuation-table charge boundary

0 / 4 / 10 / 15 in. Hg vacuum
→ Table 1 values

Type III

25 mm Hg absolute
→ current normal Table 1 endpoint

10 psig
→ low-pressure leak-test exam maximum

10 psig
→ recovery-unit cutout exam value

15 psig
→ recovery-vessel rupture-disc exam value

130°F
→ oil-heating exam value

Current Section 608 ODS Leak Repair

50 lb
→ applicability

30% / 20% / 10%
→ trigger rates

30 days / 120 days
→ repair timing

10 days
→ follow-up verification timing

125%
→ chronic-leak reporting threshold

March 1
→ report due date

Records

3 years
→ dominant retention period

SkillCat Provider Policy

50 questions / 1 hour
→ Type I, II, or III exam

100 questions / 2 hours
→ Universal exam

4 attempts
→ current SkillCat attempt allocation

4 hours
→ current SkillCat retake wait

19. Twenty Numbers to Know Cold

Before taking the Universal mock examinations, be able to explain each of these without looking at the table.

1. 5 lb — small-appliance maximum charge.
2. 15 lb — system-dependent recovery-equipment full-charge threshold.
3. 45 psia at 104°F — low/medium pressure boundary.
4. 170 psia at 104°F — medium/high pressure boundary.
5. 355 psia at 104°F — high/very-high pressure criterion.
6. November 15, 1993 — recovery-equipment date boundary.
7. 80% — Type I recovery under specified conditions.
8. 90% — post-1993 Type I recovery with functional compressor.
9. 4 in. Hg vacuum — Type I alternative endpoint.
10. 200 lb — charge boundary in several Type II Table 1 rows.
11. 10 in. Hg vacuum — important post-1993 Type II endpoint.
12. 15 in. Hg vacuum — post-1993 medium-pressure ≥200-lb endpoint.
13. 25 mm Hg absolute — Type III normal Table 1 endpoint.
14. 80% cylinder fill — recovery-cylinder safety / training concept.
15. 10 psig — Type III low-pressure leak-test exam maximum.
16. 15 psig — Type III recovery-vessel rupture-disc exam value.
17. 130°F — Type III oil-heating exam value.
18. 50 lb — current Section 608 ODS leak-repair threshold.
19. 30% / 20% / 10% — current leak-rate triggers.
20. 3 years — common Section 608 record-retention period.

The goal is not merely to recite the number.

For each one, say:

NUMBER → CONCEPT → CONDITION → UNIT

20. EPA 608 Exam Focus

Ask Four Questions Before Selecting a Number

1. WHAT CONCEPT?
2. WHAT CONDITION?
3. WHAT UNIT?
4. CURRENT RULE, EXAM VALUE, OR PROVIDER POLICY?

Example 1

Question clue:

small appliance
+
post-1993 recovery equipment
+
compressor operates

Reasoning:

Type I recovery percentage
→ 90%

Example 2

Question clue:

medium-pressure appliance
+
250-lb full charge
+
post-1993 recovery equipment

Reasoning:

medium pressure
+
≥200 lb
+
post-1993
→ 15 in. Hg vacuum

Example 3

Question clue:

low-pressure appliance
+
normal Table 1 recovery endpoint

Reasoning:

Type III
→ 25 mm Hg absolute

Example 4

Question clue:

commercial refrigeration
+
60 lb ODS charge
+
current Section 608 leak repair

Reasoning:

≥50 lb
+
commercial refrigeration
→ 20% trigger

Example 5

Question clue:

portable system-dependent recovery equipment
+
20-lb appliance full charge

Reasoning:

>15 lb
→ ordinary system-dependent equipment prohibited

21. Common Mistakes and Confusing Points

Mistake 1: Memorizing 5 lb as the Entire Small-Appliance Definition

The appliance must also be factory manufactured, factory charged, and hermetically sealed in the factory.

Mistake 2: Applying the 15-lb Rule to the Refrigerant Remaining in the Appliance

The system-dependent-equipment rule uses full charge.

Mistake 3: Treating 50 lb as the Type II Evacuation Boundary

The relevant Type II Table 1 charge boundary is 200 lb.

Mistake 4: Treating 200 lb as the Section 608 Leak-Repair Threshold

The current § 82.157 full-charge threshold is 50 lb or more of qualifying ODS-containing refrigerant.

Mistake 5: Confusing Type I 80% With Cylinder 80%

They are separate requirements / training concepts.

Mistake 6: Forgetting Which Date Matters

November 15, 1993 refers to recovery/recycling equipment, not the appliance.

Mistake 7: Mixing Inches and Millimeters

Type III:

25 mm Hg absolute

not:

25 in. Hg vacuum

Mistake 8: Calling 0 psig a Perfect Vacuum

At standard atmospheric conditions:

0 psig
≈ atmospheric absolute pressure

It is not zero absolute pressure.

Mistake 9: Applying Historical 15% / 35% Leak Rates as Current

Use the current Section 608:

30% / 20% / 10%

table when the question asks for current rules.

Mistake 10: Combining Section 608 and AIM Act Applicability

Current federal field practice has two separate leak-repair frameworks.

Do not turn:

15 lb

into the Section 608 ODS leak-repair threshold.

Mistake 11: Calling 15 psig a Universal Chiller Rupture-Disc Setting

The project uses 15 psig as a traditional low-pressure recovery-vessel examination value.

Mistake 12: Treating Provider Rules as EPA Regulations

A two-hour Universal time limit or four-attempt policy is a provider rule, not a Section 608 regulatory threshold.

22. Final Number-Selection Workflow

When a question contains a number, use this sequence:

IDENTIFY TOPIC
↓
IDENTIFY APPLIANCE / PROGRAM
↓
IDENTIFY FULL-CHARGE CONDITION
↓
IDENTIFY EQUIPMENT DATE IF RELEVANT
↓
IDENTIFY COMPRESSOR CONDITION IF TYPE I
↓
IDENTIFY PRESSURE CATEGORY IF TYPE II / III
↓
CHECK UNIT
↓
CHECK CURRENT VS HISTORICAL
↓
CHECK EPA RULE VS PROVIDER POLICY
↓
SELECT NUMBER

This prevents the most common Universal numerical errors.

Section Summary

The highest-priority Universal numbers should be learned in groups.

Charge Group

5 lb
→ small appliance

15 lb
→ system-dependent recovery limit

50 lb
→ Section 608 ODS leak-repair threshold

200 lb
→ Type II evacuation-table boundary

Type I Group

Nov. 15, 1993
80%
90%
4 in. Hg vacuum

Type II Group

0 / 4 / 10 / 15 in. Hg vacuum
200-lb boundary

Type III Group

25 mm Hg absolute
10 psig
10 psig
15 psig
130°F

Current Section 608 Leak Group

50 lb
30% / 20% / 10%
30 days
120 days
10 days
125%
March 1
3 years

Provider Group

50 questions / 1 hour
100 questions / 2 hours
4 attempts
4-hour retake wait

The next section focuses on terms that are commonly confused even when no numerical calculation is required.

References

Current Regulatory and EPA Sources

1. U.S. Environmental Protection Agency, Required Level of Evacuation of Appliances, accessed August 14, 2026.

2. U.S. Environmental Protection Agency, Stationary Refrigeration Service Practice Requirements, accessed August 14, 2026.

3. U.S. Environmental Protection Agency, Stationary Refrigeration Leak Repair Requirements, accessed August 14, 2026.

4. U.S. Environmental Protection Agency, Recordkeeping and Reporting Requirements for Stationary Refrigeration, accessed August 14, 2026.

5. U.S. Environmental Protection Agency, Refrigerant Recovery and Recycling Equipment Certification, accessed August 14, 2026.

6. U.S. Environmental Protection Agency, Test Topics, accessed August 14, 2026.

7. U.S. Environmental Protection Agency, Certification Programs for Section 608 Technicians, accessed August 14, 2026.

8. Electronic Code of Federal Regulations, 40 CFR § 82.152 - Definitions, accessed August 14, 2026.

9. Electronic Code of Federal Regulations, 40 CFR § 82.156 - Proper Evacuation of Refrigerant From Appliances, accessed August 14, 2026.

10. Electronic Code of Federal Regulations, 40 CFR § 82.157 - Appliance Maintenance and Leak Repair, accessed August 14, 2026.

11. Electronic Code of Federal Regulations, 40 CFR § 82.161 - Technician Certification, accessed August 14, 2026.

12. Electronic Code of Federal Regulations, 40 CFR § 84.106 - Leak Repair, accessed August 14, 2026.

Current Provider Sources

13. SkillCat Support, What Are the Rules for Taking the EPA 608 Exam on SkillCat?, accessed August 14, 2026.

14. SkillCat Support, How Many Attempts Do I Get on the EPA 608 Exam?, accessed August 14, 2026.

15. SkillCat Support, How Long Does Someone Need to Wait to Take the EPA 608 Exam Again?, accessed August 14, 2026.

16. SkillCat, EPA 608 Practice Test 2026: Core & Types I–III Guide, accessed August 14, 2026.

Project Cross-References

17. Section 1.5 - Examination Structure and Universal Certification.

18. Section 2.7 - Enforcement Recordkeeping and Professional Responsibility.

19. Section 5.2 - Recovery Equipment Categories.

20. Section 5.6 - Recovery Cylinders.

21. Section 5.9 - Service-Practice Requirements and Exceptions.

22. Section 7.3 - Type I Recovery Requirements.

23. Section 8.2 - Refrigerant Pressure Classifications.

24. Section 8.5 - Leak Repair Requirements and Current Regulatory Updates.

25. Section 8.8 - Type II Evacuation Requirements.

26. Section 9.4 - Low-Pressure Leak Detection and Pressurization.

27. Section 9.5 - Type III Recovery Sequence.

28. Section 9.7 - Refrigerant in Oil.

29. Section 9.9 - Type III Evacuation Requirements.

30. Section 9.11 - Quick Reference.

31. Section 10.1 - Universal Certification Comparison Tables.