NAFA CAFS TEST EXAM COMPLETE 150 QUESTIONS &
ANSWERS (LATEST 2026 EDITION)
TABLE OF CONTENTS
1. EXAM INFORMATION AND OVERVIEW .................................. 1
2. SECTION 1: FUNDAMENTALS OF AIR FILTRATION .................... 2
3. SECTION 2: FILTRATION MECHANISMS .............................. 5
4. SECTION 3: AIRFLOW AND PRESSURE ................................ 8
5. SECTION 4: FILTER TYPES AND MEDIA .............................. 11
6. SECTION 5: ELECTRONIC AIR CLEANERS ............................ 14
7. SECTION 6: HEPA, ULPA AND SUPER ULPA FILTERS .................. 16
8. SECTION 7: STANDARDS AND REGULATIONS .......................... 19
9. SECTION 8: MICROORGANISMS AND IAQ ............................. 22
10. SECTION 9: SPECIALIZED APPLICATIONS ........................... 24
11. SECTION 10: COST AND OPERATION ................................ 27
12. SECTION 11: GENERAL KNOWLEDGE ................................. 29
13. QUICK REFERENCE ANSWER KEY .................................... 32
EXAM INFORMATION AND OVERVIEW
| Item | Details |
|||
| Exam Name | NAFA Certified Air Filter Specialist (CAFS) |
| Total Questions | 100 (70 multiple choice, 30 true/false) |
| Time Allowed | 2 hours |
| Format | Open-book, based on NAFA Guide to Air Filtration |
| Passing Score | Not publicly disclosed |
| Renewal | Every 1 year(s) |
| Experience Required | Minimum 1 year field experience |
SECTION 1: FUNDAMENTALS OF AIR FILTRATION (Questions 1-15)
Question 1
,Aerosols cover a wide range of sizes. True or false?
Answer: True
Rationale: Aerosols, which are solid or liquid particles suspended in air, span a vast size range
from a few nanometers to hundreds of micrometers. This is a fundamental concept in air
filtration as different mechanisms dominate different particle size ranges.
Question 2
What is 1 millionth of a meter called?
A) Nanometer
B) Millimeter
C) Micrometer or Micron
D) Centimeter
Answer: C) Micrometer or Micron
Rationale: The micron (or micrometer) is the standard unit of measurement for describing the
size of airborne particles. One micron equals one-millionth of a meter (1/1,000,000 m).
Question 3
The air we breathe is composed mainly of which gas?
A) Oxygen
B) Argon
C) Carbon Dioxide
D) Nitrogen
Answer: D) Nitrogen
Rationale: Earth's atmosphere is composed primarily of nitrogen (about 78%). Oxygen makes
up only about 21%, with trace amounts of other gases. This is important for understanding the
medium through which particles travel.
,Question 4
A micron is approximately what fraction of an inch?
A) 1/1,000"
B) 1/10,000"
C) 1/25,400"
D) 1/100,000"
Answer: C) 1/25,400"
Rationale: One micron is approximately 1/25,400 of an inch. This conversion is essential for
understanding particle size specifications in both metric and imperial units.
Question 5
The size of particles in outdoor air are mainly _____ and smaller.
A) 100 micrometers
B) 10 micrometers
C) 5 micrometers
D) 1 micrometer
Answer: D) 1 micrometer
Rationale: The majority of particles in outdoor air, including those from combustion and natural
processes, are 1 micrometer or smaller in diameter. Understanding particle size distribution is
critical for selecting appropriate filters.
Question 6
What is capacity in the context of a filter?
A) The amount of dust a filter can hold
B) The pressure drop across a filter
C) The rated flow of air through a filter at a specified pressure drop
D) The efficiency of a filter
Answer: C) The rated flow of air through a filter at a specified pressure drop
, Rationale: In filtration, a filter's capacity refers to the amount of air it can handle, measured in
cubic feet per minute (CFM), typically at a given pressure drop. This is distinct from dust holding
capacity.
Question 7
What does CFM stand for?
A) Cubic feet per meter
B) Cubic feet per minute
C) Cubic foot mass
D) Centrifugal flow meter
Answer: B) Cubic feet per minute
Rationale: CFM (cubic feet per minute) is the standard unit of measurement for airflow volume in
the air filtration industry.
Question 8
What does FPM stand for?
A) Feet per meter
B) Flow per minute
C) Feet per minute
D) Filter pressure measure
Answer: C) Feet per minute
Rationale: FPM (feet per minute) is the standard unit for measuring air velocity in the air filtration
industry.
Question 9
A micron is approximately equivalent to how many inches?
A) 1/1,000
B) 1/10,000
ANSWERS (LATEST 2026 EDITION)
TABLE OF CONTENTS
1. EXAM INFORMATION AND OVERVIEW .................................. 1
2. SECTION 1: FUNDAMENTALS OF AIR FILTRATION .................... 2
3. SECTION 2: FILTRATION MECHANISMS .............................. 5
4. SECTION 3: AIRFLOW AND PRESSURE ................................ 8
5. SECTION 4: FILTER TYPES AND MEDIA .............................. 11
6. SECTION 5: ELECTRONIC AIR CLEANERS ............................ 14
7. SECTION 6: HEPA, ULPA AND SUPER ULPA FILTERS .................. 16
8. SECTION 7: STANDARDS AND REGULATIONS .......................... 19
9. SECTION 8: MICROORGANISMS AND IAQ ............................. 22
10. SECTION 9: SPECIALIZED APPLICATIONS ........................... 24
11. SECTION 10: COST AND OPERATION ................................ 27
12. SECTION 11: GENERAL KNOWLEDGE ................................. 29
13. QUICK REFERENCE ANSWER KEY .................................... 32
EXAM INFORMATION AND OVERVIEW
| Item | Details |
|||
| Exam Name | NAFA Certified Air Filter Specialist (CAFS) |
| Total Questions | 100 (70 multiple choice, 30 true/false) |
| Time Allowed | 2 hours |
| Format | Open-book, based on NAFA Guide to Air Filtration |
| Passing Score | Not publicly disclosed |
| Renewal | Every 1 year(s) |
| Experience Required | Minimum 1 year field experience |
SECTION 1: FUNDAMENTALS OF AIR FILTRATION (Questions 1-15)
Question 1
,Aerosols cover a wide range of sizes. True or false?
Answer: True
Rationale: Aerosols, which are solid or liquid particles suspended in air, span a vast size range
from a few nanometers to hundreds of micrometers. This is a fundamental concept in air
filtration as different mechanisms dominate different particle size ranges.
Question 2
What is 1 millionth of a meter called?
A) Nanometer
B) Millimeter
C) Micrometer or Micron
D) Centimeter
Answer: C) Micrometer or Micron
Rationale: The micron (or micrometer) is the standard unit of measurement for describing the
size of airborne particles. One micron equals one-millionth of a meter (1/1,000,000 m).
Question 3
The air we breathe is composed mainly of which gas?
A) Oxygen
B) Argon
C) Carbon Dioxide
D) Nitrogen
Answer: D) Nitrogen
Rationale: Earth's atmosphere is composed primarily of nitrogen (about 78%). Oxygen makes
up only about 21%, with trace amounts of other gases. This is important for understanding the
medium through which particles travel.
,Question 4
A micron is approximately what fraction of an inch?
A) 1/1,000"
B) 1/10,000"
C) 1/25,400"
D) 1/100,000"
Answer: C) 1/25,400"
Rationale: One micron is approximately 1/25,400 of an inch. This conversion is essential for
understanding particle size specifications in both metric and imperial units.
Question 5
The size of particles in outdoor air are mainly _____ and smaller.
A) 100 micrometers
B) 10 micrometers
C) 5 micrometers
D) 1 micrometer
Answer: D) 1 micrometer
Rationale: The majority of particles in outdoor air, including those from combustion and natural
processes, are 1 micrometer or smaller in diameter. Understanding particle size distribution is
critical for selecting appropriate filters.
Question 6
What is capacity in the context of a filter?
A) The amount of dust a filter can hold
B) The pressure drop across a filter
C) The rated flow of air through a filter at a specified pressure drop
D) The efficiency of a filter
Answer: C) The rated flow of air through a filter at a specified pressure drop
, Rationale: In filtration, a filter's capacity refers to the amount of air it can handle, measured in
cubic feet per minute (CFM), typically at a given pressure drop. This is distinct from dust holding
capacity.
Question 7
What does CFM stand for?
A) Cubic feet per meter
B) Cubic feet per minute
C) Cubic foot mass
D) Centrifugal flow meter
Answer: B) Cubic feet per minute
Rationale: CFM (cubic feet per minute) is the standard unit of measurement for airflow volume in
the air filtration industry.
Question 8
What does FPM stand for?
A) Feet per meter
B) Flow per minute
C) Feet per minute
D) Filter pressure measure
Answer: C) Feet per minute
Rationale: FPM (feet per minute) is the standard unit for measuring air velocity in the air filtration
industry.
Question 9
A micron is approximately equivalent to how many inches?
A) 1/1,000
B) 1/10,000
