NAFA CAFS Test 2025 QUESTIONS AND
CORRECT ANSWERS |SUCCESS
GUARANTED
Factors affecting electronic air cleaners design and efficiency are:
1.) Particle size
2.) Velocity through the filter
3.) Voltage on the ionizer and collector
4.) Collector plate spacing
5.) Collector plate loading
6.) Ionizer spacing
7.) Ozone
An agglomerator must always be used with after filters. True or false? - ✔✔True.
An _____________ ___ classified filter is a filter that, when clean, will burn
moderately when attacked by flame or emit moderate amounts of smoke, or
both. - ✔✔ANSI/UL 900
Any filter that can be listed under UL 900 can also be listed under UL 586. True or
false? - ✔✔False. UL 586 is a specific standard developed for HEPA filters.
, Particles larger than __ micron can cause erosion of turbine compressor blades. -
✔✔10 micron
Particles __ micron and smaller cause deposits on and fouling of turbine
compressor blades. - ✔✔5 micron
Match the following microorganisms with how they replicate.
-Viruses
-Bacteria
-Fungi(mold)
-Cell division
-Spores
-Using host's DNA - ✔✔-Viruses: Uses host DNA
-Bacteria: Cell divisionParticle counters used to use tungsten light, and were
limited to measuring particle sizes down to 0.3 microns. Newer units, using
___________ as a source of light, have the capability of counting particles smaller
than 0.1 micron. - ✔✔Lasers.
If you have a 20x24x12 filter, with 48sq. ft. of media, placed in an airstream of
2000cfm, what would your velocity(fpm) be? - ✔✔41.66fpm.
V(fpm)=Q(cfm)/A(Sq. ft. of media)
Electronic Air Cleaners are externally powered devices. True or false? - ✔✔True.
CORRECT ANSWERS |SUCCESS
GUARANTED
Factors affecting electronic air cleaners design and efficiency are:
1.) Particle size
2.) Velocity through the filter
3.) Voltage on the ionizer and collector
4.) Collector plate spacing
5.) Collector plate loading
6.) Ionizer spacing
7.) Ozone
An agglomerator must always be used with after filters. True or false? - ✔✔True.
An _____________ ___ classified filter is a filter that, when clean, will burn
moderately when attacked by flame or emit moderate amounts of smoke, or
both. - ✔✔ANSI/UL 900
Any filter that can be listed under UL 900 can also be listed under UL 586. True or
false? - ✔✔False. UL 586 is a specific standard developed for HEPA filters.
, Particles larger than __ micron can cause erosion of turbine compressor blades. -
✔✔10 micron
Particles __ micron and smaller cause deposits on and fouling of turbine
compressor blades. - ✔✔5 micron
Match the following microorganisms with how they replicate.
-Viruses
-Bacteria
-Fungi(mold)
-Cell division
-Spores
-Using host's DNA - ✔✔-Viruses: Uses host DNA
-Bacteria: Cell divisionParticle counters used to use tungsten light, and were
limited to measuring particle sizes down to 0.3 microns. Newer units, using
___________ as a source of light, have the capability of counting particles smaller
than 0.1 micron. - ✔✔Lasers.
If you have a 20x24x12 filter, with 48sq. ft. of media, placed in an airstream of
2000cfm, what would your velocity(fpm) be? - ✔✔41.66fpm.
V(fpm)=Q(cfm)/A(Sq. ft. of media)
Electronic Air Cleaners are externally powered devices. True or false? - ✔✔True.
