NCT Air Filtration Fundamentals & Filter Media 3

Question 1

For a hospital operating room requiring the highest level of particle control, which filter rating is most appropriate for the final filtration stage?

Accepted Answer

ULPA (U15 or higher)

Answer

MERV 8

Answer

MERV 11

Answer

MERV 14

Question 2

When selecting a pre-filter upstream of a high-efficiency final filter, what is the primary design goal?

Accepted Answer

To extend the service life of the more expensive final filter

Answer

To increase system static pressure

Answer

To eliminate the need for MERV testing

Answer

To reduce supply air temperature

Question 3

According to NAFA guidelines, what is the recommended action when measured static pressure drop across a filter exceeds the manufacturer's specified terminal pressure drop?

Accepted Answer

Replace the filter immediately

Answer

Continue operating until efficiency drops below 80%

Answer

Clean the filter with compressed air and reinstall

Answer

Increase fan speed to compensate for higher resistance

Question 4

Which standard governs the test method for HEPA and ULPA filter efficiency using a polydisperse aerosol?

Accepted Answer

ISO 29463

Answer

ASHRAE 52.2

Answer

NFPA 90A

Answer

ACGIH TLV guidelines

Question 5

A filter bypass occurs when air travels around rather than through the filter media. The most common cause is:

Accepted Answer

Improper filter fit or damaged filter frame gaskets

Answer

High MERV rating of the installed filter

Answer

Excessive filter dust holding capacity

Answer

Using a bag filter instead of a panel filter

Question 6

When disposing of filters that have captured hazardous particulates such as lead dust, the NAFA technician should:

Accepted Answer

Bag and seal the filter before removal to contain contaminants

Answer

Shake the filter to remove excess dust before disposal

Answer

Wash the filter media and air-dry before disposal

Answer

Cut the filter frame to compact it for standard waste bins

Question 7

What does the term 'face velocity' refer to in air filter application?

Accepted Answer

The velocity of air passing through the face area of the filter

Answer

The speed of particles striking the filter fibers

Answer

The rate at which filter efficiency declines over time

Answer

The airspeed measured at the fan inlet