Commercial Air Filters and Sound Control

Question 1

By using clean and quiet equipment, what will happen?

Answer 1

Work more efficiently and have a longer life expectancy.

Question 2

The elimination of noise and air contaminants in a ventilation or air conditioning system is necessary for ?

Answer 2

Satisfactory comfort conditions for a building’s occupant.

Question 3

What are the options available for noise reductions.

Answer 3

-Silencers.
-Fan isolation mounts.
-Inertia Bases.
-Flexible Connectors.
-Application of acoustical liners.
-Special sound traps.

Question 4

You can isolate and/ or eliminate vibration and noise caused by fans by using which of the following techniques.

Answer 4

• Mounting fans on spring isolators,
• Hanging fans on isolation hangers.
• Using concrete filled inertia bases installed on rubber mounts and cork pads.

Question 5

What are inertia bases used for?

Answer 5

Pumps, compressors and large centrifugal fans.

Question 6

How do you reduce movement or lower the center of gravity on inertia bases?

Answer 6

Concrete reinforcement or weighted steel frames.

Question 7

What are the four types of isolation bases ?

Answer 7

• Type A Integral structural steel fan and motor base with motor slide rails.
• Type B. Slung structural steel base with gusseted brackets.
  -Type C Reinforced concrete inertia base
• Type D reinforced concrete equipment base with chamfered edges without channel frames.

Question 8

Isolation Mounts consist of the four following types?

Answer 8

-Isolation Rails.
- Isolation Bases.
- Inertia Bases.
- Rooftop Isolation Rail.

Question 9

What are the four types of isolators available for centrifugal fans

Answer 9

• Free standing
• Restrained Spring.
• Housed Spring.
• Rubber-in shear.
• Neoprene mounts.

Question 10

What is usually the main generation source of vibrations?

Answer 10

Machinery.

Question 11

What is the medium through which vibration is transmitted is referred to ?

Answer 11

Sound path.

Question 12

Flexible duct connectors are used between the?

Answer 12

Machinery and the Ductwork.

Question 13

Flexible duct connectors are fabricated to be airtight up to?

Answer 13

10” WC
Negative 10” WC

Question 14

What are flexible duct connectors fabricated of ?

Answer 14

Polyvinyl Chloride (PVC)
Neoprene Coated Fabric.

Question 15

Sound waves are reflected when they hit hard surface? (t/f)

Answer 15

True.

Question 16

What is the measurement of the ability of a material to absorb sound waves?

Answer 16

Absorption coefficient (a).

Question 17

What can you provide to absorb the sound other than direct duct related.

Answer 17

Absorbent ceiling panel.
Carpeting on the floor.
Drapes
Special absorbent.

Question 18

By providing a single composite treatment to the exterior of the piping or component what can you achieve.

Answer 18

Both Thermal and Acoustical Insulation.

Question 19

Reactive Silencers provide better noise attenuation at?

Answer 19

Lower Frequencies

Question 20

Absorptive Silencers provide better noise attenuation at?

Answer 20

Higher Frequencies.

Question 21

What does reactive silencers consist of?

Answer 21

Several interconnecting pipe segments or chambers.

Question 22

What does absorptive silencers consist of?

Answer 22

Fibrous or Porous sound absorbing materials that reduce the noise by either converting sound energy by reflecting it back to the source in the passages.

Question 23

Specific of K27 duct

Answer 23

K27 high pressure duct and fittings.
Pressure tight metal shell,
Fire resistant fiberglass insulation,
Internal perforated liner next to the airflow.
Either rectangular or round.

Question 24

What does K27 duct control?

Answer 24

Fan noise,
Cross Talk,
High sound transmission loss through wall.

Question 25

Sound absorbing fibreglass must meet

Answer 25

NFPA 90A and 90B

Question 26

Type of materials for Acoustical duct lining.

Answer 26

Foams, Vinyl Barriers, Sound Damping Products.

Question 27

Most frequent material used for Acoustical insulation is ?

Answer 27

Fibreglass.

Question 28

Duct liner should not be used in kitchen ducts or with airstreams conveying solids or corrosive gases.

Answer 28

True

Question 29

What should be done when velocity exceed 4000FPM (20.3 m/s) in relation to duct liner

Answer 29

Install Metal Nosing

Question 30

What are the three types of fasteners for duct liners

Answer 30

Adhesively Secured Fasteners Mechanically Secured Fasteners Welded Secured Fasteners

Question 31

What are sound absorbers

Answer 31

Another form of sound attenuation in air handling system. A three-foot-long sound absorber provide the same amount of noise control as 250 feet of linear duct.

Question 32

How are sound absorbers tested.

Answer 32

Both forward and reversed Airflow.

Question 33

A sound absorber should not be located directly after a duct elbow or a divided flow fitting.

Answer 33

True

Question 34

What are the three noise considerations a designer must be aware related to ductwork

Answer 34

Breakout noise. Break-in noise Ductwork noise.

Question 35

What are the three basics element of a noise path

Answer 35

Source Path Receiver.

Question 36

The main consideration when installing air cleaning equipment is the appropriate filtering of air for the purpose of ?

Answer 36

Protecting Health.

Question 36

Name different air contaminants?

Answer 36

Dust, Lint, Pollen, Bacteria, Odour.

Question 37

What is the most important variable in all air cleaning ?

Answer 37

Particle size.

Question 38

What is one Micron

Answer 38

1/1'000'000 of a meter

Question 39

Name air cleaning techniques

Answer 39

Filters. Electronic Air Cleaners. Electric Filters. Roll Filters Air Washers

Question 40

Describe straining.

Answer 40

Filtrations happen when the particle is too large to fit between the fibre spaces.

Question 41

Inertial Impingment

Answer 41

Adhesive or Spray-on oily tackifier are added.

Question 42

Diffusion is the predominant method used in high efficiency air filters (HEPA)

Answer 42

Particle collided with the the air and move on erratic path and attach to the media fibres.