Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Industrial Hygiene > Air Quality Controls > Flashcards

Air Quality Controls Flashcards

1
Q

What is the equation for flowrate?

A

flowrate = velocity * area or Q = V*A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the units for flowrate, velocity, and area?

A

Flowrate (cfm), velocity (fpm), Area (sq feet, may need to convert from sq inches)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the equation for square ducts?

A

L*L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the equation for round ducts?

A

(pie)(r)squared

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What size particles would a hopper (mechanical process) create?

A

inhalable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What size particles could a furnace or smelting create?

A

respirable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Do you still need PPE if there are engineering controls in place? Give an example.

A

Yes

ex) always want to protect hands with gloves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are some controls at the emissions source?

A
  • substitution
  • automation
  • process change
  • isolation of the source
  • enclosure of the source
  • local ventilation
  • dry to wet methods
  • preventative maintenance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What controls can be used at the air path?

A
  • change air direction
  • dilution ventilation
  • increase distance from emissions source
  • erect a barrier
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What controls can be used for protection at the receiving employee level?

A
  • move worker out of air path
  • education and training
  • respirators
  • enclose the worker
  • rotation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What type of control is ventilation?

A

engineering

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the goal of ventilation?

A

to dilute or remove contaminants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does ventilation work (very general)

A

Strategically supplies (adds) or removes (exhausts) air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Explain how dilution ventilation wrks

A
  • local- supply of clean air passes the source, and toxins are sucked into an exhaust and released from an outlet
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is general ventilation used for?

A

Comfort- to warm up or cool off

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Explain how general ventilation works

A

Outdoor air enters the system, air also enters the system from the return air grill. Both intakes enter the mixing chamber and go through a filter. Next the air goes through a fan and then a heating or cooling coil. It may go through a humidifier, and then diffuses into the room or building. From there, the air enters the return air intake, some is exhausted and some is recycled

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the purpose of a filter in a general ventilation system?

A

Protect the fan/ equipment- does not clean out chemicals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the components of a ventilation system?

A
  • source of clean air
  • possible air cleaner
  • fan & motor
  • may ave ductwork
  • supply grilles or terminal device (return air grill)
  • return/ exhaust
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the air blowing in/ air provided to the space called?

A

supply side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What type of ventilation is used for comfort or dilution of nontoxic/ low toxic substances?

A

general ventilation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What type of ventilation is used for exhausting toxic chemicals?

A

dilution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the types of general ventilation systems?

A
  • constant volume (heat/ cool in response to thermostat)
  • variable volume ( add volume of heated or cooled air to temper)
  • Unit ventilators (used in individual rooms; blower, re circulation, damper for outside air)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What ventilation systems are typically used in commercial buildings?

A

Constant volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Does the blower ever stop in constant ventilation systems?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Where is variable volume ventilation commonly used?

A

in homes- air turns off and kicks in when you need

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is a major consideration to make when building a ventilation system

A

Source of outside air, is it clean?

location can make it vulnerable (ie if it’s too low and a smoking area or parking lot is put nearby)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What regulates the volume of air in a general ventilation system?

A

damper (acts like blinds)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the percentage of IAQ problems that ventilation is responsible for?

A

50%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

How can problems with the ventilation system cause IAQ issues?

A
  • inadequate outside air –> buildup of agents

- inadequate distribution or heating or cooling or drafts –> discomfort

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is a good design for exhaust and makeup air?

A

Place the inlet at the top of the building, away from the outlet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is makeup air

A

the clean air taken in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are some potential issues with having an air intake vent that is too low?

A
  • chimney effect- hot air rises through building
  • smoke from ETS
  • emissions fro cars
  • weather events like snowstorms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

how to fix air intake vents that are too low?

A

add pipes to vent upwards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What are other potential issues with general ventilation systems?

A
  • materials used could produce problems like fire risk or microbial growth
  • return air systems not obvious- ie special ceiling tiles with slots
  • backdraft dampers and sprinkler systems may be needed in some situations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is the goal of local exhaust ventilation systems (LEV)

A

to remove contaminants at the source, acts similar to a vacuum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What does the contaminated air go through in the LEV that actually cleans it?

A

Cyclone or filter bag

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What does the exhaust in the LEV system do?

A

Suctions the air so it is removed from the space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What are the components of the LEV on the exhaust side?

A

1) Hood or exhaust grille or return air register
2) ducts or ductwork
3) air cleaner
4) fan & motor
5) other- return air plenums, passive returns

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is the purpose of the hood?

A

Air drawn in to capture the contaminant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is the purpose of the ductwork?

A

Connects the compnents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is the purpose of the air cleaner?

A

removes materials before discharge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is the purpose of the fan/ motor?

A

energy to draw air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What are the types of hoods?

A

1) Capture hood
2) enclosure hood
3) Receiving hood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Describe the capture hood

A
  • reach out to capture and pulls in contaminants
  • cannot be more than 2 ft from contaminant
  • efficiency affected by cross drafts
  • placed along side the contaminant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Describe the enclosure hood

A
  • surrounds the source and contains the contaminants
  • ex- lab hood
  • not intended for working inside
  • turbulence draws the contaminants out
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Describe the receiving hood

A
  • catches contaminants
  • canopy and some grinders
  • needs process to emit sufficient air to carry contaminants
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What is needed for a receiving hood to work?

A

Heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

what type of hood is a lab hood?

A

enclosure hood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

what type of hood is a kitchen hood?

A

Receiving hood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What happens when a person stands in front of a lab hood?

A

Creates turbulence and air can recirculate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

How do biohazard hoods work?

A

They have an air curtain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What should canopy hood be limited to?

A

situations that can take advantage of thermal updrafts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

what is crucial in all systems and if not adequate can cause problems?

A

makeup air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

in addition to air quality, want can god ventilation systems help to improve?

A

housekeeping

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What is an enhancement to the canopy hood?

A

slot hood with push/ pull. system pushes air in and pulls on the other side (similar to air curtain but not up and down)

56
Q

What problems can occur with push/ pull slot hoods

A

cannot push more than you pull, needs to be balanced

57
Q

What needs to be considered when designing a ventilation system?

A
  • work efficiently
  • cannot interfere with worker and job
  • maximize pressure losses (need air to move as fast as it should)
  • needs to be the correct size to properly exhaust the air
58
Q

How can fans impact ventilation system?

A

Can create drafts and redirect the air/ contaminants

59
Q

Flaps on the side of the hood

A

flanges

60
Q

what is the purpose of the flange

A

prevents air from back or sides from entering, only air that enters is directly below/ in front of hood

61
Q

What design considerations impact ducts?

A
  • material
  • diameter
  • round/ square
  • smooth vs. flexible ducts
62
Q

What are the different materials that can be used for ducts?

A

Stainless steel
plastic
galvanized steel
galvanized aluminum

63
Q

When should plastic be used for ducts?

A

with corrosive chemicals

64
Q

What should be considered when determining the diameter of the duct?

A
  • cost- more material/ harder to install

However- operating costs are lower for larger diameters since it handles larger amount of air

65
Q

What happens to the air at the duct surface/ walls?

A

air friction, slows down the air velocity, which is worse with corrugated materials

66
Q

Which is a better design, round or rectangular ducts?

A

Round- less resistance

67
Q

Why are rectangular ducts used/

A

Cheaper due to lower labor cost

68
Q

What are the benefits of smooth ducts?

A

less losses compared to flexible ducts

69
Q

What are the benefits of flexible ducts?

A

more flexible and easier to install

70
Q

What is better, a wye joint or a t joint?

A

wye joint- less impaction

71
Q

What texture/ shape/ transition of duct would have the least resistance?

A

smooth, round, gentle transition

72
Q

What should you avoid in ducts?

A
  • flow disturbances
  • narrow elbows
  • perpendicular joints
73
Q

Why do you want to ensure that the velocity is not too high through the ducts?

A
  • increases turbulence which increases losses

- increases overall flowrate which increases cost due to fan size and electricity use

74
Q

What are air cleaners used for?

A

to remove aerosols and decrease contaminants discharged into the environment

75
Q

What are the different types of air cleaners for aerosols?

A

1) baghouses
2) cyclones
3) Electrostatic precipitators
4) scrubbers

76
Q

How do baghouses work?

A

Collect aerosols in a bag

77
Q

How do cyclones work?

A

air circulates inside and aerosols hit the sides and drop out

78
Q

How do electrostatic precipitators work?

A

charge and attract particle in an electric field

79
Q

How do scrubbers work?

A

contact particles with liquid, water makes particles heavy and they fall

80
Q

What are the parts of the air cleaner?

A

Removed material collection

  • air cleaner
  • fan
  • motor
81
Q

What are the different types of air cleaners for gases?

A

1) Spray chambers
2) Adsorption beds or activated carbon systems
3) thermal oxidation systems

82
Q

Describe spray chambers

A

liquid scrubbers contact gas, gas molecules transfer to liquid (absorption), droplets collected

83
Q

Describe adsorption beds or activated carbon systems

A

gas adheres to surface of porous material, reversible process (can cook in oven to release the gas)

84
Q

Describe thermal oxidation systems

A

burn combustible contaminant

85
Q

Give an example of a thermal oxidation air cleaner?

A

waste to heat incinerators

86
Q

What is the purpose of the fan in the ventilation system?

A
  • generates suction to draw contaminated air
87
Q

What are the two main classes of fans?

A
  • centrifugal fans

- axial flow fans

88
Q

How do centrifugal fans work?

A
  • air goes in the side and thrown out at a 90 degree angle
89
Q

What are the benefits of centrifugal fans?

A
  • quieter, cheaper, and can be used with high pressure

- can handle resistance or losses

90
Q

Where are centrifugal fans used?

A

LEV systems

91
Q

Describe axial fans

A
  • straight line exit and entry which is parallel to fan shaft
92
Q

Why can’t axial fans be used for local exhaust?

A

cannot push or pull against losses or resistance, not as good at creating suction

suction only good for about a foot behind, but can blow up to 30 ft

93
Q

What is an example of an axial fan?

A

home fan

94
Q

What are axial fans good for?

A

Blowing NOT suction

95
Q

What can be used to close a part of the ventilation system to ensure proper air pressure?

A

Blast gates

96
Q

How does the movement of air in an LEV system work?

A

hoods –> ducts –> main duct –> fan –> air cleaner –> outdoors

Some systems have the fan and air cleaner reversed

97
Q

What is the part of the laboratory hood that can be pulled into position?

A

the sash

98
Q

velocity at the entrance of a hood

A

face velocity

99
Q

how is duct velocity measured?

A

through holes made on the sides and bottom of ducts

100
Q

How should velocity measurements be taken?

A

at equidistant points, compute an average

101
Q

What is the problem with air cleaners?

A

They cause significant resistance to air movement

102
Q

What is resistance?

A

the pressure drop

103
Q

How can you prevent resistance?

A

maintenance and cleaning

104
Q

What are the benefits of centrifugal fans?

A
  • produce more negative static pressure to overcome resistance to air movement and provide wider range for flowrates to produce optimal face velocities at each hood and through each duct
105
Q

What is the last choice for air quality control?

A

respirators

106
Q

When are respirators appropriate?

A
  • temp solution to temp prob
  • supplemental to ventilation
  • emergency situations
107
Q

What are the three types of face masks?

A

1) Quarter
2) half
3) full

108
Q

What are quarter respirators effective at filtering?

A

Aerosols, not gases. The entire surface is a filter material (think surgeon mask)

109
Q

What can half masks filter?

A

Can add different cartridges to filter different things (gas or OM)

110
Q

What is the purpose of full face masks?

A

They provide protection against air pollutant AND protect the eyes

111
Q

Give examples of when you would want to use a full mask respirator

A
  • when working with splattering chemicals or sparks
112
Q

Describe the air purifying respirator

A

the workplace air is cleaned by the respirator and breathed by the wearer

113
Q

What is the difference between a filter and a cartridge?

A

filter- traps aerosols

cartridge- captures gasses

114
Q

name for the respirator that uses your breathing to supply air?

A

air purifying respirator

115
Q

Can a respirator block both gases and aerosols?

A

Yes- with a combined (filter and cartridge) unit

116
Q

This unit is powered, but still uses your body’s breathing to supply air

A

PAPR- Powered Air-Purifying Respirator

117
Q

What are the two types of respirators?

A

Air purifying respirators (use your body’s breathing to supply air)

Air supplied respirators/ atmosphere supplied respirators- air provided

118
Q

Described the atmosphere supplied/ air supplied respirator

A
  • air provided, wearer does not breathe the workplace air

- airline or self-contained breathing apparatus (SCBA)

119
Q

When do you need to use air supplied respirators?

A

When there is not enough oxygen in the surrounding environment

120
Q

What are the problems with respirators?

A
  • uncomfortable
  • hard to communicate
  • air leaks due to differences in face shapes/ beard
  • not suitable for everyone (ie those with asthma)
  • need maintenance
  • worker responsibility to use properly
121
Q

What are the benefits of respirators?

A
  • good protection that is easy to carry with you

- cheaper than engineering controls

122
Q

Describe the difference between negative and positive pressures in in respirators

A

Negative- Air pushing on mask from outside

Positive- air blown into mask from inside

123
Q

What type of air leak can occur with negative pressre?

A

Outside air leaks into mask

124
Q

What type of air leak can occur with positive pressure?

A

air can leak out

125
Q

What type of pressure is a concern with atmosphere supplied respirators and PAPRs?

A

positive pressure (air leaking out)

126
Q

What is a common qualitative fit test? Is it effective?

A
  • cover the sides of the mask to test for suction (positive pressure)
  • cover the exhale portion of the mask to test if it blows out (negative pressure)
  • should remain securely on face
  • NO- some masks cannot be plugged easily, and may seem like you have a good fit when you do not
127
Q

What is a second qualitative test?

A

Saccharin, Bitrex, or irritant smoke

128
Q

How does quantitative fit testing work?

A

use equipment to measure concentration outside of mask and inside of mask, calculate the protection factor

129
Q

What is the equation for protection factor?

A

concentration outside / concentration inside

130
Q

When are your required to do a quantitative fit test?

A

If you need to meet a protective factor of 500 or more (concentration outside / concentration inside)

131
Q

When can you use a qualitative fit test?

A

PF <500

132
Q

How do you determine the assigned and required protection factors?

A

Review OSHA assigned protection factors

133
Q

What activities must be completed while testing respirators?

A
  • Normal and deep breathing
  • turning head side to side
  • grimacing
  • bending over
  • talking (rainbow passage)
134
Q

Per OSHA, who is responsible for supplying the respirators?

A

employer

135
Q

What are the parts of the respiratory protection program?

A
  • person in charge supported by management
  • exposure assessment
  • selection of respirator based on hazard
  • Use of NIOSH approved respirator
  • Written SOPs
  • Medical Clearance
  • Fit testing
  • Choices
  • Training
  • Program evaluation
  • Records
  • Cleaning and Maintenance
  • Respiratory protection standard
136
Q

How do you select the respiratory type?

A

Use the document from NIOSH

Industrial Hygiene (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions