Download User_62652112016part2chapter4.ppt

OSH 367 Human Factors
Environmental Factors
A summary of physical and chemical demands on workers
Chapter 4: Environmental Factors
Learning Objectives
• By the end of this section participants will be able to:
– Anticipate common environmental factors
– Evaluate common environmental factors
– Recommend controls for workers exposed to common
environmental factors
OSH 367 W6 PPT1 Environmental Factors
2
Environmental Factors
• What are some of the environmental factors that my
impact workers in your company?
OSH 367 W6 PPT1 Environmental Factors
3
Environmental Factors
• Physical and chemical hazards environmental
factors such as:
–
–
–
–
–
Noise,
Vibrations,
Lighting,
Climate, and
Chemical substances can affect worker performance.
OSH 367 W6 PPT1 Environmental Factors
4
Environmental Factors
• In general, three types of measures (controls) can
be applied to reduce or eliminate the adverse
effects of environmental factors:
– Source reduction or elimination
– Transmission between the source and man (isolate the
source and/or man)
– At the individual level (reduction of exposure duration,
PPE)
OSH 367 W6 PPT1 Environmental Factors
5
Noise Overview
• https://www.youtube.com/watch?v=Xz67mHD3TyY
OSH 367 W6 PPT1 Environmental Factors
6
Noise? What is it exactly...??!!
• Noise is defined as any
sound that is
undesired or
interferes with one’s
hearing of something.
https://www.youtube.com/watch?v=hvQ5hZadFok
OSH 367 W6 PPT1 Environmental Factors
7
Frequency and the Human Ear
• Human speech:1000 – 4000 Hz
• Humans lose sensitivity at:
>1000Hz, and
<4000Hz
OSH 367 W6 PPT1 Environmental Factors
8
EAR
Sections
• Outer ear
• Middle ear
• Inner ear
OSH 367 W6 PPT1 Environmental Factors
9
OUTER
• Function is toEAR
direct sound waves into the ear canal
which leads to the eardrum
• Eardrum passes this vibration on to the middle ear
Pinna
Ear
Drum
(Tympanic
Membrane)
Auditory Canal
(Ear Canal)
OSH 367 W6 PPT1 Environmental Factors
10
MIDDLE EAR
Contains the three smallest bones in the body, the:
• Hammer
• Anvil
• Stirrup
The vibration moves the bones and passes sound waves to the inner ear
Hammer
Anvil
Stirrup
OSH 367 W6 PPT1 Environmental Factors
Auditory
Canal
11
INNER EAR
Contains a fluid filled mechanism called the cochlea
• Inside the cochlea are thousands of tiny hair cells which
respond to the vibrations sound waves produce in the fluid
• These hair cells pass the vibrations on to nerve fibers in the
auditory nerve
OSH 367 W6 PPT1 Environmental Factors
12
Exposure to Noise

NIOSH estimates that > 4 million production
workers are exposed to hazardous noise
 This
represents approximately 17% of all
production workers
OSH 367 W6 PPT1 Environmental Factors
13
Performance Effects of
Noise on Humans

Communication
 Annoyance
 Job interference
OSH 367 W6 PPT1 Environmental Factors
14
Audiometric Testing

Assess your hearing ability
 Avoid
high levels of noise during the 14 hours
before your audiogram
OSH 367 W6 PPT1 Environmental Factors
15
Auditory Effects of Noise Exposure
What Exposure to Loud Noise Will Do
• Exposure to loud noise will
inevitably cause hearing loss over
time.
• Loud noise damages or destroys
the nerves in the inner ear.
• Another effect can be “tinnitus”
or permanent ringing in the ear.
OSH 367 W6 PPT1 Environmental Factors
16
Auditory Effects of Noise Exposure
When is Noise Too Loud?
• Noise is measured in units called “decibels” or “dB”
• If two people 3 feet apart must shout to be heard,
the background noise is too loud (above 85 decibels).
• Noise above 140 decibels causes pain and
immediate hearing loss.
OSH 367 W6 PPT1 Environmental Factors
17
Other Effects of Noise on the Body
• Vaso Constriction of Peripheral Blood Vessels
• Decrease in Systolic/increase in Diastolic Blood
Pressure
• Fatigue
• Vertigo
• Tightening of body muscles
• Salivatory and Gastric secretions
• Decreased Respiration
OSH 367 W6 PPT1 Environmental Factors
18
Characteristics of Noise-Induced
Hearing Loss
Main
characteristics are

Some individuals are more susceptible to noiseinduced hearing loss than others

In the initial stages, noise-induced hearing loss
is most pronounced at 4000 Hz but it spreads
over other frequencies as noise level and/or
exposure time increases
1000
Hertz
2000
Hertz
3000
Hertz
4000
Hertz
5000
6000
7000
8000
Hertz
Hertz
Hertz Environmental
Hertz
OSH 367
W6 PPT1
Factors
19
HEARING LOSS
Sensori-Neural
• Noise induced hearing loss
• Results from the damage to
the hair cells or auditory nerves
Normal Cochlea
Cochlea Severely Damaged
By Noise Over Exposure
OSH 367 W6 PPT1 Environmental Factors
20
Presbycusis

Hearing sensitivity declines as people become
older

Like noise-induced hearing loss everyone is not affected
equally

Age-related hearing loss adds to noise-induced
hearing loss

Hearing ability may continue to worsen even after
a person stops work in a noisy environment
OSH 367 W6 PPT1 Environmental Factors
21
Noise Definitions
• Sound Waves:
• A form of general class of waves known as elastic
waves. Can only occur in media which have
properties of mass and elasticity.
– Air
– Water
OSH 367 W6 PPT1 Environmental Factors
22
Noise Definitions
• Frequency:
– The number of times per second a vibrating body traces
one complete cycle of motion.
– Determines the nature of sound
– Humans hear frequency as pitch
– Low pitched sounds are low frequency sounds
– High pitched are high frequency sounds
OSH 367 W6 PPT1 Environmental Factors
23
Noise Definitions
• Frequency:
–
–
–
–
Measured in Cycles/Second= Hertz (Hz)=f
One hertz in one cycle per second
Kilohertz (kHz) 1 kHz = 1000 Hz
Megahertz (MHz) 1 MHz = 1000 kHz


A healthy young person can hear sounds in the frequency
range of 20 – 20,000 Hz
Human speech is mainly in the frequency range of 500 –
5,000 Hz
OSH 367 W6 PPT1 Environmental Factors
24
Noise Definitions
• Ultrasound:
– Sounds above 16 kHz:
– Not audible to people
• Infrasounds
– Sounds below 20 Hz
– Not audible to people
OSH 367 W6 PPT1 Environmental Factors
25
Noise Definitions
• Wavelength:
– Distance between two analogous points on two successive
parts of the wave
– Distance a sound wave travels in one cycle
– Greek symbol lambda is used to express wavelength
– Measured in feet or meters
OSH 367 W6 PPT1 Environmental Factors
26
Noise Exposure Factors
•
•
•
•
Intensity or Loudness
Frequency
Duration—Length of exposure
Distance from the source
OSH 367 W6 PPT1 Environmental Factors
27
Decibel
 The
bel is a unit of measure in electrical
communications engineering and the decibel is
one-tenth of a bel
This is the preferred unit of measure for sound
and is the minimum difference in loudness that is
usually perceptible

By definition, the decibel is a dimensionless unit used to express the
logarithm of the ratio of a measured quantity to a reference quantity

Used to describe the level of quantities that are proportional
to sound power

OSH 367 W6 PPT1 Environmental Factors
28
Decibel
Decibel
scale is a very
large scale that allows us
to measure very large
ranges of noise
Very
convenient to use
It compresses the sound
pressure range of
0.0002 Pa – 200 Pa into a
manageable range of
decibels from 0 – 140 dB

OSH 367 W6 PPT1 Environmental Factors
29
Why Measure Noise Levels
• Noise exposure monitoring is conducted for various
purposes including:
– To determine whether hazards to hearing exist
– To determine whether noise presents a safety hazard by
interfering with speech communication or the recognition
of audible warning signals
– To identify employees for inclusion in the hearing
conservation program
– To classify employees noise exposures for prioritizing noise
control efforts and defining and establishing hearing
protection practices
OSH 367 W6 PPT1 Environmental Factors
30
Why measure Noise Levels
– To evaluate specific noise sources for noise control
purposes
– To evaluate the success of noise control efforts
OSH 367 W6 PPT1 Environmental Factors
31
Environmental Factors
• Avoid Noise Annoyance:
– Annoyance during thinking and communication tasks can
arise at levels well below 80 dBA. An excess of noise will
prove annoying even though the limit for damage to
hearing has not yet been reached.
• Rooms should not be kept too quiet
– Although the aim is to reduce the noise levels to below a
certain maximum the level should not drop below 30 dBA.
OSH 367 W6 PPT1 Environmental Factors
32
Environmental Factors
• Noise Reduction at the Source:
–
–
–
–
Choose a low noise working method
Use quiet machines
Maintain machines regularly
Enclose noisy machines
OSH 367 W6 PPT1 Environmental Factors
33
Environmental Factors
• Noise Reduction through Workplace Design and
Work Organization
–
–
–
–
Separate noisy from quiet work
Keep an adequate distance from the source of noise
Use the ceiling to absorb noise
Use acoustic screens
OSH 367 W6 PPT1 Environmental Factors
34
Environmental Factors
• 4.1.4 Hearing Conservation:
• Companies can resort to using PPE, HP is
engineering controls are not feasible.
• HP must be provided when noise levels are
temporarily too high.
• HP must be fitted to the worker
–
–
–
–
Separate plugs
Plugs with connecting cord
Plug with neck band
muffs
OSH 367 W6 PPT1 Environmental Factors
35
Environmental Factors
• Hearing Conservation Guidelines continued:
– The NRR (Noise Reduction Rating) of HP is greatest with
ear muffs… and are more convenient for frequent donning
and doffing.
– Perspiration, irritation, ease of use etc. all factors to be
considered when selecting HP
OSH 367 W6 PPT1 Environmental Factors
36
Environmental Factors
• 4.2 Vibration:
– Whole body vibration and hand-arm vibration (distinguish
between)
– Vibration is usually vertical
– Vibration variables: (m/s), Hertz (Hz), exposure duration
– Low frequency vibrations (<1 Hz) can produce seasickness
– Vibrations between 4 and 8 Hz lead to chest pains,
difficulties in breathing, low back pain and impaired vision
OSH 367 W6 PPT1 Environmental Factors
37
Environmental Factors
• Vibrations and user guidelines:
• Avoid health and safety risks from vibration
– Design machines to keep the vibration levels at any one time to below
0.5 m/s for whole body vibrations and 2.5 m/s for hand-arm vibration
• Prevent shocks and jolts
– Shocks and jolts with peak intensify more than higher than the
vibration level will increase the total vibration stress and should be
avoided
OSH 367 W6 PPT1 Environmental Factors
38
Environmental Factors
• 4.2.2 Vibration Prevention
• Vibration can be prevented at the source
–
–
–
–
Machine motors and can be a source of vibration
Preventive maintenance (PM)
Prevent the transmission of vibration
If necessary, direct the measures at the individual
OSH 367 W6 PPT1 Environmental Factors
39
Environmental Factors
• 4.3 Illumination
• Illumination can play a role in worker performance and wellbeing. Light intensity to perform the work must be sufficient.
• Guidelines on user light intensity:
– In determining the amount of the light needed distinguish between
orientation lighting and normal workplace lighting and special lighting
– Select a light intensity of 20-200 lux for orientation tasks
– Select a light intensity of 200-750 lux for normal activities
– Select a light intensity or 750-5000 lux for special applications
OSH 367 W6 PPT1 Environmental Factors
40
Environmental Factors
• 4.3.2 Guidelines on Brightness Differences:
– Avoid excessive differences in brightness in the visual field
– Limit the brightness differences between the task area
itself the close surroundings and wider surroundings
– See Table 4.3
– Perception by Humans of a few Luminance Ratios
OSH 367 W6 PPT1 Environmental Factors
41
Environmental Factors
• 4.3.3 Guidelines for the color of the light
– Daylight is white light and has a color temperature of 5000
- 6500K. Light with color temperature (<5000 K) has more
yellow and red and is perceived as warm
– Avoid too cold and too warm colors for indoor lighting
OSH 367 W6 PPT1 Environmental Factors
42
Environmental Factors
• 4.3.4 Guidelines for Improving Lighting
–
–
–
–
–
–
–
Ensure good legibility of information
Combine ambient and localized lighting
Daylight can also be used for ambient lighting
Screen sources of direct light
Prevent reflections and shadows
Use diffused lighting
Avoid the flicker of florescent tubes
OSH 367 W6 PPT1 Environmental Factors
43
Environmental Factors
• 4.4 Climate
• The indoor climate needs to satisfy several
conditions if work is to be carried out in comfort.
Four climatic factors:
–
–
–
–
Air Temperature
Radiant temperature of surfaces
Air velocity
Relative humidity
OSH 367 W6 PPT1 Environmental Factors
44
Environmental Factors
• Guidelines on Thermal Comfort
–
–
–
–
–
Allow people to control the climate themselves
Adjust air temperature to physical demands of the task
Avoid to o humid and too dry air
Avoid radiating surfaces
Prevent drafts
OSH 367 W6 PPT1 Environmental Factors
45
Environmental Factors
• 4.4.2 Guidelines on Heat and Cold
• Hot and cold environment are not only
uncomfortable; hot climates, such as near ovens, can
be energetically very stressful to the heart and lungs.
Cold and burns can injure parts of the body.
– Avoid exposure to extremely hot or cold environment
– Materials which must be touched should neither be too
cold nor too hot
OSH 367 W6 PPT1 Environmental Factors
46
Environmental Factors
• 4.4.3 Climate Controls
• Thermal comfort
– Locate equally heavy tasks together in a room
– Adjust the physical demands of the tasks to the external
climate
– Optimize air velocity
– Prevent unwanted radiation
– Limit the time spent in hot or cold environments
OSH 367 W6 PPT1 Environmental Factors
47
Environmental Factors
• 4.5 Chemical Substances
• Chemical substances occur in the environment as liquids,
gases, vapors, dusts, or solids. Some substances can
cause discomfort or present a health hazard if inhaled or
ingested or if they come into contact with skin or eyes.
• Outcomes:
–
–
–
–
Irritants
Carcinogens
Mutagens
Teratogens
OSH 367 W6 PPT1 Environmental Factors
48
TOXIC
• May Produce Illness, Internal Damage,
Possibly Death
OSH 367 W6 PPT1 Environmental Factors
49
HEALTH HAZARD DATA
• Acute
- Large Enough Of A Dose To Cause An
Immediate Response
• Chronic
- Health Effects Show Up After Repeated
Exposure Over A Longer Period Of Time
OSH 367 W6 PPT1 Environmental Factors
50
HEALTH HAZARD DATA
• Routes Of Entry
- Ingestion
- Inhalation
- Injection
- Skin Absorption
- Ethylene Glycol
- Many
Pesticides
Inhalation
Ingestion
Injection
Skin
Absorption
OSH 367 W6 PPT1 Environmental Factors
51
THRESHOLD
• The Level Of Exposure To A Substance
Where The First Effects Occur
• Whether Or Not Ill Effects Occur Depends
On
- Properties Of The Substance
- Dose
- Route Of Entry
- Susceptibility Or
Resistance Of
The Exposed
Individual
OSH 367 W6 PPT1 Environmental Factors
52
LETHAL DOSE {LD50}
The Calculated Dose Of A Substance Which Will
Cause Death In 50%Of the Animals Exposed
C
O
N
C
E
N
T
R
A
T
I
O
N
OSH 367 W6 PPT1 Environmental Factors
LD5
LD5O
53
LD100
TARGET ORGANS
Organs In Which A Substance Causes Damage
As A Result Of Exposure, Including:
Eyes
Brain
Lungs
Heart
Liver
Kidneys
Skin
Reproductive
Organs
Blood
OSH 367 W6 PPT1 Environmental Factors
54
EXCRETION OF
TOXICANTS
• Kidneys
• Liver
• Lungs
• Body Secretions
OSH 367 W6 PPT1 Environmental Factors
55
IRRITANTS
• Aggravation Of Body Tissue
Types Of Irritant Gases:
Highly Soluble Irritant Gases
• Affect The Upper Respiratory Tract
- Ammonia
Moderately Soluble Irritant Gases
• Affect The Upper Respiratory Tract & Lung Tissue
- Chlorine
Low Soluble Irritant Gases
• Affect The Lower Respiratory Tract
- Nitrogen Dioxide
OSH 367 W6 PPT1 Environmental Factors
- Carbon Monoxide
56
ASPHYXIANTS
Interferes with the supply of oxygen to the tissue
Effects
Possible Brain Damage Or Death
OSH 367 W6 PPT1 Environmental Factors
57
• Simple Asphyxiants
- Dilute The Concentration Of Oxygen In The Air Below
Normal Levels
Tissues
Hemoglobin
Circulation
Oxygen
Lungs
• Chemical Asphyxiants
- Prevent Uptake Of Oxygen By The Blood, Or Interfere With
The Transport Of Oxygen From The Lungs To The Tissues
Oxygen
Hemoglobin
Tissues
OSH 367 W6 PPT1 Environmental Factors
Circulation
58
Lungs
SENSITIZER
Repeated Exposure Produces An Allergic
Reaction
- Iodine
- Nickel
OSH 367 W6 PPT1 Environmental Factors
59
CORROSIVE
Destroys Body Tissue On Contact
- Bromine
- Sulfuric acid
- Sodium hydroxide
OSH 367 W6 PPT1 Environmental Factors
60
CARCINOGEN
Substance Which Causes Cancer, Abnormal
Cells Or Tumors
• Carcinogen
- Proven To Cause Cancer In Man
- Radiation
• Suspect Carcinogen
- Proven To Cause Cancer In Animals, But Not In Man
- Formaldehyde
- Saccharin
OSH 367 W6 PPT1 Environmental Factors
61
MUTAGEN
Substance Which Causes A Change
{Mutation} In The Genetic Material Of A
Living Cell
OSH 367 W6 PPT1 Environmental Factors
62
TERATOGEN
A Substance Causing A Birth Defect In The
Developing Fetus, But Does Not Effect The
Mother Or Father
OSH 367 W6 PPT1 Environmental Factors
63
Environmental Conditions



Chemical Compounds
Physical Agents
Biological Stress
OSH 367 W6 PPT1 Environmental Factors
64
Air Contaminants
• Vapors
• Gases
• Liquids
– Mist
– Fogs
• Solids
– Dust
– Fumes
– Fibers
– Smoke
OSH 367 W6 PPT1 Environmental Factors
65
Chemical Compounds
Are
used all over
Can enter the bloodstream
 Hazard associated with these depends
upon the solubility of the substance in
body fluids
OSH 367 W6 PPT1 Environmental Factors
66
Chemicals

Liquids

Chemicals which take the shape of their
container

Gases
 Formless fluids that occupy space
 Vapors

Gaseous form of a substance that is usually a
solid or a liquid, formed when the solid or
liquid so evaporated
OSH 367 W6 PPT1 Environmental Factors
67
Environmental Factors
• 4.5.1 Guidelines on Chemical Substances
• Most important guidelines on chemical substances
are TLV’s (threshold limit values). These are official
international limits for chemical substances in the air
and are intended to prevent adverse health effects.
OSH 367 W6 PPT1 Environmental Factors
68
Environmental Factors
• Guidelines on Chemical Substances
• Apply TLV’s or other limits as maxima for chemical substances
in ambient air
• Avoid carcinogenic substances
• Avoid peak exposures
• Exposure to mixtures of substances should be avoided
• Always remain as far below the TLV as possible
• Packages of chemicals should be labeled appropriately
OSH 367 W6 PPT1 Environmental Factors
69
Environmental Factors
• Avoid Carcinogenic Substances:
– Certain airborne substances are known to cause cancer.
Exposure to these substances must be avoided at all times.
See Table 4.7 for a list of carcinogenic substances
– International Agency for Research on Cancer (IARC)
provides the research on carcinogenic substances
OSH 367 W6 PPT1 Environmental Factors
70
Environmental Factors
• Table 4.7 Random Selection of Chemical Substances
That Are Considered to Induce Cancer
• Substance
Example of Use
–
–
–
–
–
Asbestos
Benzene
Chrome compounds
Polycyclic hydrocarbon
Vinylchloride
Thermal insulation
Solvent
Pigment
Component of tar
Raw material for PVC
OSH 367 W6 PPT1 Environmental Factors
71
Environmental Factors
• Avoid Peak Exposures
– Short term exposure to high concentrations of a chemical
substance can affect health even if the TLV is, on average, not
exceed the 8-hour limit.
• Exposure to mixtures of substances should be avoided
– TLV’s are established for purest form of a chemical
• Always aim to remain as far below the TLV as possible
– Continuing monitoring to make sure your Ee’s exposure is below
the TLV
• Packages of chemicals should be labeled appropriately
– Supplier of chemicals are required to label their containers
OSH 367 W6 PPT1 Environmental Factors
72
OSH 367 W6 PPT1 Environmental Factors
73
Environmental Factors
• 4.5.2 Measures at the Source
OSH 367 W6 PPT1 Environmental Factors
74
Environmental Factors
• 4.5.3 Ventilation
• Measures aimed at the exposure route should be
taken whenever those directed at the source are
inadequate. Measures directed at the transfer
between the source and people (ventilation of the
air).
OSH 367 W6 PPT1 Environmental Factors
75
Environmental Factors
• Chemical substances must be extracted directly at
the source
– If it is not possible to extract the release of chemical
substances, then harmful substances should be extracted
directly at the source.
– Extracted air must be released to the without being
cleaned
– EPA laws restrict the permissible concentrations of
chemical substances in exhaust air
OSH 367 W6 PPT1 Environmental Factors
76
Environmental Factors
• Table 4.8 Recommended Optimum Space and Air
Change
Nature of work
– Very light
– Light
– Moderate
– Heavy
Vol./person
10m3
12m3
15m3
18m3
Fresh Air Supply Rates
30m3 hr3
35m3 hr3
50m3 hr3
60m3 h3
OSH 367 W6 PPT1 Environmental Factors
77
Environmental Factors
• Ventilation:
– Provide an efficient exhaust system
– Pay attention to the effect on climate when designing air
extraction and ventilation
– Provide sufficient air changes
OSH 367 W6 PPT1 Environmental Factors
78
Environmental Factors
• 4.5.4 Measures at the Individual Level
–
–
–
–
–
Implement organized measures
Provide and use PPE
Use dust masks only for protections against coarse dust
Use Protective Equipment
Ensure high standards of personal hygiene
OSH 367 W6 PPT1 Environmental Factors
79