Outline

• Introduction
•Work Environment Measure definition
•Review of Workplace hazards
•Type of Environmental Monitoring
•Example of Instruments for Measurement
•Applying Work Environment Measurement
in Confined Space
 Introduction
• Industrial hygiene is the science and art devoted
to the recognition, evaluation and control of
environment factors and stresses arising in or
from the workplace, which cause sickness,
impaired health and well being, or significant
discomfort and among workers or among citizens
of the community.
• Industrial hygiene is primarily concerned with the
control of occupational health hazards that arises
as a result of or during work.
 Work Environment Measurement
• Evaluating occupational health and safety hazards
is achieved through work environment
measurement, analysis of the samples and
comparison of these results with established
standards.
• Work environment measurement refers to the
determination of environment stresses and their
hazardous effects on worker’s health through
direct measurement of hazards using industrial
hygiene equipment.
 A review of Workplace Hazards

Chemical Hazards
• DUST
Any chemical that has been classified as
•MIST
hazardous or for which relevant
•FUMES
information exists to indicate that it is
•GAS
hazardous.
•VAPOR

Physical Hazards
• NOISE
Problems relating to such things as noise,
•VIBRATION
vibration, temperature extremes,
•TEMPERATURE EXTREMES
radiation, illumination and pressure
•RADIATION
extremes.
•ILLUMINATION
•PRESSURE EXTREMES
Cont. Workplace Hazards

Biological Hazards
• VIRUSES
Any virus, bacteria, fungus, parasite, •BATERIUM
or any living organism that can cause •FUNGI
a disease in human beings. They can •PARASITES
be a part of the total environment or •OTHER DISEASE-CAUSING LIVING
associated with certain occupations ORGANISM

Ergonomic Hazards
Multidisciplinary activity dealing with • IMPROPERLY DESIGNATED TOOLS
interactions between man and his OR WORK AREA
total working environment elements •IMPROPER LIFTING
•POOR VISUAL CONDITION
as atmosphere, heat, light and sound
•REPEATED MOTIONS IN AWKWARD
as well all tools and equipment in the
POSITIONS
workplace.
Type of Environmental Monitoring

• Monitoring is a continuing program of

observation, measurement and judgment, all
of which are necessary to recognize potential
hazards and to judge the adequacy of
protection.
• Monitoring requires an awareness of the
presence of potential hazards and an
assessment of continuing basis of the
adequacy of the control measures.
Cont. Type of Environmental Monitoring

Personal / Breathing Zone Monitoring

• The measurement of a particular employee’s exposure to airborne,
contaminants.
•In personal monitoring, the measurement device or dosimeter, is
placed as possible to the contaminants’ entry portal to the body.
•When monitoring an air contaminant that is toxic if inhaled, the
measurement device is placed close to the breathing zone.

Area / environmental Monitoring

•The measurement of the contaminant concentrations in the workroom.
•The sampling device is placed in a fixed location in the work area that a
generally occupied by employees. This type of collection is also referred to as
environmental monitoring
 Example of Instruments for
Measurements
1. Illumination
The measurement of the
stream of light falling on
a surface
Lux – the unit of
measurement
• Luxmeter – a direct reading
instrument which contains photo,
light sensitive cell and
micrometers which can be
calibrated to read directly in lux
2. Noise
Sound and noise are often used interchangeably, but
generally, sound is descriptive of useful
communication or pleasant sounds such as music,
while noise is used to describe discord or unwanted
sound. Noise may be classified as continuous,
intermittent and impact.
Decibel – a dimensionless unit related to the logarithm
of the ratio of a measurement quantity to a reference
quantity.
Frequency – describes the rate at which complete cycles
of high and low pressure regions produced by the
sound source
Cont. NOISE

• Sound Level Meter – the instrument

which measures the root-mean-square
(rms) sound pressure level in decibels,
which is proportional to intensity or
sound energy flow. Consists of a
microphone, an amplifier with
calibrated volume control and an
indicating meter.
 Impulse Meter

The special instrument

which measures the
peak levels of noises
which lasts a fraction of
a second such as those
produced by hammer
blows or punch press
strokes
 Frequency Analyzer

The instrument which

measures the frequency
distribution of the
sound energy
 Sound Monitor

Statistical analyzers
developed to assist in
indicating the
percentage of time that
the sound level lies in
certain predetermined
level ranges
3. Chemical (Common Groups)
 3.1 Direct Reading Instruments

3.1.1 Single Chemical Instruments

• Designed to specifically monitor for a single
chemical
Examples:
• O2 monitors
• CO2 Monitors
• Etc.
3.1.2 General Survey Instruments

• Capable of detecting a large number of

contaminants but generally cannot distinguish
them
Example:
• Combustible gas indicator
• Explosimeters
• Photo ionization detectors
• Etc.
 explosimeters

Combustible gas indicator

Photo ionization
detectors
3.1.3 Based on Color Change
• Sampling media that change color when
contaminated air is pulled through them, and
can provide the ability to do direct reading
measurements for a wide variety of gases and
vapors
Examples
• Detector tubes
 3.2 Indirect / Integrated Air
Sampling Instruments
3.2.1 Liquid Media Samplers
• Devices which use an absorbing liquid to
capture gaseous substances
Example:
• Bubblers
• Impingers
• Etc.
3.2.2 Solid Sorbent Sampling
• A pump is used to pull air through the sorbent
wherein the sampling media may be charcoal,
silica gel, etc.
3.2.3 Passive Monitors
• Instruments used to monitor gases and vapors
and may be used relatively un attended
 4.0 HEAT STRESS

• The excessive heat load • Globe, Wet and dry

and is the aggregate of bulb
environmental and • Thermometers
physical work factors
that constitute the total
heat load imposed on
the body
• METHANE
(lighter than air)

CARBON MONOXIDE
(slightly lighter than
air)

HYDROGEN
SULFHIDE
(heavier than air)
 IT IS RECOMMENDED THAT IN
DOING STRATIFIED AIR
SAMPLING,
One should apply the 2 by 2
principle*, wherein one should test
for a duration of at least 2 seconds
at 2 feet intervals.
* This is dependent on the gas monitoring equipment used. It is
best to read the user’s manual of your gas monitor prior to use
 GAS MONITORING

 While it is very important to detect the types

and levels of gases present inside confined
spaces prior to entry, it is as important that
one continuously monitors gas levels in the
entire duration of the confined space activity
 One must always remember that whatever
activity done inside the confined space can
alter the mixture of air inside.
 Any or a combination of the following can
happen:
 Consume oxygen (and decrease oxygen level)
 Displace Oxygen
 Generate a combustible environment and
cause an explosion (an ignition source
introduced into a combustible environment)
 Release toxic gases
 Others
One can only ensure that he is in a “SAFE”
environment if he continuously monitors his
work environment.
NEVER TRUST YOUR SENSES TO
DETERMINE IF THE AIR INSIDE A
CONFINED SPACE IS SAFE!

Many gases and vapors cannot be seen or smelled.

Some can be initially smelled, but can desensitize
olfactory faculties at prolonged exposure.
More importantly, oxygen levels cannot be
determined by a person, unless one experiences its
effects
 TYPES OF GAS MONITORS

1. Fixed Systems
Remote Sensors
Audible/Visual Alarms
Control Panels
Power Supplies
. Portable Gas Monitors
2

 Single Gas Monitors

Multiple Gas Monitors

 3. Points to consider when
selecting Gas Monitoring
 Size  Ease of calibration
 Durability  Training
 Cost  Intrinsic safety
 Ease of use  Sample draw capability
 Ease of maintenance  RFI protection

Gas Detection with a Properly

Calibrated Instrument is the
ONLY SURE WAY OF KNOWING
IF DANGEROUS GASES ARE PRESENT
Questions?