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INDUSTRIAL SAFETY ENGINEERING
MODULE 5: HAZARD IDENTIFICATION
AND ANALYSIS
Hazard and risk, Types of hazards —Classification of Fire, T:
Fire extinguishers, fire explosion and toxic gas release, Sen .
hazard identification and risk assessment. Identification of iene
Inventory analysis, Fire and explosion hazard rating of process
Jants - The Dow Fire and Explosion Hazard Index, Preliminar:
hazard analysis, Hazard and Operability study (HAZOP)) a
methodology, criticality analysis, corrective action and follow-up.
Control of Chemical Hazards, Hazardous properties of chemicals,
Material Safety Data Sheets (MSDS). :
51 HAZARD AND RISK
Hazard is a source or a situation with potential to cause harm
in terms of human injury or ill-health, damage to property or
environment or both. Hazards are identified in the
performance of various activities, storage and handling of
materials, and operation and maintenance of. plants and
equipment's.
Hazard control is that function which is oriented: towards
recognizing, evaluating and working towards eliminating
hazards and destructive effects found at the work-place.
Risk
A hazard is something that has the potential to cause harm
while tisk is the likelihood of harm taking place, based on
exposure to that hazard. A hazard is something that can cause
51 [Page Module 5
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INDUSTRIAL SAFETY ENGINEERING
harm, e.g. electricity, chemicals, working up a ladder, Noise, 4
keyboard, a bully at work, stress, etc. A tisk is the chance, hj
or low, that any hazard will actually cause somebody harm,
5.2 TYPES OF HAZARDS
Hazards may be classified as under:
e Mechanical Hazards.
e Electrical Hazards.
¢ Chemical Hazards.
1, Mechanical Hazards:
These are responsible for the majority of the accidents in work
situations, therefore every workplace and equipment shoulg
be properly examined for identify-ing mechanical hazards ang
for taking mitigating measures.
Common sources of mechanical hazards are:
(a) Unguarded or inadequately guarded moving parts
or pits etc. :
(b) Machine tools, hand tools, handling materials,
lifting and other appliances.
(c) Improper ventilation, unsafe dress or apparel ete.
(d) Improper use of tools.
2. Electrical Hazards:
These may be due to contact of body with wire, cable or rail or
from stroke of lightening. The immediate effect of this is shock
which may be relatively mild or severe so as to cause death
(electrocution) depending upon the strength of the current
and/or the path it takes passing the earth through the body:
Another result is burning and the burns may be severe and
deep, especially with higher voltage.
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Causes of the electric hazards may be of the following types: ‘
(a) Electric shocks may be caused by an exposed live conductor
or a faulty piece of equip-ment.
wa mobile crane boom, a man carrying or climbing an
aluminium ladder, or vertical metal bars etc. can pa in
contact with overhead power lines, electric crane rails, open-
faced substation switchboards etc. 4
© Other causes may be unskilled electricians, improper,
instructions, defective wiring which may cause short circuit,
poor installations, misuse or overloading.
(d) Ageing and attack by foreign materials causes insulation
failures which causes elec-trical fires or cases of electrocution.
3, Chemical Hazards:
The usage of chemicals with the resultant hazardous gases,
vapours and fumes is one of the most dangerous industries.
The effects of noxious gases are:
(a) Simple asphyxiants, e.g., nitrogen gas, methane gas, carbon
dioxide.
(b) Chemical osphysciants, e.g., carbon monoxide, hydrogen-
sulphide, hydro-cyanic acid.
(0 Irritant gases, e.g., nitrogen dioxide or peroxide, flourine,
hydrogen flouride, sulphur dioxide, ammonia.
(d) Organic metallic gases, e.g., assenic hydride.
(€) Inorganic metallic gases.
53 CLASSES OF FIRE
While fire can seem like one big threatening force, it’s
portant to know that there are actually several classes of
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INDUSTRIAL. SAFETY, ENGINEERING.
ine how quickly it burns, how
i ire’s class can determine Y
fires. sou ti and the best way to suppress or put it out. The
cane classes of fires each have their own best approach to
put them out safely and effectively.
f fires are categorized by what caused the
The 5 main classes ©! fuel, and are as follows:
fire or what the fire uses as
Class A: solid materials such as wood or paper, fabric, ang
some plastics
Class B: liquids or gas such as alcohol, ether, gasoline, or
grease
Class C: electrical failure from appliances, electronic
equipment, and wiring
Class D: metallic substances such as sodium, titanium,
zirconium, or magnesium
Class K: grease or oil fires specifically from cooking
Class A Fire
Class A fires are the most common type of fire. They are
produced from common combustible materials including
wood, paper, fabric, rubber, and plastic. Class A fires have
relatively low ignition temperatures, and once the fuel or
oxygen has been depleted, the fire will burn out. A garbage fire
is one example of Class A fires. Generally speaking, if the fire
leaves ash behind, it’s likely a Class A Fire.
Water and foam agents are most often used when fighting
Class A fires.
Class B Fire
Class B fires occur when flammable liquids or gases such as
alcohol, kerosene, paint, gasoline, methane, oil-based coolan's
or propane ignite. Class B fires are most common in industrial
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settings, but they may also occur i
is ‘ : ir in residenti, :
settings. Co B fires have a low Gent te commercial
burn easily at any temperature if exposed toa fire "means they
B fires also spread rapidly and produce a thick black. irce. Class
they burn. smoke as
Water is not effective when dealing with C
es lass B fires,
Carbon Dioxide (CO2) or dry chemical agents are ier aeten
‘0
fight these fires.
Class C Fire
Class C fires are those fires that have live electrical currents or
electrical equipment as a source of fuel. Such fuel sources could
include electric tools, appliances, motors, and transformers.
Class C fires are most common in industrial settings that deal
with energy OF electrically-powered equipment, like wind
turbines. However, Class C fires can also occur in commercial
or residential settings due to issues like faulty wiring.
annot be fought with water—in fact, it can
d, a non-conductive chemical agent,
should be used to put out the flames.
Electrical fires ¢
make it worse. Instea
including clean agents, s
Class D Fire
‘be those fires that occur with a combustible
Class D fires descri
als include
metal fuel source. Common combustible met
aluminum, lithium, magnesium, potassium, titanium, and
zirconium. These types of combustible metals are most often
used in laboratories and in manufacturing, s0 the biggest
danger for Class D fires occurs in these industries.
to explode, so it
d, dry powder
e flames by
Water can cause some combustible metals
should not be used to fight Class D fires. Instea
agents can be used to absorb heat and smother thi
blocking off the fire’s oxygen supply.
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ee king fires that occur as a result of
mee ar ak woke liquid like grease, oil, vegetable
ue eee 7 t. Class K fires are technically a type of liquiq
fat, or animal a separated out as their own class because of
fire, but ae tting, Class K fires are most common in the foog
cee and restaurant industry, but can occur in any kitchen,
Like other liquid fires, water should not be sprayed onto Class
K fires. Instead, wet chemical agents are the best method to use,
5.4 TYPES OF FIRE EXTINGUISHERS
i s of fire extinguishers exist in order to address
aes classes of fires. Each fire class describes the fue|
or material a fire is burning or what caused it to start —
therefore, using the right extinguisher is essential to put out the
fire safely.
Fi How to Fire
‘ire . .
Class Fuel Type Suppress. ay her
Freely ABC/ powder,
Class A burning caenek water, water
combustibles 8 mist, foam
ABC/ powder,
Burning é CO2, water
Class B liquid or gas Smothering anisticleas
agent
Non ane pe
ClassC | Electrical fire | conductive c = 2, ee
chemicals mist, le
agent
ClassD | Metallic fire | Dry powder Powder
: agent
Class K Cooking or | Smothering, | Wet chemical,
—ftease fire | wet chemical water mist
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Water
Water is the primary liqui i
although ie eee les ee eee
drawback for pure water fire extinguishers is foe S
suitable for use in freezing conditions since the i ; : in
will freeze and render the extinguisher unusable eae pera
of water fire extinguishers contain antifreeze which vill. =
the extinguisher to be used in freezing conditions. Wee vee
fire extinguishers can also sometimes contain wetting a .
which are designed to help increase its effectiveness sexinet
ve. These extinguishers are intended primarily for use on
Class A fires.
Water mist extinguishers are a type of water fire extinguisher
that uses distilled water and discharges it as a fine spray
instead of a solid stream. Water mist extinguishers are used
where contaminants in unregulated water sources can cause
damage to personnel or equipment. Typical
excessive
museums, and book
applications include operating rooms,
collections.
Film-forming foam type
AFFF (aqueous film-forming foam) and FFFP (film-forming
ishers are rated for use on both Class
fluoroprotein) fire extingu!
Aand Class B fires. As the name implies, they discharge a foam
material rather than.a liquid or powder. They are not suitable
for use in freezing temperatures. An advantage of this type of
extinguisher when used on Class B flammable liquid fires of
appreciable depth is the ability of the agent to float on and
secure the liquid surface, which helps to prevent reignition.
Carbon Dioxide type
The principal advantage of Carbon Dioxide (CO2) fire
extinguishers is that the agent does not leave a residue after
‘se. This can be a significant factor where protection is needed
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INDUSTRIAL SAFETY ENGINEERING
for delicate and costly electronic equipment. Other typical
applications are food preparation areas, laboratories, and
printing or duplicating areas. Carbon dioxide extinguishers are
listed for use on Class B and Class C fires. Becatise the agent is
discharged in the form of a gas/snow cloud, it has a Telatively
short range of 3 ft to 8 ft (1 m to 2.4 m). This type of fire
extinguisher is not recommended for outdoor ; use where
windy conditions prevail or for indoor use in locations that are
subject to strong air currents, because the agent can Tapidly
dissipate and prevent extinguishment. The concentration
needed for fire extinguishment reduces the amount of oxygen
in the vicinity of the fire and should be used with caution when
discharged in confined spaces.
Halogenated agent types
i, Halon
The bromochlorodifluoromethane (Halon 1211) fire
extinguisher has an agent that is similar to carbon dioxide in
that it is suitable for cold weather installation and leaves no
residue. It is important to note that the production of Halon has
been phased out because of the environmental damage it
causes to the earth’s ozone. Some larger models of Halon 1211
fire extinguishers are listed for use on Class A as well as Class
B and Class C fires. Compared to carbon dioxide on a weight-
of-agent basis, bromochlorodifluoromethane (Halon 1211) is at
least twice as effective. When discharged, the agent is in the
combined form of a gas/mist with about twice the range of
carbon dioxide. To some extent, windy conditions or strong ait
currents could make extinguishment difficult by causing the
rapid dispersal of the agent.
ii, Halon Alternative Clean Agents
There are several clean agents that are similar to halon agents
in that they are nonconductive, noncorrosive, and evaporate
after use, leaving no residue. Larger models of these fire
5.8|Page Module 5INDUSTRIAL SAFETY ENGINEERING
extinguishers are listed fo:
C fires, which makes opie aren ne
electronic equipment. When di
oe ined fram of a yar na hen agents are in the
evaporates after discharge with about twie te. oe
carbon dioxide. To some extent, windy a ae
currents could make extinguishing difficult by eee ae oH
dispersal of agent. Clean agent type eitinguigics don ae
detrimental effect on the earth’s ozone so the: one wet
widely available than Halon type extinguishers. iia
table for use on fires in
Dry chemical types
i. Ordinary Dry Chemical
The fire extinguishing agent used in these devices is a powder
composed of very small particulates. Types of agents available
include sodium bicarbonate base and potassium bicarbonate
base. Dry chemical type extinguishers have special treatments
that ensure proper flow capabilities by providing resistance to
packing and moisture absorption (caking).
ii. Multipurpose Dry Chemical
Fire extinguishers of this type contain an ammonium
phosphate base agent. Multipurpose agents are used in exactly
the same manner as ordinary dry chemical agents on Class B
fires. For use on Class A fires, the multipurpose agent has the
additional characteristic of softening and sticking when in
contact with hot surfaces, In this way, it adheres to burning
materials and forms a coating that smothers and isolates the
fuel from air. The agent itself has little cooling effect, and,
because of its surface coating characteristic, it cannot penetrate
below the burning surface. For this reason, extinguishment of
deep-seated fires might not be accomplished unless the agent
is discharged below the surface or the material is broken apart
and spread out.
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Wet chemical
The extinguishing agent can be comprised of, but is not limiteg
to, solutions of water and potassium acetate, Potassium
carbonate, potassium citrate, or a combination of th
chemicals (which are conductors of electricity). The liquia
agent typically has a pH of 9.0 or less. On Class A fires, the
agent works as a coolant. On Class K fires (cooking oi] fires),
the agent forms a foam blanket to prevent reignition. The Water
content of the agent aids in cooling and teducing the
temperature of the hot oils and fats below their autoignition
point. The agent, when discharged as a fine spray directly at
cooking appliances, reduces the Possibility of splashing hot
grease and does not present a shock hazard to the Operator,
Wet chemical extinguishers also offer improved Visibility
during firefighting as well as minimizing cleanup afterward,
Gass8 | Cane
Flammable| Flammable
Uquids | Gases
(0g eanes
Methane)
Dry powder types
These fire extinguishers and agents are intended for use on
Class D fires and Specific metal
ls, following special techniques
oun manufacturer’ 8 recommendations for use. The
Suishing agent can be applied from a fire extinguisher or
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INDUSTRIAL SAFETY ENGINEERING
by scoop and shovel. Usin;
IB A sce
toasa hand propelled fire eine shovel is often teferred
T.
5.5 STRUCTURE OF
IDENTIFICATION AND RISK Asonsenane
ENT
One of the "root causes" of ral
incidents is the failure to dently sei illnesses, and
present, or that could have been aitihgadt azittds that are
of any effective safety and health program ue a
ongoing process to identify and assess such ipa
To identify and assess hazards, employers and workers:
e Collect and review information about the hazard:
present or likely to be present in the workplace. ;
Conduct initial and periodic workplace inspections of
the workplace to identify new or recurring hazards.
Investigate injuries, illnesses, incidents, and close
calls/near misses to determine the underlying
hazards, their causes, and safety and health program
shortcomings.
Group similar incidents and identify trends in injuries,
illnesses, and hazards reported.
Consider hazards associated with emergency or
nonroutine situations.
Determine the severity and likelihood of incidents that
could result for each hazard identified, and use this
information to prioritize corrective actions.
55.1 HAZARD IDENTIFICATION
Action item 1: Collect existing information about workplace
hazards
Information on workplace hazards may alread
employers and workers, from both interna
Sources,
ly be available to
1 and external
S11] Page Module 9INDUSTRIAL SAFETY ENGINEERING
How to accomplish it
|
|
Collect, organize, and review information with workers to
determine what types of hazards may be present and which
workers may be exposed or potentially exposed. Information
available in the workplace may include:
e Equipment and machinery operating manuals.
e Safety Data Sheets (SDS) provided by chemica]
manufacturers.
¢ Self-inspection reports and inspection reports from
insurance carriers, government agencies,
consultants.
¢ Records of previous injuries and illnesses.
¢ Workers compensation records and reports.
¢ Patterns of frequently-occurring injuries and illnesses,
¢ Exposure monitoring results, industrial hygiene
assessments, and medical records (appropriately
redacted to ensure patient/ worker privacy).
* Existing safety and health programs (lockout/tagout,
confined spaces, process safety management, personal
protective equipment, etc.).
¢ Input from workers, including surveys or minutes
from safety and health committee meetings.
* Results of job hazard analyses, also known as job
safety analyses.
and
Information about hazards may be available from outside
sources, such as:
¢ National Safety Council, and Department of Labour &
Employment websites, publications, and alerts.
* Trade associations.
Labor unions, state and local occupational safety and
health committees/coalitions , and worker advocacy
groups.
* Safety and health consultants.
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Action item 2: Inspect the workplace for safety hazards
Hazards can be introduced over time as workstations and
processes change, equipment or tools become worn,
maintenance is neglected, or housekeeping Practices decline.
Setting aside time to regularly inspect the workplace for
hazards can help identify shortcomings so that they can be
addressed before an incident occurs.
How to accomplish it
¢ Conduct regular inspections of all operations,
equipment, work areas and facilities, Have workers
participate on the inspection team and talk to them
about hazards that they see or Teport.
¢ Besure to document inspections so we can later verify
that hazardous conditions are corrected. Take photos
or video of problem areas to facilitate later discussion
and brainstorming about how to control them, and for
use as learning aids.
« Include all areas and activities in these inspections,
such as storage and warehousing, facility and
equipment maintenance, purchasing and office
functions, and the activities of on-site contractors,
subcontractors, and temporary employees.
¢ Regularly inspect both plant vehicles (e.g., forklifts,
powered industrial trucks) and transportation vehicles
(e.g., cars, trucks).
¢ Use checklists that highlight things to look for. Typical
hazards fall into several major categories, such as those
listed below; each workplace will have its own list:
o General housekeeping
o Slip, trip, and fall hazards
0 Electrical hazards
© Equipment operation
© Equipment maintenance
©. Fire protection
5.13] Page Module 5Ca
DUSTRIAL SAFETY ENGINEERING.
o Work organization and process flow,
(including staffing and scheduling)
Work practices
Workplace violence
Ergonomic problems
Lack of emergency procedures
« Before changing operations, workstations, or
workflow; making major organizational changes, ee
introducing new equipment, materials, or Processes,
seek the input of workers and evaluate the planneg
changes for potential hazards and related risks,
020. 0: oO
Note: Many hazards can be identified using common
knowledge and available tools. For example, we can easil
identify and correct hazards associated with broken stair Tails
and frayed electrical cords. Workers can be a very usefy]
internal resource, especially if they are trained in how to
identify and assess risks.
Action item 3: Identify health hazards
Identifying workers! exposure to health hazards is typically
more complex than identifying physical safety hazards. For
example, gases and vapors may be invisible, often have no
odor, and may not have an immediately noticeable harmful
health effect. Health hazards include chemical hazards
(solvents, adhesives, paints, toxic dusts, etc.), physical hazards
(noise, radiation, heat, etc.), biological hazards (infectious
diseases), and ergonomic risk factors (heavy lifting, repetitive
motions, vibration), Reviewing workers' medical records
(appropriately redacted to ensure patient/ worker privacy) can
be useful in identifying health hazards associated with
workplace exposures,
How to accomplish it
* Identify chemical hazards =review SDS and product
___.._ labels to identify chemicals in the workplace that hav?
5.14|Page 7 Module >a
INDUSTRIAL SAFETY ENGINEERING
low exposure limits, are highly volatile, or are used in
large quantities or in unventilated spaces, Identify
activities that may result in skin exposure to chemicals.
Identify Physical hazards ~identify any exposures to
excessive noise (areas where we must raise our voice
to be heard by others), elevated heat (indoor and
outdoor), or sources of Tadiation (radioactive
materials, X-rays, or Tadiofrequency Tadiation).
¢ Identify biological hazards -determine whether
workers may be exposed to sources of infectious
diseases, molds, toxic or Poisonous plants, or animal
materials (fur or scat) capable of causing allergic
reactions or occupational asthma.
¢ Identify ergonomic risk factors -examine work
activities that require heavy lifting, work above
shoulder height, repetitive motions, or tasks with
significant vibration.
e Conduct quantitative exposure assessments -when
possible, using air sampling or direct reading
instruments.
e Review medical records -to identify cases of
musculoskeletal injuries, skin irritation or dermatitis,
hearing loss, or lung disease that may be related to
workplace exposures.
Action item 4: Conduct incident investigations
Workplace incidents -including injuries, illnesses, cise
calls/near misses, and reports of other concerns- provi:
clear indication of where hazards exist. = oe
i igating inci rts, we can i hazards
investigating incidents and repo! ee ie hich
that are likely to cause future harn aa
investigation ask always be to identify the root ue “ :
there is often more than one) of the incident or
order to prevent future occurrences.
ae
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How to accomplish it
e Develop a clear plan and procedure for conductin,
incident investigations, so that an investigation can
begin immediately when an incident occurs, The
plan should cover items such as:
Who will be involved
Lines of communication
Materials, equipment, and
needed
o Reporting forms and templates
Train investigative teams on incident investigation
techniques, emphasizing objectivity and Open.
mindedness throughout the investigation Process,
Conduct investigations with a trained team that
includes representatives of both mana:
workers.
©. Investigate close calls/near misses.
Identify and analyze root causes to address
underlying program shortcomings that allowed
the incidents to happen.
Communicate the results of the investigation to
managers, supervisors, and workers to Prevent
recurrence.
Supplies
gement ang
Effective incident investigations do not Stop at identifying a
single factor that triggered an incident. They ask the questions
"Why?" and "What led to the failure?" For example, if a piece
of equipment fails, a g00d investigation asks: "Why did it fail?"
"Was it maintained Properly?" "Was it beyond its service life?"
and "How could this failure have been prevented?" Similarly,
a good incident investigation does not stop when it concludes
that a worker made an error. It asks such questions as: "Was
the worker provided with appropriate tools and time to do the
work?" "Was the worker adequately trained?" and "Was the
worker Properly supervised?"
5.16 |Page m “Module 5INDUSTRIAL SAFETY ENGINEERING
Action item 5: Identify hazards
and nonroutine situations
potential hazards. Plans and Proce:
for responding appropriately and safely to h; :
with foreseeable emergency 'Y to hazards associated
tuations. Scenarios and nonroutine
si -
How to accomplish it
e Identify foreseeable emergency scenarios and Nonroutine
tasks, taking into account the types of material and
equipment in use and the location within the facility.
Scenarios such as the following may be foreseeable:
* Fires and explosions
* Chemical releases
* Hazardous material spills
* Startups after planned or unplanned equipment
shutdowns
* Nonroutine tasks, such as infrequently performed
maintenance activities
* Structural collapse
= Disease outbreaks
* Weather emergencies and natural disasters
" Medical emergencies
* Workplace violence
Action item 6: Characterize the nature of identified hazards,
identify interim control measures, and prioritize the hazards
for control
The next step is to assess and understand the hazards
identified and the types of incidents that could result from
Worker exposure to those hazards. This information can be
517 |Page Module 5
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used to develop interim controls and to prioritize hazards for
permanent control.
How to accomplish it
¢ Evaluate each hazard by considering the Severity of
potential outcomes, the likelihood that an event or
exposure will occur, and the number of workers who
might be exposed.
¢ Use interim control measures to protect workers until
more permanent solutions can be implemented.
Prioritize the hazards so that those presenting the Breatest
tisk are addressed first. Note, however, that employers
have an ongoing obligation to control all serious
recognized hazards and to protect workers.
Note: "Risk" is the product of hazard and exposure. Thus, risk
can be reduced by controlling or eliminating the hazard or
reducing workers! exposure to hazards. An assessment of risk
helps employers understand hazards in the context of their
own workplace and prioritize hazards for permanent control,
5.5.2 RISK ASSESSMENT TOOLS
Risk assessment tools, sometimes called “risk assessment
techniques,” are procedures or frameworks that can be used in
the process of assessing and managing risks. There are many
ways to assess risk, making risk assessment tools flexible and
easy to use for a variety of jobs, industries, and needs,
mmonly used risk assessment tools in
different businesses, All of them are used often and are easily
applicable to different Situations. These tools are:
1. Risk matrix
2. Failure Mode and Effects Analysis (FMEA)
3. Decision Tree
4. Bowtie Model
5.18 | Pag eu
“Module 5INDUSTRIAL SAFETY ENGINEERING
1. Risk Matrix
A risk matrix is a visual Tepresentation of risks laid out in a
diagram or a table, hence its alternate name as a risk diagram.
Here, risks are divided and sorted based on their probability of
happening and their effects or impact. A risk matrix is often
used to help prioritize which risk to address first, what safety
measures and risk mitigation plans to take, and how a certain
task should be done. Risk matrices can come in any size and
number of columns and rows, depending on the Project and
risks being discussed.
Likelihood r Highly
Likely |Unt
y |Unlikely} likel
Fatality a
Major Injuries
Consequences}
Minor Injuries
Negligible Injuries
2. FMEA
The Failure Mode and Effects Analysis (FMEA) risk
assessment tool was first discovered in the 1940s by the US
military to identify all possible issues or failures in a design,
ptocess, product, and service. This tool is often used during a
product or service's design or proposal stage to actively study
possible risks and discover their effects. FMEA has two parts
to it:
* Failure Modes: the failures, problems, and issues that
occur
* Effects Analysis: the analysis of the failures’ effects
S19|Page “Module 5
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3. Decision Tree
Risk Assessment Tool: Decision Tree
IfA>B
MEN
Ifyes, then: If no, then:
MN N
Possibility 1 Possibility 2 Possibility 3
XN
Possibility 4
The decision tree risk assessment tool works
Project managers a template to calculate
values of different results and the likelihood
Insome cases, a decision tree is also often u
the value of a Project, product, or service.
by Providing
and visualize the
of achieving them,
sed to help calculate
To use this tool, one starts with one element, Product, or
service they want to evaluate, and then Creates different
branches from it with different goals. When carried out, the
final product looks like a flowe
hart similar to a tree with
different branches, hence the name.
4. Bowtie Model
The Bowtie Model risk assessment tool aims to show the causal
links between different sources of risks and their
Consequences, The left side of the diagram shows what causes
the tisk, the right shows their Potential outcomes, and then
both sides meet in the middle with a Single risk called “Event.”
The left and
right sides of the Event
le.
one risk. Wh to
look like a bowti ‘en drawn out, the model starts
5.20|Page
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Risk Assessment Tool: Bowtie Model
Tg
Clair
Uses of Risk Assessment Tools
Risk assessment tools are an essential Part of performing risk
assessments and risk management tasks. Not only aie
make risk assessments easier, but they also help put different
risks into perspective and help create contingency plans better.
Some things risk assessments tools can help with are:
e Creating and spreading awareness on different
hazards and risks
¢ Identifying who are most at risk of encountering or
suffering from certain risks
¢ Determining what control measures and programs are
required for which risks and what need to change in
existing rules
Preventing and mitigating injuries, fatalities, and
illnesses ;
Meeting legal requirements on certain industry-
specific tasks where applicable
55.3 Assessing the Consequences
In assessing the consequences of a hazard, the first question
should be asked “If a worker is exposed to this hazard, aa
bad would the most probable severe injury be?”. For this
SETS Mo dullect
og
521] Pageing that 4 hazard and injury is
ith its severity.
consequence into
ds to death
‘ous injury
be irreversible,
ni
_ serious damage to health
requiring medical attention
« Fatality ~ lead
. Major or seri
which may tment
ing treatme :
“ i nm _ reversible health damage which may
e Min we medical attention but limited _ ongoing
vreatment). This is less likely to involve significant time
ff work. a
. Negligible injuries - first aid only with little or no lost
time.
To illustrate how this can be used in the workplace we will use
k. A hazard involved could
the example of a metal shearing tas! 1
include a piece of metal flying out of the equipment while in
use. In this example the probable most severe injury would be
“Major or Serious Injury” with the possibility of bruising,
breakage, finger amputation.
5.5.4 Assessing the Likelihood
Inassessing the likelihood, the question should be asked “Tf the
hazard occurs, how likely is it that the worker will be injured?”.
This should not be confused with how likely the hazard is to
occur, Itis common to group the likelihood of a hazard causing
worker injury into the following four categories:
Very likely - exposed to hazard continuously.
* Likely - exposed to hazard occasionally.
© Unlikely - could happen but only rarely.
. ied unlikely - could happen, but probably never
will,
S(Paze eo gule 5
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In the metal shearing example, the question should not be
“How likely is the machine expected to fail?” but instead
“when the machine fails and causes metal to fly out, how likely
is the worker expected to be injured?”. If in our example we
observe a safe distance between the machine and worker and
proper PPE being worn, we could rate it as “Unlikely” given
our observations.
5.6 THE DOW FIRE AND EXPLOSION
HAZARD INDEX
It is a method for ranking the relative fire and explosion risk
associated with a process,
The index is developed by the Dow Chemical Company and -—
ublished by the American Institute of Chemical Engineering,
Dow (1994) (www.aiche.org), evaluating the potential risk
from a process and assessing the potential loss. A numerical
“Fire and explosion index” (F&EI) is calculated, based on the
nature of the process and the properties of the Process
materials. The larger value of the F&EI, the more hazardous
the process.
5.6.1 Objectives of dow fire and explosion index
Quantify:
The expected damage potential due to fire & explosion
incidents in realistic terms.
Identify:
Equipment that is likely to contribute tothe creation or
escalation of an incident.
Communicate:
The fire & explosion potential, to design teams and also the
Plant personnel,
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© Itis tailored for the storage, handling, and Processing
of explosive and flammable material in the chemical
rocess industry. ;
a a systematic approach based on the rating form,
Suitable to be used at an early stage of a project and for
auditing the existing plant. :
© The final rating number (ie Fé&EI) provides a relative
ranking of hazards. :
© It is also used for estimating damage radius (using
Dow correlation) and estimate the financial loss in the
event of an accident (using consequence analysis
form).
5.6.2 Assessment of hazard
Fire and explosion Degree of hazard
| __indexrange |
1-60 Light
61-96 Moderate
97-127 Intermediate
128-158 Heavy
>159 Severe
To assess the potential hazard of a new plant, the index can be
calculated after the Piping and Instrumentation and
equipment layout diagrams have been prepared. In earlier
versions of the guide, the index was then used to determine
what preventative and protection measures were needed. In
the current version, the preventative and protection measures
that have been incorporated in the plant design to reduce the
hazard-are taken into account when assessing the potential
loss: in the form of loss control credit factors.
5.6.3 Calculation of the Dow F & EI
The procedure for calculating the index and the potential loss
is set out. The first step is to identify the units that would have
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The basis of the F & Elis a Material Factor (MF). The MF is then
multiplied by a Unit Hazard Factor, F3 to determine the F & El
for the process unit, The Unit Hazard factor is the product of
two factors which take account of the hazards inherent in the
t the general and special
operation of the Particular process uni
process hazards,
Material factor
The material factor is a measure of the intrinsic rate of energy
Telease from the burning explosion or other chemical reaction
of the material. Values for the MF for over 300 of the most
“ommonly used substances are given in the guide. The guide
SO includes a procedure for calculating the MF for substances
MSpace ar Module 5
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INDUSTRIAL SAFETY ENGINEERING
not listed from knowledge of the flash point, (for dusts, dust
explosion tests) and a reactivity value, Nr. The reactivity value
is a qualitative description of the reactivity of the substance,
and ranges from 0 for stable substances, to 4 for substances that
are capable of unconfined detonation.
In calculating the F&EI for unit the value for the material with
the highest MF, which is present in significant quantities ig
used.
Table 5.1 Some typical material factors
MF Flash Heat of combustion
point°C Mi/kg
Eee
Acetaldehyde 24 —39 24.4
Acetone 16 -20 28.6
Acetylene 40 gas 48.2
Ammonia 4 gas 18.6
Benzene 16 -ll 40.2
Butane 21 gas 45.8
Chlorine 1 — 0.0
Cyclohexane 16 —20 43.5
Ethyl alcohol 16 13 268
Hysengen 21 gas 1200
Nitroglycerine 40 — 18.2
Sulpiur 4 ee 93
Toluene 16 40 313
Vinyl Chloride 21 gas 18.6
General Process Hazards
The general process hazards are factors that play a primary
role in determining the magnitude of the loss following an
incident
* _ Exothermic chemical reactions: the penalty varies from
0.3 for a mild exotherm, suchas hydrogenation, to 125
for a particularly sensitive exotherm, such as nitration.
5.26 | Page ~ “Module 5
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Endothermic Processes;
reactors only,
Special process hazards
The special process hazards are factors that are known from
experience to contribute to the probal
bility of an incident
involving loss.
Toxic materials: the Presence of toxic substances after
an incident will make. the task of. the emergency
Personnel more difficult, The factor applied ranges
from 0 for non-toxic materials, to 0.8 for substances
that can cause death after short exposure.
Sub-atmospheric pressure: allows for the hazard of air
leakage into equipment. It is only applied for pressure
less than 500 mmHg (9.5 bar).
Operation in or near flammable range: cover for the
Possibility of air mixing with material in equipment or
Storage tanks, under conditions where the mixture will
be within the explosive range.
Dust explosion: covers for the possibility of a dust
explosion. The degree of risk is largely determined by
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the particle size. The penalty factor varies from 0.25 for
particles above 175 pm, to 2.0 for particles below 75
pm.
Relief pressure: this penalty accounts for the effect of
pressure on the rate of leakage, should be a leak occur,
Equipment design and operation: becomes More
critical as the operating pressure is increased. The
factor to apply depends on the relief device setting and
the physical nature of the process material.
Low temperature: this factor allows for the Possibility
of brittle fracture occurring in carbon steel, or other
metals, at low temperature.
Quantity of flammable material: the potential loss will
be greater the quantity of hazardous material in the
Process or in storage. The factor to apply depends on
the physical state and hazardous nature of the Process
material, and the quantity of material.
Corrosion and erosion: despite good design and
materials ‘selection, some corrosion problems. may
arise, both internally and externally. The factor to be
applied depends on the anticipated corrosion rate.
Leakage-joints and packing: this factor accounts for
the possibility of leakage from gaskets. Pump and
other shaft seals and packed glands. The factor varies
from 0.1 where there is the Possibility of minor leaks,
to 1.5 for process that have slight:glasses, bellows or
other expansion joints,
Use of fired heaters; the presence of boilers or furnaces,
heated by the combustion of fuels, increases the
Probability of ignition should: a leak of flammable
Material occur froma Process. unit. The risk involved
will depend on the sitting of the fired equipment and
the flash Point of the process material.
Hot oil heat exchange’ system: most special heat
exchange fluids are flammable and are often used
age “Module 5INDUSTRIAL SAFETY ENGINEERING
above their flash Points; so their use in a unit increases
the risk of fire or explosion. The factor to apply
depends on the quantity and whether the fluid is
above or below its flash Point.
¢ Rotating equipment: this factor accounts for the
hazard arising from the use of large pieces of rotating
equipment: compressors, centrifuges, and some
mixers,
5.6.4 Basic preventative and protective measure
The basic safety and fire Protective measures that should be
included in all chemical Process design are listed below. This
list is bases on that given in the Dow Guide, with some minor
amendments.
a) Adequate, and Secure, water supplies for fire fighting.
b) Correct structural design of vessels, piping, steel work.
c) Pressure-relief devices.
d) Corrosion-resistant materials and adequate corrosion
allowances. :
e) Segregation of reactive materials,
f) Earthing of electrical equipment.
g) Safe location of auxiliary electrical equipment,
transformers, switches gear.
h) Provision of back-up utility supplies and services,
i) Compliance with national codes and standards.
j) Fail-safe instrumentation.
k) Provision for access of emergency vehicles and the
evacuation of personnel.
}) Adequate drainage for spills and fire-fighting water.
m) Insulation of hot surfaces.
n) No glass equipment used for flammable or hazardous
materials, unless no suitable alternative is available.
0) Adequate separation of hazardous equipment.
P) Protection of pipe racks and cable trays from fire.
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q) Provision of block valves on lines to main processing
areas.
rt) Protection of fired equipment (heaters, furnaces)
against accidental explosion and fire.
s) Safe design and location of control rooms.
5.6.5 Simplified procedure for calculating Dow F&EI
5.7. PRELIMINARY HAZARD ANALYSIS
The Preliminary Hazard Analysis (PHA) is usually the first
attempt in the system safety process to identify and categorize
hazards or potential hazards associated with the operation of
a proposed system, process, or procedure. The PHA may be
preceded with the preparation of a Preliminary Hazard List
(PHL). It provides rationale for hazard control and indicates
the need for more detailed analyses, such as the Subsystem
Hazard Analysis (SSHA) and the System Hazard Analysis
(SHA). The PHA is usually developed using the system safety
techniques known as Failure Modes and Effects Analysis
(FMEA) and/or the Energy Trace and Barrier Analysis (ETBA).
PHA development can be somewhat simplified through the
use of a Preliminary Hazard Matrix identifying a Generic
Hazard Group. The PHA Report can be generated based upon
the evaluation and analysis of system hazard risk.
Preliminary hazard analysis (PHA) is a semi-quantitative
analysis performed with the intention of identifying
5.30|Page Module 5INDUSTRIAL SAFETY ENGINEERING
potential hazards and accidental events that can cause an
industrial accident.
— 2 aces tanks the identified accidental events
acct 0 their severity and pro
follow-up actions. Proposes hazard controls and
There are several formats of Preliminary hazard analysis that
can be used under different names, such as Rapid Risk Rankin
and Hazard Identification (HAZID). PHA should be toe
out in the early stages of a Project and continue throughout the
system or product's life cycle to identify those accidental _
events that should be subject to a more-detailed risk analysis,
As a broad, initial study, the preliminary hazard analysis
focuses on identifying immediate hazards, assessing the
severity of potential accidents that could occur because of these
hazards, and identifying safeguards for reducing the risks
associated with the hazards. By identifying weaknesses early
in the life of a system, PHA aims to save time and money that
might be required for major redesign if the hazards were
discovered at a later date.
Characteristics Of PHA
It relies on brainstorming and expert judgment to
assess the significance of hazards and assign a ranking
to each situation.
It is typically performed by one or two people who are
knowledgeable about the type of activity in question.
¢ Itis applicable to any activity or system
It can be used as a high-level analysis early in the life
of a process.
It is used to generates qualitative descriptions of the
hazards related to a process. Provides a qualitative
ranking of the hazardous situations; this ranking can
be used to prioritize recommendations for reducing or
Module 5
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eliminating hazards in subsequent phases of the life
cycle. :
© Quality of the evaluation depends on the quality and
availability of documentation, the training of the
review team leader with respect to the various analysis
techniques employed, and the experience of the
review teams.
Advantages and Disadvantages Of PHA
Advantages
¢ Helps ensure that the system is safe
¢ Modifications are less expensive and easier to
implement in
¢ the earlier stages of design
¢ Decreases design time by reducing the number of
surprises
Disadvantages
¢ Hazards must be foreseen by the analysts
* The effects of interactions between hazards are not
easily recognized
5.7.1 Procedure for Preliminary Hazard Analysis
The procedure for conducting a preliminary hazard analysis
consists of the following steps. Each step is further explained
on the following pages.
1. Define the activity or system of interest. Specify and clearly
define the boundaries of the activity or system for which
Preliminary hazard information is needed.
2. Define the accident categories of interest and the accident
Severity categories. Specify the problems of interest that the
risk assessment will address (e.g,, health and safety concerns,
environmental issues). Specify the accident severity categories
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that will be used to priorit
oon Prioritize resources for risk reduction
3. Conduct review. Identif i
E fy the major hazard: ssoci:
accidents that could result in undesirable een rc
5. ,
identify design criteria or alternat;
a dace ts dulce Tnatives that could eliminate or
4, Use the results in decision ii
making. E i
assessment recommendations and the. pitas hee on
: . . ley are
intended to achieve (e.g., improved safety and Satter tal
performance, cost savings). 9
Determine implementation criteria and plans.
1. Define the activity or system of interest
Intended functions. Because all risk assessments are
concerned with ways in which a system can fail to perform an
intended function, clearly defining these intended functions is
an important first step in any risk assessment. This step does
not have to be formally documented for most preliminary risk
assessments.
Boundaries. Few activities or systems operate in isolation.
Most interact with or are connected to other. activities or
systems. By clearly defining the boundaries of anactivity or
system, especially boundaries with support systems such as
electric power and compressed air, the analysis can avoid (1)
overlooking key elements of an activity or system at interfaces
and (2) penalizing an activity or system by associating other
equipment with the subject of the study.
Example:
Functions of interest
* Safe handling and use of fuel oil for an LNG cargo ship
dull 5INDUSTRIAL SAFETY ENGINEERING
* Safe handling and use of LNG car;
go for an LNG Cargo
ship
Boundaries
¢ Include only shipboard systems or Operations
2. Define the accident cate
gories of interest and the accident
severity categories
Accident categories
The following Paragray
hs describe three o
types of accidents of
f the most common
interest in a PHA:
Person Overboard
Exposure to high temperatures (eg., through
steam leaks)
Fires or explosions
Environmental issues. The tisk assessment team Tay look for
Ways in which the Conduct of a Particular activity or the failure
of system can damage the environment, se environmental
issues may be caused by many mechanisms, including the
following:
the water, either intentional
or unintentional
Equipment failures (e.g,
Material spill
Disruption of
ira the €cosystem through over utilization
of'a marine area
» Seal failures) that result ina
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These economic risks may
including the following:
¢ Business risks such as contra:
revenue, etc.
¢ Environmental Testoration costs
¢ Replacement costs for damaged equipment
ctual penalties, lost
Some risk assessments may focus only on events above a
certain threshold of concern in one or more of these categories
Accident severity categories
During a PHA, a team assesses the severity of the various
accidents that can occur with each of the hazards. Establishing
severity categories with definitive boundaries allows the team
to assess each accident against a consistent measure of severity.
It- thus provides the framework — for Prioritizing
recommendations for risk reduction alternatives.
3. Conduct review
Performing a PHA identifies major hazards and accident
situations that could result in losses. However, the PHA
should also identify design criteria or alternatives that could
eliminate or reduce those hazards. Obviously, some experience
is required in making such judgments. 'The team performing
the PHA should consider the following factors:
¢ Hazardous vessel equipment and ‘materials, such as
fuels, highly reactive chemicals, toxic substances,
explosives, high pressure! systems, and other energy
storage systems
* Safety-related interfaces between equipment and
materials, such as material interactions, fire or
535|Page Mod ule 5STRIAL SAFETY. ENGINEERING
losion initiation and propa}
INDU!
gation, and control or
expl
shutdown systems !
«Environmental factors that may influence the vessel or
facility equipment and materials, such as vibration,
flooding, extreme temperatures, electrostatic
discharge, and humidity
ting, maintenance, and emergency
dures, such as human error potential, crew
functions to be accomplished, equipment layout and
accessibility, and personnel safety protection
Vessel support, such as storage, equipment testing,
training, and utilities
« Safety-related equipment, such as mitigating systems,
redundancy, fire suppression, and personal protective
equipment.
4, Use the results in decision making
Judge acceptability. Decide whether the estimated
performance for the activity or system meets an established
goal or requirement. _- -
Identify improvement opportunities. Identify the elements of
the activity or system that are most likely to contribute to
future problems. These are the items with the largest
percentage contributions to the identified risks.
Make recommendations for improvements. Develop specific
suggestions for improving future activity or system
performance, including any of the following:
¢ Equipment modifications
«Procedural changes
. Administrative policy. changes, such as planned
maintenance tasks or personnel training
rity allotation of resources for improvements. Estimate
how implementation of expensive or controversial
pat eiage: “wodule 5
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SAFETY
recommendations for ENGINEERING
improve, ‘i
performance, Compare the econo will affect future
recom vaments to the total life-cycle ic benefits of these
recommendation, “osts of implementing each
5.88 HAZARD AND OPE
(H AZOP) RABILITY STUDY
AHAZOP isa systematic assessment tool used to identi id
address potential hazards in industrial Processes a
incident occurs that could affect the Safety of people or aus
while hindering Productivity. HAZOP studies are typically
performed while new facilities are being designed and
constructed, when new processes are added or when processes
change. Most regulatory agencies also Tequire periodic
HAZOP studies on existing processes.
The HAZOP assessment is typically performed by a small team
that breaks each step of a process. down for individual review
to identify potential deviations from the original process
design. Like all PHAs, HAZOPs go beyond the review of how
a process is ‘supposed to operate in order. to identify
unintended outcomes and explore their potential ripple effects
on health and safety.
58.1 The HAZOP Study Process
A Hazard and Operability Study systematically ria
each element “in a process. The goal is to find Eee
Situations that would cause that element to pose a hazar
ee ee ee Se ee 5
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limit the operability of the process aS a whole. There are four
basic steps to the process:
1, Forming a HAZOP team
2, Identifying the elements of the system
3. Considering possible variations in operating
parameters
4, Identifying any hazards or failure points
Once the four steps have been completed, the resulting
information can lead to improvements in the system, such as
adding caution signs or traffic signs. The best way to apply the
results of a HAZOP study will depend on the.nature of the
system.
1. Form a HAZOP Team
To perform a HAZOP, a team of
People with a variety. of ex
maintenance, instrumentation,
workers is formed, including
pertise such as: operations,
engineering/ process ‘design;
ded. These should not be
perience, knowledge, and an
5.38| PageINDUSTRIAL SAFETY ENGINEERING
2. Identify Each Element and its Paramet
eters
The HAZO} i
e : i team will then create a plan for the complet k
proc SS, i lentifying the individual ste ent Th
typically involves using the Piping and vine clement ae
(P&ID), or a plant model, as a guide for ment diagrams
— and component of a Process. For each coast eee
wae. & ei 2: ‘ement,
bie Sere - planned operating parameters wien ste
al Point: flow rate, Pressure, temperatu: ibrati aad
Bit Te, vibration, and
3. Consider the Effects of Variation
For each parameter, the team considers the effects of deviati
from normal. For example, “What would happen if fe
pressure at this valve was too high? What if the oie Wi ‘
unexpectedly low? Would the rate of change in pressure (det,
p) pose its own problems here?” Don’t forget to consider the
ways that each element interacts with others over time; for
example, “What would happen if the valve was opened too
early, or too late?”
4, Identify Hazards and Failure Points
Where the result of a variation would be a danger to workers
or to the production process, we've found a potential problem.
Document this concern, and estimate the impact of a failure at
that point. Then, determine the ‘likelihood of that failure; is
there a real cause for the harmful variation? Evaluate the
existing safeguards and protection systems, and evaluate their
ability to handle the deviations that we've considered.
5.8.2 Results of a HAZOP Study
Because HAZOP is a mental exercise, it can be implemented as
Part of the planning of a new work process, even before a
feclity is built. Existing facilities and processes can also be
“sessed with HAZOP.
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; in the planning stage of a
OP ety ‘neane that all potential
il re wl be identified. The HAZOP team will write
causes of fail nt weighing the potential deviations, their
an soerences, theit causes, and the protection requirements,
aan Ea changes to the plan can be made to prevent
a ek irom arising, or to mitigate their effects.
P
Where a HAZ!
new process,
‘liti be ongoing, working to
isting facilities, a HAZOP may me
i Laue process without any specific end date. Instead of
an le, large assessment, the study's results will be released
‘ a Sear of action items, as each problem is identified and a
solution is created.
In both cases, when a hazardous condition is identified,
recommendations may be made for process or system
modifications, or further study by a specialist may be Tequired.
AHAZOP study might recommend these typical actions:
¢ A review of existing protection system designs bya
specialist
Adding or modifying alarms that warn of deviations
Adding or modifying relief systems
Adding or modifying ventilation systems
Increasing sampling and testing frequency
5.9 CONTROL OF CHEMICAL HAZARDS
A chemical hazard is any
substance, regardless of its form—
that can potentially
cause physical and health hazards to
People, or can result in harm to the environment. It can also be
defined as the actual risk associated with specific chemicals,
such as skin burns, long-term Negative impact to health, lasting
environmental damage, fires, or even explosions.
WPlP age eats BeeINDUSTRIAL SAFETY ENGINEERING
5.9.1 Types of Chemical Hazards
recor
5 % as
Flame Over Circle Ee)
o]1 6] 6 |
ee eee a
Health hazard - This symbol shows a person with damage
and pertains to. chemicals that can cause serious and long-term
negative’ impacts on health. Carcinogens are also substances.
that are known to be cancer-causing chemicals. They are
categorized as either natural or manmade, but it is crucial to
note that even’ a’ sinall amount of this’ type of chemical can
severely damage human health.
ACLs ey
Flammable - The symbol for this is a flame and it pertains
to chemicals or highly flammable gases that may catch fire or
ignite once exposed to air or other ignition sources or elements.
lrritant/hazardous/hazardous to the ozone layer - ae
symbolized by a big exclamation point and refers to chemicals
that usually cause redness, rashes, or inflammation 2 Ae
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INDUSTRIAL SAFETY ENGINEERING
affected area. Although the presence of symptoms is normally
short-term, there are still instances where they. create long-
lasting effects on others. It is also known to either catise harm
to individuals or pose a threat to public health by harming the
ozone layer.
Gas under pressure - The symbol for this is a gas cylinder
and it pertains to gases that are stored under pressure and may
explode if heated or refrigerated gases that may cause burns or
injury.
Corrosion - This pictogram shows corrosion of material and
skin. It refers to chemicals that can cause severe skin burns and
damage to the tissue once contacted with.
Explosives - This is symbolized by an exploding bomb and
pertains to chemicals that may explode or can cause a mass
explosion.
Oxidizers - This pictogram shows a flame over a circle and
symbolizes chemicals or substances that, under certain
conditions or exposure to other chemicals or elements, can
cause severe physical hazards such as fires or explosions.
Hazardous to the environment = The symbol for this is a
dead tree and fish. It refers to chemicals that can cause lasting
damage to the environment.
Toxic - This pictogram shows a skull and crossbones, and
symbolizes chemicals that even at a very low exposure—can
cause irreversible changes or mutations toa person’s DNA,
damage to health, or even fatality.
5.9.2 Controlling Chemical Hazards
Once the hazards involved in the handling and use of
chemicals are identified, the next stage is to put control
measures in place. This includes,
542|Page “Module 5
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¢ Elimination- Opti :
altogether, > "S Which get rid of the hazard
¢ Substitution- Replaci
Ng a hi ¢ 5
less hazardous One wheter ae chemical with a
ie.
¢ Engineering Controls- Fp,
- Fu
ventilation, etc. me Hoods, local exhaust
e Administrative control-
Procedures (SOP), caution
e Personal Protective eq
glasses, hand gloves, etc,
: Standard Operating
Signages, etc,
uipment- Lab Coats, safety
1. Elimination
The risk control measure that has the greatest level of
effectiveness is elimination. Before any other control measures
are considered, elimination must be applied first. Elimination
is the method of totally Temoving a hazard or hazardous
practice from the workplace. Some examples of eliminating the
use of a hazardous chemical in the workplace include:
¢ Eliminating the use of chemical adhesive by using
fasteners such as screws or nails.
¢ Eliminating the use of flammable- forklift gas by using
electric power forklifts instead of LPG powered forklifts.
2. Substitution
If we can’t successfully eliminate the use of a hazardous
chemical in our business, we must then try to substitute it.
Substitution is when we replace the use of a hazardous
chemical with another chemical that is less hazardous and
Presents a lower level of risk.
Sometimes, substitution can be hard to achieve because the
dangerous properties of hazardous chemicals are often we
makes them very effective in manufacturing and chemic:
Processes,5.44| Page
INDUSTRIAL SAFETY ENGINEERING
3. Isolation
If it’s not possible to substitute the use of a hazardous
with another chemical that is less hazardous,
isolate the hazardous chemical from peo]
incompatible substances.
chemical]
we must then
ple and other
This can be done in a number of ways, for example: If one Part
of a manufacturing process involves the use of a hazardous
chemical, we could build a ventilated enclosure over this Part
of the manufacturing process. This enclosure would stop the
airborne contaminants from this area moving into other areas
of the manufacturing facility where people are present, The
airborne contaminants that are generated inside this enclosure
should be vented to the outside atmosphere in a safe location
where people don’t congregate.
If large quantities of hazardous chemicals are stored in the
workplace, we could isolate these hazardous chemicals from
people by storing them outdoors in a compliant chemical
storage container. Isolating hazardous chemicals from people
by storing them outdoors reduces the risk of harm to People in
the event of a workplace fire or chemical spill. 2
4. Engineering Controls.
If isolation cannot be achieved, you can im,
engineering controls to reduce the
hazardous chemicals.
plement a range of
tisk associated - with
Engineering controls are: physical in nature. They are’ devices
or processes that eliminate exposure to hazardous chemicals.
Engineering controls can be used to:
* Minimise the generation of hazardous chemicals
Suppress or contain chemicals —
Limit the area of contamination in the event of spills
“Module. 5INDUSTRIAL SAFETY ENGINEERING
Engineering controls can incl
chemicals.
5. Administrative Controls
If there is still a chemical risk price hi
e hii
implemented, then you must ree ee controls are
developing administrative contro} nee sthig by
Administrative controls aren’t as effective as oth
because they don’t control the hazard at i ae
Administrative controls rely on human teligviour “a nd
supervision, therefore, they aren't as consistent or reliable as
other controls.
Administrative controls are generally written Policies and
procedures that outline the best work Practices to minimise
exposure to hazardous chemicals.
These policies can include things such as:
e Reducing the number of people exposed to hazardous
chemicals :
e Reducing the duration and frequency of exposure to
hazardous chemicals
e Reducing the quantity of hazardous chemicals kept on
site through inventory reduction methods such as just
in time supply. -
6. Personal Protective Equipment
Personal protective equipment (PPE) should not be relied on
to control risk.
Instead; PPE should only be used as a last resort when other
more effective control measures have been used and the
has not been eliminated.
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PPE can also be used as interim protection until higher level
controls are fully implemented. PPE is also a useful way to
gher level controls when carrying out high-risk
brasive blasting.
supplement hi
work such as spray-painting and al
Some examples of PPE can include:
e Chemical resistant glasses
e Face shields
e Chemical resistant gloves
e Protective clothing
e Shoe covers
e Respiratory equipment
5.10 HAZARDOUS PROPERTIES OF CHEMICALS
Chemical substances that have the ability to create a physical
or health hazard are considered hazardous. Due to their
properties chemical hazardous substances may be, but are not
limited to being toxic, explosive, flammable, self-reactive,
oxidizing, or corrosive. Exposure to these substances by
different routes including inhalation, dermal absorption, or
ingestion can lead to adverse health effects, enhancing the need
to know about the hazards associated to these substances
beforehand.
5.10.1 Toxic
A toxic substance is a substance that can be poisonous or cause
health effects. Chemicals can be toxic because they can harm us
when they enter or contact the body. Exposure.to a toxic
substance such as gasoline can affect your health. Since
drinking gasoline can cause burns, vomiting, diarrhea and, in
very large amounts, drowsiness or death, it is toxic. Some
chemicals are hazardous because of their physical properties:
they can explode, burn or react easily with other chemicals.
Since gasoline can burn and its vapors can explode, gasoline is
also hazardous. A chemical can be toxic, or hazardous, or both.
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5.10.2 Explosive
Explosive, any substance 0; i
produce a volume of rapidly expendi can be made to
brief period. Basically, chemical explosives iS io an extremely
detonating, or high, explosives and (2) det ° two types: (1)
explosives. Detonating explosives, such as Nene or low,
are characterized by extremely rapid deco rand dynamite,
development of high pressure, whereas pastion and
explosives, such as black and smokeless led agrating
merely fast burning and produce telatively low priwiaee’
5.10.3 Flammable
Flammability is the ability of a chemical to burn or ignite
causing fire or combustion. The degree of difficulty required 6
cause the combustion of a chemical is quantified through fire
testing.
5.10.4 Self-reactive
Self-reactive chemicals are thermally unstable liquid or solid
chemicals that can undergo exothermic decomposition
without interacting with oxygen.
Self-reactive chemicals can start decomposing due to:
e. Heat
¢ Contact with acids
¢ Contact with heavy metal compounds
¢ Contact with bases
¢ Friction
¢ Impact
5.10.5 Oxidizing
Oxidizing chemicals ‘aré materials that spontaneously evolve
oxygen at room temperature or with slight heating or promote
Combustion: This class of chemicals includes:
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© Peroxides ¢ Nitrates
© Chlorates °
e Perchlorates
Strong oxidizers are capable of forming ex;
when mixed with combustible,
materials.
Permanganates
plosive mixtures
organic or easily Oxidized
5.10.6 Corrosive
Corrosive chemicals are defined as chemicals that can cause
damage to body tissues. These chemicals can be dangerous ig
they come into contact with user’s skin, tissues, eyes, and body
Parts. Corrosive materials can irritate eyes, burn skin, irritate
and burn the inner lining of the nose and throat if inhaled, and
have other Negative effects if users are not careful when
' handling these chemicals,
:
°
3
Me
3
2
a
A
z
hydroxide, Potassium hy
examples of bases.
5.11
droxide, and sodium hydroxide are
MATERIAL SAFETY DATA SHEETS
(MSDs)
A Material Safety Data Sheet (MSDs) is a document that
contains information on the potential hazards (health, fire,
Teactivity and environment;
al) and how-to work safely with the
Storage, handling -and
S all related to the hazards of the
are prepared by the supplier
OF manufacturer of the material. It is i the
hazards of the Prod mie
uct are, how t hat
to expect ifthe a ‘0. use the product safely, wl
tions are not followed, what to do
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if accidents occur, how to
Tecognize sym,
overexposure, and what to do if such incidents eet
occur.
The purpose of a safety data sheet is to a
a ct a: i
for safely storing, handling, and baieictae ae reference
product. ig the chemical
The specific contents of the document y; lependi
d ri
nature of the substance and the arinrara Tt will, te eae
typically include the following information: : age
¢ Product Information: product identifier (name),
manufacturer and suppliers names, addresses, and
emergency phone numbers :
e Hazardous Ingredients
e Physical Data
e. Fire or Explosion Hazard Data
¢ Reactivity Data: information on the chemical
instability of a product and the substances it Tay react
with
e Toxicological Properties: health effects
e Preventive Measures
e First Aid Measures
e — Preparation Information:- who is responsible for
preparation and date of preparation of MSDS
Employers and employees need the information contained on
MSDSs to protect themselves from hazardous chemical
exposures and to work safely with chemical products. The
result will be a reduction in chemical source illness and injuries
in the workplace. Since the HCS became effective, the use and
distribution of MSDSs have proven to. be.an effective and
efficient way to ensure that employers and employees can
obtain necessary information on the hazards associated with
€xposure to chemicals in the workplace.
oe. Module 5