1. 1

2. Confined Space Safety out Line
Course objective :
contains the requirements for practices and procedures to protect employees in general industry
from the hazards of entry into permit-required confined spaces (i.e., permit spaces). The
standard requires employers to develop a written confined space entry permit program and
provide employee training.
WHO SHOULD TAKE THIS CLASS?
Employees who may enter confined spaces with potential hazards are required to receive
confined space safety training.
Result Expecting after completing this training course students will be able to:
• Identify the hazards commonly found in confined spaces, including atmospheric
hazards and physical hazards.
• Identify the roles and responsibilities of the Entrant and Attendant as defined by OSHA
for various personnel during confined space operations.
• Understand the use and need for a confined space permit.
• Understand basic emergency activities during a confined space emergency, including
the hierarchy of rescue.
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3. Index table
Contents Page No.
Suction one ( theoretical ) 5
1.0 Confined Space Overview 6
2.0 Hazards and Risk Factors 7
2.1 Hazard Categories 8
2.2 Risk Factors 9
3.0 Flammable Atmospheres 16
3.1 Causes 16
3.2 Chemical Toxicology Overview 18
3.3 Toxic Atmospheres 21
4.0 Hazards 23
4.1 Physical Hazards 23
4.2 Mechanical Hazards 23
4.3 Importance of Safe Work Procedures & Training 23
4.4 Importance Creating a Confined Spaces Entry Program 24
5.0 Risk Assessment & Management 28
5.1 Ensure Risks Are Known & Control Measures Are Followed 30
5.2 Importance of a Full Assessment 30
5.3 Training 31
5.4 Isolation 32
5.5 Lock-Out Energy Sources 33
5.6 Exposure to Product and Hazardous Substances 33
5.7 Clear or Neutralize Hazardous Substances 34
5.8 Physical Hazards 34
5.9 Climatic Factors 35
5.10 Electrical Hazards 35
5.11 Access and Egress 35
5.12 Hazardous Atmospheres 38
6.0 Emergency Procedures 42
6.1 What To Do When Work Ceases 43
7.0 Permit To Work 43
7.1 Steps of A Permit System 43
7.2 Advantages of Permits To Work 44
7.3 Usage 44
8.0 Job Hazard Analysis (JHA) 49
8.1 Analysis 49
8.2 Preventive Measures 50
9.0 Hazards Evaluation 51
9.1 Selecting Hazard Evaluation Techniques
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4. 4

5. Day 1
Saturday 18 Sep. 2010
5

6. Suction (A)
Understanding
The confined space
Theoretical
Process
CONFINED SPACE
1. OVERVIEW
Confined spaces may be encountered in virtually any occupation; therefore, their
recognition is the first step in preventing fatalities. Since deaths in confined spaces
often occur because the atmosphere is oxygen deficient or toxic, confined spaces
should be tested prior to entry and continually monitored.
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7. Many workplaces contain spaces that are considered "confined" because their
configurations hinder the activities of any employees who must enter, work in, and exit
them. For example, employees who work in process vessels generally must squeeze
in and out through narrow openings and perform their tasks while cramped or
contorted. The term "confined space" is used to describe such spaces. In addition,
there are many instances where employees who work in confined spaces face
increased risk of exposure to serious hazards. In some cases, confinement itself
poses entrapment hazards. In other cases, confined space work keeps employees
closer to hazards, such as asphyxiating atmospheres or the moving parts of
machinery. The term "permit-required confined space" (permit space) is used to
describe those spaces that both meet the definition of "confined space" and pose
health or safety hazards.
A Broad Definition
The various definitions of a Confined Space as cited in standards, codes and
regulations may differ slightly but basically they refer to:
Enclosed or semi enclosed areas where access and egress may be restricted and/or
hazardous conditions may occur while workers are engaged inside.
Some definitions also include the following provisions:
• Space of a size to enable a person to enter the space and perform assigned
work; and
• Space not designed for continuous occupation.
HAZARD
In relation to a person, means anything that may result in injury to the person or harm
to the health of the person.
RISK
In relation to any injury or harm, means the probability of that injury or harm occurring.
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8. What Makes Confined Spaces Hazardous?
A confined space by its definition is an enclosed space or enclosure. This creates
hazards through reduced air circulation and ventilation. This provides the opportunity
for local concentrations of hazardous or flammable substances to increase to unsafe
levels and/or for oxygen levels to decrease to unsafe levels.
A confined space is defined in terms of the limited means of entry and exit. This refers
to situations where rapid escape, especially rapid egress or where disabled or
impaired persons are involved, may be impeded. These limitations may be due to:
• The design of the space (e.g., such as a valve inspection pit where a ladder is
required for entry/exit); and
• The size, shape and location of the means of entry and exit (e.g., a 1 meter
diameter hole at the base of a tank).
These design factors may not necessarily be hazardous in themselves (i.e. they do not
directly cause injury/disease) but they do have the effect of increasing the risk of
serious injury resulting as a consequence of exposure to a hazard. This would include
situations where:
• Rapid escape is not possible (e.g., employee working at the bottom of a storage
tank. The tank has not been isolated and fills rapidly with water. The employee
is not able to reach the access ladder in time); and
• Rescue is impeded.
Examples of Confined Spaces
Some examples of confined spaces include manholes, sewers, boilers, tunnels, pipelines, wells,
fuel tanks, ballast tanks, storage tanks, tank cars and tank trucks, vats, process vessels, septic
tanks, sewage lift stations, vaults, silos, bins, and ventilation and exhaust ducts. Some of these
are easily recognized as confined spaces, while others may not be generally considered as such.
For example, deep empty swimming pools, deep trenches, deep open top tanks, pits and roof
spaces.
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9. 2. HAZARDS AND RISK FACTORS
Distinction Between Hazards And Risk Factors
A distinction may be made between the hazards in a confined space (for example,
those conditions, substances and materials which are capable of causing death, injury
or harm to health) and those elements which effect the risk of death, injury or harm to
health. These elements are commonly referred to as "risk factors". Oxygen
deficiency, for example, can be considered to be a hazard in a storage tank. The
presence of decaying organic matter using the same situation could be considered to
be a risk factor as it would increase the likelihood of oxygen deficiency taking place.
2.1 Hazard Categories
9

10. The types of hazards involved have been grouped into the four categories below.
There is, of course, considerable scope for overlap. Carbon monoxide, for example, is
both highly flammable and highly toxic. Such hazards are discussed however, in the
context in which they pose the greatest risk. Carbon monoxide therefore, is primarily
considered to be a hazardous substance, being highly toxic. It will burn at
concentrations above 12.5 % but will cause death within minutes at concentrations
above 1.28 %.
1. Oxygen Deficiency
Oxygen deficiency is a common cause of death in confined spaces. This can occur
through the dilution of oxygen levels due to the presence or introduction of other gases
or by chemical reactions which absorb the oxygen within the confined space.
2. Flammable Atmospheres
The small spaces involved and lack of ventilation, can lead to concentrations of
flammable substances (i.e. dusts, mist, gases) increasing to hazardous levels. The
substances involved can include:
• residual material within the space (e.g., fuel and solvents);
• by-products of chemical reactions (e.g., strong bases such as caustic soda
react with metals such as aluminum, chromium and zinc to produce hydrogen
gas); and
• solvents used in the cleaning of the space (e.g., alcohols and toluene) and
contaminants leaking into the space (e.g. LPG or Propane).
3. Hazardous Substances
The small spaces involved and lack of ventilation can lead to concentrations of
hazardous substances increasing to life threatening levels. The substances primarily
involve residual materials within the space and substances used in work processes
(e.g., solvents).
4. Physical and Mechanical Hazards.
Confined spaces such as chemical tank trucks, process furnaces, and industrial
boilers may be of irregular shapes and divided into smaller sections by walls, tubes,
and baffle plates. They may house both fixed and portable equipment including
stirrers, mixers and agitators. Lifelines may also be severed on projections or tangled
up on interior obstacles like conduits, cable hangers and mechanical fittings. The task
of assessing these convoluted spaces for atmospheric hazards is much more difficult
since toxic gases and vapors may become trapped in hard-to-reach pockets.
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11. 2.2 Risk Factors
The above hazards, and their associated risk factors, are fully discussed below. The
risk factors involved in confined spaces are discussed in terms of:
• nature of the contents of the space;
• by-products of chemical reactions involving substances within the space;
• work that is performed within the space;
• leakage from any conduits that run through the space; and
• introduction of contaminants (below ground tanks).
Day 2
Sunday 19 Sep. 2010
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12. 2.2.1 Oxygen Deficiency
Physiology of Respiration
The human body is a biological engine in which the lungs act as both an air intake and
exhaust. When air is drawn into the lungs, oxygen passes from the alveoli (the air sacs
within the lungs where gas transfer occurs) into the bloodstream and carbon dioxide
passes from the bloodstream into the alveoli. This process of gas transfer is known as
diffusion.
Diffusion operates on the principle that a gas will move from an area of high
concentration to one of low concentration until equilibrium is established (i.e. the
concentration is equal in both areas). When air is drawn into the lungs the
concentration of oxygen in the air is higher within alveoli than in the capillaries that
flow around them. Oxygen then passes from the alveoli into the blood. Conversely, the
concentration of carbon dioxide in the blood is higher than in the air. Carbon dioxide
then passes from the blood into the alveoli. During exhalation the carbon dioxide is
then expelled.
12

13. Inadequate amount of Oxygen can
lead to simple asphyxiation and death
The amount of oxygen carried by the blood depends primarily upon the concentration
of oxygen within the inhaled air. This is shown by the graph below.
As the airborne concentration of oxygen decreases, the amount carried by the blood
initially shows only a gradual decrease. When the airborne oxygen concentration is
10.5 % (i.e. 50 % of normal), the blood is still carrying approximately 85 % of its
normal level. However, when the airborne concentration falls below 8.4 %, there is a
marked decrease in the amount of oxygen carried. The resultant effect upon the body
is shown in the table below.
Oxygen
Symptoms
Concentration
21 % None (normal oxygen level)
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14. 15 % No immediate effects
14 % Fatigue, impaired judgment
10 % Dizziness, shortness of breath, deeper and more rapid
breathing
7% Stupor (State of unconsciousness) sets in
5% Minimum amount that will support life
2%-3% Death within 1 minute
As the table above indicates, oxygen concentrations down to approximately 16 % can
be tolerated. However, this is at the expense of increased demands upon the
cardiovascular system. An oxygen concentration of 15 % for example, will show no
immediate effects, but the load upon the cardiovascular system is equivalent to a
workload of three kcal/min.
The blood normally holds reserves of oxygen. The blood returning to the lungs (to
release carbon dioxide) still carries over 40 % of the oxygen it held initially. This is why
you can hold your breath for around 3 minutes without adverse effects. Your body is
able to consume this "reserve store" of oxygen. However, if you were to continue to
breathe in an atmosphere containing very low levels of oxygen (where the air drawn
into the alveoli has a lower concentration of oxygen than in the blood flowing around
them), the diffusion process would operate in reverse. With every breath you take, you
would be expelling oxygen instead of absorbing it. Consequently, your "3 minute
reserve" would be depleted extremely rapidly.
These points highlight some of the more insidious aspects of oxygen deficiency
within confined spaces:
• If the oxygen depletion is a gradual one, the initial effects may go unnoticed due
to their gradual onset. When the symptoms reach a noticeable level, impairment
may rapidly follow.
• If a person enters a confined space with extremely low levels of oxygen,
collapse can occur extremely rapidly as the person exhales oxygen.
• If the work performed within the confined space requires less exertion than the
effort required to escape from the space, then by the time the employee
realizes there is a problem, it may be too late.
2.2.2 Causes of Oxygen Deficiency
Processes Involved
14

15. A decrease in the oxygen levels can occur through one or more of the following
processes:
• combustion;
• chemical reaction;
• dilution;
• displacement; and
• adsorption.
a. Combustion
Oxygen may be consumed through activities that involve the use of open flames (e.g.,
welding, torch cutting, brazing) and by, for example, the operation of compressors and
pumps.
An additional hazardous substance hazard may also be created through incomplete
combustion. This may lead to the creation of carbon monoxide as a combustion by-
product. This gas interferes with the blood's ability to transport oxygen and can create
problems even with normal oxygen levels. A Carbon Monoxide level of 0.003% may be
considered unsafe.
b. Chemical Reaction
Relevant chemical reactions include the following:
c. Corrosion
Corrosion is a chemical reaction that involves the conversion of a metal to a metal
oxide. Iron pipe-work, for example, in the presence of moisture and air, will rust and
corrode. In other words, the surface of the iron and the oxygen in the air will combine
to form rust.
d. Fermentation
Fermentation is a reaction usually involving the decomposition of sugars or starches
into alcohol and carbon dioxide. This can occur in fermentation vats for beer or wine
making, or in silos containing grain that may be subjected to moisture or wet
conditions.
e. Decomposition
The breakdown of organic material (either in the space or from contaminants such as
leaves washed into a drain) involves the absorption of oxygen and the production of
15

16. carbon dioxide. Where sulfur containing materials are present (e.g., in sewers)
Hydrogen Sulfide gas (H2S) may also be produced.
f. Dilution
The introduction of other gases into an enclosed space can dilute the oxygen levels.
This can occur through venting from conduits, from the presence of gases used to
purge the space or from leaking gas cylinders.
Example
A faulty valve on a nitrogen purge line is causing
nitrogen to leak into an unused chemical storage
tank (dimensions 2.5 m x 2.0 m x 2.0 m) at the rate
of 0.5 liter per minute.
In very general terms, the oxygen concentration in the tank can be calculated using
the formula:
2,100
% O2= ( --------------------------) x 100
(10,000 + (0.5 x t))
where:
10,000 = total volume of the tank (in liters)
2,100 = volume of Oxygen within the tank (i.e. 21 % of 10,000)
0.5 = rate of leakage (in liters per minute)
t = number of minutes
After approximately 360 hours, the Oxygen level would be at 10%.
After approximately 44 days, the Oxygen level would be 5%.
g. Displacement
Gases that are heavier than oxygen will over time settle at the bottom of the space,
thereby displacing the oxygen within the space. These gases can include residual
contents, chemical by-products (e.g. grain fermentation) or other gases entering the
space. Below-ground spaces are of particular concern in this respect.
h. Adsorption
In some situations, oxygen may bind with the surface of a material within a confined
space. Example of newly constructed water filtration tanks partly filled with a slurry of
activated carbon and water from which the water was drained off and the tanks
16

17. sealed. The following morning two workers entered one of the tanks to smooth out the
carbon bed and adjust the interior sprinkler mechanism. When they did not appear at
lunch time, co-workers went looking for them. Their bodies were found on top of the
carbon bed. Subsequent tests showed that 24 hours after closure, the oxygen levels
had dropped to 12%. Other tanks in the area were checked. Some which had been
closed for several days showed oxygen levels of only 2%.
Investigators discovered that the dry, activated charcoal had no effect on the oxygen
level. However, the damp carbon, which had previously been considered to be a non-
hazardous material, had apparently selectively adsorbed ambient oxygen.
3. FLAMMABLE ATMOSPHERES
LEL AND UEL
All flammable vapors, gases and dusts have a minimum concentration below which
propagation of flame does not occur on contact with a source of ignition. This is known
as the lower flammable explosive limit (LEL). There is also a maximum concentration
of vapor or gas in air above which propagation of flame does not occur. This is known
as the upper explosive limit (UEL). A gas is explosive only between its LEL and UEL.
For example, methane is explosive only when mixed with air in a concentration
between 5% and 15%. Because air is only 21% oxygen, most concentrations are quite
low. Consequently, when mixed with air many of these gases rapidly drop below the
minimum level. In confined spaces however, this dilution may not occur. This can be
due to:
• the small size of the space involved;
• the lack of air flow; and
• the gas concentrating in the bottom of the space (if it is heavier than air) or the
top of the space (if it is lighter than air).
3.1 Causes
Flammable atmospheres can arise in the following situations:
a. Inadequate Venting of Contents
One of the most frequent causes of explosions in confined spaces is inadequate
venting. For example, if a tank that has a capacity of 100,000 liters and has only been
99% vented, this means there is still 1000 liters of the product, for example, petroleum
vapors, which could settle and form an explosive mixture.
b. Cleaning Agents and Solvents Used In Work Processes
Many activities conducted in confined spaces involve cleaning and refurbishing. Such
processes may require spray painting or cleaning by use of solvents, both of which
17

18. can be of a flammable nature. For example, a painter had just finished spraying the
interior of a 21-foot long by 11-foot diameter horizontal tank. He passed a ladder and
portable electric light through the manhole to a second man standing outside. This
employee had just laid the ladder down when he heard a muffled explosion. Turning
towards the tank, he saw flames inside and noticed that the painter's clothes were on
fire. After being pulled out of the tank, the painter explained that he inadvertently
bumped his spray gun on a second lamp inside. When the bulb broke, it ignited the
paint vapors. The painter died in hospital three days later.
c. Chemical Reactions of Materials Within Spaces
Strong bases such as Caustic Soda, react with some metals such as aluminum,
chromium and zinc to produce hydrogen gas.
The toxic effect of a combination of two
chemicals may be far greater than the
sum of the toxic effects of each.
d. Decomposition
Decomposition of organic material has already been noted in the Oxygen Deficiency
section. This can lead to the formation of methane and hydrogen sulfide. If the
confined space contains strong bases or acids, these may react with metals to
produce hydrogen gas. If the space is enclosed at the top, this could lead to the
formation of a pocket of hydrogen. For example, an aluminum ladder placed into a
incompletely empty tank of caustic soda, or hydrochloric acids used as a stripping
agent on iron pipe work.
e. Leakage of Cylinders and Conduits
Leakage of cylinders can occur as a result of the nature of the work being performed in
the space. For example, cylinders containing LPG or propane gas may be used for hot
work and if they have faulty seals, there may be the accidental release of their gases
within the space. Existing conduits and pipes, on the other hand, may leak their
contents due to fatigue or corrosion that has occurred over time.
f. Contaminants
Flammable products such as petroleum and LPG are heavier than air. Consequently
they can flow below ground level confined spaces.
18

19. An example of the above occurred when a sewer contractor, who was installing an
interceptor line, experienced an explosion and fire caused by an accumulation of LPG
in the soil. The LPG had leaked from storage tanks and accumulated on the water
table. As the ground water seeped into the excavation, the LPG accumulated in the
ditch atmosphere, as well as in the open-ended sewer line. A spark from the backhoe
provided the ignition.
g. Elevated Oxygen Levels
Elevated oxygen levels occurring through leaking pipes or cylinders can affect
flammability levels and cause things to combust more readily. As the level of oxygen
increases above 21% the following occurs:
• flammable substances ignite more readily;
• they burn at lower concentrations; and
• they burn more rapidly.
Potential sources may include oxy-acetylene cylinder sets, and where oxygen is
supplied through pipe-work.
3.2 Chemical Toxicology Overview
Dose-Response Relationships
 The toxicity of a chemical is defined by the
amount (dose) of the chemical that will
produce a response. The greater the dose,
the more severe the response will be.
 There is a balance between toxicity and dose;
 Dose is the AMOUNT of something you are
exposed to, or come in contact with;
 The less the toxicity, the greater the dose you
can tolerate without ill effects;
 The greater the toxicity, the less dose you can
tolerate without becoming sick.
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20. High Toxicity - Low Dose
For example, acetone is a highly toxic chemical. However, you could work safely with
it, if you were outside or in a well-ventilated room where your dose would be very low.
As the chart below shows, your hazard potential for working with acetone in a well-
ventilated room would be low.
Low Toxicity - High Dose
Example: Nitrogen gas has a low toxic rating. It is found in great amounts in the air we
breathe. However, if you were in a confined space that had only nitrogen gas in it (a
very high dose), you would soon die because of the lack of oxygen. As the chart
indicates, your hazard potential for working in a room filled with nitrogen would be
high.
Affecting Factors
 The Amount Entering the Body. (D)
 The Length of Time.(D)
 The Rate of Absorption into the Blood.
 The Physical Nature of the Chemical. (T)
 The Chemical Nature of the Chemical. (T)
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21.  The Age of the Individual.
 The Health of the Individual.
Measuring the Toxicity
 PARTS PER MILLION - ppm
 PARTS PER BILLION - ppb
 PARTS PER TRILLION - ppt
 LETHAL DOSE - LD50
 LETHAL CONCENTRATION - LC50
 THRESHOLD LIMIT VALUE - TLV
 IMMEDIATELY DANGEROUS TO LIFE AND HEALTH – IDLH
 PERMISSIBLE EXPOSURE LIMIT - PEL
LETHAL DOSE - LD50
The LD50 is the amount of a material that, when administrated to laboratory animals,
kill half of them. The expression is made in milligrams of the substance administered
per body weight of the animal expressed in kilograms (mg/kg).
When extrapolated to humans, the lethal dose of an average person who weighs w
kilograms is LD50 x w.
LETHAL CONCENTRATION - LC50
The LC50 is the concentration of a material that, normally express as parts per million
(ppm) by volume, that when administrated to laboratory animals, kill half of them
during the period of exposure.
THRESHOLD LIMIT VALUE
• The TLV is the upper limit of a toxin concentration to which an average healthy
person may be repeatedly exposed on an all-day, everyday basis without
suffering adverse health effects.
• Gaseous substances in air, the TLV is usually express as parts per million
(ppm).
• Fumes or mist in air, it is expressed in milligrams per cubic meter (mg/m3).
• TLV values are set by the American Conference of Governmental Industrial
Hygienist (ACGIH).
• PEL: Permissible Exposure Limit. Set by OSHA
21

22. • TLV (TWA) is an 8-hour time-weighted average believed to be the average
concentration to which most workers can be exposed during an 8-hour
workday, day after day, without harmful effects.
• TLV (STEL) is a 15 minute “short term exposure limit” should not be exceeded
at any time during the work day.
Ceiling (C) is a maximum concentration never to be exceeded even instantaneously.
• An IDLH level represents a maximum concentration from which one could
escape within 30 minutes without experiencing any escape-impairing symptoms
or any irreversible adverse health effects.
IMMEDIATELY DANGEROUS TO LIFE AND HEALTH - IDLH
IDLH levels are published for many substances by OSHA and NIOSH.
In practice, when the concentration of a toxic substance in a given area is known,
IDLH levels may be used for determining whether self-contained breathing apparatus
is needed when entering the area. If the concentration exceeds the IDLH level,
positive- demand, self-contained breathing apparatus should be used.
EXPOSURE MODEL
LC50
T LD50
I TLV
M PEL
E
SAFE
EXPOSURE
0
3.3 Toxic Atmospheres
Toxic atmospheres may be defined as atmospheres that contain substances that have
the inherent ability to cause harm to the body. In confined spaces toxic atmospheres
may result from:
• Products
• By-Products; and
• Work Processes.
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23. a) Products
As per flammable atmospheres - inadequate venting or purging or toxic products
may be introduced into spaces in the form of solvents used as cleaning agents.
b) By-Products
By-products of chemical reactions, involving contents, can occur. For example:
Hydrogen sulfide is formed in sewers. It is both highly flammable and toxic by
inhalation.
Nitrogen oxide toxicity can occur in grain silos. Nitrogen oxides can be generated in
such processes and locations as intermediates or as rejected waste products. As
these oxides may undergo inter-conversion by decomposition, interaction or
reaction with oxygen, they are rarely released pure into the atmosphere, but occur
as mixtures, the composition of which depends upon the source and the local
conditions.
Carbon dioxide may be produced from or through fermentation. For example, a
worker entered a molasses pit through a 53 cm manhole and immediately called
out for help. Two other men entered in response to the worker's cry. All three were
fatally overcome. Measurements made 10 days later showed that the atmosphere
in the pit contained 1% oxygen, 3% carbon dioxide and 5,000 ppm ethanol,
strongly suggesting that the molasses had fermented.
c) Work Processes
Work processes that may involve solvents, or may generate welding fumes and
carbon monoxide, may result in very hazardous or toxic work environments.
Solvents
Two teenage boys died after being overcome by fumes from a degreasing vat at
Noble Park, Victoria, in September 1981. The solvent being used was the highly toxic
material trichloroethylene. Both boys were in their first jobs, and they were given the
task of cleaning out the sludge from the bottom of the vat. They were given no
instruction, or warning of the toxicity of the material.
Welding Fumes
When welding is performed in confined spaces, appropriate and sufficient mechanical
ventilation must be provided and maintained to keep fume concentrations within
acceptable levels. Contaminated air must be exhausted from the work space and
discharged clear of the source of intake air.
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24. Carbon Monoxide
Toxic atmospheres resulting from carbon monoxide can occur if proper work process
planning is not employed. For example, in Australia in 1974, two men died from
carbon monoxide poisoning when they operated a petrol-driven pump inside a water
tank. The operation of such a pump is, of course, quite safe in the open, but extremely
hazardous in a confined space.
4. HAZARDS
4.1 Physical Hazards
Examples of physical hazards include energized electrical conductors, moving
machinery and temperature extremes. Unlike most atmospheric hazards which are
invisible, many physical hazards can be detected by our senses. For example, we can
see unguarded machinery and feel the effects of temperature extremes. Although we
cannot actually see electricity, we can infer potential electrical hazards from things like
flexible electrical leads, switch-gear and exposed electrical components.
4.2 Mechanical Hazards
Mechanical hazards may be present in confined spaces both as fixed and portable
equipment. Commonly encountered fixed equipment includes mixers, agitators blender
blades, fans and stirring augers. Conveyors may also be found in spaces where solid
materials such as grain or fertilizers are handled, processed or stored.
4.3. Importance of Safe Work Procedures & Training
It is therefore essential that personnel at workplaces where confined spaces may be
encountered be trained to identify potentially hazardous situations and able to call
upon skills or skilled operatives to assess and implement safe procedures prior to work
commencing. It must also be emphasized that wherever practicable all alternatives to
confined space entry must be considered.
The skills and training referred to extend from early identification and assessment of
potentially hazardous situations through to appropriate emergency and rescue
procedures. This lecture covers the requirements for Emergency Response but does
not include detailed information on Rescue Techniques, as this is a specialist field.
24

25. The importance of early identification of potentially hazardous situations is illustrated
by accident records that show more than half the fatalities associated with confined
spaces occur among ill prepared personnel attempting to rescue co-workers in
distress. This indicates that both workers and would-be rescuers have encountered
unexpected hazards that they were not adequately trained to identify and deal with. It
also indicates that systems of work and procedures were either inadequate or not
adhered to.
4.4 Importance Creating a Confined Spaces Entry Program
It is essential that persons having control of workplaces where work in confined
spaces may be necessary ensure that personnel are competent to readily identify such
situations and are provided with clear and precise guidelines in the form of a confined
spaces entry program that must be enforced.
The confined spaces entry program should include provision for Entry Permits that
detail the type of work to be conducted and the results of a risk assessment that must
be completed prior to entry.
Small or enclosed spaces of some description can be found in many workplaces but
most are not a risk to persons engaged there during normal operations. Problems
develop where a combination of difficult access and egress occur with the possibility of
exposure to hazards such as those described in the first lecture of this series.
It is important, however, to recognize that confined space does not necessarily mean
small-enclosed space. A combination of difficult access with a risk of exposure to a
physical hazard or suspect atmosphere (such as might be found in a ship's hold, a
powerhouse boiler or a bulk oil tank at a refinery) would be deemed a confined space
situation.
Common problem areas for hazard identification are explained below.
4.4.1 Unfamiliar Hazards
Problems could occur where building or maintenance work is being completed and
employers find themselves faced with non-routine situations and hazards that staff are
not trained to identify or address. These problems can be exacerbated where
specialist contractors are engaged who may introduce new hazards to an installation
they have little knowledge of.
Physical Shape of the Work-Site Changes
Work in confined spaces may be difficult to monitor within workplaces (such as
construction sites and shipyards) where numerous industrial processes and
procedures are being conducted at the same time as the physical shape of the work
site is constantly undergoing rapid change.
25

26. Structural Steel Skeleton in a Shipyard
Inadequate Hazard Identification
In the practical sense, it is important to maintain a focus on the risk factors associated
with the work site and the work to be conducted rather than rely upon strict
interpretation of one or other of the various definitions of a confined space. Experience
has shown that hazardous situations can be ignored due to misinterpretation of
definitions that cause workers to incorrectly assume there to be little or no risk.
One such situation occurred where an upholsterer was overcome by vapors while
applying surface coatings in a below decks cabin of a boat. No special precautions
were taken as the situation was not considered a confined space due to the cabin
being a regular workstation under normal operating conditions (contrary to most
definitions of a confined space). A risk assessment should have caused the risk of
exposure to vapors to be considered and appropriate ventilation provided. The
appropriate interpretation of definitions should have been that the cabin was not a
regular workplace or workstation for an upholsterer applying potentially hazardous
products to large surfaces.
Confined Space in a Boat Cabin under Construction
26

27. The Hazard Develops Over Time
Many projects in industries such as steel fabrication may start as simple steel
skeletons but gradually develop into enclosed tank like structures that ultimately
become confined spaces. Such projects include the hulls of ships and the bodies of
road and rail tankers.
Confined Space created during Construction of a Ship's Hull
The tendency for workers in these industries is to overlook the hazards or ignore the
risks as the confined space is formed. Although the enclosed spaces may in
themselves not pose any significant risk, the introduction of metal work processes
such as cutting and welding into such spaces does. These are also typical areas
where confusion arises if a focus is maintained upon the definition of a confined space
as opposed to assessing the risk as the project develops.
It should be noted that operations to repair such units that have previously been in
service face increased risks due to the unknown or uncertain nature of the internal
environments resulting from the products carried.
Road Tanker damaged by a Blast during Hot Work
27

28. Similarly, the construction of fibreglass units such as boats and swimming pools may
commence as open structures and develop into potentially hazardous confined spaces
as construction nears completion. Toxic and flammable vapors from the fibreglass
process may collect where workers have restricted means of egress.
Fibreglass Boat Hull under Construction
Every Situation Requires Hazard Identification
In industries or utilities such as water supply and sewerage management, work in
confined spaces such as inspection pits and sumps is commonplace. The recognition
of such a place of work as a confined space may be well understood and accepted but
each situation still requires formal hazard identification as a start to the assessment
process. It may be that the hazards that deem one such installation to be a confined
space may differ from those to be found in another and complacency or assumptions
on the part of workers can lead to tragedy. This is especially important where
movements of air are likely as hazardous atmospheres can form in pockets and
envelop unsuspecting workers operating in tunnels, trenches and pits that form
integral parts of larger systems. It is also not uncommon for fumes from internal
combustion engines or escapes of natural gas to accumulate in below ground spaces.
Open Pit over a Sewer on a Construction Site
28

29. 5. RISK ASSESSMENT & MANAGEMENT
What is a Risk Assessment?
 An assessment of the risk is nothing more than a careful examination of your
work area with regard to what could cause harm to people.
 To weigh up whether the precautions in place are sufficient or if more may be
required. The aim is to eliminate or reduce the risk to an acceptable level.
 A risk assessment is the systematic identification of potential hazards in the work
place by personnel as a first step to controlling the possible risks involved.
In safety, management terms the evaluation of risk involved in a given process or
activity centers around the following questions.
 What is the hazard (potential to cause harm)?
 What is the likelihood of exposure (in the given circumstances occurring)?
 What is the likely outcome (taking into account any existing controls)?
Hazards
Look for hazards that could result in harm in your area, activity, process or equipment
that you are using.
Hazards may be physical, chemical, biological or ergonomic in nature.
Physical hazards include the potential to harm posed by inadequate or excessive
lighting, temperature, noise/vibration, pressure, humidity and radiation.
Chemical hazards are associated with those solids, liquids, gases etc, with the
potential to cause injury or harm to those exposed.
Biological hazards are more specialized but include moulds, fungus, spores etc.
Ergonomic hazards are the potential to harm due to poor workplace design.
The consideration of the man/machine interface e.g. computer workstations, lifting and
handling, slipping and tripping.
How do you perform a risk assessment?
There are eight steps to performing a satisfactory risk assessment
1. Focus for assessment
2. Identify activities
3. Identify hazards
4. Who at risk
5. Evaluate risk
6. Review controls
7. Record Decisions
8. Review Regularly
29

30. How do you assess risk levels?
Risk levels are categorized in a numbered format. Each hazard is given a rating and
this is multiplied by the probability that these hazards will occur, as shown in the
following equation.
Risk level = Hazard severity x Likelihood of occurrence
Potential hazards in the workplace
• Portable and fixed electrical appliances
• Tools and equipment
• Handling of materials
• Trailing cables
• Access and egress
• Fire exits
• Heating and ventilation
• Sanitary conveniences
• Chemicals
• Cleaning substances
• Dusts & powders
• Biological hazards (bacteria, viruses, etc.)
• Repetitive actions
• Working alone
• Stress
Identified Hazards
The following hazards have been identified in the operation of This Corporation:
Assessed Hazards
• Burns from fire
• Inhalation of smoke or chemical
• Burns from electrical/gas plant
• Cuts from plant
• Ingestion of Chemicals
• Contact with electricity
• Blood borne pathogens
• Airborne harmful substances
• Handling of hazardous materials & spillage
30

31. Consequence Probability
1 2 3 4 5
Safety & Common or Known to Could Not likely Practically
Health repeating occur or “It occur, or to occur impossible
occurrence has “I’ve heard
happened” of it
happening”
1 1 2 4 7 11
2 3 5 8 12 16
3 6 9 13 17 20
4 10 14 18 21 23
5 15 19 22 24 25
5.1 Ensure Risks Are Known & Control Measures Are Followed
Once a confined space and the associated hazards have been identified, it is essential
that systems and procedures be followed to ensure that workers are not exposed to
unacceptable risks. It is also necessary to ensure workers are aware of such risks and
understand procedures and their responsibility to comply with them.
Experience has shown that many employers and workers fail to implement appropriate
systems for safe work in confined spaces because they fail to recognize the risks or
find it convenient to ignore precautions where productivity or worker comfort may be
compromised. The policy must be, "If in doubt, do not enter!"
5.2 Importance of a Full Assessment
Having identified a confined space situation it is necessary to assess the risks and
consider the means by which those risks can be eliminated or minimized. Assuming
that entry is unavoidable, it is essential, due to the degree of risk, that consideration be
given to the hierarchy of control when selecting appropriate control measures rather
than simply relying upon personal protective equipment.
Although few confined spaces situations will include all the hazards and risk factors
covered in the two lectures in this series, it is vital that the possibility of them occurring
be considered. It is also vital that the assessment includes consideration of the nature
of the plant or installation being worked upon as well as the work to be conducted and
any interaction that may occur.
5.2.1 Special Precautions May Be Necessary
31

32. Special precautions may be necessary, especially where potentially hazardous surface
coatings are to be applied or hot work of any kind is to be conducted. Such special
precautions should be documented on the Entry Permit or an appropriate Hot Work
Permit that should be issued where any process is to be employed that would
introduce a source of ignition.
5.2.2 Determine the Degree of Risk
It is also important during the assessment phase to realistically gauge the degree of
risk and to ensure that the control measures to be implemented are practicable. Where
workers and employers fail to gain a real understanding of the hazards and risk factors
involved there can be as much a tendency to over compensate, as there is to
underestimate the control measures required. This can cause workers to be
encumbered with unnecessary personal protective equipment during the course of
exacting operations.
5.2.3 Select, Train & Supervise
It is also necessary during the assessment phase to consider the suitability or
otherwise of the personnel who will be required to conduct the work. The physical
capabilities and fitness of individuals needs to be considered, as does the level of
training. A Responsible Person should be appointed to supervise the work, and certain
persons should be authorized to conduct essential duties.
5.3 Training
5.3.1 Confined Spaces Entry Program
It is essential that persons involved with confined space entry receive appropriate
training in all aspects of the work including an understanding of all relevant systems
and procedures. A confined space entry program should coordinate and document the
training and skills development of workers and should include hazard identification and
risk control, use of equipment and individual responsibilities. Training should also
include emergency response and first aid.
5.3.2 Responsible Person Must be Appointed
A Responsible Person should be appointed (often the supervisor) to take overall
responsibility for the confined space work. This person should have a total
understanding of all aspects of the work, be trained to use all equipment and be
competent to coordinate operations in the event of emergency.
5.3.3 Observers Responsible For Emergency Response
32

33. Observers must be appointed and trained to the same level as the persons entering
the confined space, as they are responsible for emergency response and are usually
part of the rescue team. In many instances, the observer is also a skilled worker and
may change positions at breaks or shift changes. This alternating of roles, where
practicable, helps to build trust and commitment between team members.
Observers should be capable of being in continuous communication with those in the
confined space. They should also be able to observe those in the confined space if
practicable. They should also operate and monitor equipment used to ensure safety
during entry and work in a confined space. In addition, if necessary, they should
initiate rescue procedures.
5.3.4 Emergency Response Training
Appropriate training should also be provided for those associated with the provision of
equipment and worker support even though they may not personally be required to
enter or work in the confined space. Rescue workers require specialist training and
although they may not necessarily be part of the team conducting the actual work they
must be available in the immediate area in case of emergency.
Practice drills and rescues are also an essential part of confined space training. The
procedures must be well rehearsed and followed at all times to ensure those reactions
are automatic. Each practice drill should be assessed and procedures modified to
address any problems identified. Stand by personnel must be trained to adhere to
approved procedures and not rush to the aid of a co-worker in distress.
5.4 Isolation
5.4.1 Isolate or Disconnect Pipes & Ducts
All plant, equipment and sources of energy connected to the confined space must be
totally isolated or disconnected. All connecting pipes or ducts must be physically
disconnected, blanked off or otherwise sealed. It is not adequate to simply shut off
valves, as it is not uncommon for them to leak. Where the closing of valves is the only
option then two in the same line must be locked out with a bleed between them to
ensure no equalization of pressure should one leak.
Example
Workers at a fruit processing factory were exposed to steam that was introduced into
holding tanks where they were working when valves connecting the tanks to other
parts of the production line opened unexpectedly.
5.5 Lock-Out Energy Sources
33

34. All sources of electrical energy and connections to remote equipment associated with
the plant being entered must be isolated and locked out. Particular attention must be
paid to any automatic start up or shut down procedures, especially where computers
are utilized in control systems. Any sources of mechanical energy or mechanical
drives such as agitators, gears or shafts etc. must be identified and either
disconnected or otherwise disabled. Other components that may be free to move and
thereby constitute a risk to workers must be chocked or locked out.
Example
A worker was crushed when working on a semi-automatic brick-pressing machine that
was activated by a remote limit switch. The main press had been isolated from the
power supply but a secondary unit that forced raw material into the press had not.
Further information on lock out and isolation procedures can be found in the lecture
'Lock-Out and Tag Out' in the Risk Control section of this series.
5.6 Exposure to Product and Hazardous Substances
Importance of Assessment
Where maintenance, repair or refurbishment of plant or an installation is to be
conducted it is essential that assessment be made of the risks associated with
possible exposure to product from that plant prior to entry. Workers required to enter a
confined space or an enclosed area must be made aware of any potential hazards and
equipped with appropriate knowledge and equipment to tackle those hazards should
they be encountered.
Examples
Workers were overcome when exposed to toxic fumes at a chemical plant when they
entered a large open pit to complete maintenance work. No assessment had been
conducted to determine the product that had been held in the pit and no testing of the
atmosphere conducted even though hazardous substances were the products of the
plant.
A product that is not necessarily hazardous in itself may become so in a confined
space. There have been situations where workers have been overcome by oxygen
deficiency caused by displacement of air by food derivatives when entering vats at
food manufacturing plants, mistakenly confident that any atmosphere associated with
food would have to be harmless.
34

35. Typical Confined Space in a Food Processing Plant
5.7 Clear or Neutralize Hazardous Substances
Where risk assessment identifies substances remaining in plant and systems under
repair, provision must be made for appropriate cleaning or purging. Areas where
hazardous substances may be found should be placarded and additional information
should be sought from management records and Material Safety Data Sheets to
ensure that all hazardous properties of the product or substances are cleared or
neutralized.
5.8 Physical Hazards
5.8.1 Consider the Vicinity
The physical hazards that workers may be exposed to in confined spaces are many
and varied and include environmental factors. Consideration should also be given to
any work or treatment being conducted on the exterior of the confined space or in the
vicinity.
5.8.2 Barricade, Sign-Post & Deal with Physical Hazards
Wherever possible the area or plant in question should be roped off or barricaded and
sign posted to indicate that confined spaces work is being conducted. Receivers or
holding tanks in production lines or process plants must be totally isolated from
associated machinery and allied processes and procedures. Where railway rolling
stock is being entered, wagons should be parked on side rails with points locked out or
the rails to the work area scotch blocked to prevent accidental shunting. Road
transport units should have barriers at each end to prevent other units from
accidentally bumping. Trenches or pits should be cordoned off to prevent traffic or
machinery from approaching. Where entry is required to furnaces or boilers,
precautions must be taken to ensure workers are protected from possible falls of dust
and debris or damaged linings such as refractory bricks, etc.
35

36. 5.9 Climatic Factors
Possible exposure to environmental factors (such as extremes of heat and cold, or
water entering the work site) must be considered. Where possible, enclosures should
not be exposed to the heat from the summer sun as internal temperatures can soar,
giving rise to the risk of heat stress for workers or possible release of toxic fumes.
Similarly, precautions should be taken wherever possible to ensure that internal
temperatures are not allowed to fall, or rain water enter the confined space due to
exposure to adverse weather conditions. It is especially important to consider such
environmental factors where workers may be required to enter spaces associated with
storm water or drainage that could be subject to flash flooding.
5.10 Electrical Hazards
All sources of electrical power provided for the confined spaces work must be low
voltage where possible or provided with earth leakage protection that is situated
outside the confined space. It is recommended that portable electric hand tools be
double insulated. In some situations it may be necessary to provide an electricity 'kill
switch' for the observer so that all power can be instantly isolated in the event of
emergency.
5.11 Access and Egress
Requirements
Two aspects of access and egress must be considered where confined space entry is
required.
36

37. 5.11.1 Normal Access & Egress
The first is for safe controlled passage under normal or routine conditions where
workers are aware and prepared for unavoidable restrictions. The need for swift
evacuation in the event of emergency or alarm must be taken into consideration at this
time.
Confined Space Access Platform showing Emergency Chute
5.11.2 Rescue of Injured Workers
The second area of consideration is the rescue of an incapacitated worker. Although
rescue procedures are not included in this lecture it is vital that consideration be given
to the potential difficulties that may be encountered should such a situation eventuate.
At this stage the need for a safety harness and a means of lifting or removing an
incapacitated worker from the confined space should also be considered.
5.11.3 Prevent Falls During Access & Egress
Risks associated with restricted access and egress include falls from heights, falls into
depths or voids, restricted openings and/or obstacles within the path of workers.
The risk of falls is common where access is required to large vessels or structures with
inspection ports or hatches at or near the top. Difficulties can be caused not only by
the need to gain access to the point of entry from the outside but also from the inside.
Although suitably erected and secured ladders may suffice for some simple tasks,
such as inspection in low risk areas, they are not sufficient where equipment is
required to be ported or in foreseeable life threatening situations that may require
rescue or assistance. The risk of injury from falls must also be considered where
workers are required to enter sunken areas or where breaks in the level of floors are
likely to be encountered.
37

38. Where access is required at heights for other than the simplest operations it is
essential that a working platform or scaffold of some description be considered. This
should provide for a secure point of entry for those entering a confined space as well
as a safe workstation for those observing and monitoring operations. Such work
platforms would also facilitate the transfer of equipment in and out of the confined
space and provide a secure base for any emergency or rescue procedure.
5.11.4 Size of Openings for Access & Egress
Restricted openings can cause major problems for confined space workers, especially
where access must be gained through hatches or ports designed for product rather
than personnel. Any such opening to be used for access and egress of workers must
be of a minimum size that may vary with the requirements of local regulations. It is vital
that any such means of access is assessed with due consideration of the physical
characteristics of all personnel that may be called upon to enter and any foreseeable
situation that may arise. It is not acceptable to simply utilize an opening that can
accommodate only the smallest worker or workers in a non-stressful situation. In many
situations, it can be virtually impossible to retrieve an unconscious worker through an
access way that was difficult to negotiate when conscious.
5.11.5 Consider Creating a Temporary Opening
This vital area is one where the hierarchy of control must be considered. Workers are
often exposed to unnecessary difficulties associated with access and egress when
other simple measures, such as the provision of a temporary hatch or opening, could
very easily be provided and closed upon completion of the work. Secondary openings
such as these would also provide for improved ventilation and in some situations
improved light.
Temporary Access Hatch in the Hull of a Ship
38

39. 5.11.6 Ensure All Obstructions Are Identified
Obstructions within confined spaces must also be considered prior to entry. Where
inspection from the outside is not sufficient to give clear indication of obstructions then
plans or advice from those with knowledge of the installation should be obtained. It is
not acceptable to allow a worker to enter a confined space with little or no knowledge
of the interior and assume they will find their way around. If information cannot be
obtained that will allow for knowledgeable assessment to be made prior to entry, then
other means of completing the work must be considered or additional precautions
implemented.
5.12 Hazardous Atmospheres
High Risk to Workers
The internal atmospheres of confined spaces may be flammable, toxic, oxygen
deficient or oxygen rich, which may give rise to risk of fire and explosion or impaired
physical capability for persons entering. The composition of atmospheres can also
change very rapidly especially if residues or deposits are present or the space not
effectively isolated.
The result of explosive ignition in a confined space can be catastrophic and has been
known to blow tanks apart. The risk of workers encountering atmospheres hazardous
to life is also very real and all possible measures must be taken to test and make safe
or ensure that airline respirators are utilized.
5.12.1 Use Gas Detector to Monitor Atmosphere
The first stage of assessment is to consider the use or product to which the area has
been subjected. It is also essential that records be maintained of any cleaning or
purging procedures that have been conducted. It is also vital to ensure that no closed
or hidden compartments have been neglected or overlooked.
It is also necessary, in all but the most
obvious situations where a hostile
atmosphere is not a consideration, to test
the atmosphere prior to entry. Testing
must be conducted at least daily or at the
start of each shift and be monitored
continuously whenever workers are inside.
39

40. Common Gas Detector
A gas detector of some description will be used to
measure the levels of various flammable gases and
oxygen present in the atmosphere. Most gas detectors
are equipped with alarms that activate when oxygen
levels fall below 19% or climb above 21%, which is the
normal safe range for human respiration. The type of
gas detector or monitor usually used in such situations
also sound alarms when hazardous levels of carbon
monoxide occur, or concentrations of flammable gases
that exceed 5% of the lower explosive limit (LEL) are
detected.
LOWER EXPLOSIVE LIMIT (LEL)
It is important to understand that the LEL is the lowest concentration of flammable gas
in an atmosphere that will sustain combustion. The alarms on gas detectors are
usually set to activate at 5% of that level, as is required by most standards and codes,
not when flammable gases reach 5% of the total atmosphere.
Steel Tank Destroyed by a Blast during Confined Space work
Monitoring Is Still Required Even If Gas Free Certificate Issued
Where confined spaces have been purged or cleaned, usually with steam, it is often
the practice to issue a Gas Free Certificate. Such Certificates should only be taken as
an indication that a unit or space has been cleaned and should not be taken as a
guarantee that the internal atmosphere will continue to be safe. Testing and monitoring
is still essential.
40

41. Day 3
Monday 20 Sep. 2010
41

42. 5.12.2 Take Appropriate Precautions When Testing
In larger confined spaces, or where movement of air is
likely, it will be necessary to test the atmosphere at
extremities or in connecting areas if they cannot be
isolated.
A common mistake by workers about to enter confined
spaces is to test the atmosphere only at the point of entry.
Another common mistake is to test at point of entry and
then enter to test extremities without appropriate
precautions being taken. This can cause them to actually
find the hazardous atmosphere for which they are testing
but to not be prepared or protected when they encounter Confined Space worker
it. This is especially true where heavier than air gases with Airline Respirator
collect at the bottom and extremities of enclosed areas.
It is vital that where there is any possibility of encountering a hazardous atmosphere
then full protective measures, such as airline respirators that can guarantee a safe
supply of respirable air, must be used until the atmosphere is proven to be safe.
Eliminate Cause If Monitoring Detects Danger
Where contamination is detected at any time after an atmosphere has been declared
safe it is essential that steps be taken to determine the cause and appropriate action
taken to eliminate the source. It is not acceptable to simply purge and re-enter when
testing equipment indicates the contaminant levels to be reduced to acceptable levels.
If Safe, Provide Mechanical Ventilation
Where the atmosphere can be guaranteed to be safe, mechanical ventilation should
be provided to maintain a flow of fresh air during the period of occupation. The supply
of fresh air must also be adequate to purge any contaminants from the work processes
being conducted.
If Unsafe, Apply Hierarchy of Control
Where the atmosphere cannot be guaranteed, appropriate protective measures must
be maintained but with the hierarchy of control being considered at all times.
5.12.3 Monitoring and Observation
What the Observer Must Do
42

43. Where an enclosed workplace is identified to be a confined space, no person is to
enter unless an observer is appointed and positioned at the point of entry. The
observer must be identified on the Entry Permit and must attend at all times the
confined space is occupied. He or she must have received appropriate training in all
aspects of the work in hand and understand how to use, read and interpret any
equipment being used to monitor the internal environment. They must also be
conversant with emergency procedures and in constant communication with the
occupant of the confined space.
6. EMERGENCY PROCEDURES
Provision must be made for rescue of the occupant should an emergency arise, and
procedures and equipment must be appropriate for the hazards likely to be
encountered. The rescue personnel will therefore by necessity need to be trained and
equipped to at least the same level as the occupant in relation to safe work in confined
spaces.
Where more than one person is likely to be working in a confined space the provision
for rescue must take this into consideration. Where several confined spaces occur in
close proximity, for example, where three tanks or boilers are being constructed next
to one another, one designated rescue team may be appropriate. However, should an
emergency arise in one it will be necessary for work to cease in all confined spaces
43

44. and personnel evacuated until the emergency is over and the rescue team is again
free to respond.
6.1 What To Do When Work Ceases
When work ceases for breaks or end of shift, all sources of potential hazard must be
removed from the space and the area rendered safe. Equipment such as spray
painting guns or potentially hazardous products such as paints or surface treatments
must be removed. Gas lines for cutting and welding equipment must be turned off and
removed. At the end of a shift all electrical supplies would normally also be turned off.
However, during short breaks the low voltage electricity would usually be maintained
for lighting, as would any equipment for the monitoring of the internal atmosphere.
Upon completion of the confined space work, it is necessary for all personnel to be
accounted for and entry permits to be signed off and submitted to the responsible
person.
7. PERMIT TO WORK
A permit to work is formal written authority for persons, usually trades-persons, to
carry out work including maintenance on plant, a building or an item of equipment. The
permit to work is issued by an authorized person. This person must have a clear
understanding of the equipment, be aware of any hazards that may be involved and be
trained in the operation of the permit to work system.
The permit is a written statement by the authorizing person that hazards associated
with the task have been identified, assessed and necessary control measures put in
place. Any special precautions to be taken by the trades-person are clearly defined
and the authorizing person states if it is safe to carry out the task.
A permit to work does not include instructions to the trades-person on how to perform
the work for which they are specially trained, nor is it a reflection on their competency.
7.1 Steps of a Permit System
1. The job is identified and authorized person is consulted.
2. Plant or item is prepared for maintenance and is inspected by authorized
person.
3. Permit prepared and precautions are entered.
4. Permit discussed with trades-person at the work site.
5. Permit is to be signed by authorized person and trades-person.
6. Original of permit is kept open in the supervisor's office and the job copy of
permit is on the job with the trades-person.
7. Original of permit is signed off by trades-person.
8. Original of permit signed off after inspection by authorized person.
9. Job completed, or permit ended.
44

45. 10. Original of permit is filed for reference.
11. Job copy of permit discarded.
12. Regular auditing of the originals, and other action including training if required.
7.2 Advantages of Permits to Work
A well prepared Permit to Work system can make maintenance safer in many ways,
some of which are:
• It prevents an unauthorized person from initiating a job, a permit can only be
issued by a person authorized to do so.
• A trades-person will have confidence that those hazards affecting his personal
safety have been considered and assessed before work is started.
• A permit to work provides a plan to carry out the work safely.
• It forms a basic checklist that enables the tradesperson to concentrate on the
job and to avoid the need to make snap decisions under pressure.
• Clear lines of responsibility are identified.
• The likelihood of confusion is reduced due to the need for the permit to work to
be fully discussed with and countersigned by the tradesperson at the work site.
• The permit to work system lets all affected people know that work is to be
carried out on an item of equipment or plant.
• The chance of work beginning by contractors without proper instruction is
reduced.
• The risk of someone trying to operate the equipment whilst it is being worked on
is greatly reduced.
• The permit to work is a permanent record of precautions taken prior to
maintenance work being carried out.
7.3 Usage
A Permit to Work is to be used with work involving any of the following:
1. Contractors - Any work involving contractors on site is to be covered by a
Permit to Work. Contractors may or may not be familiar with the site and a
permit to work provides a formal method of assessing any Health and Safety
issues that the contractor and the site management may have to consider in
relation to the task involved.
2. Hot Work - Hot work includes welding, flame cutting, brazing, grinding or any
activity likely to produce heat or sparks. Permits are not required for safe areas
designated for such work such as welding bays in maintenance workshops.
3. Confined spaces - A confined space is an area that is substantially enclosed.
A permit to work is required in all circumstances involving this type of work. A
safety person who is familiar with the plant, the activity and who has been
45

46. briefed as to the action to take in the event of a problem arising is to be present
at all times a person is within the confined space. The plant must be isolated of
all the services to the enclosed space and consideration must be given to the
activity being carried out. For instance, hot work may require special extraction
and or breathing apparatus. The temperature of and the time duration a person
may be in the enclosed space should be considered and specified on the
Permit to Work. If fumes are known to have existed, they must be tested to be
clear before entry is allowed.
4. Pressure Vessels - Any activity involving welding a pressure vessel should be
covered by a permit to work and must be carried out only by a suitably coded
welder. Maintenance activities involving work on pressure lines may need to be
considered for permit to work where there is a hazard to personnel working
which cannot be covered by a sites normal isolation practices or safe systems
of work.
5. Work at Height - Any work involving access to roofs and or trenches must be
covered by a permit to work. Work within the factory where there is a risk from
falling objects that would endanger personnel or equipment should also be
covered by a permit to work.
6. Chemical or Highly Flammable Areas - Work on chemical lines or tanks
should be covered by a permit to work where that work is not a routine task
covered by a safe system of work. Lines should be isolated from the supply,
emptied and decontaminated as necessary. A permit is to be used where
electrical equipment is to be used in chemical areas where highly flammable
chemicals are present. For example - drills.
7. Electrical Systems - Where there is a hazard to personnel working which
cannot be covered by a sites normal isolation practices or safe systems of work.
All 11kV working must be covered by a Permit to Work.
8. Safety and Emergency Systems - Where there is a hazard to personnel
working which cannot be covered by a sites normal isolation practices or safe
systems of work.
9. Lone Working - Where a person is to work alone within an area of the site
away from other personnel who can reasonably be communicated with then a
permit to work is to be issued. The person and checkers are to be briefed on
the procedure for lone working.
10. Lock-Out – Tag-Out.
11. Cold Work.
12. Blasting.
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47. 13. Internal Combustion Engines Inside Company Buildings.
7.3.1 Permits Issued For Hot Work
Before authorizing the issue of a HOT WORK PERMIT, factors such as the following
must be taken into account.
1. Emptying and cleaning the equipment of flammable material.
2. Isolating from sources of hydrocarbons by means of disconnection, blanking,
insertion of blinds. No reliance should be placed on closed valves.
3. Sealing off sewer and drains within a radius of 75 feet (23 meters).
4. Clearing away any flammable material in the work area.
5. Location and earthing of welding or other equipment being used.
6. Degree of risk and potential sites of accidental release of hydrocarbons in the
area.
7. Provision of fire-fighting facilities and the need for stand-by fire attendant, if
necessary.
8. Testing by means of a combustible gas detector to ensure gas-free condition of
the equipment and surrounding area.
9. Frequency of repeating gases free testing or the need for use of portable
continuous gas detector with visual and audible alarms.
10. Containing and extinguishing weld sparks and molten slag.
11. The presence of substance such as lube oils and bitumen may give off vapours
when heated.
12. Adjacent areas where work is taking place which may affect this work area.
7.3.2 Permit Issued For Cold Work
A COLD WORK PERMIT must be obtained to cover general work, which is not regarded
as hot work.
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48. The COLD WORK PERMIT is required to cover such work as cold cutting and tapping,
wire brushing, de-scaling, scaffolding, chemical cleaning, air driven power tools, entry
into sewers, deep drains, chambers, or buildings which may have contained toxic gas or
dust etc.
Before authorizing the issue of a COLD WORK PERMIT, factors such as the following
must be taken into account.
1. Is equipment, plant and location free of oil, gas and vapour?
2. Has equipment been depressurized?
3. Are the equipment, plant and location, electrically isolated?
4. Are there adjacent areas where work is taking place which may affect this work
area?
7.3.3 Welding On Live Equipment
This action covers welding on equipment which is in service and where the equipment
cannot be depressurized and freed of gas/oil so that it can be covered only by a PERMIT
issued for Hot Work.
WELDING ON LIVE EQUIPMENT includes welding of stubs into lines or vessels prior to
drilling for hot tap for welding brackets on tanks and patch work.
Occasions may arise when there are good reasons
for carrying out welding work on pipelines, vessels, tanks or other equipment whilst in
normal operations, e.g. in an emergency where there may be a greater risk in shutting
down equipment than in carrying out live welding under carefully pre-planned and
controlled conditions.
Apart from the normal safety precautions to be observed when carrying out hot work, or
hot work on live equipment, additional precautions are necessary.
Welding should not be done on any equipment containing pure oxygen or compressed
air (unless the air has been filtered to remove oil mist and chemicals if heating would
decompose the chemicals and form an explosive mixture, caustic soda or a combustible
mixture).
Immediately prior to commencement of welding or hot work on live equipment, a suitably
qualified person should check that the PERMIT conditions are adequate to ensure the
necessary control and should himself be present at the start of the job and thereafter
keep in close touch at frequent intervals with the senior man on the job.
7.3.4 Excavations
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49. Poorly planned excavations can result in damage to underground services, such as
electrical lines, natural gas lines, water lines, sewers and drains.
The consequence of damaged service lines is often complete shutdown of operations
resulting in major business losses.
Permits are written to prevent damage to underground equipment and services.
Excavations may expose hazardous materials, which have leaked and are
contaminating the soil.
Permits ensure that procedures to protect workers from exposure to toxic substances
have been identified.
Permits are written to ensure that necessary equipment is present and in good working
order.
7.3.5 Internal Combustion Engines
Internal combustion engines produce poisonous gases such as carbon monoxide, and
oxides of nitrogen.
Permits ensure that procedures are followed that will prevent equipment emissions
from contaminating air inside buildings and confined spaces.
7.3.6 Lock-Out –Tag-Out
Lockout Is Defined as:
The Placement of a Lockout Device on an Energy Isolating Device, in Accordance
With an Established Procedure, Ensuring That the Energy Isolating Device and the
Equipment Being Controlled Cannot Be Operated Until the Lockout Device Is
Removed.
Is used for energy isolation
 Hydraulic
 Pneumatic
 Mechanical
 Radioactive
 Thermal
 Electrical
 Chemical
49

50. 8. JOB HAZARD ANALYSIS (JHA)
• JHA is a procedure which helps integrate accepted safety and health principles
and practices into a particular operation.
• In a JHA, each basic step of the job is examined to identify potential hazards
and to determine the safest way to do the job.
Four basic stages in conducting a JHA are:
1.Selecting the job to be analyzed.
2.Breaking the job down into a sequence of steps.
3. Identifying potential hazards
4.Determining preventive measures to overcome these hazards.
8.1 Analysis
Some of the More Common Hazards:
A. Caught In
• Rotating Parts
B. Contact With
• Electrically Energized Parts,
• Hot Surfaces,
• Chemicals; Corrosive, Skin Absorbable, or Inhalation Hazardous,
• Sharp Objects,
• Cutting or Grinding Surfaces.
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51. C. Struck By
• Overhead Lifts,
• Overhead Work or Loose Debris,
• Chains or Cables under Tension,
• Crane or Sling Failure
D. Fall From or Into
• Holes in Working Surfaces, Platforms, Scaffolds,
• Missing or Loose Guardrails, Open Platform Gates or Chains,
• Inadequate Tie off Points and Lanyard Length.
E. Slip or Trip
• Objects Projecting Into Walking Path,
• Debris on Walking Surface or Loose Surface Material,
• Uneven Surfaces,
• Slick Surfaces, Oil, Water.
Briefly, ask:
• Can any body part get caught in or between objects?
• Do tools, machines, or equipment present any hazards?
• Can the worker make harmful contact with objects?
• Can the worker slip, trip, or fall?
• Can the worker suffer strain from lifting, pushing, or pulling?
• Is the worker exposed to extreme heat or cold?
• Is excessive noise or vibration a problem?
• Is there a danger from falling objects?
• Is lighting a problem?
• Can weather conditions affect safety?
• Is harmful radiation a possibility?
• Can contact be made with hot, toxic, or caustic substances?
• Are there dusts, fumes, mists, or vapors in the air?
8.2 Preventive Measures
In order of preference:
• Eliminate The Hazard
• Contain The Hazard
• Revise Work Procedures
• Reduce The Exposure
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52. 9. HAZARDS EVALUATION
A Hazard Evaluation (HE) study is an organized effort to identify and analyze the
significance of hazardous situations associated with a process or activity. Specifically,
HE studies are used to pinpoint weaknesses in the design and operation of facilities
that could lead to accidental chemical releases, fires, or explosions.
Understanding of risk requires addressing three specific questions:
• What can go wrong?
• How likely is it?
• What are the impacts?
RISK
UNDERSTANDING
What are
How likely What can
The
Is it? Go wrong?
impacts?
FOUNDATION FOR RISK ASSESSMENT
Historical Analytical Knowledge
experience methods and intuition
Aspects of Understanding Risk
9.1 Selecting Hazard Evaluation Techniques
A successful HE program requires tangible management support; sufficient,
technically competent people (some of whom must be trained to use HE techniques);
an adequate, up-to-date information database; and the right tools to perform HE
presented in these guidelines has been applied in the chemical process industry and is
appropriate for use in a wide variety of situations.
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53. 9.1.1 What-If Analysis
The What-If Analysis technique is a creative, brainstorming examination of a process
or operation. Hazard analysts review the subject process or activity in meetings that
revolve around potential safety issues identified by the analysts. Each member of the
HE team is encouraged to vocalize What-If questions or specific issues that concern
them. The What-If Analysis technique can be used to examine virtually any aspect of
facility design and operation (e.g., buildings, power systems, raw materials, products,
storage, materials handling, in-plant environments, operating procedures, work
practices, management practices, plant security, and so forth). It is a powerful HE
technique if the analysis staff is experienced; otherwise, the results are likely to be
incomplete. What-If Analysis of simple systems can easily be conducted by one or two
people; a more complex process demands a larger team and longer or more meetings.
A What-If Analysis usually reviews the process, beginning with the introduction of feed
material and following the flow until the end of the process (or the boundary defined by
the analysis scope). What-If Analyses can also center on a particular type of
consequence (e.g., personnel safety, public safety, or environmental safety). The
results of a What-If Analysis usually address potential accident situations implied by
the questions and issues posed by the team. These questions and issues often
suggest specific cause for the identified accident situations.
Example:
The ammonia and phosphoric acid react to form diammonium phosphate (DAP), a
nonhazardous product. The DAP flows from the reactor to an open-top storage tank.
Relief valves are provided on the storage tanks and the reactor with discharges to
outside of the enclosed work area.
1. If Phosphoric acid feed rate is greater than ammonia, it result in off-spec – safe
reaction
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54. 1. If both flow rates increase, than the rate of energy release may accelerate, and
the reactor, as designed, may be unable to handle the resulting increase in
temperature and pressure.
1. If Ammonia feed rate is greater than Phosphoric acid, than unreacted ammonia
may carry over to the DAP storage tank
• Any residual ammonia in the DAP tank will be released into the enclosed
work area, causing personnel exposure. Ammonia detectors and alarms
are provided in the work areas.
An example What-If question is:
Sample page from What-If Analysis Table for DAP Process Example
Process : DAP Reactor Analysts: Mr. Safety, Mr. Design
Topic Investigated: Toxic Releases Date: 05/13/2004
What-If Consequence/Hazard Safeguards Recommendation
The wrong feed Potentially hazardous Reliable vendor Ensure adequate material
material is phosphoric acid or handling and receiving
delivered instead ammonia reactions with Plant material procedures and labeling
of phosphoric contaminants, or handling procedures exist.
acid? production of off-
specification product.
The phosphoric Unreacted ammonia Reliable vendor Verify phosphoric acid
acid concentration carryover to the DAP concentration before
is too low? storage tank and filling storage tank.
release to the work area
The phosphoric Potentially hazardous Reliable vendor Ensure adequate material
acid is phosphoric acid or handling and receiving
contaminated? ammonia reactions with procedures and labeling
contaminants, or exist
production of off-
specification product.
Valve B is closed Unreacted ammonia Periodic Alarm/shutoff of ammonia
or plugged? carryover to the DAP maintenance (valve A) on low flow
storage tank and through valve B.
release to the work area Ammonia detector
and alarm
Flow indicator in
phosphoric acid line
Too high a Unreacted ammonia Flow indicator in Alarm/shutoff of ammonia
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55. proportion of carryover to the DAP ammonia solution (valve A) on high flow
ammonia is storage tank and line through valve A.
supplied to the release to the work area
reactor? Ammonia detector
and alarm
Hazard and Operability Analysis (HAZOP)
The Hazard and Operability (HAZOP) Analysis technique is based on the principle that
several experts with different backgrounds can interact in a creative, systematic
fashion and identify more problems when working together than when working
separately and combining their results. Although the HAZOP Analysis technique was
originally developed for evaluation of a new design or technology, it is applicable to
almost all phases of a process’s lifetime.
The essence of the HAZOP Analysis approach is to review process drawings and/or
procedures in a series of meetings, during which a multidisciplinary team uses a
prescribed protocol to methodically evaluate the significance of deviations from the
normal design intention. HAZOP Analysis technique is distinctively different from other
HE methods because, while the other approaches can be performed by single
analysts (although in most cases, it is better to use an interdisciplinary team), HAZOP
Analysis, by definition, must be performed by a team of individuals with the specific,
necessary skills.
The primary advantage of the brainstorming with HAZOP Analysis in that it stimulates
creativity and generates new ideas. This creativity results from the interaction of team
with diversities backgrounds. Consequently, the success of the study requires that all
participants freely express their views, but participants should refrain from criticizing
each other to avoid stifling the creative process. This creative approach combined with
the use of a systematic protocol for examining hazardous situations helps improve the
thoroughness of the study.
The HAZOP study focuses on specific points of the process or operation called “study
nodes,” process sections, or operating steps. One at a time, the HAZOP team
examines each section or step for potentially hazardous process deviations that are
derived from a set of established guide words. One purpose of the guide words is to
ensure that all relevant deviations of process parameters are evaluated.
The following is an example of creating deviations using guide words and process
parameters.
Guide Words Parameter Deviation
NO + FLOW = NO FLOW
MORE + PRESSURE = HIGH PHASE
AS WELL AS + ONE PHASE = TWO PHASE
OTHER THAN + OPERATION = MAINTENANCE
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56. Guide words are applied to both the more general parameters (e.g. react, mix) and the
more specific parameters (e.g., pressure, temperature). With the general parameters,
it is not unusual to have more than one deviation from the application of one guide
word. For example “more reaction” could mean either that a reaction takes place at a
faster rate, or that a greater quantity of product results.
LIST OF TERMS
Airline Respirator - A respirator through which compressed clean air from a source
remote from the workplace is supplied to the wearer at a suitable pressure by means
of an airline or air hose.
Attendant - A person designated by the department head in charge of entry to remain
outside the confined space and to be in constant communication with the personnel
working inside the confined space.
Authorized Entrant - A person who is approved or assigned by the department head
in charge of the entry to perform a specific type of duty or duties or to be at a specific
location at the job site.
Bonding - The joining of two or more items with an electrical conductor so that all
ends joined have the same electrical charge or potential.
Entry - The action by which a person passes through an opening into a permit-
required confined space. Entry includes ensuing work activities in that space and is
considered to have occurred as soon as any part of the entrant's body breaks the
plane of an opening into the space.
Entry Permit - The written or printed document that is provided by the employer to
allow and control entry into a permit space and that contains the information specified
in this program.
Entry Supervisor - Department Head or the designated representative responsible for
determining if acceptable entry conditions are present at a permit space where entry is
planned, for authorizing entry and overseeing entry operations, and for terminating
entry as required by this program.
Note: An entry supervisor also may serve as an attendant or as an authorized
entrant, as long as that person is trained and equipped as required by this
program for each role he or she fills. Also, the duties of entry supervisor may be
passed from one individual to another during the course of entry operation.
Hazardous Atmosphere - An atmosphere that may expose employees to the risk of
death, incapacitation, impairment of ability to self-rescue (that is, escape unaided from
a permit space), injury, or acute illness from one or more of the following causes:
• Flammable gas, vapor, or mist in excess of 10% of its lower flammable limit
(LFL).
• Airborne combustible dust at a concentration that meets or exceeds its LFL.
56

57. NOTE: This concentration may be approximated as a condition in which the dust
obscures vision at a distance of 5 feet or less.
• Atmospheric oxygen concentration below 19.5% or above 23.5%.
Hot Work - Any work involving burning, welding or similar fire-producing operations.
Also, any work that produces a source of ignition, such as grinding, drilling, or heating.
Hot Work Permit - The employer's written authorization to perform operations (for
example, riveting, welding, cutting, burning, and heating) capable of providing a source
of ignition.
Immediately Dangerous to Life or Health - An atmosphere that poses an immediate
threat of loss of life: May result in irreversible or immediate severe health effects; may
result in eye damage/irritation; or other condition that could impair escape from a
confined space.
Lower Explosive Limit (LEL) - The minimum concentration of a combustible gas or
vapor in air that will ignite if an ignition source is introduced.
Material Safety Data Sheet (MSDS) - A document describing the properties and
hazards of a substance including its identity, uses, ingredients, health hazards,
precautions for use and relevant first aid and emergency procedures.
OBSERVER – A competent person assigned to remain on the outside of, and in close
proximity to, the confined space. The Observer is sometimes called the Stand-by-
Person.
Oxygen-Deficient Atmosphere - An atmosphere that contains an oxygen
concentration of less than 19.5% by volume.
Oxygen-Enriched Atmosphere - An atmosphere that contains an oxygen
concentration greater than 22% by volume.
PPE - Personal Protective Equipment: Any devices or clothing worn by the worker
to protect against hazards in the environment. Examples are respirators, gloves, and
chemical splash goggles.
PEL - Permissible Exposure Level: - Concentration of a substance to which an
individual may be exposed repeatedly without adverse effect.
Purging - The removal of gases or vapors from a confined space by the process of
displacement.
Standby Person - A person designated by the department head in charge of entry to
remain outside the confined space and to be in constant communication with the
personnel working inside the confined space.
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58. 58

59. 59

60. CONFINED SPACE ENTRY PERMIT
Site:
Permit Number:
Permit Validity Period: (date/time): To
Confined space identification code (if identified):
Notes:
A. AUTHORIZED PERSONNEL
Attendants and Shift for
Workers Authorized Entry Attendants and Shift Fire watch (hot work)
B. KNOWN HAZARDS (indicate specific hazards with initials)
Oxygen deficiency (less than 19.5%)
Oxygen enrichment (more than 23.5%)
Flammable gases or (more than 10% of LEL)
vapors
Airborne combustible dust (meets or exceeds LFL)
Toxic gases or vapors (more than PEL)
Mechanical hazards
Electrical hazards
Engulfment hazards
Materials harmful to skin
Other:
Other:
Other:
Other:
Other:
C. EMPLOYEE TRAINING AND PRE-ENTRY BRIEFING
1. Safe Entry and Rescue Training Conducted on:
2. Mandatory Pre-Entry Briefing Conducted on:
3. Does this job require any special training: o Yes o No
- If yes, type of training required:
4. Trainer Name: Signature:
60