safety engineering course highlights for chapter 3

1. Week 3
Equipment Hazards

2. Topics
• What is a machinery?
• Hazards of working around machinery
•Working safely with machinery
• Assessing the probability of risk
• Example
• Exercise

3. CILOS
CILO1. Interpret detailed knowledge and an understanding of
the principles of safety and health in Engineering as well as
environmental protection and associated issues.
CILO2. Explain in detail the various types of hazards in related
engineering processes

4. What is a machinery?
Machinery is:
“an assembly of linked parts or components, at least
one of which moves, with the appropriate machine
actuators, control and energy circuits, etc. joined
together for a specific application, in particular for the
processing, treatment, moving, or packaging of
material.”

5. What is a machinery?
Safeguarding of machinery provides detailed
guidance for the design, installation, use and
maintenance of machinery.
The use of machinery in a workplace exposes workers
using it, and people near it, to various hazards.

6. Hazards of working around machinery
Hazards associated with working near or on machinery vary depending on
the exact machine used but can include exposure to:
1. moving parts (e.g., risk of injuries from entanglement, friction, abrasion,
2. cutting, severing, shearing, stabbing, puncturing, impact, crushing,
drawing-in or trapping, etc.)
3. energy (e.g., electrical, electromagnetic, magnetic, etc.)
4. heat or cold
5. noise

7. Hazards of working around machinery
6. vibration
7.radiation
8.gas or liquid under pressure (e.g., injuries from injection
or ejection by hydraulic systems, pneumatic systems,
compressed air, paint sprayers, etc.)
9. psychosocial hazards (e.g., stress, job content, work
organization, cognitive factors, etc.)

8. Hazards of working around machinery
Because there are many different types of machines and
processes, a risk assessment should be conducted for
each machine or situation, and in some cases, before each
use.
It may be necessary to involve individuals with specialized
or technical expertise (i.e., engineer, safety professional,
manufacturer, etc).

9. Working safely with machinery
Each piece of powered equipment should be assessed using the following process:
How can we assess the risks in a machinery?
• Understand how the machine is designed.
• Understand how to use the machine safely.
• Identify all tasks performed by and associated with the machine:
a) What hazards may occur from use and misuse of the machine?
b) What moving parts and corresponding safeguards are currently in place?
• Identify who will be using the machine, and how often the machine will be used.
• Determine what materials are used with the machine (e.g., sheet metal, wood,
metalworking fluid, oil, etc.).

10. COMMON MECHANICAL HAZARDS

11. Working safely with machinery
Each piece of powered equipment should be assessed using the following process:
What is the method of assessing a powered equipment or machinery?
• Estimate the risk of each hazard by considering the:
Severity of possible injuries and or incidents, and
Probability or likelihood of occurrence.
• Eliminate the hazard(s) where possible.
• Use protective measures to control the risk of each hazard including considering:
the design,
safeguarding and protective devices,
administrative controls, or
other measures.
• Re-assess to estimate the new risk level.
• Repeat the process if the risk level has not been eliminated or effectively controlled.

12. Assessing the probability of risk
Severity of the injury can be determined by asking two main questions:
• What type of mechanical or other hazard is involved?
• What type(s) of injury could happen?
The probability of the injury should be determined by reviewing information about
the machine’s operation such as:
o exposure to a machine that could cause the injury while working with or
around the machine (e.g., entanglement, contact with blade, etc.)
o potential human behaviour while performing these tasks
o reports of machine breakdowns, etc.

13. Assessing the probability of risk
These three factors can be combined to determine the
probability of injury from a particular task.
Determine a risk rating for each type of injury by assuming no
protective measures have been installed on the machine.
This evaluation will help when determine if sufficient action has
been taken to prevent injury.
An example of a mechanical hazard is: contact and/or
entanglement with unguarded moving parts on a machine.

14. Assessing the probability of risk
Some of the injuries that can occur as a result of mechanical hazards are as follows:
impact - being hit by ejected parts of the machinery or equipment
friction and abrasion - e.g. use of sander
entrapment - being caught in a moving part of a machine or equipment or plant
stabbing and puncture - e.g. nail gun use
high pressure fluid injection - a pinhole leak in a hydraulic hose can burst and inject hydraulic
oil into a persons hand for example

15. Assessing the probability of risk
Some of the injuries that can occur as a result of mechanical hazards
are as follows:
crushing - collision of plant with a person is one example
shearing - can be two moving parts (sharp or otherwise) moving
across one another
cutting - severing of a human body part by a cutting motion e.g.
amputation of finger on a cutting machine
entanglement - for example a loose sleeve getting caught in a
moving part and drawing the person into the machine

16. Example
Rotating motion can be dangerous; even smooth, slowly rotating shafts can
grip clothing, and through mere skin contact force an arm or hand into a
dangerous position. Injuries due to contact with rotating parts can be severe.
Collars, couplings, cams, clutches, flywheels, shaft ends, spindles, meshing
gears, and horizontal or vertical shafting are some examples of common
rotating mechanisms which may be hazardous. The danger increases when
projections such as set screws, bolts, nicks, abrasions, and projecting keys or
set screws are exposed on rotating parts, as shown in the figure.

17. Example

18. Exercises
Exercise 1.
Identify four non-mechanial hazards that may be encountered on
woodworking machines and outline the possible health and safety effects
from exposure in each case.
Exercise 2. A carpenter is using a hammer and chisel to cut out a recess in a
wooden door.
(i) Identify four unsafe conditions, associated with the tools, which could
affect the safety of the carpenter.
(ii) Outline suitable control measures for minimizing the risk to the carpenter
when using the tools.
<Exercise 3. > Identify two mechanical hazards associated with moving parts
of a machinery and two non-mechanical hazards to which a machine
operator may be exposed.

19. Quiz Time
Q1.What are the risks of moving parts of machine?
a) Can cause crush injuries to fingers and hand
b) Can cause pinch injury if caught in between moving parts
c) Can cause injury to eyes by flying objects
d) All of the above
Q2. Machine guard must ____________
a) allow to work by providing opening
b) be easy to remove on demand
c) not create a new hazard
d) be temporary and weak to break in event to facilitate urgent work
q3. What types of machine parts and which area must be guarded?
a) Motor to pump connecting shaft
b) Power transmission apparatus
c) Belts, flywheel, and other moving parts
All of the above

20. Quiz Time
Q4.What are the major causes of machine accidents?
a) Lack of inspection and maintenance practice
b) Poorly maintained worksite
c) Absence or damaged machine guards
d) Bad Housekeeping
Q5.What are the hazards associated with machine operation?
a) Unguarded machine parts
b) Loose clothing
c) Flying objects during chipping and cutting work
d) All the above
Q6. What is the purpose of machine guarding?
a) To provide the physical barrier
b) To prevent machines to breakdown
c) To prevent machines to damage mechanically
d) All of the above

21. END
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