Modern Design of Machinery Guarding and Presence-Sensing Safety Report

This report provides an overview of modern machinery guarding and presence-sensing devices used to prevent occupational injuries. It begins by highlighting the prevalence of workplace accidents and injuries, emphasizing the importance of machine guarding. The report details common machine hazards such as hazardous motions, shear points, and points of operation. Various types of machine guards, including fixed, adjustable, and interlocking guards, are described, along with presence-sensing devices like safety light curtains, laser scanners, and safety mats. The report concludes by stressing that a proper understanding and installation of these safety devices are crucial for reducing machine-related workplace accidents. References to various studies and guidelines support the information presented, emphasizing the need for effective safety measures in industrial settings. Desklib offers more resources for students, including past papers and solved assignments.

MODERN DESIGN OF
MACHINERY GUARDING AND
PRESENCE-SENSING DEVICES
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Introduction
■ Work accidents or occupational
accidents refer to discrete
occurrences in the course of work that
lead to mental or physical
occupational injuries
■ Occupational injuries encompass
bodily damage that results from
working.
■ Some of the most common
occupational injuries involve the
hands, spine, eyes, lugs, skin and the
bones.

Occupational injuries
■ Occupational injuries can result due to
exposure to a range of workplace
hazards
■ The International Labour Organisation
states that more than an estimated 337
million accidents occur on the job every
year, leading to occupational diseases
(Ilo.org 2018).
■ This accounts for an approximate 2.3
million deaths among people.

Singapore statistics
■ The rolling injury rate over a period of 12 months was around
1.3/100,000 employed individuals (Wsh-institute.sg 2018)
■ 268 workers were found to sustain major workplace injuries,
■ The rolling injury rate for them was 16.8/100,000 employed people.
■ Approximately 1.5 incidents occurred for every million man-hour that
had been worked (accident frequency rate)

Machine guards
■ Each piece of machinery are found to be
in possession of a set of unique
mechanical and non-mechanical
hazards.
■ Machines are responsible for causing
different types of injuries among their
operators, ranging from minor burns,
abrasions and cuts to severe ones such
as, lacerations, fractures, amputation or
even crushing.

Common hazards
A wide variety of actions and motions have the capability of presenting
hazards to the workers who are operating in or around the machinery.
Three of the most common types of hazards are given below:
■ Hazardous motions
■ Shear points or pinch points
■ Points of operations (Vallmuur et al. 2016)

Machine guarding
■ Machine guards refer to protective
devices that have the power of
covering pieces of a machine that are
in motion, and might pose danger to all
workers.
■ These are a major form of safety
feature that are installed on or around
machines, which are identified to be
responsible for occupational injuries
among workers or operators (Parker et
al. 2016)

Mechanism of machine guarding
■ Machine guards are termed as rigid forms of physical barrier that
are designed in a way that allows the enclosure or covering of
machine parts, commonly designated unsafe for human contact.
■ Coupled with adjustable or interlocked safety operations these
guards also result in an increased protection level for all kinds of
point-of-operation guarding (Wshc.sg 2018).

Types of machine guarding (1)
■ Fixed guards are permanently attached to the
machinery by screws that prevent workers
from accessing any danger zone from all
directions.
■ These guards cannot be removed from the
machines without proper tools
■ Adjustable guards can be moved or
reconfigured, based on the work dimensions
that is being performed (Chinniah 2015)
■ These guards help in handling materials of
different sizes and also protect the operators
present in the danger zone

Types of machine guarding (2)
■ Interlocking guards are another type of
machinery guarding that disengage or
shut down the power of the machine,
when they are opened or taken out of
their normal position.
■ The guards stop motion of the
dangerous operations and lead to
manual restart of the machinery under
such conditions (Yamin et al. 2014).

Presence-sensing devices
■ Presence-sensing devices are another
safety device that are principally used for
pressing brake safety.
■ They are at times preferred over the
machinery guarding due to their role in
increasing the productivity of the
operations by increasing the access for
routine maintenance of the machinery
(Wshc.sg 2018).

Types of PSDs (1)
■ Safety light curtains that contain two
retroreflective muting sensors and a
muting box allow the workplace access,
without halting any other work process.
■ Safety light curtains have corner mirrors
and provide guarding for the perimeter,
for the entire work zone (Irfani 2015).
■ Laser scanners are also configured in a
way that assist in the easy detection of
irregular areas present in the workplace.