and welcome to the series of lectures on principles of construction management we start a discussion
in a module relating to construction safety on what is the importance of safety and why
should a construction manager be very well versed with the issues that go to prevent
accidents and the discussion today is focused on some examples which are extremely relevant
as far as accident prevention in the construction sector is concerned that is accident prevention
at construction sites now as i have said in the introductory lecture
in this module that construction safety and construction quality or perhaps two areas
which are not given the due place as far as instruction in construction management or
project management is concerned in a word civil engineering curriculum reasons for that
could be very many including the lack of the right information as far as academic institutions
of people what teaching academic institutions is concerned so far this module especially
relating to construction module i would like to actually acknowledge the help support and
the material which i have received from my colleagues in the construction industry and
thats indeed extremely grateful acknowledged a lot of information presented in this lecture
and the next one and perhaps in this module is actually based on actual events a different
sites and actual safety related documents of different construction companies
so the information is being shared for educational purposes to create an awareness towards construction
safety and enable the students in civil engineering and related feels to be aware of the different
issues that going to construction safety in the spirit of the disclaimer given in the
document which i shared with you from the occupational safety and health administration
though effort has been made to acknowledge the help and the specific details from the
sites and from the literature wherever possible at times it may not have been possible but
that is in advertent now moving on to the statistics relating to
construction worker fatalities by events or exposure we find that this pie chart tells
us what is the nature of accidents leading to fatalities as for as construction sites
is concerned and that is the data which has been uploaded apparently for two thousand
sixteen falls slips transportation related accidents contact with objects and equipment
exposure to harmful substances or environment violence or other injuries by persons or animals
and fires and explosions if you are somehow able to take care of falls transportation
related incidents and contact with objects in equipment we would be able to take care
of more than seventy five percent of the construction worker fatalities and thats indeed a very
very large number we have already gone through the statistics
a little bit in the last class and this really shows the importance of handling construction
safety at site at the root level discussion in our lecture today would be relating housekeeping
to the accidents in the construction sites excavation related issues working at height
which includes ladders scaffolds and general topics relevant to working at heights electrical
safety lifting and rigging and special topics which is in red because we are not going to
talk about it today but in a subsequent lecture so coming to the agent of todays discussion
which is these five topics lets come to the first one housekeeping good housekeeping essentially
involves keeping the construction site clean it is a major cause for slips falls in the
construction site and is a major hazard its important that the work area is kept tidy
good housekeeping prevents accidents and a clean work site is a safe work site do not
leave sharp objects lying around as this can cause accidents and ensure proper practices
in disposing construction waste keeping tools properly and maintaining proper supervision
these are examples of proper and improper ways of keeping tools and equipments at construction
sites we see here that the site is so much more clean and this place is a cluttered site
a cluttered site is a very very difficult site to navigate and is the cause for accidents
so that is what we mean when we say good housekeeping is a very important part of construction management
it must be ensured that the sites are kept clean parts of his scaffolding reinforcing
parts bits and pieces of concrete aggregate kneels these should not be allowed to be spread
all over the place they are needs to be a proper cleaning that has to be ensured especially
in areas where people are walking more frequently in cases that its impossible to do that at
a particular point in time those area should be barricaded and i am going to show you some
photographs of a real site where this has been ensured so moving forward coming to excavation
what does excavation mean excavation means that as far as a ground is concerned we remove
a part of the ground so this removal of earth and its deposition somewhere is basically
what is excavation so what are the kind of issues that are involved as far as construction
safety is concerned relating to excavation work excavation poses a threat to the collapse
of science and fall into the excavated area and danger to nearby areas so as for as the
collapse of sides is concerned the explanation is simple that if we excavate this area whether
this sides should be vertical or they should have a certain slope depends on the type of
soil depends on the depth of excavation whether the soil is wet or dry the groundwater table
and so on so all these things put together help us evaluate
the threat arising out of collapse of the sites fall into the excavated area basically
means that if at a construction site we have created an excavation here then unless this
area is barricaded somebody walking here can just fall into this excavated fit it could
happen to a person or it could happen to an equipment as far as danger to nearby areas
is concerned the issues the following if at a site we are carrying out excavation here
we have to be careful that this area here which might already have some construction
work that might get affected because in this part we are going to remove the earth portion
here which may have some construction already existing this might be affected because we
have remove this earth so the issues relating to overburden and so
on have to be also born in mind by the safety personal at the site it couldnt danger this
building it couldnt danger this building or it could trigger a collapse of the side so
coming to what are the kind of options what are the kind of measures that need to be taken
as for as excavation related issues is concerned the first thing that comes to mind is obtained
work permit before commencing work barricade all excavated areas appropriately and put
up suitable warning signs ensure that the sides of the pit are showed before going down
to work shoring refers to any kind of means that is adopted to hold this phase firm and
this is a plate or it could be something else which is driven into this ground so that this
failure of the slope is prevented now how to we ensure that this shoring remains
in place that depending on the depth of excavation involves putting up struts such as this we
must ensure that the shoring and struts and whatever means have been taken is in place
and not showing any signs of distress before a worker goes down to work the work actually
happens at the bottom of the pit and before we get into the pit we must ensure that the
shoring is in place and is healthy ensure that proper access is provided before entering
any excavation and note the position of this access if you look at an excavated pit in
plan if this is the section so in order to be able to access this area very often we
create steps in this part of the pit or we provide ladders at different places to lower
the workman into the pit so those ladder should be in place and the
workman should know that those ladders have been installed and her safe any shift in the
shoring should be investigated and acted upon it is possible that the shoring that has been
provided on the sides is distressed on account of the side pressure from the soil it could
happen for whatever reason but the point is that as far as excavation in the pit is concerned
if any shift or distress in the shoring is noticed it should be acted upon before continuing
with the excavation never do anything that is likely to endanger yourself or others special
attention should be paid to loads and vibrations in the neighborhood we have talked about this
a little bit earlier that if there is some activity in the neighborhood here that could
also cause distress to the excavation depending on its depth and other factors and while this
excavation is going on it should be ensure that vibrations and loading in neighbouring
areas is also controlled to the extent possible now moving on lets talk a little bit about
working at height which includes ladders scaffoldings and other topics coming to ladders first this
should be used for access only for a limited period of work it should not be made a practice
that work at a certain height is carried out with the workman on the ladder for long periods
of time ladders cause accidents if they are improperly fitted not properly secured when
stepped upon with greasy substances that is the shoes are not proper and there could be
so many other factors so basically as far as safety while working with ladders is concerned
some of the steps could be do not use defective ladders
make sure that the ladders are properly secured and tide before use do not place a ladder
on loose material or lean it against fragile material what is being said is this that if
this is the ground and this the wall where ladders to be fixed when fixing the ladder
which has the verticals like this and the rungs here this point here should be properly
secured this place when the this place where the ladder rest on the ground should not be
loose or fragile sometimes it is not possible to ensure that completely and in those conditions
if a ladder cannot be secured at the lower end a coworker should hold it firmly at the
ground it should be held in place and there should be a coworker which holds it in position
ladder should extent about three feet or a meter above the landing that is what is shown
here if possible a avoid working of the ladder for a long time which i have already said
only one person at time should climb on the ladder no materials should be carried in hands
when using ladders all ladder should be periodically inspected
and cleared for use now what could be the kind of inspections that is required for a
ladder it could include all these fittings of the rungs to the verticals it could include
the integrity of the rungs it could include the fixtures at the bottom it could include
friction pads at the bottom of the ladder which help the ladder get a better grip on
the ground so these are some of the things that have to be carefully and consciously
watched and only then the ladder should be used at a side this picture here is of course
a cartoonists way of looking at the right way of using the ladder and the wrong way
of using the ladder we can see that this person here is trying to work on a wall not facing
the wall which leads to a very avoidable unnatural position for doing the work and is a safety
hazard as for as the ladder is concerned so moving forward lets talk of scaffoldings
the causes for accidents is for as scaffolding is concerned could be the collapse of scaffolds
falls from scaffolds and fall of materials of the scaffold and some of the preventive
measures would be there should be erected modified in dismantled by competent persons
only there are people who are trained to assembles scaffolds modify scaffolds and dismantle them
nobody else should unnecessarily try to do this work please remember that one of the
important things as for as safety is concerned is that there should be competent people who
are doing their job people who think that another persons job is very simple and they
can do it should as far as possible avoid doing that there will be some fine print in
their job description which you are not aware of and that could lead to accidents
the firm work the scaffolding should be erected on firm ground with sole plate and base plate
with the safe means of access and egress should be fully planked platform with the minimum
width of six hundred mm and suitably tied to the structure all platform should have
guardrails top rail and mid rail and toe boards and bracings on all four sides and this is
a typical scaffolding which gives you the different details us to what are the components
and how they have to be held in place so proper training program will enable workers to become
proficient as far as handling scaffoldings are concerned now as far as construction sites
are concerned the safety group can insist that a program for training workers by a competent
person as far as assembling this scaffolding is concerned is held but the program of course
has to be held by somebody who is in charge of the operations we have to identify the
right kind of people to hold the program and make sure that the people handling scaffolding
at their sites are properly trained you recall that fall from heights is the highest
killer as far as accidents in construction sites is concerned as far as fall from heights
is concerned include fall of materials fall of persons and collapse of the structure itself
and the required actions include do not work on edges of buildings which are not barricaded
use proper access to climb up the scaffold do not try to cross or jump in opening very
often there is an opening and we should not try to just jump from one side to the other
in fact if this opening is large the management has to ensure that appropriate platforms are
created at certain distances if required so that workers working from one side can go
together side safely and these platform obviously have to have handrails and barricades and
so on always use proper access stairways should
have handrails and as far as prevention of falls from heights is concerned its a long
list openings in floors should be barricaded or covered up very often in multistory buildings
there are openings in the floors which are left for various reasons and its important
that they are all the time barricaded or covered up so that a worker does not fall through
the opening never sit on or lean against guardrails safe work platforms and gangways should have
secure guardrails and toe boards do not work at heights if one feels weak or dizzy the
important thing here is that only the worker knows that he or she is not in the best health
to carry out a certain work its important that there is enough confidence
and the atmosphere generated in the site is such that a worker who is not feeling well
is not allowed to work at site its a hazard do not allow extra persons or workers on working
platforms and minimize the material being carried to and stored on working platforms
provide safety harness lifeline and other required p p e as we will see in subsequent
slides use safety nets and permits working from height has another aspect that if there
is work going on at height at a particular location a fall from an object whether its
a small nut or a bolt could could cause an injury to somebody whos passing by below the
person below may not even be aware of the work being carried out at a height of twenty
thirty forty meters and therefore with the permit system it should be ensured that the
area with the work is going on is properly barricaded at the ground level so that there
are no passes by and people know that there is work going on in appropriate precautions
have to be taken so moving forward lets talk a little bit about
edge protection barriers that prevent a person from falling down is what edge protection
is and these barriers should be constructed by a competent team and constructed using
appropriate materials like steel pipes steel wire ropes and so on and tied and anchored
using standard means such as posts u clamps etcetera now this slide in the next couple
of them have been taken from the internet to just show how the importance of fall protection
has been highlighted in different ways to this particular slide for example shows the
hierarchy of fall protection in a preferred order of control for fall hazards as the hierarchy
progresses so does the risk the best thing to do is to eliminate the hazard altogether
and the worst thing we can do is to just put an advisory that some work is in progress
in the middle we have passive control methods such as putting the physical barriers and
we have active methods like the fall restraint system as the one thats being shown here and
we have another fall arrester system which is being shown here
so moving forward this is one of the examples of the fall arrest system which is used to
arrest in employee while falling from a working level it consists of an anchorage connectors
dee ring a body belt or body harness and may include a lanyard deceleration device lifeline
or a suitable combination of these as far as working in heights is concerned of course
its a very dangerous activity at a construction site and could lead to serious injuries and
deaths and thats why it is one of the most prominent reasons for accidents in construction
sites and it should be essentially avoided by suitable access equipment and safety provisions
some of which we have discussed in the discussion today now coming to electrical safety which
is the next topic as far as we are concerned for the day
its another common problem which leads to injuries to people shocks and it also a cause
for fire the hazard includes burns shocks fire and electrocution the dangers are particularly
increased where electrical equipment is used in adverse conditions for example if the site
is wet or in damp areas where the voltage requirement is lethal accidents can be prevented
by proper practices sufficient training and supervision so some of the safety measures
that we can take is installation of earth leakage circuit breakers at all work sites
and this will protect the workers in the event of a leakage provide weather and overload
protection to electric circuits always switch off the supply after using electrical equipment
never tamper with any electrical installation leave all electrical connection to trained
and qualified personnel so time and again it is to be emphasized that
people who are trained to do a job should be the only people doing that job it may appear
to be simple but it may not be that simple do not use appliances with defective parts
do not carry out excavation around existing underground cables and continuing with the
set of measures all electrical equipment should be periodically inspected and certified for
use this will bring up issues relating to defective equipment for the attention of the
supervisors all equipment must be provided with a three pin plug three pin socket outlet
insulated cable and should have their specifications name plate attached in a clear location of
course this three pin plug or a three pin socket would largely depend on the kind of
voltage supply and the location of the construction site but what must be ensured is that a proper
plug and socket is always used keep fire extinguishers sand buckets at the
electrical booth and electrical equipment just in case there is an event use spark proof
and flame proof field distribution boards and use the required p p e so if we are able
to ensure compliance with these kind of measures we would be able to ensure affair reduction
as far as accidents related to electrical work at construction sites coming to the last
topic for the discussion today which is lifting and rigging please remember that lifting and
shifting of materials is widely done by cranes failure of cranes leads to potential hazards
including overturning of the cranes collision of either the crane or the load that it is
carrying with a structure overhead electrical hazards where the boom of the crane hits a
life cable load failure material damage personal injury and so on as far as some preventive
measures as far as crane failure is concerned all cranes should comply with the manufacturers
specifications safe work load load capacity angle according to the load chart should be
adhered to the crane capacity obviously is related to
the boom length angle at which the job is being lifted and so on so there is a chart
which the manufacturer gives and there should be no compromise in using that tag lines are
used to restrict the swinging of the loads whenever required a proper tag line should
be used to ensure that the swing of the load is restricted training of operators and dedicated
signalmen for each crane is an absolute must standard hand signals should be used only
one man should give the signal and if a signal is not visible to the operator obviously in
this day and edge we could use walkie talkies but what we must ensure is that there is a
coordination between the person giving the signal and the guy whose operating the crane
often times they are not able to see each other and they are relying on signals being
sent or communication between the two that has to be proper ensure that there is no one
below the load and that brings us to the whole story of permits once again periodic inspection
of all machinery and equipment check load center of gravity correct slings softeners
where required and so on so the moral of the story as far as discussion today is concerned
is training of workmen competent people doing their job and periodic inspection of all kinds
of equipment being used whether it is cranes slings or it is electrical equipment drills
hammers whether it is excavation equipment the excavation sites the shoring and so on
if you are able to ensure some of this we will be having a safer construction site this
slide here gives the some of the references of the websites and literature with which
would help you get a better understanding and gives you case studies of construction
accidents and i look forward to seeing you again in a subsequent class where will be
talking about possible construction accidents under certain special conditions
thank you