and welcome once again to the series of lectures on principles of construction management and
in the last couple of lectures we have been talking about construction safety and in the
last class we had talked about some specific considerations or reasons because of which
construction sites are more vulnerable to accidents we will continue that discussion
today and talk about some special topics which was left out from the last class now before
we do that i must once again acknowledge the help and support and the material received
from my colleagues in the construction industry and i must admit that a lot of information
presented in this lecture is actually based on actual events at different sites and actual
safety related documents of a few construction companies and this information is being shared
only for educational purposes to create an awareness towards construction safety
moving on this was our agenda for the last class we have covered housekeeping right down
to lifting and rigging and what was left for a subsequent discussion was some special topics
now before we go to special topics and start discussion today let me show you some pictures
of construction sites drawing from the kind of classification we had done last time so
here are two pictures which show an extremely cluttered site and you can imagine that working
in these sites is an additional challenge than working in normal environment to self
the picture on the left has bars lying all over the place and the workers have to be
very careful to avoid tripping on these bars as they move carrying a bar from one place
to another similarly the picture on the right is another
cluttered site compare to these sites lets look at a site like this where there is construction
material there is scaffolding plates there are all kinds of materials but they are nicely
start at one place barricaded and the passage where people have to move is clearly defined
and very neat the same is the situation in the site on the right so we can see that these
places where there are bars are sticking out and so on that has been nicely barricaded
so that nobody really works into an area which is more hazardous you will recall that we
discussed safe work practices as far as excavations are concerned and these are pictures which
show shoring and struts to support the shoring and providing access using ladders
so you can see with this ladder extends beyond this point of rusting as far as the shoring
is concerned when you had spent some time talking about working with ladders so here
we see some safe practices while working at heights with ladders and this picture here
especially shows us how to handle a ladder so there is ladder should extend the meter
beyond this point there is working between the styles there is ladder secured at the
top which is being shown here there is an additional point of contact for the ladder
which is given here the ladder on the level surface is secured at the bottom and so on
so its required that we spend enough time and effort to identify the kind of precautions
that we need to take or that we can take at a construction site to prevent accidents continue
with our discussion on ladders here we see a correct use of the ladder and an incorrect
use of the ladder so you can see that this is a bad practice something which the workers
need to be trained not to do similarly if we see this slide here also is an example
of the right way of working with ladders and the wrong way of working with ladder facing
directly towards the steps facing the work activity and steps being side on as far as
the work activity plane is concerned makes a lot of difference when it comes to safe
working with ladders continuing with our discussion on working
with heights here we can see instillation of safety nets in a big way as far as a building
construction site is concerned and this picture here shows us what are the different design
considerations or theoretical considerations that go into the design of a harness so moving
on here we see some unsafe electrical work practices at site it could be non isolation
of electrical parts it could be defective cords and wires it could be the cover not
been provided on the junction box or it could be an unused opening which is not closed all
these becomes sources for increase in the vulnerability and susceptibility as far as
accident is concerned now lets come back and continue our discussion on some special considerations
or special topics in construction safety as far as their relevant from the point of view
a construction site so first thing that we take up today is cutting
and bending of reinforcing bars engineers and supervisors should prepare a safe work
procedure and train and educate workers before commencement of work and only trained and
authorized personnel should operate the machine the bars should be arranged with enough access
way for workers to be moving around you recall that one of the first slide that i showed
for a poor housekeeping slide involve basically workers moving around with reinforcing bars
and this is precisely whats been talked about here that we must arrange and provide for
an appropriate access way so that the workers who have to carry the bars for bending to
the machine can do that without the danger or with the minimum danger of tripping as
far as the operation itself is concerned of bar bending the operator and helper must have
a good communication its important that we understand each others methods of work and
the sequence of operations that each of them has to perform
the helper should be trained to do the task the operator should ensure that the helpers
hand is clear from the moving parts i leave you with the food for thought the diameter
of bars used in the construction industry special in the heavy construction try to find
out what is the diameter of the bars involved and then try to find out the unit weight of
bars of different diameters why i am giving this assignment is basically that once you
understand a per meter length of the bar of different diameters especially in heavy construction
maybe let say thirty two mm or even twenty five mm for that matter you will realize that
handling a bar requires a fair amount of strength and a fair amount of effort much poor so the
effort involved or the power involved in the machines when they are bending these bars
or cutting these bars is phenomenal and in case there is any accident it could be a serious
debilitating accident as far as the workers are concerned so please understand please
do try to find out the diameters used in the heavy construction and the unit weight of
the bars the length of the bars which is available at sites most of the time and how it is actually
assembled when it comes to reinforce concrete construction
now this picture here shows a very good practice of shielding the protruded ends of a reinforcement
at site here another example of hazard a situations in construction site is confined spaces any
space having limited access or egress when subjected to hazards like deficiency of oxygen
toxic and flammable gasses or substances dust etcetera would qualify to be a confined space
examples for this would be pipes vessels tanks silos trenches and ducts you will recall the
two slides that i showed you about the excavation work but the picture on the right was something
which could qualify as a confined space especially if you are working let say three meters four
meters or five meters below the ground so i call upon you to find out what is the technical
definition of a confined space and at the end of it it becomes a judgment that no matter
what the definition is if there is a reason to believe that there will be limited access
or egress if the opportunity to the worker to leave that place in case of an emergency
is limited that place becomes a confined space and if it becomes a confined space the rules
governing confined space handling become operational that is something which is a construction
manager as a safety officer or a safety professional one must be aware of
as far as the hazards in the confined space are concerned it could be oxygen deficiency
or enrichment presence of toxic or flammable gases chemical hazards fire hazards electrocution
heat or cold caught in between moving equipment poor lighting and so on so there can be a
situation where if in a confined space we suddenly see a moving equipment there is no
place to escape and that becomes a death trap more or less similarly there would be challenges
arising out of poor lighting in confined spaces so these are the kind of things which we must
address when we are talking of confined spaces and the challenges posed in terms of safety
preventive actions in this case would be appropriate permits check at entry access and ventilation
check levels of oxygen and flammable vapour and toxic gases entry book and supervisors
present continuously at working place use proper ventilation and ladder if required
use only twenty four volt lamp for elimination display boards for confined space work being
done power tools used in confined spaces must be insulated and provided with proper earthing
ensure presence of proper fire fighting and rescue teams good communication between the
workers in the confined space and outside and finally use the required ppe these are
some of the examples of confined spaces and we can see man wholes tunnels and pipes has
definite examples of people having to work in confined spaces moving forward lets talk
about what is called hot work in the construction industry and hazards in this area would be
heat electrical hazards cutting and welding and radiation a kind of preventive action
that we talk about in these conditions would include read and understand the contents of
the permit and follow them in letter and spirit i would like to draw your attention to the
word permit which has been often on as far as our discussions is concerned
so this is a system by which an announcement is made appropriate approvals are taken for
a particular work to be undertaken in a particular area so there is a large site a certain area
and if we want to carry out certain work it could be confined space it could be working
at heights it could be hot work in a certain area then there has to be a system in place
so that approvals have been taken and other people informed of that nature of work being
done for a particular period of time check the area to prevent fire because in case of
hot work its extremely vulnerable for fire check gas cylinders and apparatus for leak
hot work often involves working with flames and for that we often use gas cylinders and
we must ensure that they are not leaking when welding be sure that masks are used and the
area is barricaded check fire hazards to prevent fire ensure the presence of an operator and
fire extinguisher confine fire spark range with proof sheet and do not place combustible
materials in the fire spark range and lets continue with this list we must ensure proper
ventilation inspect and check proper earthing welding cables gas cutting hose machine regulator
and so on may provide proper welding and gas cutting booth which could be made with a g
i sheet with weather protection that basically says that in the site we isolate an area provide
a lot of the right infrastructure in that area but that sometimes is possible sometimes
its not possible and it depends on individual conditions
gas cutters should be provided with gas friction lighters and matches should not be used check
all fitting such as gauges flashback arrestors non return valves gas cylinders and cutting
torches proper use of proper personal protective equipment safety shoes helmet hand gloves
goggles face shields etcetera we will talk about the specific ppes and their specifications
in a subsequent lecture but the spirit of it i am sure is clear to you and these pictures
here show you two examples of hot work in one case you are talking of bituminous construction
and another case we are talking of pipe welding and grinding and we can see a lot of sparks
flying around so you can imagine that these sparks pose a major hazard as far as fire
is concerned and effort needs to be made to confine these sparks to a local area
similarly when working with hot bituminous mixes one has to be very careful to protect
your feet with the use of proper books and in order to warn people that the worker may
be working its also important that people in the neighborhood or near this work site
are also warned that this is hot work and thats why we need a placard like this which
is shown because the worker working with bituminous mixes or the hot bituminous mix would be wearing
the right kind of ppe but not necessarily a passerby not necessarily a person not directly
involved with the work and if he is not wearing that protection that person might get injured
causing an accident as far as the construction site is concerned
so moving forward lets spend some time on falling objects we talked about it briefly
last time cover up all the openings because they become the source for objects to be falling
through and hurting somebody or hitting somebody down below debris and other materials can
fall through these openings and hurt someone below do not throw debris or waste materials
from height its a very bad practice because somebody at the top may not necessarily know
if there is somebody walking around at a lower level or because of the action of wind and
so on the place where you are targeting the debris to get deposited might change and hit
somebody where you thought the debris would not even reach wear your safety helmet all
the time use entrances that are provided with overhead shelters do not go under suspended
loads prevent tools from falling by placing them in a suitable toolbox and provide suitable
toe boards dispose of debris down the chute provided it depends on the kind of debris
it depends on the amount of debris we may have to construct a chute through which the
debris can be just dumped from the top and it reaches the bottom the chute also becomes
an environmental protection measure because it localizes any dust going into the atmosphere
another special conditions as far as construction sites is concerned is the use of machines
we cannot live without using machines at a construction site and we have to observe certain
precautions all machinery must be securely fenced so that they do not fall do not used
machines with an exposed dangerous spot hands should never be placed near a machine with
rotating parts whether its a peddles to fan or any such machine make use of push sticks
when pushing at timber across a circular blade check that hand tools are in good condition
before use all the effective tools must be reported to the supervisor its important from
the employers point of view where all tools and tackles are maintained and defective tools
are not used but at the same time it is the employees responsibility it is the workers
responsibility to ensure that the tools that we are working with are shown proper respect
the tools should not be miss handled and used for purposes other than what they are meant
for only then will they have a long life and here are some of the pictures of using safe
practices when handling machines chemical cleaning is another area which has a small
application as far as construction safety is concerned at sites
and the hazards involved are pollution of the environment toxic gases and machinery
or equipment hazards and the preventive measures were obviously include work permits barricading
of work area display of sign boards checking of all the flanges nuts bolts valve and connections
before and during the work inform all nearby employees and workers use of proper ppe such
as hand gloves safety shoes helmets and if there any choke lines of valves then use a
wooden hammer and remove the obstacle its important that it is ensured that all the
lines are free they are not choked we will not spend too much time on fire fire is a
major hazard at construction sites and could cause major injuries to people and destroy
property leading to serious disruption of work poor safety practices include allowing
overheating of machineries in proper storage of flammable and combustible liquids and hot
work which is welding and cutting and preventing measures would include adequate fire safety
training effective measures for all hot work good maintenance of electrical equipment restriction
of smoking only to smoking areas storage and cleanup of combustible and flammable liquids
and regular inspections of course fire engineering and fire safety is a very vast topic and i
am touching upon this only for the sake of completeness and we would probably need an
entirely different course to talk about the hazards of fire and how it is handled from
an engineering point of view as far as manual handling is concerned very often we have workers
and labour handling heavy loads having very specialized kind of loads please remember
that even handling a twenty kg bag is not easy a twenty kg bag handling versus reinforcing
bar which is spanning let say three four five meters having the same weight are two different
things and therefore if not properly taken care of
manual handling could lead to injury and pain in the lower back and hand injuries so here
we are talking of not only accidents here we are also talking about health of worker
and health is also one of the very important assignments or it is very much within the
scope of work as far as safety is concerned so the safety group is charged not only with
the responsibility of ensuring that there is a safe environment for working which is
accident free but also charged with the responsibility of ensuring that the environment is such that
long term effects such as pain in the lower back they do not come and haunt the workers
for preventive measures could include proper training in handling load using mechanical
aids where possible and taking help if load is heavy and wearing appropriate ppe and periodical
medical checkups close the discussion for today i would leave you with a problem for
in fact two problems lets consider the following scenarios in construction
project pressure testing of a pipeline and painting we have in this discussion today
and in the previous class talked about specific scenarios excavation hot work confined spaces
welding and so on so i am giving you two scenarios pressure testing of a pipeline and painting
pressure testing means that we have set up a pipe line which has several joints and finally
what we want to do is to put a (( )) here (( )) here and try to fill this pipeline with
the fluid and apply pressure so we want to make sure that the pipes are in good condition
the joints are in good condition and the pipeline itself is worthy of views it needs the requirements
so this is what is accomplished or this is what is the object of carrying out what is
called a pressure test of a pipeline similarly there could be a situation where we are painting
a large tank in these two cases list the hazards involved and measures that can or should be
taken to minimize the possibility of an accident while working
so much the same way as we have done in the previous slides try to do these two assignments
on your own and try to figure out how we can work or how should we work when we are working
for these two cases with this we come to our close for the discussion today and here is
a list of references which will help you understand the whole idea of construction safety and
construction safety management better and i look forward to seeing you once again in
a subsequent discussion thank you