Loading

Alison's New App is now available on iOS and Android! Download Now

Study Reminders
Support
Text Version

Set your study reminders

We will email you at these times to remind you to study.
  • Monday

    -

    7am

    +

    Tuesday

    -

    7am

    +

    Wednesday

    -

    7am

    +

    Thursday

    -

    7am

    +

    Friday

    -

    7am

    +

    Saturday

    -

    7am

    +

    Sunday

    -

    7am

    +

Introduction to Fatal Falls
So today’s class we will talk about fatal falls and what is the hazard on fall all about. So finally this lecture in the subsequent lecture will be on concreting operation. So one fatality will be followed by a particular operation where this fall hazard is too much. So we will cover accordingly in the remaining few weeks. So what do you mean by hazards in construction case
so in construction based on the place or the mode of fatality.
The researchers have categorized the fatality into 4 different categories so number 1 in the rank
is false the next is struck by or Cav-in then we have caught in between an electrocution. So this
order it changes from place to place but falls is always ranked as number 1 in many of the
construction sites. If you see the trend in falls even though so much efforts have been taken place
in several construction firm.
(Refer Slide Time: 01:29)
The number of Fatal falls is still now the higher side only and this is the record which I have
taken from 2011 to 14 which also shows there is an increase in number in the number of falls.
This is not that we do not take any preventive measure on falls but still the projects are little complicated and complex in nature. And there are other issues also behind which the fatality in
falls has not come down.
(Refer Slide Time: 01:57)
So now let us talk more about falls if you look at falls there is actually fall on the same level or
on the same floor on the walking or working surface that is how it is generally referred. So that
falls is generally associated with 2 other terminology which is nothing but slips, trips and falls.
So let us try to understand what is, this slips trips and falls? So slip when there is 2 little friction
or traction d between feet and the working or walking surface.
Then you try to imbalance and try to fall at its primarily called slip. Trip is when your foot starts
to move but you, gets hit with an obstacle but your body getting to move another is that you lose
your balance and you just fall. So slip or trip is associated with the fall and fall generally happens
as a result of these 2 so falling on the same level or surface.
(Refer Slide Time: 02:57)So what is this real issue on falls? Even falls on the same level should be avoided. So reasons for
some of the falls on the same level as a result of slip or a trip can be a wet flow it can be
improper housekeeping you can see a picture of a construction site. Wherein know all the
materials are scattered all over the working platform and the center of gravity imbalances. May
be you try to instead of getting stepping down a ladder and pushing to the ladder to other
position.
And then trying to reach out an activity or a material you try to know grab the material from the
place where you put the ladder. So as a result you result in awkward positions or postures in job
sites. So you lose the balance and then you try to fall off an example can be show here so this is
the person and the center of gravity is actually know can be marked as the triangle keeping in the
lower to a chest level to your legs these are the 3 points.
And if you try to move your body wherein this middle point goes away from these 2 points then
you, lose your balance and try to fall off. So maybe you try to work something on your floor
level or something away from your place and you try to extend sideways or upper. As a result
body aquarium starts changing and in there is a fall. Impact generally whatever has been reported
so far. As a result of falls on the same level is only minor injury and this we have seen earlier what, is
minor injury falling the first classes. So it can be a, sprains, strains, bruises, contusions, fracture
and abrasions whatever you want. Affected body parts can be anyone of the body parts.
(Refer Slide Time: 04:51)
So what are the possible falls to predominantly lower level not on the same level. Now we are
really talking about the falls so there is an IS code which has given a very big list on what are all
the possible falls to a little specific height or a lower level. So from height such as various floors
or scaffolding sloping roofs, hoists, ladders or poles, platforms etc., which are all erected for
execution of the work.
In pits so always falls need not happen from a height above ground floor and then to the ground
floor. It can also happen from the ground floor level to what we call basement or something like
a pit or open hole or something. So in pit such as lift shafts or down stairs or chutes, basement
and excavations into water maybe you slip inside a water body. So it can be wells, sea or etc.,
through roof covering such as tiles, slates or sheets.
And falls from sloping of fragile roofs in sewers through manholes are tunnels which can contain
also other hazards like foul air dirty water filth and so on. From chimney’s steel structures plant
machinery etc., such as hoists, cranes, trucks, dumpers and so on. So this is not the complete so
falls can happen from anywhere so in any part of your construction work. So we have to be very
careful with the falls.(Refer Slide Time: 06:23)
So now the question that can come to you is what is the height below? Which I am, say if above
which I should take proper precautions. So there is also a statistics on the fatal falls with regard
to the height of the structure or from where the worker or person has fallen down. So if you see
the height of the structure it starts from 6 feet less than 6 feet to more than 30 feet height. And
the percentage of fatality as a result of all is also given here so this is a record in 2015.
So in 2015 16.9% of all fatal falls where from height 10 feet or less so OSHA recommends any
fall protection for height above 6 feet which is considered as a and tolerable limit. So above 6
feet if you want to work in sight it recommends that there should be proper fall protection
devices.
(Refer Slide Time: 07:26)So what happens when a person is about to fall? So anatomy of fall so you should first know
why this fall is very dangerous and what happens when you try to fall? So this fall is very
dangerous hazard because of the reason that the minute you try to realize you are about to fall
you would have fallen very you know much in dug. So it takes 0.33 seconds to become aware
that you are about to fall.
And in the 0.33 seconds your body would have fallen at least 2 feet it takes 0.66 seconds for the
body to react. So in that 0.66 seconds the body would have fallen at least 6 to 7 feet and by the
time you generate movement realize that you are falling and you try to grab something in close
by. You would have at least fallen 10 feet and in 2 seconds the estimated fall is about 64 feet. So
that is where fall is considered to be really dangerous.
(Refer Slide Time: 08:29)So if you see the violations we can still prevent falls as explained in the first class many of these
hazards can be easily prevented or at least minimized in the size if you fall or certain safety
protocols. So if you look at violations in 2019 there is an, compilations on violations as given by
OSHA. So among the 10 violations at least 4 violations with regard to falls where around 15000
for; thousand something as against 31,000.
So half of all the violations that happened in 2019; there all related to fall only because of the
violations. There are the falls are still happening in construction sites and which should be
avoided.
(Refer Slide Time: 09:19)Now some more statistics where are the real falls happening? We know falls are there but from
where exactly the major fatality has happened. From roof that ranks number 1 fatal falls next is
ladder and the third is scaffold so we are going to discuss only these 3 hazards in detail in
today’s class. Roof, ladder and scaffold so types of non-fatal falls again from ladder and that is
really high from ladder lot of non-fatal falls have happened.
And the next one is from staging on scaffolds and who are all the workers who have been
affected with the fatal falls are ironworker, roofer, welder, laborer and so on. So (()) (10:06) is
also is little know a quite a number of people are really affected because of the fall hazards.
(Refer Slide Time: 10:15)
So now let us start looking at each one of the hazards in detail so number 1 holes and openings.
So holes are openings you know primarily it is an open space from where something falls or a
person falls. So now what is the dimension? Dimension various from ocean and also IS code
talks about the different dimensions and OSHA says something else. So that you can really refer
to but in general logical sense if you want to understand what is a hole and what is a opening?
Holes are nothing but very small opening on your floor or your ground surface from where you
may try to fall material or objects or you may also have a slip or a trip hazard. Some of the
pictures here are all shown here will tell you what is a hole. And opening here really large gap or
void or a floor on working surface and where in a person and objects along with the person can
also fall and have a hazard. Hole means a gap or a void it can be in a floor roof or other walking working surface which
should be covered and example can be pipe opening, belt holes and so on. And an opening which
is measuring more than 30 centimeters or more as given by the IS codes so in a floor, platform
pavement through which employees can fall to a real lower level. Example is hatch way, stair or
ladder opening, pit or large manhole.
So similarly there is a related terminology in walls when the same opening happens along the
wall, or say similarly you have a hole and an opening also.
(Refer Slide Time: 12:07)
So how do we now overcome this hazard for a hole there is a specific way to overcome you can
have, hole covers. So the, hole covers again there are so many ways of thinking about what can
be right cover and how to identify and show that it is hole cover. So hole covers if you want to
put it on a road way then this cover should at least support 2 times the maximum axle load of the
largest vehicle that as passed through that cover.
In a given particular day maybe you think off a very large vehicle that is supposed to cross the
road and the maximum axle road of that largest vehicle at least 2 times the load it has to be
supportive this hole is to be able to tolerate. And other covers should support twice the load of
weight of employees, equipment, material whatever is supposed to pass on in that cover. And these cover should also be secured should not be displaced by the moment of people in wind or
equipment.
And all these covers should be brightly color coded and then nicely it is, of hole cover and
written maybe as warning hole cover do not remove and all these can be done. The lot of ways of
warning the work those who are passing by this is not an normal regular floor and it is a hole,
cover just laid over there.
(Refer Slider Time: 13:38)
Some more pictures on opening so this is a floor opening and this is a wall opening and both
these hazards are not properly safe guarded.
(Refer Slide Time: 13:52)Then unprotected sides and edges when you talk about wall openings and so on then other
terminology which comes close by is, unprotected sides and edges. So the edges in along as slab
construction or may be a roof construction should also be properly safeguarded. If you see here
that is the rope for safeguarding but it is not a real protection and otherwise if you want to use
rope as a safeguard measure then there should be standard practice off how to put the ropes.
So this is a staircase edge protection you can see the staircase here and there is no edge
protection at all even this floor is also protected properly.
(Refer Slide Time: 14:35)This is an unprotected sides and edges if you see here this complete opening is not at all
safeguarded.
(Refer Slide Time: 14:45)
This is also one edge of a floor and completely its unsafe there is no protection at all here.
(Refer Slide Time: 14:59)
So what are the ways to safeguard opening like this maybe it is an opening or maybe it is an wall
opening or it can be an open edge or a floor. So the only one way to protect is guard rails which
we will see little later after understanding what is a roof, slope and so on? Because both these
hazards require the same small protection so now in the roof slopes the roof slopes are conventionally classified as 3 types number 1 is flat roof then you have low slope roof and other
one is steep slope roof.
Flat roof suppose if there is a run of 12 you have to have a raise of 0 to 2 then it is primarily
called as a flat roof for the same 12 run you may have 2 to 4 then it is called a low slope roof and
4 and above on the run then we call it as steep slope roof. And each employee whether they are
working on the slope roof or a steep slope roof should have a proper fall protection in place. And
even for flat roof where that is an unprotected edges or slides along all the 4 corners. Then again
there should be a adequate fall protection in place for those workers.
(Refer Slide Time: 16:21)
So now, the fall protection as I told for any opening or any unprotected edges sides or for a slope
proof is primarily called guard rails. So what is this guard rails? This guard rail is primarily
nothing but a 3 line member 3 horizontal lines. The top line is primarily called top rails then we
have mid rails and toe board and with adequate vertical planks along the support so that these 3
rails are position.
And the height of all these rails are also given so the top rails should be least 43 inches in height
and the mid one should be 21 and the toe board should be at least 3.5. And if you want to leave a
gap between the floor and toe board it should not be more than 0.25. So this is what is a
dimension; of the 3 rails and if you talk about the load the top rails should able to withstand 200
pounds of weight which comes on it.The mid rail at least 150 and toe board should be at least 50 and the thickness also it is all given
here in this picture and as such the guard rail should be in place in the sides. Now if you talk
about the weight requirement the entire guard rail should be able to support at least 200 pounds
or 100 kg’s of force on any direction along the top edge. It can be on outward, forward,
downward direction whatever direction you apply that can be a deflection. And the deflection
should not be more than 39 inches from the walking or the working surface.
So if this is 43 plus or minus 3 and this deflection can go only till here so in this deflection is
nothing but is mentioned as 39. It cannot go below that if that is the case then this rails has to be
inspected and accordingly braced for use. And this; guard rail are used if they are used as the
point of axis for ladder ways or something then they should have a proper gate also. So that they
are not disturbed and actually the people are walking in and move out is the guard railing place.
If any site is using manila or plastic or synthetic ropes then they should also be tested very
frequently in order to check for the strength requirements. Whether they are still withstanding the
strength requirements or not?
(Refer Slide Time: 19:04)
These are some of the pictures on where guard rails are in place. This is primarily and now floor
opening and there is a guard rail which is painted in orange color which is bright which is
actually visible from far off distance saying that there is a garden rail in place. This is a wall opening which again as the guard rail in place and as a safety precaution this is also a floor and
wall opening which has primarily a guard rail.
So this is a wall opening and the guard rails are missing here and this is also a picture of a wall
opening and where there is a guard rail missing. And suppose if the worker as to use tilts or
elevated heights to reach the roof surface. Then accordingly the guard rail heights, has to be
elevated and adjusted as shown in this picture.
(Refer Slide Time: 19:56) Break Video here


So we have discussed about the floor or roof openings and slopes of the roofs and also we have
talked about hole, covers and guard rails which are primarily major safety precautions for when
you are working on for against falls. Now the next hazard is primarily a scaffold if you see
scaffold now let us discuss what is, this scaffold? Where is it used? And what are the other
terminology types of scaffold and everything you see along with the safety precaution as well.
If you see a very simple scaffold in a small construction site it looks very simple like this with lot
of you know logs on different places tried vertically and horizontally. Through which people
claim and do the air concreting and brick work and masonry work.
(Refer Slide Time: 20:49)So in general if you see this scaffold terminology so scaffold is nothing but an elevated
temporary working platform. For enabling the workers to know to climb up on to the, and
reached the working place and this is temperature structure which consist of standards put logs,
ledgers and generally of bamboo or timber or even metal aluminum. There are so many scaffold;
material as come in place and also we have customized scaffold as well as commercially
available manufactures scaffold also available these days.
To, provide a working platform for workmen and material during construction maintenance
repairs and demolition to support or allow hoisting and lowering of workmen their tools and
materials. So the difference parts number 1 is standard or upright it is a vertical or a near vertical
member used in the construction of scaffold for transferring the load to the foundation. So these
are the main member in these scaffolds.
The next one is putlog is as scaffold members planning from your ledger to ledger or from the
ledger or standard to a building and upon which the platform rests. And what is the ledger it is a
horizontal member which ties the standard at right angles and which may support the putlogs and
also the other staff members. Brace a member fixed diagonally across 2 or more members in a
scaffold primarily to have the stability of the holes start scaffold.
Raker it is an inclined member fixed to the scaffold to ensure stability and tie is used to tie the
scaffold for the structure in order to prevent the horizontal movement of the scaffold. (Refer Slide Time: 22:40)
If you see some pictures of this scaffold these are the pictures and all the parts are all labeled
here. And if you see here if the scaffold platform is not stable you can also have an base plate so
that this scaffold are firmly put in place.
(Refer Slide Time: 23:00)
Now let us talk about each and every part of the scaffold and what does the safety requirements
talk about. So scaffolds capacity each scaffold or its scaffold component should be capable of
supporting without any failure at least 4 times the maximum intended load. If you plan for a load
x it should be at least able to accept 4x the load. And platform construction so each platform unit shall be so installed between the adjacent units and the space between the platform and the
uprights is not more than 1 and half centimeters wide.
So suppose if these are your standards between your standard and your planks scaffold plants
you can have not more than 1 inch width gap. And between the scaffolds planks you should not
have any gaps and it should be so arranged so closely like this. And these are the outriggers in
order to have a fixed mobile scaffold in order to keep it in position. And also you can have hatch
platforms for movement of people and material.
(Refer Slide Time: 24:19)
Some do’s and don’ts on the scaffolds do not sit on the hand rails these hand rails are the guard
rails are primarily for safety of the scaffold in order to prevent people from falling down. So you
should not be sitting on the hand rails do not throw anything from this scaffolds it falls on the
people or any public who are passing by that place. And do not over load this, scaffold
unnecessarily do not try to keep material more than what is necessary and even though it can
support 4 times the load.
(Refer Slide Time: 24:54)Scaffold platform now let us talk about the platform. So the platforms should not be where the
platforms are to be overlapped in order to have a very long length of the scaffold. So they can be
overlapped only on this supports and this overlap should not be less than 12 inches or 30
centimeters in width. And this should happen only along the supports and not on the middle of
the support.
And the scaffold planks beyond the end support shall not be more than 12 inches and not less
than 6 inches. You should not be used as the cantilever action or something so people should not
be loading material or something over there. But only for an, end support and end vicinity it can
be extended.
(Refer Slide Time: 25:48)Now platform width if it is not more than 2 meters then it is primarily used for painters,
decorators and other people and other men and material also can use. For other men and material
platform which could be 500 mm and for painters, decorators you have a platform they need a
platform width of 300 mm. If the platform height is more than 2 meters above the ground or
from the floors from where material are lifted and supplied. Then you can have a standard
platform width of 500 mm.
You can also have axis ways or rank ways like this and for usage and this is also a bad working
platform for usage. And even though, workers have not used a proper PPE also in the particular
picture.
(Refer Slide Time: 26:40)Now the scaffold end platform as a cantilever should not be loaded up and use like a cantilever
means. Unless it is specifically designed for tipping load which is primarily the cantilever action
unless it is specifically designed and recommended. It should not be used as a normal platform
the side and end brackets designed to support people only and not for equipment. And for other
only for inspections for checking something people can use but not for loading and storage of
materials.
And these do not store materials and only store materials on scaffold which are for immediate
use and if it is for a long term use after 1 day or 2 day only you need something then do not load
those materials on to the scaffold. Also do not overload the platform too much of materials
because it can have this trip hazard also when workers on passing by this scaffold.
(Refer Slide Time: 27:42) Means of access to scaffolds how do these workers are along with the equipment and material try
to access the scaffold. So that means IS code and OSHA recommends 3; means as an access to
scaffold. One is ladder worker can use ladder or there can be ramps or stairways. Stairways are
generally used when you want to the scaffold for a long term purpose. For example a
construction will take like for several months it run for several months when it is not advisable to
use a ladder or ramp better make as stair case.
Otherwise ladder is safest means of use if it is for short term purpose and ramps are also used for
easy lifting of materials and movement of materials. So stairways for scaffold exceeding 4 meter
in height stairways are the safest means of access. And how should these stair ways be for
preventing from falls. The treads and risers should be uniform width and height in anyone
particular flight.
And the minimum width should be 1 meters and maximum angle of ascent should be 50 degrees
and the stair railing should be there on all open sides. Handrails should be there on closed sides
and standard railings and toe boards should also be there on all landings. You should have an,
safety precautions of guard rails and even on the landing. Ramps or gangways and its
advantageous for access to scaffold platform from hoisting towers and from adjacent floor levels.
But if you have difference in level between; the 2 platforms when ramps are on the good source
of solution. If the ramps or runway is 1.5 meters above the ground floor level then it is recommended to have a protection with the standard rails and toe boards. And the slope of ramp
should not exist 2 is to 3 in the sense for every 2 meters in height the horizontal length should be
3.
If the slope is more than 1 in 4 on the sense so your horizontal is 4 and vertical is 1 if it is more
than that. Then there should be a proper fall protection on either sides or the ramp should also
have cleeds or places. So, that it has creates friction for the moment of material and people. The
last option is ladders there are so many ways of mains to access you have portable ladders there
are hook on ladders and attachable ladders.
Hook on ladders and attachable ladders are generally designed along with the scaffolds. So along
with the scaffold it comes with the proper design and portable ladders are designed separately.
And we will talk about the safety of portable ladders and in the next few slides.
(Refer Slide Time: 30:50)
Some quick recap on hazards in scaffolds so; this is a picture on improper scaffold if you see
here the scaffold itself is not done properly. And there can be hazard of no cards or maybe a
danger here poor housekeeping along the platform you should not be loading material on the
platform. And also the platform is not regular in the sense they actually know not aligned
properly so that the workers may have a fall hazard.So improper support if you see here the ladder itself is not in place and the worker is trying to
operate something with the roof. So this is an improper support improper access you should also
have a proper means of access for accessing a scaffold and this is not a proper access. If you see
here these are the; improper access to reach and scaffold. Improper working platform if you see
here all the planks are overlapped not on the supports.
But also you should be secured so that the planks are not disturbed for by the movement of
people and material or equipment. If you see here it is not properly fixed in place and no safety
harness by the worker for working in scaffolds then incomplete walk way. The walkway itself is
a gap as a huge gap or an opening unsafe act of using the scaffold for resting. So these are all
some of the pictures to show and this is what we have discussed on scaffolds.
(Refer Slide Time: 32:28)
Now let us move on to types of scaffold researchers have classified the scaffolding to 3 types.
Number 1 is supported scaffold which is called conventional scaffold supported scaffolds are all
either fixed to the ground or they are mobile which can be still fixed to the firm or fixed to the
ground. And these have platforms supported by rigid load barring members such as poles, legs,
frames are outriggers and they are either mobile or they are permanently fixed to 1 place.
Suspended scaffolds are generally you know hanging scaffolds are from 2 rigid supports which
are actually overhead. They are primarily from the roofs are somewhere above the building
construction and from their through ropes or strings there is a scaffold platform and from where the workers try to finish up their work. The other one is specialty scaffolds and there are lot, of
example in specialty scaffolds like horse scaffolds, crawling boards and so on.
And the last one is aerial lifts, aerial lifts are like cherry pickers are boomed trucks wherein using
a truck on boom you can have a small aerial lifts and workers can reach the particular place and
finish up their work. So these are the 3 types of very famous 3 types of scaffolds and we will talk
about the safety measures only for supported scaffolds and for suspended scaffolds.
(Refer Slide Time: 34:08)
Now supported scaffolds there are so many types available number 1 is fabricated frame which
we also called it as a poles scaffold and again there are so many types available there. The other
one is mobiles scaffold which can be move from one place to another along with the guard rails and the platform deck and access to the scaffold it can be moved.
(Refer Slide Time: 34:35)And the third one is ladder jacks scaffolds which has 2 ladders along with the scaffold support and through which again there are several types of ladder jacks support are there. And with this
also this scaffolds can be moved and accessed. (Refer Slide Time: 34:55)
Now safety measures for supported scaffolds and again there are so many points listed out here
but many of them will be really simple and easy for you to go through. If you go through along
with the steps number 1 is all the scaffold should be designed and constructed properly. And if
you want to get a commercial manufactured assembly then you should not have different manufacturer parts which can be you try to fix it in the site. It should be from a single manufacturer or it should be compatible so that the coupling and others are all easily getting fasten. Otherwise they are not advisable to be used in the construction sites design each scaffold and also never fix the parts if they are not compatible with each other.