MODULE 3 - CLASS NOTES - MCN401 - INDUSTRIAL SAFETY ENGINEERING
MODULE 3 (Safety Issues in Construction)
Introduction to construction industry and
safety Issues in construction Safety in various
construction operations – Excavation and filling – Under-water works – Under-pinning & Shoring –
Ladders & Scaffolds – Tunneling – Blasting – Demolition – Confined space – Temporary
Structures. Familiarization with relevant Indian Standards and the
National Building Code provisions on construction safety. Relevance of
ergonomics in construction safety. Ergonomics Hazards - Musculoskeletal
Disorders and Cumulative Trauma Disorders.
The
Industrial Plants and Equipments are installed, tested and commissioned at
site. The Safety Aspects involved during Project construction phase are
different from those during regular operation and maintenance phase.
The
various stages of project Construction include:
·
Civil Works.
·
Receiving and Storage
of materials and equipment, spares.
·
Erection
·
Testing, Commissioning.
·
First Energizing.
·
Trial operations
·
Handing over to
operating staff
Safety
is important during every stage of the Project Construction. Some activities
(Civil, Mechanical, Electrical, Storage, etc.) are carried out simultaneously
and therefore the chances of accidents are more.
During
various stages of project construction, different hazards gain significance.
For example, during Civil works, pit-falls, falling of objects, collapse of
structures may happen. During erection work; falling of persons from heights,
failure of cranes/slings, falling of equipment, fires caused during welding
etc. are possible. During testing / commissioning: electrically caused
shocks/fires/explosions are quite possible. During storage of equipment prior
to erection; fire hazards are possible.
Field
Quality (Site Quality) Management ensures good quality of Site Work at every
stage of construction. Good Field quality ensures higher reliability and safety
of plant and equipment during operation. Construction quality has long term
effects on safety. Poor quality during construction enhance possibilities of
equipment failure, fire hazards and accidents during regular operation of the
plant and equipment.
Main
reasons for accidents at construction sites are:
·
Falling persons.
·
Falling materials.
·
Transport machinery
accidents.
·
Lifting equipment.
·
Excavation, etc.
Following are the common hazards during
the project construction:
·
Accidents due to pitfalls
in trench, excavations.
·
Fall of persons from
height.
·
Accidents due to
failure of cranes, slings, ropes or shackles.
·
Falling of objects on
human body.
·
Explosions / Fires.
·
Road accidents.
·
Collapse of structures,
walls or slabs.
·
Electrical accidents.
·
Equipment failures.
·
Lightning.
The accidents at site may occur due to
one or more of the following:
·
Lapse in Management.
·
Human error or
negligence or ignorance.
·
Failure of Plant or Machine
component or subsystem.
·
Unavoidable natural
cause (floods/storms/lightning).
EXCAVATION AND FILLING
The
serious hazards in excavation jobs are due to falls and falling objects. A
cubic meter of earth weighs more than one tone and falls of the size are all
too often fatal to workers involved.
Here
excavation means a man-made cut. cavity, trench or depression formed by earth
removal for the purpose of constructing the road, rails, canals. dams,
buildings, etc. Excavations is also required to be carried out for borrow pits
and quarries.
The
primary concern in exaction related work is cave-in. Cave-ins are much more
likely to be fatal to the employees involved than other construction related
accidents.
To
ensure the safety of those involved, excavation work has to be properly
planned, managed, supervised and executed in order to prevent accident. Persons
involved at all stages should be aware of the hazards involved and the
procedures in place to control the risks associated with this type or work.
Common Excavation Hazards (Causes
of Collapse)
·
Failure of the soil
because it cannot support its own weight. Loose rocks or soils are responsible
for this.
·
Breakdown of the
strength of the soil by moisture - usually caused by heavy rain or frost.
·
Failure caused by
vibration from the movement of vehicles nearby.
·
Failure due to the
weight of loads placed near the edge of excavation.
·
Failure due to the
variation in the nature of the soil, such as pockets of sand.
· Failure due to the
sides of excavations being struck by heavy loads such as pipes, when they are
lowered
·
Unsuitability of
adjacent structure on excavation near its foundation.
·
Falling of any
person/equipment in the pit.
Safety
Provisions during Excavation
·
The position of
underground installations such as sewers, water pipes and electrical cables should
be verified and in case of their existence, they must be isolated. If they
cannot be isolated or removed or shutdown, they should be fenced, hung up or
otherwise protected.
·
On every part likely to
be visited by persons or where transport vehicles ply, the area should be
suitably fenced, guarded or barricaded to barricaded to prevent fall of
persons, vehicles or live stock into the excavated area.
·
Warning sings should be
erected and in the night hours the area should be illuminated to warn pedestrians
and vehicular traffic.
·
Arrangements should be
made to prevent external vibrations due to rail/road traffic.
·
On steep slopes,
workers shall not be permitted to work on above the other.
·
No excavation of
earthwork below the level of any foundation of a building or structure shall be
commenced un less adequate steps are taken to prevent danger
·
Additional precaution
be taken to prevent slides, slip or cave-ins when excavations are made in
locations subject to vibrations from rail-road or highway traffic, etc.
·
In all trenches 1.5 m
or more in depth, ladders should be provided.
·
Excavation areas should
be adequately lighted for night work.
·
During hours of
darkness all public sidewalks should be adequately illuminated and warning about
the excavation should be provided.
·
A flagman should be
posted to warn the public or approaching trucks and to direct the trucks in and
out of the site of excavation.
·
Arrangements shall be
made to save other structures in the affected zone or in the vicinity of the
area of excavation, from collapse.
·
The sides of every
excavation, where there is a danger of fall or dislodgment of earth, rock shall
be securely supported by adequately braced to any timber of suitable quality
material
·
All loose stones,
projecting clumps of earth and unstable material that may come down on workers
in trench should be removed and the excavated sides should adequately have
braced and trench suitably guarded.
·
Stockpiles of loose
materials should not be located in the immediate vicinity of overhead power
lines and materials should not be piled against walls as it may endanger the
walls.
·
Excavated materials
should not be stacked within 1/3 rd of depth of the pit or 1 m whichever is
more, away from the edge of any excavation and should be stored and retained so
as to prevent it from falling or sliding back into the excavation and to
prevent excessive pressure upon the side of the excavation.
·
Where pumping is being
carried out to lower the ground water level, subsidence of adjacent structure
may result. The characteristics of the supporting soil may be changed by
pumping
Protection of Employees and Public
Fencing
- Excavations carried out at any place
to which the public or cattle's have or might gain access must be guarded to
avoid danger to people. A fence 1 m high or a combination of signs, barriers,
lights, makers, flags or sentries may be necessary to provide adequate
protection for the public and employees. These safety devices must be properly
maintained until the excavation is completed
Notices
and Warning Signs - notice or warning signs must be placed at all
exits and entrances to the work area to warn a person
Protective
helmets, Goggles, Hearing Protection -
·
Where employees could
be injured by objects falling from above, adequate overhead protection must be provided.
Hard hats / Helmets must be worn both in the excavation and out of the
excavation.
·
Where there is a
foreseeable risk of injury to the eyes, suitable eye protection must be worn.
Windblown grit and dust are the most common sources of eye damage in excavation
work.
Illumination
-
·
Excavation areas shall
be adequately lighted for night work.
·
During hours of
darkness all public sidewalks shall be adequately illuminated and warning
lights about the excavation shall be provided to ensure safety of pedestrians
and vehicular traffic.
·
In case of power
failure, all workplaces where excavation works are carried out should be
illuminated through emergency generators.
·
Glare from artificial
lighting greatly increases the risk of falls from slipping or tripping,
therefore suitable shades may be necessary to eliminate this problem.
Use
of Plant and Machinery -
·
The excavation
equipment should be parked at a distance of not less than the depth of the
trench or at least 6 m away from excavated sides for trenches deeper than 6 m.
·
With the use of power
shovels and draglines, the banks of trenches become unstable and thus dangerous
for persons working nearby. These conditions should be watched and suitably
remedied.
·
The vehicles should not
be permitted to be driven too close to the pit.
UNDER-WATER WORKS
Underwater
construction work is an area which requires extensive training. Not only does
the worker need to worry about the regular dangers that come with working with
tools, now he is working in a different medium, water, which has an effect on
the work actually being done, plus he needs to use special breathing equipment.
Some
of the work can be on bridges, power stations, ships, submarines, marinas, etc.
And each type of job will have its own special requirements. Diving poses, a
unique risk, because if a problem arises the diver's life could be in immediate
danger.
Hazards
1. Compression
& Decompression
The
bends, also called decompression sickness. This is a condition when a diver
rises too quickly. Nitrogen that is in his body, from breathing compressed air,
needs time to leave the body. If this is not allowed, then the diver can
experience the bends. The only cure for this is a decompression chamber, which
must be present whenever scuba work is being done. Warning signs are; sore
joints, itchy skin, vision and hearing difficulty, paralysis, and death.
2. Nitrogen
Narcosis
This
is an affect similar to alcohol intoxication. This condition is caused because
more gases are breathed, while underwater, from the oxygen supply. Because of
the greater pressure, these gases are absorbed into the body easier than at sea
level.
3. Oxygen
Toxicity
This
is a condition where higher levels of oxygen are breathed. This has an affect
on the body, and can result in; disorientation, trouble breathing, trouble with
vision, lung damage, seizures, and death.
4. Construction
Related Safety
laws
of physics and chemistry function differently in underwater. This needs to be
part of the training of anyone that will work underwater. Welding, for example,
functions differently at underwater. Chemicals react differently. The weight of
objects is less and things move slower in underwater. No one should be
attempting any underwater work unless they have been properly trained.
Safety precautions
There
are many conditions which contribute to making underwater work difficult. These
include adverse currents, unstable footing, poor visibility and low
temperatures. A constant source of danger comes from the falling or rolling of
cut-away pieces. These, combined with the dangers involved in operating an electric
arc capable of producing fatal shock, severe burns and explosive gas pockets,
create a situation where the diver must be extremely alert. The following precautions must be
observed:
·
Extreme familiarity
with their diving equipment.
·
Check working condition
of equipment.
·
Plan the dive: time,
depth, work to be done and stick to the plan.
·
Never dive alone.
Always have at least one partner that you will stay close to.
·
Have a rescue plan in
place.
·
Know where the nearest
decompression chamber is located and how to get help.
·
Descend slowly.
·
Ascend slowly with the
scheduled breaks.
·
Monitor air supply
regularly during the entire dive.
·
The best way to prevent
decompression sickness is to avoid diving too deep, do not stay deep above the
recommended time, ascend slowly with regular stops along the way, and limiting
number of dives per day
·
Careful examination
should be made before starting the cut to learn how the cut-away pieces will
fall and whether there are any projections or cause a piece to swing around in
an unexpected manner.
·
Be extremely careful
when cutting tightly-bound wire rope e.g., wire wrapped in a ship's propeller.
When severed, the wire can back-lash with spring-like force.
·
Before cutting, ensure
that diving equipment will not be in the path of slag from the cutting
operation.
·
Avoid cutting overhead
if possible, since the falling molten material will seriously damage the diving
helmet, dress and umbilical.
·
Never put down or carry
an electrode holder while the power is on. Never change an electrode while the
power is on.
·
The diver must never
allow any body part or equipment to come in contact with the grounded work when
the safety switch is closed.
·
Care should be taken
with diver-carried large loose metallic items (i.e., wrenches and backpacks) to
ensure no contact is made with a live electrode or the work.
UNDER-PINNING
In
construction, underpinning is the process of strengthening and stabilizing the foundation
of an existing building or other structure. Underpinning may be necessary for a
variety of reasons:
•
The original foundation
is simply not strong or stable enough.
•
The intended usage of
structure has changed.
•
The properties of the
soil supporting the foundation may have changed
•
The construction of
nearby structures necessitates the excavation of soil supporting existing
foundations.
•
It is more economical,
due to land price or otherwise, to work on the present structure's foundation
than to build a new one.
•
The existing
foundations of the building have moved – this is caused by poor soil or changes
to the soil conditions (e.g. subsidence has occurred).
•
There has been a
decision to add another storey to the building, either above or below ground
level, and the depth of the existing foundations is inadequate to support the
modified building or load (weight) of it.
Hazards
and Safety measures – Underpinning
Most
types of underpinning involve digging holes under buildings in confined spaces.
The existing structure is expected to defy gravity and temporarily arch over
the excavation. Collapses can occur and the following related risks must be
identified and managed accordingly -
•
Investigate services
before starting excavation
•
Always do excavation at
angle greater than angle of response of soil
•
Check that underpinning
pits cannot get flooded or be gassed
•
Strengthen
superstructure before digging
•
Check that walls above
are strong enough to support themselves over pits
•
Support sides of
excavations
•
Ensure that workers can
escape from pits easily
•
Use threaded couplers
instead of dowel bars to connect reinforcement rods between sections of shallow
mass concrete underpinning
•
Ensure strengthening of
nearby surrounding structures
•
Provide all required
PPE’s (Safety Harness, Safety Helmet, Safety Shoes, Mask, Safety Goggles,
Safety Jacket
•
Ensure safe access and
ventilation to pits
SHORING
Shoring
is the process of temporarily supporting a building, vessel, structure, or
trench with shores when in danger of collapse or during repairs or alterations.
Shoring may be vertical, angled, or horizontal. Proper installation, use and
dismantling of shoring systems can help keep workers safe and prevent collapses
during construction, renovation, and expansion. When installing and using
shoring, it’s vital to follow all state and central regulations to ensure
worker safety. Here are a few general guidelines that cover the basics of
shoring safety:
·
A qualified person
should survey the jobsite for hazards that could cause issues with the shoring
system. If hazards are uncovered, they should be corrected as needed.
·
Plan the shoring’s
installation in advance. This includes ensuring that the right equipment is
available to safety finish the work.
·
Inspect all equipment
before use. If a defect is found, the affected item should be removed and
repaired. Defective equipment should never be used.
·
Obtain a shoring
drawing from a qualified professional. The drawing should be used onsite at all
times.
·
Handle the shoring
equipment with care, and only use the equipment as it was intended.
·
Don’t erect, dismantle
or alter the shoring equipment without the approval of a qualified supervisor.
·
Inspect the shoring
system through the duration of a project. If there’s any doubt about the safety
of the shoring, stop use immediately and contact a qualified supervisor.
·
Shoring systems should
not be used for fall protection. Furthermore, workers should not use shoring
systems if they feel dizzy or lightheaded.
·
Do not climb on the
cross braces.
·
Periodically adjust
uneven grade conditions. Do not force braces on frames; level the shoring
towers for the proper fit.
·
Follow proper safety
practices during dismantling. Nothing should be removed from the shoring system
until a qualified supervisor has given their approval.
LADDERS, SCAFFOLDS, TEMPORARY
STRUCTURES
SCAFFOLDS
A
scaffold can be defined as "any temporarily provided structures on or from
which persons perform work in connection with operations or works".
Scaffolds
are the temporary wooden or metal framework or platform for supporting
workmen/material during construction, erection, repair or painting of a
building/structure. As far as possible, only steel scaffoldings should be used.
The materials used on all scaffolds should be in sound condition suitable for
the purpose and free from defect.
Scaffolds
Hazards
Accidents due to scaffold collapse are
common. Apart from collapses the other hazards are:
·
Unsecured ladders slip,
·
Use of unsuitable or
faulty materials,
·
Inadequately supported
scaffold board,
·
Inadequate or irregular
platform width,
·
Omission of guards rails
or toe-boards,
·
Failure to secure
scaffolds to the building/structure or to brace it adequately, and
·
Overloading of platform
and scaffolds.
Safety
Measures
In view of the above hazards, following
safety measures should be taken to prevent scaffolding related accidents:
· The designer should ensure that drawings and instructions show sufficient details and that they are easily understood by erectors. Most of the entering are designed for vertical loads while lateral forces as a result of the dynamic effect are usually neglected during the design. Therefore, lateral stability is equally important.
·
Horizontal bracings are
essential at various levels to ensure that support struts and scaffolding tubes
do not buckle under vertical load.
·
Every scaffold
including supports shall be of good constructions of suitable and sound material and of adequate strength
·
Boards and planks used
for the floors shall be of uniform thickness, butt jointed, closely laid, and
securely fastened in place.
·
Every scaffold shall be
securely supports or suspended and shall, where necessary be sufficiently and
properly strutted or braced to ensure stability.
·
All scaffolds or
working platforms of any nature shall be securely fastened to the building or
structure, or if independent of the building shall be braced or guyed to
prevent sway.
·
In the construction of
dams sufficient anchorage shall be provided in the dam itself at the time of
construction.
·
Persons should not be
allowed to work from scaffolds during storms or high winds.
·
Scaffoldings should be
inspected at least every 7 days
The main items to be checked are:
§ The
alignment and support of the standards (upright),
§ The
straightness,
§ The
adequacy of bracing,
§ The
ties of the building,
§ The
tightness of couplers,
§ The
soundness, support and security of planks and platform,
§ The
guard-rails and toe-bars,
§ The
condition and security of the ladders, and
§ The
ground supporting the baseplate.
·
When work is being
performed above a scaffold platform, a protective overhead covering shall be
provided for the men working on the scaffold.
·
Whenever workmen have
to work or constantly pass under a scaffold on which men are working, a screen
or other protection shall be provided to catch any falling material. Such
protection shall extend outside the scaffold properly in order to catch any
material falling off the edges of scaffold platforms. 12 mm wire mesh netting
of No. 18 gauge or better may be used for the purpose.
·
Side screens shall be
provided on scaffolds erected along passageways
·
During dismantling of
scaffolds, necessary precautions shall be taken to prevent injury to persons
due to fall of loose materials, bracing and other members of the scaffold shall
not be removed pre-maturely. While dismantling, the entire scaffold shall be maintained
stable and rigid so as to avoid the danger of collapse. Nails from the planking
and various members of the scaffold shall be carefully removed and all material
carefully piled.
Ladders
·
Ladders should be of
good construction, sound material and adequate strength. No ladders with
defective or missing rung or with any rung which depends for its support solely
on nails, spikes etc. should be used.
·
Wooden ladders should not
be painted, as paint covers up the defects.
· Whenever platform is 1.5 m or more above the ground ladder or stairway should be provided. Every ladder used for a vertical height of more than 9 metres should be provided with an intermediate landing with guard-rails.
·
The materials and tools
should wherever practicable, be pulled up with a rope, and should not be taken
by ladders.
·
A ladder should not be
placed upon a box, barrel or other movable insecure object. The slipping of
ladders at either end should be carefully guarded against where the supporting
surfaces are smooth and vibrating.
·
Where a ladder is used
as a means of communication or as a working place the ladder shall rise, or
adequate hand-hold shall be provided, to a height of at least 1 metre above
the- place of landing
·
When using a ladder or
a step ladder, the user should always face the ladder. The transportation of
materials by ladder should be reduced to the minimum.
·
The use of ladders for
other than a means of access should be eliminated.
·
All ladders shall be
periodically inspected. The stability of ladders should be eliminated.
·
Portable ladders should
be in a safe position before being climbed. The slipping of a ladder at either
end should be carefully guarded against. especially where the supporting
surfaces are smooth or vibrating. If necessary, a person shall be stationed at
the base of the ladder to prevent it from slipping.
·
A ladder should never
be placed on slippery, oil surface or a vibrating footing unless the ladders is
held by another person or securely fastened to prevent it from slipping or
twisters.
·
Workers using ladders
should (i) avoid wearing slippery boots or shoes, and (ii) avoid carrying heavy
or bulky loads.
·
Metal ladders should
not be used in the vicinity of exposed live wire.
·
Only one person at a
time should be permitted to work from a ladder.
TUNNELING
Hazards
·
Hard physical labor can
cause bodily injuries.
·
Roof falls or cave-ins
can cause head injuries, crush injuries, suffocation or death.
·
Exposure to crystalline
silica dust and cement dust can lead to respiratory, lung or skin problems.
·
Exposure to chemical
vapors can cause lung problems, including chemical pneumonitis, which can lead
to respiratory failure and death if left unchecked.
·
Exposure to radon can
cause lung cancer.
·
Oxygen-deficient
atmospheres can contribute to breathing problems, such as asthma.
General Safety Precautions in
Tunnelling
·
Make sure the tunnel’s
floor is clean and dry.
·
Ensure proper covering
for light and power lines to avoid open flames and electricity
short-circuiting.
·
Ensure that electric
lines and light are insulated and secured completely.
·
Always ensure the
presence of doctors and medical equipment at the worksite.
·
Always ensure the
presence of sufficient water supply and firefighting equipment.
·
Avoid storing unused
tools, construction material and machines in the tunnel.
·
Make sure that the
tools and machines to be used are efficient and well-maintained.
Make sure to visit working platforms and check them occasionally.
·
Install an efficient
communication system inside the tunnels to send and receive essential
information.
·
Ensure the workability
and efficiency of power system, communication system, lighting and safety
devices occasionally.
·
Each worker should take
essential precautionary measures for his safety by wearing a steel helmet,
rubber gloves, goggles and protective clothing while working.
·
Provide a double power
supply to the tunnels to avoid safety hazards due to a power failure.
·
During scaling, the stroke
of the hammer should not be hollow, but hard. A hollow hammer stroke signifies
a loose rock.
·
Ensure proper
ventilation and drainage system in the tunnel.
·
Install signboards for
safety on several occasions in the tunnel.
·
No one should be
allowed to enter the tunnel without permission.
BLASTING
Blasting
is a process of reduction of rocks or hard soil into fragments with the help of
explosives. The blasting operation involves drilling of holes, installation of
a detonator and charge, detonating the charge, and removal of debris.
Safety Precautions while Blasting
·
For the safety of
workers, red flags shall be prominently displayed around the area where
blasting operations are to be carried out.
·
All the workers at the
site shall withdraw to a safe distance of at least 200 meters from the blasting
site.
·
An audio warning by
blowing whistle shall be given before igniting the fuse.
·
The blasting operation
shall be carried out under the supervision of trained personnel.
·
The blasting shall not
be done within 200m of an existing structure unless permitted explicitly by the
engineer in writing.
·
All procedures and
safety precautions for the use of explosives, drilling, and loading of
explosives before and after shot firing and disposal of explosives shall be
carried out corresponding to government rules
DEMOLITION
Problems, hazards and uncertainties are
much greater during demolition since it is frequently carried out by the
unskilled workers. The design engineers have the responsibility not only for
the safe design and construction but also for the safe demolition of the
structure at the end of its designed life.
Common Safety Hazards and Environmental
Aspects in Demolition
·
Unintentional collapse
of structure or part of it.
·
People and objects
falling from heights.
·
Striking overhead or
underground services.
·
Manual handling
activities associated with demolition and material movement.
·
Generation of
Demolition debris.
·
Hazardous substances in
debris.
·
Dust emission.
·
Generation of noise.
·
Effect on climate.
·
Segregation of the
generated debris into hazardous and non-hazardous debris.
Actions to be taken before any
demolition work is taken up:
•
It should be preceded
by a site survey which should be comprehensive and cover the position of
screens, scaffolds etc.
•
Protection of the
public shall be ensured and also methods to ensure the stability of surrounding
buildings/structures from the danger of collapse due to withdrawal of support
or undermining of the foundations shall be paid attention.
•
The electric power to
all services within the structures to be demolished should be shut off or
discontinued at outside the building.
•
All gas, water and
steam service lines should be shut off or otherwise controlled outside the
structure to the demolished.
•
The structure to be
demolished should be adequately fenced and cordoned off and suitable board
shall be prominently displayed to warn the public.
• Measures for dust suppression / control shall be in place.
FAMILIARISATION WITH RELEVANT INDIAN STANDARDS ON CONSTRUCTION SAFETY
FAMILIARISATION WITH NATIONAL BUILDING CODE PROVISIONS ON CONSTRUCTION SAFETY.
The
National Building Code of India (NBC), a comprehensive building Code, is a
national instrument providing guidelines for regulating the building
construction activities across the country. It serves as a Model Code for
adoption by all agencies involved in building construction works be they Public
Works Departments, other government construction departments, local bodies or
private construction agencies. The Code mainly contains administrative regulations,
development control rules and general building requirements; fire safety
requirements; stipulations regarding materials, structural design and construction
(including safety); building and plumbing services; approach to sustainability;
and asset and facility management.
The Code was first published
in 1970 at the instance of Planning Commission and then first revised in 1983.
The second revision of the Code was in 2005, to which two amendments were
issued in 2015.
Due
to large scale changes in the building construction activities, such as change
in nature of occupancies with prevalence of high rises and mixed occupancies,
greater dependence and complicated nature of building services, development of
new/innovative construction materials and technologies, greater need for
preservation of environment and recognition of need for planned management of
existing buildings and built environment, there has been a paradigm shift in
building construction scenario. Considering these, a Project for comprehensive
revision of the Code was taken up under the aegis of the National Building Code
Sectional Committee, CED 46 of BIS and its 22 expert Panels; involving around 1000
experts. As a culmination of the Project, the revised Code has been brought out
in 2016 as National Building Code
of India 2016 reflecting the state-of-the-art and contemporary
applicable international practices.
The comprehensive NBC 2016
contains 12 Parts some of which are further divided into Sections totalling 33 chapters.
The Code has been published in two volumes containing all the Parts and
Sections.
CONTENTS OF NBC
2016
VOLUME 1
PART 0 INTEGRATED APPROACH –
A PRE-REQUISITE FOR APPLYING THE PROVISIONS OF THE CODE
PART 1 DEFINITIONS
PART 2 ADMINISTRATION
PART 3 DEVELOPMENT CONTROL
RULES AND GENERAL BUILDING REQUIREMENTS
PART 4 FIRE AND LIFE SAFETY
PART 5 BUILDING MATERIALS
PART 6 STRUCTURAL DESIGN
Section
1 Loads, Forces and Effects
Section
2 Soils and Foundations
Section
3 Timber and Bamboo
3A
Timber
3B
Bamboo
Section
4 Masonry
Section
5 Concrete
5A
Plain and Reinforced Concrete
5B
Prestressed Concrete
Section
6 Steel
Section
7 Prefabrication and Systems Building and Mixed/Composite Construction
7A
Prefabricated Concrete
7B
Systems Building and Mixed/Composite Construction
Section
8 Glass and Glazing
VOLUME 2
PART 7 CONSTRUCTION
MANAGEMENT, PRACTICES AND SAFETY
PART 8 BUILDING SERVICES
Section
1 Lighting and Natural Ventilation
Section
2 Electrical and Allied Installations
Section
3 Air Conditioning, Heating and Mechanical Ventilation
Section
4 Acoustics, Sound Insulation and Noise Control
Section
5 Installation of Lifts and Escalators and Moving Walks
5A
Lifts
5B
Escalators and Moving Walks
Section
6 Information and Communication Enabled Installations
PART 9 PLUMBING SERVICES (INCLUDING
SOLID WASTE MANAGEMENT)
Section
1 Water Supply
Section
2 Drainage and Sanitation
Section
3 Solid Waste Management
Section
4 Gas Supply
PART 10 LANDSCAPE
DEVELOPMENT, SIGNS AND OUTDOOR DISPLAY STRUCTURES
Section
1 Landscape Planning, Design and Development
Section
2 Signs and Outdoor Display Structures
PART 11 APPROACH TO
SUSTAINABILITY
PART 12 ASSET AND FACILITY
MANAGEMENT
Salient Features
of National Building Code 2016 (NBC 2016)
1) Detailed provision
for streamlining the approval
process in respect of different agencies in the form of an
integrated approval process through single
window approach thereby avoiding separate clearances from various
authorities, with a view to ensuring ease of doing business in
built environment sector.
2) Progressive computerization of approval
process, for enabling online submission of plans, drawings and other
details, and sanction thereof.
3) Updated mechanism of ensuring certification of
structural safety of buildings by the competent professional and
peer review of design of buildings.
4) Defining the roles and responsibilities of all professionals and
contractors involved in a building construction project.
5) Comprehensive planning norms for minimum amenities to be provided in a
city/town.
6) Detailed provisions
relating to requirements for accessibility in buildings and built
environment for persons with
disabilities and the elderly.
7) Planning and development
norms, such as, Transferable Development
Rights (TDR) and Accommodation Reservation (AR).
8) Provisions for underground or multi-storeyed parking as also
mechanized parking of
vehicles.
9) Norms for solar
energy utilization.
10) Requirements for
buildings on podium for ensuring fire
and life safety in such buildings.
11) Fire and life safety in modern
complex buildings including the high rises, glazed buildings,
atria, commercial kitchen and car parking facilities.
12) Updated structural design
provisions for wind and seismic loads, imposed load due to helipad,
and blast loads, for safe design and construction of buildings with due
focus on ductile detailing.
13) Latest research and development inputs and provisions on concrete,
steel and masonry buildings with a view to ensuring disaster resilient buildings.
14) Updated provisions on engineered use of bamboo in housing and other
building construction.
15) Promotion of use of agricultural
and industrial wastes including construction and demolition wastes in building construction
without compromising the quality and safety.
16) Inclusion of provisions
on self-compacting concrete, high
performance concrete and steel fibre reinforced concrete.
17) Updated provisions on prefabricated construction technique for speedier
construction.
18) New chapter on
structural use of glass in
buildings.
19) New and alternative
building materials, and technologies for building construction such
as, reinforced masonry, confined masonry building construction and masonry wall
construction using rat-trap bond.
20) Construction project
management guidelines for timely completion of building
projects within the budgeted cost with desired quality.
21) Habitat and other welfare requirements for workers at construction site.
22) Inclusion of modern lighting techniques such as LED and induction light and their energy consumption.
23) New provisions on
compact substations and updated provisions
on installation of energy meters.
24) Comprehensive provisions
relating to lightning protection of buildings.
25) Provisions on aviation obstacle lights; electric vehicle charging and car
park management.
26) Protection of human beings from electrical hazards and against fire
in the building due to leakage current.
27) Use of refrigerants for
air conditioning addressing zero ozone depletion potential (ODP) and ultra-low global
warming potential (GWP).
28) Provisions pertaining to metro
trainways and metro stations with respect to fire and life
safety; and air conditioning, heating and ventilation for metro stations.
29) High speed lifts for tall buildings.
30) New chapter on escalators
and moving walks for
comfortable and safe movement of people.
31) New chapter on information
and communication enabled installations in
buildings.
32) Updated provisions on water supply, drainage and sanitation for
modern high rise buildings and complexes.
33) Provisions relating
to swimming pools covering
hygiene and safety.
34) Updated provisions
on rainwater harvesting.
35) New chapter on solid
waste management covering
various solid waste management systems within the building and building
complexes.
36) Updated provisions
on piped gas supply in
houses, and in hospitals for medical purposes.
37) Promoting quality of outdoor built environment
through updated provisions on landscape planning, design and development.
RELEVANCE OF ERGONOMICS IN CONSTRUCTION SAFETY
Ergonomics
(also known as Human Engineering) is defined by I.L.O. (International Labour
Organisation) as, "the application of human biological sciences in
conjunction with engineering science of the worker and his working environment
so as to obtain maximum satisfaction for the worker which, at the same time,
enhance productivity". Thus ergonomics is a Multi- disciplinary science
comprising subjects like anatomy, psychology, physiology. sociology,
engineering, anthropologist, physics and medicine.
The
word 'ergonomics' is made up of two words "ergons" which means 'work'
and "nomos" which means 'natural laws'. Therefore, ergonomics may be
defined as the scientific study of the relationship between man and his working
environments.
OBJECTIVES
The
objective of ergonomic study is to optimise the integration of man and machine
in order to improve productivity and
accuracy with less physical and mental strains. Ergonomics helps to
·
Reduce injuries and
disorders.
·
Ensure worker safety.
·
Ensure worker
productivity.
·
Reduce compensation
costs.
·
Reduce absenteeism.
·
Comply with
regulations.
ERGONOMIC HAZARDS - PROBLEMS DUE TO POOR ERGONOMICS
Main
problems due to poor ergonomics are;
1. Musculoskeletal
Disorders (MSDs)
Musculoskeletal Disorders (MSD) are soft-tissue injuries typically caused by sudden or sustained exposure to repetitive motion, force, vibration, and awkward positions. They can affect the muscles; nerves; joints; and in the upper and lower limbs, neck, and lower back. Workplace design plays a crucial role in the development of an MSD
2. Cumulative Trauma Disorders.
CTDs, or repetitive strain injuries, are soft tissue injuries caused by repeated activity. Many workplace tasks become risky when they are overdone. They can be performed safely for a limited amount of time and with adequate rest periods at regular intervals. However, when they are performed too often or for too long without allowing the body to recover, these tasks can result in a repetitive strain injury.
These injuries generally develop in smaller parts of the body, such as the fingers, wrists, elbows, or neck. In the construction industry, the three most common types of CTD are tendon disorders, nerve disorders, and neuro-vascular disorders.
3. Worker
dis-satisfaction and increased absenteeism.
4. Increased
compensation cost.
5. Increased worker turnover rate.
6. Lower
quality.
7. Lower
productivity.
The
causes responsible for the above problems are:
·
Bending.
·
Heavy lifting.
·
Reaching.
·
Using continuous force.
·
Working with vibrating
equipment.
·
Repetitive motions.
·
Awkward postures.
·
Low or high temperature
of workplace.
Following
workplace conditions are important in ergonomics risks/hazards:
·
Posture. Whether work
can be done in normal body positions (or standing).
·
Workplace layout.
Whether controls and displays are properly located for optimum use.
·
Hand Tools. Proper
wrist and arm orientation when using, proper size and shape of tools, force
Requirement
of tools.
·
Manual Material
Handling. Weight and size of materials.
·
Bending and Twisting.
Bending and/or Twisting as part of job especially during lifting
or
material transfer.
·
Use of Computers.
Distance from monitor, viewing angle, keyboard height, chair design
Workplace Characteristics Constituting Ergonomic Hazards
Some
of the common workplace characteristics which constitute hazards and should be
removed or reduced are:
·
Handling over size
objects.
·
Handling loads above
shoulder height or below knee height.
·
Handling objects away
from the body (i.e. with arms out-stretched).
·
Working with twisted
and bent body.
·
Moving loads over long
distances.
·
Working requiring
repetitive head and neck movements.
·
Work requiring
excessive forward or sideways reaching.
·
Working with the body
leaning forward.
·
Working with bent
wrist.
·
Hand tools that are not
balance or are difficult to hold or have a better handle
·
Table work or key board
work with elbows away from body.
·
Controls/levers that
require high forces to operate.
·
Workplaces where short
height employees cannot reach or longer employees can not reach or longer employees
do not fit.
·
Static muscular loads.
·
Poorly designed chairs.
·
Inadequate lighting or
in wrong direction or in contrast colours.
· Working in a fixed posture for a long periods.
·
Tasks requiring
repeated focussing of eyes at different distances.
·
Slippery and/or
obstructed pathway.
·
Excessive noise.
·
Excessive heat and
humidity.
APPLICATION OF ERGONOMICS
1.
How to Avoid Hazards.
·
Avoid fixed work
positions. They reduce the blood supply to muscles.
·
Keep elbows close to
the body.
·
Avoid positions where
arms are raised above shoulder level.
·
Use lighter hand tools.
·
Support your elbows.
·
Provide sufficient
rest.
·
Utilize jigs and
fixtures.
2. Possible Solutions to Ergonomics Problems.
·
It should be recognized
that often 'repetitive motion injury' is mistakenly felt to be a type of
short-term weakness or fatigue. Actually it is the start of potentially more
serious injuries.
·
Address complaints in a
timely manner.
·
Employee output should
be regularly checked and compared, if it is falling down, its reasons should be
analysed.
·
Interact with the
worker and discuss the possible solutions. Promote employees suggestions.
·
Redesign/modify the
work station in consultation with the employee. Employee should feel the part
of the process.
·
Utilize gravity when it
can help move material to the work area or station. This helps to prevent
unnecessary material handling.
3. Working
Environment
Environmental
aspects include considerations regarding illumination, climatic conditions
i.e., temperature, humidity noise vibrations, fresh air, smoke, fumes, bad
odours, house-keeping etc., so that risk of health is reduced and efficiency of
worker is increased.
4. Areas related to Fatigue
Areas
which causes fatigue are studied in order to reduce them. This study helps not
only in reducing the fatigue, but also the losses which may otherwise be caused
due to fatigue.
Some
of the causes for fatigue which are studied under ergonomics are: influence of
hours of work, rest pauses, illumination, atmospheric conditions, monotony and
boredom, speed etc.
5. Design of Workplace
Workplace
is a space in a work area/machine which must accommodate a worker/operator(s),
who may be sitting or standing. Adjustable seats (height and back) with foot
and arm rest be provided, as backaches, neck
aches
and other muscular strains due to bad seating and incorrect working posture for
a long duration. The interaction of the operator with the immediate workspace
around him is influenced by many factors, such as seat design, the working desk
and adjacent machine. These factors are responsible for the position and
postures of the users and their productivity.
All
tools and materials required must be located within the normal grasp area and
as far as possible in front of the worker. Working desk must be so designed
that use of both hands can be taken simultaneously.
6.
Design of Machinery and Control (Man-Machine System)
When
a worker operates or uses a machine. instrument or tool, it is essential that
man-machine must be considered as a single working unit from the design point
of view. Machine must be so designed that worker can use both hands and foot
simultaneously for operating it and all the levers. pedals. instruments. hand
wheels, knobs and buttons must be located within normal grasp at a suitable
height and in front of the operator. Foot pedals must be provided with suitable
retuning springs. Care must be taken to avoid eye strain. muscular and mental
strain.
Fatigue
may further be reduced, if proper use of jigs or fixtures, stops or guides is
taken. The size of the driver's cab and
the placement of gearshift and brake pedals etc., are generally designed to
suit common man, resulting transportation operator, if he is a taller or
shorter than average, readily succumb to fatigue, through straining to reach
the breaks, gears, and other controls. Therefore, provisions of modifications
to be done, to improve health and reduce accident rates.
Design
and location of various manual controls, knob, levers, wheel etc., should not
cause excessive physical and mental strain to the worker. All controls should
move in one direction for one kind of action e.g., acceleration or retardation
It
is clear, from the above, that if ergonomic principle is observed in the design
of work places, then the operator will be more efficient, less strained and
tired and consequently less liable to have an accident.
KTU MODEL QUESTIONS
1. List
the various safety features of ladders. (3 Marks)
2. How
safety of the workers can be ensured during a demolition operation. (3 Marks)
3. Identify
the various hazards during the different stages of building construction. (7 Marks)
4. Discuss
the safety and fire protection facilities required for a high rise building as
per National building code. (14 marks)
5. Discuss
the important types of ergonomic hazards associated with industries. (7 Marks)
Dear Faculty & Students ,
Corrections will be done later with proper acknowledgement.
Thank you
Dr Manoj Kumar B