Good morning students this is the course on architectural acoustics in the NPTEL platform
and this is the the the eighth week lecture on the last lecture of the last week. So,
the lecture number 40 it is on the urban noise control and the architectural consideration.
So, if you remember the last 2 lectures, we have given we have discussed the control
of urban noise based on the urban planning consideration.
So, in the architectural consideration and in this lecture the objective of the lecture
will be through discuss the outdoor noise mitigation through some kind of a design
strategies by architectural design strategies and also not only the urban noise or maybe
the outdoor noise also will do some thought we will discuss some thoughts on the the
mechanism of reduction or control of the building noise. There are some part of the building
may also create some kind of a noise and that sometimes very bad and we have to actually
mitigate from that . So, again if you just go to the last
2, last 2, 3 lecture back that we are actually prying to mitigate can the noise the urban
noise and we thought or we have proposed 3 type of strategies, one cut down from the
source. So, noise is actually taken very seriously and from the source point of view people are
going to cut it off. We have discussed in the very I think 38th lecture on that . Second
one 39 lecture what we have discussed is that, the path between the source and the receiver
do some changes and landscaping and barrier and the formation change and try to make the
receiver in a sound shadow zone and the you get the benefit and the third one is this.
Now we road noise source is taken care of, then the it is taken care of by the the path
and third now you taken care of the receiver. You see the how the receiver can be placed
receiver can be designed and that can be reduce your noise and all .
So, there are many strategies, but it can be clubbed into 3 strategies, one is site
planning and building placement and orientation, this is one of the way the architect actually
start thinking thought of the landscaping and the site planning all together and then
the building orientations and all and go for the next step next stage of the development
of the building plans and all. Also its also covers the i mean the some layout planning
and the space programming and the space segregation arrangement of the space also take care in
the next level after this planning, site planning is done and finally, people me apply some
kind of the acoustical the treatment architectural acoustical treatment that already you have
discussed in the the lectures transmission loss and all those kind of a think and those
treatment can be done inside the building or maybe the the the the the wall between
the outdoor and the indoor those those particular wall which segregate the noise also .
In the site planning criteria the hospitals education buildings and residential buildings
are treated under the noise sensitive building and that should be located in the quiet area.
So, as an when I got a site, I will try to locate the which areas or the quiet area
and I will put those kind of a buildings in that area see the it is better to have
a high setback and its always preferably if there is a very heavy noise source as a
railway track or maybe a highway a 45 meter setback is um preferred for a
noise sensitive zone I see I am not talking about the 45 meter pushing back all the building,
but the noise sensitive buildings which may be a school or which may be a a a a
inpatient department of a hospital sometimes it may be a old age home or those
kind of the the the areas those kind of the areas or maybe a temple which required a
kind of a the silent zone area can be thought of at a distance 45 meter from that
noise source or so, but 30 meter is sometimes its good enough to have that
particular zone as a 30 meter away from that particular road.
So, the first consideration in the site planning is how much setback I may get for those
zone, of course in between this 30 meter or 45 meter i may have some other the buildings
al also all other part of the habitat also which may not that much noise sensitive .
Next is the it has to be planned such a way that the minimum amount of glazing, minimum
amount of the meaning of the hazard which is exposed to the noise should be exposed
to the noise. In case of the hospital the sensitive area like the treatment room this
consulting rooms then the operation theatre and all those has to be move away from
the outdoor noise it is as far as possible has to be overlooked and has to be pushed
back and this windows should not be overlooked to that particular should be overlook
to the pa pa acoustical shadow area should not be overlook to the bright zone
and all those kind of a zone . We also try to minimize the ground reflection
effect which I have talked about adduct in the last lecture and it should not be dwellings
and all those things which are noise sensitive should not be surrounded by the the hard
pavement because it will give you reflection rather it should be the the the surrounded
by some soft pavement like the planting and all those and also the narrow pave road between
the adjacent tall building has to be also going to be avoided which as the the second
point of this slide because this tall building adjacent building may create the noise or
may not create the noise and it will between if there is a kind of a motion or maybe a
traffic and that will create some kind of the the mutual reflection and that can
be act as a multistoried known as a multistoried effect also .
Again this is a another important criteria if you are thought of some old age home or
may be some relaxation area for a old age people or maybe a sleeping area for some
residential zone which is having a old age people or maybe people sleeping zone sleep
not a sleeping zone, but the bedroom facing zone or whatever sides that should be or not
to be faced in the play areas of the playground for the older children that is a communication
noise can be created in the in the field where there are older people are playing cricket
football or whatever and they shout and that particular noise may disturb the old age
bedroom areas or the old age areas where there are going to relax .
So, this is a small sketch that is going to give you a kind of a understanding that
how this 45 meter or 30 meter whatever I talked about can be implemented. So, a main road
which is a noise source can we first shield by maybe a boundary wall and then the rows
of trees and then maybe there is a parking which gives you a kind of a first set back
and the barrier then I can provide some semi noisy zone which is emergency then the OPD
outpatient department then the diagnostics this 3 and the IPD this 4 are the the 4 coordinate
of a hospital and hospital though out of this 4 coordinate this emergency OPD diagnostics
or the relatively noisy zone where people actually go talk wait then listen to somebody
are talking with waiting for something. So, this is a kind and IPD the inpatient department
is the patient which is under treatment and there in the ward and operation theatre and
all these areas and the ICU where all are actually very close to this all the the
sub areas of this IPD and that can be directed to the lower or the other part or the deeper
part of the site and the quiet zone can be thought of and this quiet why it is quite
zone because it is directly shield by this building and it is no direct entry, if there
is a entry direct entry like from this particular main then this particular with the building
can be exposed. So, there is no direct road there is a road and there is a sub road or
the link road so that also helps. Next is some orientation issues are there,
suppose there are some road and there is open window sorry window is there exposed window
so and this window actually create some kind of a lick sound lick. So, they are maybe this
particular protection can be made a kind of a protection can be made . So, I have drawn
4 type of orientation with respect to the road and with respect to the road and the
window. So, wall this black colour protection wall can be thought of, can be or can be
placed to provide the the the full noise barrier create a full noise barrier, but of
course, its will spoil your elevation sometimes and it mean give you a kind of
a, so um some kind of the the the some kind of additive things in your elevations
or which may not you may not like or your client may not like, but kind of
shielding can be thought of maybe this to are very much not possible , but sometime
this can be extension type of a things can be possible and it can be one of the way
to handle the the bad orientation windows and creating the shielding of this sound .
Next is a internal planning in internal planning the critical areas should be segregated
from the non critical areas non critical areas like corridor kitchen, bathroom, which
actual are elevator the lift shape or the the staircase block can have the very close
to the noise zone or the noise source and that will create a barrier to the critical
zone critical areas of the bedroom and the living space .
The noisy rooms should be separated from the quite areas as far as possible in general
it is desirable to group together. So, have a I think I I have a sketch
on that in the next slide. The window door should be kept away from the noisy zone side
of the building and whatever it possible it should be kept away from that noisy zone , even
the noisy courtyard or the noisy areas has to be designed such a way that it should be
not directly facing towards the any skylight or any kind of the punchers the the the wall
punctures. So, sometimes we create some kind of a noisy
area maybe some kind of a the the play areas or maybe some kind of a traffic area
as were people actually go talk with each other or some time some small area where there
is a amphitheater or some kind of a informal amphitheater gathering areas also with
some time is very maybe very noisy and there is office building which is part
of the office building which required some kind of a the sound insulations kind of
a thing. So, we have to see the there should not be any skylight or those kind of a things
are the window should not be faced to each other .
The unloading bays refuse disposal boiler houses workshops etcetera laundries are
actually the the new sense area where actually there are lot of mechanical and the lot of
other equipment will be run throughout the day or a part of the day and it should be
isolated from that from the noise sensitive zone as far as possible . The kitchen is another
area where you can have lot of airborne sound and also from the structure borne sound because
of the vibrations and all which again has to be take in separated away and the very
seriously you have to design that particular separation from the sensitive zone to this
kitchen at area . So, there are some kind of a internal planning
can be done in the vertical line also. So, in multistoried hospitals also we can have
the OPD up and ICU and this things furthermore up which is very very noise sensitive area
and it put the ground floor areas and all under OPD and the emergencies and all .
This is another way I have just discussed you make the noisy zone shielded by
the some noisy shielded by some kind of a a grouping of some kind of building which
is bara garage and the sit out for a bungalows and then next is the kitchen dining which
is in semi noisy zone and your the study and the bathrooms and sorry study and the
bed rooms and all can be put in the the the the further more further deep deeper part
of the site on the noise sensitive zone can be created .
Similarly, if you go for a planning for a courtyard the this particular u shape inverted
u shape courtyard can be used for the the any outdoor space which is required some kind
of a noise sensitive outdoor space also or we make go for a kind of the both the u
shape and create a interesting space in between and courtyard space of course, and that courtyard
space and the second block which is actually creating that kind of the interesting courtyard
can be a noise sensitive block I have already told you about that hospital the the site
plan. So, you pushed back and create a noise sensitive zone over there .
The balcony protections, so I have a told in the last lectures also the the diffraction
of the sound and all and this particular the balcony which is exposed to the roadside is
dangerous, sometimes it actually that will going to allow the noise how suppose there
is a the I mean the the noise source from the street vehicles and because of the
reflection direct reflection of this hard surface above balcony ceiling it will direct
the noise to your bed rooms or maybe your living areas which is actually triggered
the noise level inside in your building. So, we need some kind of a solution, this
is the problem the noise comes from the road straight in the balcony goes down to the the
room the solutions are possibly one is you put the this balcony overhang and make
a kind of a projections like the vertical projections and that will cut off that will
cut off so, there will be any sound comes like this side will cut of reflected back
and there will be no reflection towards the room that is one and another one is you can
put some kind of a absorptive board the in su sound insulation or sound absorptive
board that will going to reduce domain kind of reflection .
So, some of the noise level I have listed down from the NBC 2016, which is desirable
or not desirable, but which is the maximum amount of noise level is desirable for a particular
area. So, the auditoria, concert hall, radio, TV studios is very very noise sensitive me
may allow only 20 to 25 dB . So, those are the some list I have given over here. Restaurants
are ok with 50 to 55 because people will talk with each other so that is a end of area
where noise is not that much sensitive . Then there are some source of noise in the
building some plumbing noise because of the plumbing or the the flow of water, the water
hammer which is sudden interruption of the water by virtue of the the air interrupt
air in it, pump noise, loose and defective plumbing water dropping from the tap
overflowing of the water at the source of the plumbing noise and the precautions of
the plumbing noise has to be taken you have to separate out the acoustical noise areas
from that and from the noise sensitive zone .
The reduction of the airborne sound transmission yes we have to do for the partition wall,
but not the light weight partition wall the heavy partition wall which will reduce the
noise we can ma maximize the or minimize the structure borne sound transmission also
because there are some pump noise and all which is vibrating we can also again this
the the the the high amount of mass surface of the wall mass will create a resilient kind
of a thing first resilience because of the transmission point of view and sometimes
may put the felt or those kind of a resilient layer mineral wool and all to resilient
that particular structure borne sound and also we can minimize the water hammer pressure
by virtue of some kind of concealing the pipes in the in the wall that always we do that
will reduce down the noise from the water hammer.
We can regulate valve regulatory valve and all has to be also may be concealed in a shaft
which actually triggered some kind of a the the the turbulency and that can create
some kind of vibration and noise. The sanitary lines should be conceal in a
duct because sanitary lines because of the flushing of the water in the sanitary that
sudden fall of the water from that pipe will create noise and that can be enclosed in a
shaft which is a air tight shaft and gasket and all with if there is a door also that
can be a gasket and all and regular maintenance is also very necessary.
So, other areas where there is a air conditioning plant that can also create some kind of a
noise. The noise from the mechanical equipment and those kind of a thing also generate those
kind of a noise, air flow noise can be is comes from the duct. So, those noise if
I want to see I have 1 small video for you and that I will run that is from our one of
our plant AC plant in our campus . So, this is the video in that you can see the there
are some equipment in the duct this particular machines create vibrations they are on bench
and they are some insulations also and this particular AC plant is a made of by double
wall the double wall cavity wall which also reduced noise .
So, this is one of the video old one, the new one is in our Nalanda which is a new one
and the it gives you relatively less amount of noise because of it is a new because
it is properly maintained its only 1 year old this particular building. So, the amount
of noise all the the instruments are also very new. So, the amount of noise is little
low , but as even its gets older there are some leakage more leakage some maintenance
slaps may propagate the more amount of noise or more amount of sound.
So, that that is some of the example of this particular air conditioning noise which comes
from lot of equipment and the flow from the fan then duct and the air handling units and
all . So, how to the take the precautions from
those we can have several branch of the pipes or the ducts which take care of the
different I mean the complete below amount of flow the air flow of course, that may be
a high having maybe high installation or maintenance cost, but that will minimize the noise because
if it is handle less amount of air . Noise sensitive rooms are also very should
be kept away from the AHU, AHU the air handling unit where in HA floor of a multistoreyed
building the air come the threated air comes over there and the return air mix and all
those operations you know. So, there is a fan there is a fan which pump the on circulate
the air to that particular flow also. So, that is very noisy that has to be segregated
thus duct is should be hang by some resilient adjustable kind of a hanger. So,
any flow goes in to that if it is very steep then it is vibrate its very very
noisy, but if it is a resilient layer it can be vibrate and that vibration due to the vibration,
the structure borne sound may not propagate use gypsum board enclosure in the duct, because
because of the flow of the air inside the duct and the air air conditioning duct is
circular or sometimes it is rectangular, if it is rectangle, there are some kind of
the the vertex and all those the the turbulence form and it may vibrate. So, it and that maybe
a turned, so, that can be another kind of a turbulency occur.
So, though tho those noise due to the turbulence has to be the shield or has to be isolated
from the outside. So, we can go for some kind of a gyp board duct and if you can introduce
some kind of air space between the duct and the enclosure which is good also, of course,
those those duct or also insulated, because of the thermal point of view because of the
loss of ethanol those also gives you very good um acoustical barrier or acoustical observer
as act as a acoustical observer . Provide gradual reducer is a another issue
then instead of suppose you you are taking a main duct have some size and from the branch
duct will be of different size. So, sudden change of that size will again create a sudden
turbulence. So, give some kind of the reducer single step or the double step reducer or
sometime you may goes again some some the inside of the this things with the insulated
layer , the the the the streamline shaped grilled is also important where the final
discharge is made and the highly noise sensitive room should be kept with the noise um silencer
are those kind of a attachment. So, I have again some photograph from our
Kharagpur IIT AC plant where the this insulated this particular duct is insulated actually
it is there is a the caster and duct and there is a insulation and over the insulation
this is the aluminum foil has been done . This second for photograph is reducer see
this is the higher diameter pipe this is a lower diameter pipe . So, there is a reducer
it should not be abrupt that suddenly and then if there is a abrupt thing then it will
create a kind of a if these are those noise sorry that turbulence .
This is again the observer or some kind of a foam and then there is a rubber
rubber sheet has been wrapped around to that will provide 2 important things
one definitely it will give you a thermal insulation and also it will give you the acoustical
insulations also . I have noted down some points from the
our central pollution control board then norms or the public address system that
create the noise um due to the community noise and all and what are their guidelines. If
you just go through a licensing system is proposed because the before you play any
public address system or the loudspeaker for any occasion a licensing system need to be
done the restriction of the loudspeaker between the night times is also required and it
has been properly monitor we do not follow always those kind of guidelines which actually
bothering sound and people sometimes they are helpless in that situations um. I
have notice that in several locations in the in sometimes in the time of some festivals
and all the people run the show in still late night and then it will be disturb for some
old people living people and the infant . The loudspeaker should not be direct directed
as to towards should be towards the audience, but not towards the the neighbourhood or community
and the control systems, license system, control system should also check what is output
level of this loudspeaker and the permissible level should not be should not be more than
5 dB a above the ambient, everything is there, everything is there and as per the
norms as per the rules provided by the CPCB what is problem that we sometimes may
not monitor regularly very frequently and people will actually break the law and
that create the urban noise scenario that is very poor scenario in that case we also
I mean the community and the people are also very very much sensitize to a reach with
that . The construction activity noise its I again
a very tremendous noise has been sometimes created to this is a limited to 75 dB
. If it is industrial area and it is 65 dB of course, for 5 min duration equivalent sound
level for other areas is mentioned by CPCB acoustical barrier is should be created because
if there is a construction the are the periphery the surrounded buildings are all come under
that particular sound, come under that particular the sound pollution because construction
noise are very very serious, very very high pitch There should be fence all around
there should be some if there is some kind of a stockpiles that may be placed in that
in between the the the site and the other part of the community through shield the noise
construction of temporary earth bund is also sometimes advisable because earth is always
available by explanation of the soil. So, again I have a videos very small video
of construction noise of one of the site from one of the site you can actually see how much
is the noise form a particular tile cutting machine .
Tile cutting is one of the issue that create a high pitch and vey annoying noise . So,
this is 1 only but there are lot of other activities which actually propagate
the construction noise . It is very much essential to take care of that, not only for the people
outside, also for the people who are actually working over they are continuously exposed
to that particular sound and of course, it is more than 65 dB or more than 5 minute
exposer level also and the burning of crackers is also come under some kind of loss nowadays
and the what is the because it is very sensitive issue and sometimes pin code is
also intervene that. So, as per the CPCB once again the it should
not be more than 90 dB at a 5 meter distance know a particular cracker will blast , the
bursting of the cracker during night is also band and the crackers is permitted only in
the public festivals like Diwali and all, but sometimes we also I mean the enjoy the
this crackers and all not only Diwali may be in the some other gatherings and some
marriage parties and all . So, that is all for this lecture and that
is all for the course on architectural acoustics . I hope you have thoroughly gain some
knowledge through this particular course and the homework for this particular lecture is
that taken an example of a old age home located at the edge of a busy urban road and prepare
a schematic plan for your this this old age home how to mitigate the outdoor noise
and prepare a again checklist to control the air condition plant noise for a air condition
plant what should be the checklist being architect are being a supervisor level also you can
checklist. So, next is your may be the end semester
examination and um i hope if you go through the PPTs and the lectures, it will be very
helpful for you to score a very good marks in the end semester and this lecture on
architectural acoustics what professor Gupta has taken in that middle portion in
the design of auditorium, studios, outdoor radius and all will be helpful for you to
design the architectural spaces in future and being in architect or if you are
in a arena of teachers like us it will be helpful for you to explain the future students
in architecture and wish you all the best and for the your end semester and also
for your future. Thank you very much .