Sound absorbing material using Rockwool or mineral wool

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SOUND ABSORBING
MATERIAL IN FLOOR
SEMINAR REPORT

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ACKNOWLEDGEMENT
I would like to acknowledge head of the civil department for her invaluable guidance
during the course of this project work.
I would like to express my sincere thanks to Asst prof…… from the Department
of Civil Engineering at ……College of engineering for her help, guidance and assistance
in all stages of this project. The constant encouragement, support and inspiration she
offered me were fundamental to my project work.
I would like to thank all the lecturers in the ….. College of engineering from
whom I learned much and developed my skills.
Finally, I would like to thank all those who gave me advice or assistance that
contributed to my project.

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ABSTRACT
The present scenario of living is different from the earlier ages in many sorts of
features; expedited technological growth has caused us to live between machines, their
operations and in an environment synchronized with their relationships with us. The
rising use of automation and fabricated methodologies has impacted us in a variety of
ways. The result being less pleasant environments in terms of polluted resources,
increased exposure to toxins and not to mention the ever growing increased auditory of
sound. While our forefathers lived in relative tranquility, we are subjected to an
incredible increase in the sources of noise and noise intensity both inside & outside our
buildings, often with serious and harmful effects. This over exposure to sound has
forced to devise techniques and methodologies in order to control and mitigate over
hearing conditions. Hence “Acoustics” can be defined as a science of sound, which deals
with origin, propagation and auditory sensation of sound, and also with design &
construction of different building units to set optimum conditions for producing
&listening speech, music, etc. the study of acoustics is a very necessary discipline these
days as it employs designing interiors of auditoriums, theatres, and other structures to
enhance their audacity features.

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CONTENTS
SL NO DESCRIPTION PAGE No:
1 ACKNOWLEDGEMENT 3
2 ABSTRACT 4
3 Chapter 1 INTRODUCTION 5
4 Chapter 2 METHODOLOGY 6-19
5 Chapter-3 CONCLUSION 20
6 REFERENCE 21

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CHAPTER 1
INTRODUCTION
Building acoustics is the science of controlling noise in buildings. This includes the
minimization of noise transmission from one space to another and the control of the
characteristics of sound within spaces themselves.
Building acoustics are an important consideration in the
design, operation and construction of most buildings, and can have a significant impact
on health and wellbeing, communication and productivity. They can be particularly
significant in spaces such as concert halls, recording studios, and lecture theatres and so
on, where the quality of sound and its intelligibility are very important.
Building acoustics can be influenced by:
 The geometry and volume of a space.
 The sound absorption, transmission and reflection characteristics of surfaces enclosing
the space and within the space.
 The sound absorption, transmission and reflection characteristics
of materials separating spaces.
 The generation of sound inside or outside the space.
 Airborne sound transmission.
 Impact noise.

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CHAPTER-2
METHODOLOGY
 Install bats between joist webs, on top of the bottom flanges, use bat width that
corresponds to the joist spacing.
 Install bats snug around any pipes located in the joist cavity area.
 Use rigid wire insulation stays between bottom flanges, 24” on-centre and no
more than 6 inches from bat ends, to assist in insulation support.
 When necessary, cut mineral wool insulation with serrated knife or table saw.
 Glass fiber insulation may not be substituted for mineral wool insulation as fire
resistant component.
 Compressing mineral wool to a 2 inch thickness to fit under mechanical pipe /
ducts does not compromise the fire resistance if the bats remain tight to top of the
bottom flanges.
2.1 ROCK WOOL
It is a general name for fibrous materials that are formed in by spinning or drawing
molten material or rock materials such as slanged ceramics.

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Rockwool is an inorganic insulator made from stones or rocks by blowing a jet of steam
through molten rock (such as siliceous rock or limestone) or slag. More advanced
production methods involve spinning molten rock in high-speed spinning heads
Applications of rock wool include thermal insulation (as both structural
insulation and pipe insulation, though it is not as fire-resistant as high-temperature
insulation wool), filtration, soundproofing, and hydroponic growth medium..
Rockwool is widely used as a soilless growing medium for plants and comes in various
forms and various sizes to suit various types of gardens, including Rockwool slabs,
Rockwool cubes, and loose Rockwool chunks. Cubes are popular for starting seeds, and
once they germinate and become seedlings, the cubes can be transplanted into slabs
Rockwool is a popular soilless growing medium for gardening and hydroponics because
it holds water well and allows air to circulate the root zone for exceptional plant growth.
Its strength makes it suitable for root support. In the hydroponics industry, Rockwool
competes with other types of grow mediums like grow stones, clay pebbles, coco coir,
Oasis cubes, floral foam, vermiculite, perlite, and gravel.
Rockwool is lightweight, and can be reused. It provides a sterile growing environment for
plants, and although it starts out with a naturally high pH, with proper conditioning its pH
can be stabilized to make it suitable for plant growth.
The fibers in Rockwool are abrasive and can release micro particles that can irritate or
itch when in contact with the skin. For this reason, growers will often soak the Rockwool
before planting. Furthermore, Rockwool should not be used in residential areas with high
moisture levels (such as most basements) because fibers can absorb moisture and become
a medium for mold growth.
In addition to being a popular soilless grow medium, Rockwool is used in a wide array of
applications and products due to its very high melting point and because it is an excellent
insulator. For example, it is often used for fireproofing, fire stops, and other temperature-
sensitive applications such as cooking appliances. When sourcing Rockwool for your
hydroponics system, do a little bit of research beforehand to make sure you end up with
horticultural-grade Rockwool.

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2.2 MANUFACTURING PROCESSOF ROCKWOOL
Blast furnace slag and other materials are both heated and re-melted in a cupola or
electric arc furnace at 1,500 - 1,600℃, or else after being removed from the blast furnace
the molten slag is kept at approximately the same high temperature and is allowed to flow
out from the bottom of the furnace. The molten slag is then blown to form fibers by
centrifugal force or similar means. The fibrous rock wool is collected in a collection
chamber. The process to create the final product differs depending on the application. To
create “granulated wool,” the rock wool is separated and granulated. To create “formed
products” such as board or mat shapes for housing applications, binder is added to the
wool and it is hardened in a curing oven and adjusted to a fixed density and thickness.

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2.3 FEATURES OF ROCKWOOL
 Made from natural, sustainable material
 Typically contains up to 75 percent recycled content
 Retains heat well and traps air, which slows the transfer of heat
 Non-combustible and fire resistant to about 1,400 degrees
 Highly water repellent
 Excellent sound-deadening properties
 Higher insulating value than fibreglass
 Long-term performance—rock wool doesn’t degrade over time
 Allows moisture to escape (which deters mold and mildew)
2.4 IMPORATANCE OF ROCKWOOL INSULATION
Rock Wool Insulation could be the best choice for proper insulation of your cavity or
frame walls, roof rafter or lot. Bearing in mind that lately people pay much more
attention to insulation, but not only thermal insulation which is the primary goal that
everyone have in mind when choosing an insulation material, but also acoustic insulation
which can also be very important, especially of party walls and floors. This is where rock
wool insulation can be very effective, considering its properties and performances in both
thermal and acoustic insulation. But before choosing this type of insulation material,
there are some things you should know about regarding the material itself and its varieties
and applications.
Definition
Rock wool insulation implies a specific manufacturing process of rock wool (also
known as mineral or stone wool), which is made by using molten rock (usually basalt), a
binder and usually a little oil to decrease appearance of dust. All the materials are placed
inside a vertical furnace and heated at very high temperatures of approximately 1600° C.
The result is producing mineral or rock wool consisted of fine fibres which are then
processed into final product packed into rolls or slabs. The characteristics of rock wool

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insulation will furthermore depend on its density, since the manufacturing process
enables to achieve different densities formed into various shapes.
Rock wool is a fire resistant material thanks to high temperatures used in the melting
process, so it is often used for preventing fire from spreading due to its ability to block
heat transfer. This is important, since if used properly, rock wool insulation will not only
protect your home, but also have positive effects on energy consumption. Bearing in
mind its ability to retain water, this could present a problem on one hand which can
effectively be dealt with if the water is able to drain out, but keeping in mind that moist
and water does not have consequences to rock wool insulation properties. On the other
hand this property of rock wool has made it very popular for hydroponics and
horticulture use. Rock wool insulation is also eco-friendly, not only because it is
recyclable, but also because it generates only a small amount of waste (not only
manufacturing but also installation waste), since materials can be reused in the
manufacturing process. Rock wool insulation has many applications, but is especially
efficient when used for masonry cavity and timber frame walls, roof rafter insulation,
loft and suspended floor insulation or acoustic separation
of flats.
Classification
Rockwool offers a wide set of products created from
natural volcanic rock, including:
 Cavity Insulation Slabs available in 50 mm, 80 mm
and 100 mm sizes, which are very easy to install, water repellent and fire resistant,

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with overall great thermal and fire insulation, non-combustible and thus has very
wide application, especially in buildings up to 12 m high, or even buildings 12-25 m
high if certain conditions are met.
 Flexi Insulation Slab in 50 mm and 100 mm
sizes. Flexi insulation slabs are easy to install and
handle, compatible with every width, due to its
patented flexi edge, produce no waste, especially
applicable to partitions where they provide both
fire and acoustic benefits and often used to reduce
noise, applicable to walls, partitions, roofs and floors.
 RWA45 Slab and RW5 Universal Insulation Slab,
both available in two sizes, 50 mm and 100 mm. This
type of rock wool insulation is very easy to install and
requires no maintenance, cost-effective water repellent
and can resist temperatures of up to 230° C, used for
roofs, walls, floors, ventilation plant and acoustic ceiling
and partition panels.
 Earth wool RS45 (available in four different
sizes, 25 mm, 50 mm, 75 mm and 100 mm), RS60
Universal Insulation Slab and Earthwool
RS100 Universal Insulation Slab (available in
two sizes, 50 mm and 100 mm), used for internal
partitions, between timber and metal stubs and
rafter and floor joists. It is very lightweight and thus easy to install and cut to right
size, odorless and rot proof, it has high vapor resistance, can be used at temperatures
of up to 850° C, depending on the density and
classified as non-combustible.
 Earth wool Flexible Insulation Slabs, available in
50 mm and 100 mm sizes, used for internal
partitions, between timber and metal stubs and

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rafter and floor joists, available in weatherproof packaging, making it easy to unload
and store outside, widely applicable and moisture tolerant.
 DriTherm 32 Ultimate Cavity
Slab (available in 65 mm, 75 mm, 85 mm
and 100 mm sizes) and DriTherm 37
Standard Cavity Slab (available in 65 mm
and 100 mm sizes), used for thermal
insulation of masonry cavity external walls,
in buildings up to 12m high in any exposure
zone or multi-storey applications up to 25m in height, odourless, rot proof and non-
hygroscopic, has virtually no vapor resistance, allowing your wall to breathe, contains
a water repellent silicone binder ensuring that no liquid water can reach the inner leaf
of masonry and represents no known threat to the environment.
 Earth wool Acoustic Insulation Roll, available in 50 mm, 75 mm and 100 mm sizes,
used for sound insulation of separating walls, separating floors, internal floors and
timber and metal stud partitions, has excellent
acoustic and sound absorption properties,
dimensioned to suit studs and joists at 400mm or
600mm centers, where long roll lengths enable
quick and economic installation and friction fits
between studs, ensure continuity of the absorbent
layer with no air gaps.
2.4 INSTALLATION ROCK WOOL
In order to insulate our ceiling, we have used both fiberglass rolls and pre-cut
bats. The mineral wool rolls we bought were about 50 feet, but the rolls can have up
to 100 feet. In addition, they might be faced or unraced.

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In order to fill the space between the wood studs, you have to cut the rolls to the
needed length, by using a sharp utility knife and a straight edge.
Mineral wool bat
We also used mineral 4” thick wool bats to insulate the ceiling. The bats come in
different lengths and widths; therefore you should buy the product which requires the
least amount of cuts.
Bat insulation is available with and without facing. We recommend you to buy faced fats,
as they will be easier to install and because the paper layer has the role of an anti-
vapor barrier. If you buy bats without facing, you’ll have to attach a plastic foil.
Mineral wool between studs
Before installing the mineral wool insulation, you have to measure the thickness of the
wood studs and the distance between them. In our case the space between the wood studs
is about 24” on center, just enough to fit 23” wide mineral wool bats. Nevertheless, you
should use 15” wide insulation when the studs are 16” spaced. Cut the mineral wool bats
or rolls to fit them into place, in a professional manner.

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Last but not least, cut the mineral wool with a sharp utility knife, by using an
aluminum straight edge. Remember that you have to wear a respiratory mask while you
work with mineral wool, as the fibers are very toxic.
Installing mineral woolinsulation
Installing mineral wool insulation
Start installing the mineral wool from one corner of the room. If the bats are faced, then
you have to staple through their flanges to the inside of the wood joists. If you use
unfaced batts or rolls, the friction will hold them into place.
Securing mineral wool with wire
Nevertheless, we can secure the mineral wool layer with wire, as you can see in the
image. The process is straightforward: use a hammer and install several nails in the wood
studs and then using the wire make a network, as to support the mineral wool. The pattern
shouldn’t be geometrically perfect, but should be dense enough to support properly the
boards of mineral wool.

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If you have to install drywall directly to the wood joists, we recommend you not to secure
the batts with wire, otherwise you won’t be able to hand the boards level.
Installing the second layer of insulation
The next step is to install a second layer of mineral wool, as to fill in the gap between
the metal studs and the future drywall ceiling. In addition, as we have previously
mentioned, the second layer will also improve the thermal and acoustical insulation.
In order to fix the mineral wool strips, we have proceed exactly in the same way, as in the
previous steps. Make sure you cut properly the mineral wool, as not to leave any gaps
between the boards or layers. Any gap would affect the efficiency of the insulation.
Installing double adhesive tape
After we have finished installing the second layer of mineral wool on the whole surface,
we decided to fix an anti-vapor and moisture barrier, as we have used unfaced batts.

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Consequently, we started by installing a double adhesive tape on the metal track, all
around the room’s perimeter. This is a proper method to attach the polyethylene foil, as it
prevents air moisture and vapors to form.
Installing polyethylene vapor barrier
Next, measure the surface of the room and cut the plastic foil to those specific
dimensions, using a utility knife. Start with one corner of the ceiling and attach the anti
vapor foil to the ceiling joists. If you do not want to use double adhesive tape, you could
just staple it along the walls every 5” / 15 cm.
2.5EXAMPLE OF ROCKAPPLICATIONS
2.6 CHARACTERISTICS FEATURESOF ROCKWOOL
 Sound Absorbent

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 Unique non-directional structure of ROCKWOOL stone wool insulation is denser than
traditional insulation products
 Non-directional fibers help to absorb acoustic waves and can reduce the intensity and
propagation of noise
 Effectively reduces airflow and sound transmission
 Higher air flow resistivity means better sound attenuation
 Fire Resistant
 ROCKWOOLstone wool can withstand temperatures up to 2150º F (1177º C);
consequently, it does not contribute to the development and spread of fire or the release
of toxic gases
 Water Repellent
 ROCKWOOLstone wool is water repellent yet vapor permeable
 The long-term R-value of stone wool is unaffected by moisture over time, due to the
inherent drying potential of the product
 Completely resistant to rot, mildew, mould and bacterial growth—contributing to a safer
indoor environment
 Dimensional stability
 Retains its characteristics over time
 Minimal changes in size and performance are evident with changes in temperature and
humidity
2.7ADVATANTAGES AND DISADVATAGES
Advantages
 Rockwool stone wool fibres can withstand more than 1000°C without melting – this
means it can slow the spread of fire in a property where it to catch fire.

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 Rockwool has fantastic thermal insulating properties. 120mm of our dual density slabs
when attached to the exterior of a property will take the u-value down to 0.3 which means
the building will then conform to building regulations
 Rockwool stone wool has great acoustic insulating properties, so it can really can help
with sound reduction if installed on a busy road for example.
 The final advantage is that Rockwool is breathable, therefore it allows moisture to travel
across the wall which can help dissipate damp (from in the house).
Disadvantages
 Rock wool is more expensive than and not as common as other insulating materials.
 That same quality that makes it durable also makes it an environmental nuisance.
 Thrown away it does not biodegrade - its rock. A million years from now it will still be
sitting where ever it was disposed of.

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CHAPTER-3
CONCLUSION
 With increase in awareness and standard of living of people the acoustic materials have
bright future.
 Usage of rock wool which is cost effective can make the build sound insulating in an
economical way.
 Particularly rock wool is best fit for the acoustics problems due to its performance and
also low cost production also textiles act as a dual role with decoration, cushion.
Upholstery etc is also act as acoustic
 Use of recyclable and eco friendly product for an acoustic textile further confirm its
position in market
 Rock wool can withstand high degree of temperature about 1000°C without melting so it
can also use as a fire resistant in residential buildings.

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REFERENCE
[1] J. V. Apicella(1988) ’’Particulate, Sulfur Dioxide, And Fluoride Emissions From
Mineral Wool Emission, With Varying Charge Compositions’’, American Rockwool, Inc.
Spring Hope, NC, 27882, Alumina Company Of America.
[2]J. L. Spinks, "Mineral Wool Furnaces", In: Air Pollution Engineering Manual, J. A.
Danielson, ed., U. S. DHEW, PHS, National Center For Air Pollution Control.
[3] "Mineral Wool or Mineral Cotton", Appleton's Annual Cyclopedia and Register of
Important Events of the Year 1891.
[4]Tom Alexander; Don Parker (1994). The Best of Growing Edge. New Moon
Publishing.
[5]Weiner, Ethan(2000) Acoustic Treatment and Design for Recording Studios and
Listening Rooms. "Without question, the most effective absorber for midrange and high
frequencies is rigid fiberglass