A presentation on Upgraded Insulation Systemsby

N. SrinivasLloyd Insulations India Limited

LLOYD INSULATIONS (INDIA) LIMITED

Thermal Insulation

A provision made to retard heat flow from a hot surface to a cold environment from a warm environment to a cold surface

This simple device in Industry has acquired enormous importance in recent times for what it can do for us if we were to give a very little extra attention

Todays need is for Correctly designed and well installed

insulation system.

Which is Easy on the purse

Speedy to erect

Stays maintenance-free & Efficient in service

An efficient insulation in place serves our best interests

in todays context

Economy: safety :smoother process control at Plant level

Substantial reduction of fuel costs & enhanced profitability at the corporate level

Reduction of Greenhouse gas emissions at the larger Global level

There is urgent need for thrift in our energy consumption pattern. Poor insulation is a major drain on energy and resources in industry today

There is an urgent need to have a close look at what it means to specify correct performance levels in insulation.

Potential for energy loss from a hot surface

From a metallic surface at 30 C ambient temperature and wind

velocity 3m/sec

Difference between

ambient and surface

temperatureC

Heat loss kcal m2.hr

25

40

100

150

225

340

600

1910

3225

5330

Heat-in-leak into cold surfaces

Difference in

Temperature between

ambient & Surface

C

Heat in-leak

Kcal/m2h

Exposed area per

Tonne of

refrigeration m2

5

10

15

20

38

76

125

165

79

40

24

18

Ambient considered : 38 C Surface Absorptance:0.8

Shape of Surface : SphericalProperly designed insulation can restrict the above valuesdown to 10 - 15 kcal / M

Heat Transfer through Mass Insulation

Components of Heat Transmission

Thermal Insulation

From this, we can see that

insulation is a major tool in

improving energy

availability

Financial Implications of Performance Specs

0

50000

100000

150000

200000

250000

300000

40 50 60 70 80 90

1982

1988

1991

1998

2004

2008

System details:Pipe Dia-(NB): 100mmSurface Film Coeff

:12kcalm2hr CAmbient Temp : 29 CHours of Operation : 8000

YearsConversion Eff.: 100%

Surface Temp. over

insulation in C (specified)

Co

st o

f lo

st h

eat

/ 1

00

mtr

s /

ann

um

in

Rs.

Economic reasons for Thermal insulation in industry

Reduces fuel consumption, and hence overall cost of operation

Reduces capacity requirements for heating/cooling systems (e.g., boilers/ refrigeration units, etc)

Benefits of higher profits to owner

Savings in Project Capital costs

Economic Thickness

0 1 2 3 4 5 6 7 8 9 10 11

TOTALCOST

LOSTHEAT

COST

INSUL

ATION

COST

CO

ST P

ER Y

EA

R, R

S

INSULATION THICKNESS, INCHES

MINIMUM

COST

The basic criterion for thermal insulation is Economics

However, major role of Insulation is in helping in attaining equilibrium of Process temperatures, while

assuring safety against burns in a plant

The Insulation System is the barrier against avoidable heat transmission.

Any amount of care in design and implementation is worth the trouble

Thermal Insulation Systems- Importance Of Design

The function of Thermal insulation is performed not just by a single material, but by an assembly of engineered provisions or components termed as, Thermal Insulation System. As called for in all such works, there is need for careful design of all such elements.

The task of the insulation designer is to evolve system which fit the need-like a glove to a hand that would wear it.

Insulation System Design

Insulation system should perform to the expected level, undiminished over its life.

This needs full data on material behavior under all conditions of exposure.

In particular, designers need to know what would make a material lose its properties.

Features of a material are important-but their limitations are even more so!

The hazards of being an insulation designer is that we have many manufacturers whose data are simply not reliable or representative.

We have to evolve our own database for properties of materials-insulants, adhesives,

cements, or specialities.

We, at Lloyds have been actively generating and reviewing such databases for all these years...

Insulation design

Thermal designs are carried out using well researched calculation protocols.

Design of the physical system poses maximum challenge since it needs in depth knowledge of what\makes materials work and what makes them fail. It needs detailed study of system dynamics.

Take for example, the design to take into account moisture entry ,expansion and contraction etc when the pipe or vessel is heated up and/ or cooled down-cyclically.

Design for thermal growth or shrinkage

It needs a very detailed analysis of each layer of insulation, the effect of the temperature at that layer, a comparison with what the metal surface may have undergone due to change in the temperature the metal may have seen.

Relative growth of one or the other element, unless factored in, becomes the source of damage and breakdown...

Design for thermal growth or shrinkage

Relative growth of one or the other element, unless factored in, becomes the source of damage and breakdown...

7500

Properties of Materials in insulation

Some important details of what makes them work and what makes them fail

Factors in selection of Thermal Insulating Materials

Significant parameters involved are:

Thermal Properties

Mechanical Properties

Chemical Properties and

Commercial Factors

Although listed last, commercial factors play animportant role in our choices.

Broad material properties to consider in

selecting materials

Is it Alkaline or is it acidic (pH)

Chemical Reactivity / passivity to MOC

Combustibility

Compressive Strength & Breaking Load

Is it prone to water ingress due to Capillarity

Is it Abrasive? and, Most importantly,

THERMAL PROPERTIES

Thermal Properties of Insulation Materials

Important thermal parameters of thermal insulation materials are

Temperature resistance- limiting service temperature

Thermal conductivity

Coefficient of Expansion / Contraction

Thermal diffusivity, and

Thermal shock resistance

Thermal Insulation Materials

Chemical Properties

Compatibility with the metal surface

Compatibility with environmental media

Rate of deterioration arising out of the above-if any

Expected life of insulation material

Thermal Insulation materials are made of many basic forms

Flake : Vermiculite, Mica

Cellular : Polyurethane foam (PUF), Foam glass, Expanded Polystyrene, Cellular concrete

Granular: Calcium Silicate, Magnesia & Perlite

Fibrous : Mineral fibres, ceramic fibres

A material can be a combination of any of the above as

Well (e.g. Microporous insulation)

Thermal Insulation Materials

Extra Low Thermal Conductivity Materials

Microtherm

Pyrogel / Cryogel

Micro porous insulation

Long chains of SAS particles help to keep solid heat conduction to a minimum.

Spaces in the structure smaller than the mean

free path of an air molecule eliminate most of

the gaseous heat conduction.

Mineral oxide opacifiers effectively block infra

red radiation.

Microporous insulation is based on nano-structured sub-micron synthetic amorphous silica (SAS) and other environmentally safe materials.

Microtherm

What are Aerogels?

Nanoporous solid

Aerogels refer both to a structural morphology and a method to produce them (supercritical extraction from gels)

Open-cell structure with up to 99% open porosity (our blanket is 93-95% open volume)

Translucent silica aerogels are often called frozen smoke

Average pore diameters of 10 nm create unique

properties

Reduced mean free path for gas molecules

Reduced energy and mass transport

Traditional silica aerogels are weak and brittle

Lowest k-Value

0

20

40

60

80

100

120

-200 -100 0 100 200 300 400

Mean Temperature ( C)

Th

erm

al

Co

nd

ucti

vit

y, k

(mW

/m-K

)

0-100-200-300 100 200 300 400 500 600 700

Mean Temperature ( F)

Th

erm

al C

on

du

ctiv

ity, k(B

tu-in

/hr-ft

2-F

)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Pyrogel

Expanded

Perlite

Mineral Wool

Calsil

Thickness Comparison

Hot Insulation Materials manufactured on commercial scale..

Rockwool / Mineral wool- by far the most widely manufactured worldwide

Calcium Silicate- limited to countries where raw materials are available.

Ceramic Fibre- its high refractoriness making it a material of choice for high temperatures

Foam Glass-predominantly specified for low temperatures and load bearing applications

Fibrous Materials Raw materials like rocks, minerals and others used

as additives and correctives are available in plenty-particularly in India

They are made using dry processes- hence are free from contaminants normally associated with process water.

They are easily available in various usable forms: Blankets, Semi-rigid slabs, or preformed pipe

sections

Moulded blocks and shapes

Loose fill

Encapsulated / laminated constructions

Sprayable and cement type formulations

for trowel application

Commonly used Hot Insulation Materials

Mineral wool : our Rockloyd range

Rockloyd Mattress

Rockloyd Slab

Rockloyd Pipe sections

- Conform to IS 8183, BS 3958 &ASTM-C-592/ C-612 IS 9842& C-547.

- Incombustible when tested as per IS 3144- Concurrently approved as A-15, A-30 & A-60 Class fire barrier

insulation under SOLAS,

Selection of Insulation Materials

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

38 93 149 204 260 316 371

Mean Temperature C

Therm

al C

onductiv

ity W

/mC

Rockwool Pipesections (ASTM C 547)

Perlite (ASTM C 610)

Calcium Silicate (ASTM C 533)

Insulation Materials for High Temperatures

Ceramic Fibre: Supercera range

(RT grade up to 1260 C

HT Grade up to 1430 C )

Supercera needled Blankets and fabrications such as:

Folded modules

Encased flexible sections

Supercera Bulk Fibre

Supercera rigid Boards / Vacuum formed blocks & Shapes

Moist felt / Paper / Rope

Calcium Silicate.

Insulation Materials for High Temperatures

Ceramic Fibre: Supercera range

Also used as Fire protection in

Structural Steel applications

Cable Trays

Ship Bulkheads / deckheads

Turbine Insulation

Removable Type Pads

Supercera Ceramic fibre Removable Pads for Turbine Insulation

Commercial Cold Insulation Materials

Polyurethane Foam (PUF)

Polyisocynurate Foam (PIR)

Foamglass

Phenolic Foam

Expanded Polystyrene (EPS)

Low Temperature Insulants

Among the listed materials, Polyurethane and Polyisocyanurate, representing products of lowest Thermal conductivity are materials of choice because of the easy availability in commercial quantities and the versatility they offer.

As is well known, these materials offer great flexibility to the specifier and user since they can be applied as Preformed shapes or installed in-situ- by Pouring or by spray.

Urethane Foams-the ultimate cold insulant..

Rigid Urethanes Foams are a family of Engineered Plastics which have received enormous R&D inputs worldwide.

Today, any features that an application may demand can be built in by careful selection of chemical ingredients and precise engineering of their chemistry.

Insulation Finishes

The outer cover over insulation..

Weather Barriers/ claddings- These all have one basic function - to protect insulation from the known hazards like external media, mechanical abuse etc.

External coverings are what we get to seeing in a completed plant or pipeline. Aesthetics becomes a secondary, but significant role assigned to this provision.

Insulation Finishes

Metal Cladding- some important issues..

As can be easily appreciated, all metal cladding materials need careful selection from external corrosion point of view as a first consideration.

However, another important aspect concerns corrosion from within- contributed by condensation of vapours from the insulation system on the inner surface.

Since most insulants are faintly alkaline, such condensed water attacks the metal particularly Aluminium and causes it to pit and fail as a barrier.

All metal cladding, as a rule need protection on the inner surface- like a factory laminated Poly Surlyn treatment.

Cladding Materials

Metal Claddings with Moisture Barrier

PolySurlyn

Polyethylene

Surlyn

Polyethylene

Metal Corrosion

Pits

Weather Barrier

Installed on outer surface of thermal insulation, these protect the insulation from the weather (rain, snow, sleet, wind), solar radiation, or atmospheric contamination & mechanical damage.

They significantly contribute to protection of the insulant and play a vital role in the life of the system.

Being the final exposed surface, its selection involves study and knowledge of all external and environmental factors the system is to encounter.

Metallic claddings

As is well known, metallic sheeting fabricated into close conforming cover, with edge detailing to lap and seal effectively, is probably the most popular external cladding.

However, Plastics, like High Density Poly ethylene (HDPE), PVC and special polymers are specified for niche applications / duties.

Most popular metal cladding is based on Aluminium- in specific alloy grades for specific duties.

When steels are specified, they are either of suitable grades of SS or of Carbon steels with a metallurgical protection like galvanizing, Aluminizing or a treatment consisting of a combination of Zinc and Aluminium.

Outer Cladding Systems for Insulation

Metallic Cladding Materials

Aluminium or Galvanised Steel Bare or Colour coated.

Zincalume or Aluminised Steels

Stainless Steel

Other cladding systems

Cementaceous plasters

Liquid applied reinforced Coatings

HDPE and PVC sheets / sleeves

Vapour Barrier in cold service

Installed on the high vapour pressure side-I.e., the warmer side of the insulation systemprior to cladding), Vapour Barrier (or Vapour retarder as it is referred sometimes) is designed to arrest entry of moist vapour into the insulation, causing it to soak and possibly to freezing.

Insulating Material, when wet can be 30 times more conductive and would no longer be an insulant!

Freezing of water is always accompanied by volumetric expansion resulting in rupture.

In cold insulation system, therefore, the soundness of the VB virtually determines how good the insulation system is.

Vapour Barrier in cold service

Weather cum Vapour Barrier

There are a set of materials, which serve both as a weather barrier and vapour retarder at the same time.

These are mostly in the form of Mastics- trowelled or brush applied- which set to becoming a tough outer skin.

Important factors in cold insulation

Adequacy of insulation to limit heat ingress to be below process limits.

Adequacy of thickness to prevent condensation on the exposed surfaces- this involves the emittance of the surface. A reflective surface like Aluminium would call for very high insulation thickness to prevent surface condensation. Colour coating is a very effective solution.

Prevention of water vapour transmission fromthe warm side to the cold side of the insulationhas to be ensured under all conditions- i.e., thesystem should feature a good Vapour Barrier.

A word on Vapour Barriers..

Often Bitumen and products are used. These are not fire-safe, durable nor Elastomeric- which are all veryimportant needs.

These materials once in wide use have no place in thepresent day Insulation specifications.

Excellent Vapour Barrier products are now available andno compromise is therefore necessary

Insulation Pipe supports

Todays plants need a wide expanse of extremely low temperature piping.

Unless supports are highly insulating, the exposed surfaces would attract condensation and very heavy corrosion at these important bearing points- with corroded load bearing points and avoidable unsafe slippery floors underneath.

SUPERTHERM Pipe supports

These are made from Highest efficiency insulants i.e., Urethanes, made to high density to afford an Engineered load bearing capacity.

These are made in all the possible shapes and with specific features- for sliding, guide and anchor duties.

Support design and selection are very vital design inputs for the Process Piping Engineeer / designer.

Thermal Insulation for Cryogenic Temperatures

Fields calling for cryogenic engineering

Storage & handling systems for Cryogenic liquids- LNG

Air seperation and N2,O2,Inert gas plants

Rocket Fuel handling Systems in Dept of Space

Environment Simulation Chambers for Space programs

Nuclear Engineering- liquid H2 plants, materials development

Electronics- Superconductivity studies

Biological Applications

Food preservation

Special Manufacturing Processes

Thermal Insulation for Cryogenic Temperatures

INSULANTS FOR CRYOGENIC DUTY: Mass type materials which qualify for this duty up to -160 C

are:

- Cryogenic grade Polyurethane / Polyisocyanurate

- Cellular glass

Cladding System for Shell Insulation

Lloyd Standing Seam SS 2000 Tank Cladding system

The SS 2000 profile is site roll formed using

Zimmermann Roll Former which permits

rolling any length as required. Normally, a

length over 12 mtr is not transportable and

hence site roll forming offers this advantage.

Maintainability of Insulation

One of the aspects which suffers badly due to these factors is the Maintainability of insulation.

When specialist agencies are given the responsibility to design and detail out the system, good engineering practices are automatically built in.

These get diluted badly when low cost and haste become the buzzwords!!

Maintenance of Insulation

There are many places where damages almost always occur:

Gaps or unsealed joints admit water through poor weather barrier jacketing

Job done without expansion breaks rips the cladding, Spillage ruins the weather-barriers, and soaks into the

insulation through unprotected edge detail. Unfilled projections through the insulation cause

disintegration of the weather-barrier and result in peelback

sealant in Weather-barriers shrinks and cracks admitting water freely.

Foot loads coming as a surprise on a design not capable of bearing them.

Maintenance of Insulation

Insulation when selected properly and installed wellis an excellent investment, and good maintenanceprotects that investment. Poorly applied insulation isa large drain on resources - both in terms of poorerEnergy economics and in terms of higher costs ofrecurring maintenance that it entails.