Non-Metallic Duct Board AIC Tech 14 Sep - ASHRAE India · Non-Metallic Duct Board ... more area contact. (Ref: Test ... At bends/Elbow slightly better than metal duct Same as Metal

TWIGA

IMO certified by-

SAINT GOBAIN

A Technical Licensee of-

Non-Metallic Duct Board

U.P.Twiga Fiberglass Ltd.

AIC Tech

14th Sep.2013

TWIGA

IMO certified by-

SAINT GOBAIN


Purpose of A HVAC Duct

• To carry conditioned air from AHU to conditioned place without gaining much temperature/loosing energy.

• To deliver noise free air.

• To maintain quantity (flow rate) and quality of conditioned air:

-Minimum leakage,

-Minimum frictional loss,

- Minimum pressure loss

- No contamination

All these above parameter can be met with Metallic and Non

metallic HVAC ducts subjected to proper installation.

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How non metallic duct helps better

• High level of thermal and acoustic insulation according to required standards what conventional systems with lower thickness of insulation cannot achieve.

• Minimize leakage rate (< 1%, 80% better than Metal duct) hence provide better energy conservation.

• Duct fabrication and insulation in one single operation.

• Speedy execution with minimum wastage.

• Small modifications can be accommodated in fast and effective manner.

Non Metallic insulated duct system is technologically more

advanced and provide efficient ducting envelope in comparison

to conventional metal ducting system.

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Agenda

• Non metallic duct

• Product Features

• Application Features

• Performance

• Summary

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Non metallic duct

• Long insulation boards (typically 3 m) converted to rectangular ducts with the help of specially designed tools. Insulation material –either High density Glass wool or Plastic foams suitably laminated with multilayer facings on both faces.

• Outer face is tough/reinforced and inner face is without reinforcement, designed to have grooving operation easily.

• Straight Duct modules can be joined through male-female edges to make longer ducts.

• External faces are cut/joined differently to produce Elbow, Offset, reducer.

• One or more elbow, straight ducts etc are cut and joined accordingly to produce- r-joint, triple-joint, and other complicated duct network.

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Product Features: Duct joints

• Ship-lap joint to join two straight duct module.

• Perfect sealing

• Least leakage rate

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Product Features-Laminations

• Integrated Lamination options. Sometimes multicolor options.

• External side-Aluminum foil/ decorative laminations

• Internal side-Aluminum or Black glass cloth Textile

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Application Feature-Straight Duct Method

(SDM)

• Single piece ducting- only one joint length wise.

• Multiple pieces for higher dimension duct. (external perimeter>3m).

• Wastage reduction is done by joining cut pieces from duct boards to make complete duct.

Redpoint

Redpoint

Redpoint

Bluepoint

Bluepoint

Red point

Blue point tool to cut chair-shape joints and leave a flap for duct closure.

Red point tool to cut chair-shape joints in order to foldduct boards to 90`.

Black point tool to cutshiplaps for flat piecesfabrication.

A

A

A A

A A

AA

B

B

Two pieces in -L- duct

-U- single piece andflat piece duct

Single pieceduct

Four piecesduct

B

B

B

B

B

B

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Application Feature- Sealing

• Stapling and Taping in Straight duct module and joining of two modules together.

• Adhesive and Taping for Elbow, Offset

• All joints are inspected from inside.

• Curing time need to be provided before going for test/operation.

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Application Feature- Straight duct to Other

shapes

• External guidelines to help proper cutting at 22.5o

• No/minimum wastage

• Elbow, Offset, r-joint, triple joint, double offset etc.

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Application Feature-Reinforcement, metal

profiles, fittings

• H-profile to join grill/diffuser.

• All sort of metallic air supply components can be fitted with non metallic ducts with the help of profiles.

• Reinforcement for bigger sized ducts at certain pitch.

2

3

41.- CLIMAVER duct2.- U-shaped profile3. Sheet metal screws4.- Metal plate

1

CLIMAVER

CLIMAVER

CLIM

VER

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Network with Non metallic ducts

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Performance

• Thermal

• Acoustic

• Fire

• Stiffness and Pressure

• Pressure Loss and Leakage

• Limitations

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Thermal Performance

• Thermal Conductivity <=0.032 W/m.K

• Thermal Resistance(25mm)

>= 0.75 sq.m.K/W

• ECBC/ASHRAE compliant.

• 6-19 mm thick insulation does not comply ECBC. Non metallic ducts have 41 % more thermal resistance.

• Insulation efficiency (U-value improvement) of non metallic ducts : 28% w.r.t 19mm thick insulated metal ducts

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Acoustic Performance

ACOUSTICAL ABSORPTION (dB/ m)

Duct 400 x 500 mm

Frequency (Hz)

125 250 500 1.000 2.000 4.000

Metal duct – no insulation /Foam duct 0.07 0.07 0.19 0.19 0.1 0.07

Metal duct – External insulation 50 mm 0.14 0.14 0.38 0.38 0.2 0.14

Non metallic fiberglass duct with

aluminum lining1.26 1.26 1.26 4.99 3.97 3.01

Non metallic fiberglass duct with textile

lining1.67 4.99 5.52 8.86 9.45 8.86

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Fire Performance( glass wool ducts)

• Ducts made of inorganic glass fiber insulation is incombustible in nature.

• Minimum/Zero smoke emission.

• No incandescent droplets.

• Complies/Supersede International Mechanical Code- limited spread of fire/ flame/toxic fumes.

• Unlike rubber/polyethylene based external insulation it is completely safe at core and least potential to fire hazard.

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Stiffness and Pressure

• Stiffness:

Class R5 according to EN-13403 (MAXIMUM LEVEL)

Tested in accordance with EN-13403

• Pressure:

Ductboards can stand pressure up to 800 Pa with no evidence of breaks(Tested at 2000 Pa, derated by 2.5)

Tested in accordance with EN-13403

Classification for board stiffness

Stiffness class Flexural rigidity [EI] N

mm2

R 1 55,000

R 2 90,000

R 3 160,000

R 4 200,000

R 5 300,000

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Pressure Drops and Leakage

• Similar to Metal ducts owing to its aluminum facing based surface backed with rigid and flat insulation boards . ASHRAE charts for metal ducts can be consultant pressure drop.

• Leakage rate is quite low than metal ducts( less than 1%, best/D category) owing to its ship lap joints – tight fit and more area contact. (Ref: Test report extract).

• Conventional Metal ducts have approx. 5% leakage rate.

PRESSURE DROPS IN CURVED ELBOWS AND IN

THREE-PIECE DUCT ELBOWS

0

10

20

30

40

0 1.75 3.5 5.25 7 8.75 10.5 12.25 14

Speed in m/ s

Pre

ssu

re d

rop

in m

m c

.a.

Curved

Elbow

300x300

Three-

pieces Duct

300x300

Curved

Elbow

390x320

Three-

pieces Duct

390x320

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Erosion/Particle Migration(IAQ requirement)

18 m/s for 5 Hr.

0.022µgm/cu.m against maximum

limit of 60µgm/cu.m

EN 13403 / UL

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Limitations

• Smoke or gasses evacuation.

• Outside placed ducts, or buried, without protection.

• Vertical ducts 3 m without reinforcements

• USE LIMITS

- Static pressure >800 Pa (80 mm c.a.)

- Air speed > 18 m/s

- Internal air temperature > 90ºC

- External air temperature > 65ºC

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Summary

Parameter Non Metallic-

Glass Wool

ducts

Non Metallic-

Foam Ducts

Metallic Ducts+

19mm Insulation

Thermal

Resistance

High (ECBC

compliant)

High (ECBC

compliant)

Low (Non

compliant)

Acoustic

Parameter

High absorption Low absorption Low absorption

Frictional Loss of

Pressure

Meets ASHRAE

requirement

At bends/Elbow

slightly better than

metal duct

Same as Metal

duct

Meets ASHRAE

requirement

Leakage Rate <1% 3-4% 5%

Maximum

Pressure

800 Pa ( Test at

2000 Pa)

Same Suitable for

Higher pressure

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Summary, cont.


Glass Wool

ducts

Non Metallic-

Foam Ducts

Metallic Ducts+

19mm Insulation

Fire Parameter Best in class. Non

combustible at

core. No

incandescent

droplets

Plastic foam is

combustible in

nature. Fire

droplets possible.

PIR ducts are

comparative

better than PUF

Combustible with

plastic/rubber

based insulation.

Fire safe with

Glass wool

insulation

Stiffness/Rigidity Meets Highest

class (R5)as per

EN std.

Rigid Highest rigidity,

better than non

metallic ducts

Erosion Zero erosion Zero Erosion Depends on

proper installation

of acoustic lining.

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Summary, cont.


Glass Wool

ducts

Non Metallic-

Foam Ducts

Metallic Ducts+

19mm Insulation

Application Need better

skilled applicators

Need better

skilled applicators

Factory made

ducts. Installation,

insulation

application does

not need mush

skilled applicators

Ease of operation Duct making and insulation in a single

operation at much faster speed and

less number of persons

Two different

operation with

different set of

applicators. Noisy

and jobs need

much more

manual labor.

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Summary, cont.


Glass Wool

ducts

Non Metallic-

Foam Ducts

Metallic Ducts+

19mm Insulation

Adaptability at site High, minor changes can be

accommodated with minimum

resource.

Low, difficult to

modify once duct

is fabricated.

Cost Competitive. Low cost for

transportation. Indirect cost saving-like

installation/labor cost, speedy

execution etc.

Similar to Non

metallic duct.

Suitability/

Limitation

Upto 800 Pa and 18 m/s , Not for

buried and external ducts.

No limitation for

pressure or

velocity. Used as

Buried and

external ducts.

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Q&A

Documents

Non-Metallic Duct Board AIC Tech 14 Sep - ASHRAE India · Non-Metallic Duct Board ... more area contact. (Ref: Test ... At bends/Elbow slightly better than metal duct Same as Metal