The project class B2ca

How formulations can influence the PVC cables fire behaviorP VC F O R U M I TA L I A : CA B L E S G R O U P

How formulations can influence the PVC cables fire behavior• Cables Group Italy

• The project class B2ca

• Fire performances of old and new cables

• Focus on smoke acidity

• The importance of R&D

• Conclusions

Introduction

Cables Group Italy• The group was born in 2013 with the aim to develop new formulations

for cables with better performances in term of flame retardancy, smoke suppressant properties and smoke acidity

• The project was called B2Ca

Cable Group Italy

B2ca PROJECT• The project is divided in 3 steps

1) Evaluation of the cables on the market before CPR

2) R&D for getting improvements on compounds on lab scale tests

3) Evaluation of the new cables on CPR basis

• The target?

Classification B2ca and the best possible on subclasses

B2ca PROJECT

1) Evaluation of the cables on the market before CPR

B2ca PROJECT

FROR: Italian type of cable FR PVC Rz type

FG7OR: Italian type of cable

G7 type (HEPR)FR PVC based

Filler profile

FR PVC R2 type

FR PVC Rz type

Several kinds of cables have been tested with new CPR rules

1) Evaluation of the cables on the market before CPR

B2ca PROJECT

Several kinds of cables have been tested with new CPR rules

N07V-K: Italian type of cable

FR PVC R2 type

1) Evaluation of the cables on the market before CPR

Type Class Smoke Droplets Acidity

FG7OR Dca S2 d1 a3

FROR Cca S2 d0 a3

N07V-K Dca S2 do a3

B2ca PROJECT

Classes and subclasses according to CPR

2) Lab scale tests

• Evaluation of flame retardancy.

• Evaluation of smokes suppressant properties.

• Evaluation of the smoke acidity.

Fire behavior

• Mechanical properties.• Thermal stability.• Volume resistivity.• Good processability.

Match of the properties of the type of compound and the processability.

We loop over and over againuntil we reach the best compromise

R&D for getting improvements on lab scale tests on specific types of compounds

B2ca PROJECT

More than 70 compounds have been tested according to the following technical

standards

B2ca PROJECT

2) Lab scale tests:

Fire behavior

Cone calorimetry (ISO 5660 – 1a)

Oxygen index (ASTM D 2863)

Smoke Density Rate % (ASTM D 2843)

Smoke acidity (EN 60754 part 1 and 2)

Type of compound

Tensile strength & Elongation @ break before and after aging

Water absorption

Insulation properties

Etc….

a.t. specific technical standard 0f type of compound

Technical standards performed

B2ca PROJECT

2) Lab scale tests:

O L D C O M P O U N D S

• SDR % : [75 – 85] %

• pH: [2,50 – 2,80]

• Conductivity: [100 – 220]µS/mm

N E W C O M P O U N D S

• SDR %: [55 – 65] %

• pH: [3,50 – 3,90]

• Conductivity: [10 – 28] µS/mm

Comparison of some critical physical properties

B2ca PROJECT

2) Lab scale tests:

80

60

0

10

20

30

40

50

60

70

80

90

SDR %OLD New

Comparison of some critical physical properties : SDR % mean values

B2ca PROJECT

2) Lab scale tests:

2.65

3,75

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

pHOLD New

B2ca PROJECT

Comparison of some critical physical properties : pH mean values

2) Lab scale tests:

160

16

0

20

40

60

80

100

120

140

160

180

ConductivityOLD NewµS/mm

B2ca PROJECT

Comparison of some critical physical properties : conductivity mean values

3) Tests on cables

•All tests required by specific standard of the cable

•Processability

Verifying the match of cables’ characteristic a.t. specific standard.

•THR, HRR, FIGRA, Burn lenght;•TSP1200, SPR•Droplets•Smoke acidity•27 CM chamber test

Performing the tests a.t. CPR •Identification of the Classes

•B2ca, Cca, Dca, Eca or Fca

•Identification of Subclasses• S1a, S1b, S2, S3;• d0, d1, d2•a1, a2, a3

Classification of the cable

Production and classification of the cables

B2ca PROJECT

3) Tests on cablesEvaluation of fire performances a.t. CPR: standard performed

• EN 60332-1-2 (Vertical flame propagation on single cable)

• EN 50399 (Vertical flame propagation on bunched cables)

• EN 61034-2 (smoke density in 27 m3 chamber)

• EN 60754-2 (Test on gases evolved during combustion of materials from cables –Part 2: Determination of acidity (by pH measurement and conductivity)

B2ca PROJECT

FIRE PERFORMANCES:OLD AND NEW CABLES

Comparison b/w old and new cables

New Cables Class Smoke Droplets Acidity

FG16OR16New code of FG7OR

Cca S2 d0 a3

FROR B2ca S2 d0 a3

FS17New code of NO7V-K

Cca S1 do a3

Old Cables Class Smoke Droplets Acidity

FG7OR Dca S2 d1 a3

FROR Cca S2 d0 a3

N07V-K Dca S2 do a3

FIRE PERFORMANCES:OLD AND NEW CABLES

We improved the flame retardancy reaching the class B2ca for some kinds of cables

But we have to get better values in terms of smoke densityand smoke acidity

So other sets of lab scale tests are scheduled to reach the new targets

We verified a quite better performance in term of dripping in comparison to the Halogen Free systems

The most difficult task is the reduction of smoke acidity

FOCUS ON SMOKE ACIDITYTechnical standards a.t. CPR

• EN 60754-2

• Tubolar Oven at fixed temperature ranging b/w 935°C up to 960°C

• Determination of pH and conductivity

The method used 4 PVC before CPR

• EN 60754-1

• Tubolar Oven at temperature ranging b/w 790°C up to 810°C

• Determination of mg of halogens in 1 g of compound

• Temperature ramp

FOCUS ON SMOKE ACIDITY

To understand the differences b/w the two standards we need to introduce the theory of acid

scavenging for the reduction of smoke acidity

FOCUS ON SMOKE ACIDITY

ACID SCAVENGING THEORY

°C

Stabilization zone

PyrolysisMassive release

of HCl 1,2Uncharted Zone

Stable reaction products with HCl: 810°C for EN 60754-1Acid scavengers active until PVC is still alive

Single step RXN

Multiple steps RXN

Stable reaction products with HCl: 960°C for EN 60754-2

FOCUS ON SMOKE ACIDITY

Chlorinated aromatic hydrocarbons

Loss of HCl

Acid scavenging theory: inert substance

°C

Stabilization zone

PyrolysisMassive release

of HCl 1,2Unchart Zone

Al(OH)3 Al2O3

MM phr

PVC K70 100

ATH 80

DINP 50

STAB 5

Al2O3

ATH starts the decompositions b/w 180°C and 200°C, releasing water. It acts as heat sink, dilutes the flame, dilutes the polymer and plasticizers, creates a char of Al2O3 [3].

LOI 28 [%O2]

pH 2,22

Conductivity 212 µs/mm

From a AS point of view ATH is ineffective due to the chemical inertia of Al2O3 .

FOCUS ON SMOKE ACIDITY

°C

Stabilization zone

PyrolysisMassive release

of HCl 1,2Unchart Zone

MgCl2 Decomposition in MgO + HCl

MM phr

PVC K70 100

MDH 80

DINP 50

STAB 5

Mg(OH)2 / MgO

LOI 28 [%O2]

pH 2,27

Conductivity 188 µs/mm

MDH starts the decompositions b/w 300°C - 320°C, releasing water. It acts as heat sink, dilutes the flame and as dilutes the polymer / plasticizers [3].

Acid scavenging theory: ineffective AS

From AS point of view in single step reaction MDH is ineffective due to the instability of its reaction product [4]

FOCUS ON SMOKE ACIDITY

Acid scavenging theory: efficient AS

°C

Stabilization zone

PyrolysisMassive release

of HCl 1,2Unchart Zone

AS5 AS5-HCl

MM phr

PVC K70 100

AS5 80

DINP 50

STAB 5

pH 3,11

Conductivity 30,1 µs/mm

AS5 is stable up to PVC is still alive and it reacts efficiently with HCl, trapping it in a reaction product.

Its reaction product is stable up to the maximum temperature required by EN 60754-2

FOCUS ON SMOKE ACIDITY

From 23°C to 800 +/-10 °C @ 20°/min

EN 60754-1: used before CPR

“800 °C“ mean a higher number of stable substances

Advantages

We can use easily multi steps reactions, enhancing synergism b/w substances

With temperature ramps the acid scavengers have more time to trap the evolving HCl

FOCUS ON SMOKE ACIDITY

Fixed b/w 935°C and 960°C

EN 60754-2: a.t. CPR

Higher temperature means a smaller number of stable substances

Disadvantages

Decomposition makes free HCl again

Without temperature ramps the acid scavengers have no time to trap the evolving HCl efficiently

FOCUS ON SMOKE ACIDITY

Differences in numbers

E N 6 0 75 4 - 2

• pH: 3,54

• Conductivity [µS/mm]: 10,4

E N 6 0 75 4 - 1

• pH: 4,00

• Conductivity [µS/mm]: 3,8

• The test is performed with the temperature ramp and the final temperature of EN 60754-1

• But pH and Conductivity are measured, instead of the mg’s of halogens on gram of compound.

• That to permit a comparison b/w EN 60754-1 and EN 60754-2, focusing on the effect of ramp and final temperature on data’s.

We tested the same compound with the two standards

[H+] = 2,88 x 10-4 mol/L [H+] = 1 x 10-4 mol/L

The concentration of protons is 3 times higher

in EN 60754-2

FOCUS ON SMOKE ACIDITY

Relationship b/w pH and conductivity

0

50

100

150

200

250

300

350

400

450

1 2 3 4 5 6 7

R m

icro

S/m

m

pH

Nonlinear regression (R micro S/mm)

Experimental data's Model

0

50

100

150

200

250

300

350

400

450

0 50 100 150 200 250 300 350 400 450

R m

icro

S/m

m

Prev by Model (R micro S/mm)

Prev(R micro S/mm) / R micro S/mm

In in the bubbling devices the stronger electrolyte is always HCl

FOCUS ON SMOKE ACIDITY

The importance of R&D in PVC

Last «adjustments» were at the end of 90’s for ROhS requirements

After 2008 an impoverishment of LV formulations is evident

HFFR eroded more and more market to PVC

Case history: Plenum cables in USA (NFPA 262): R&D permitted the production of compounds with a quite high flame retardancy with low smoke emissions, avoided the banishment of PVC from plenum conduits

THE IMPORTANCE OF R&D

Conclusions

The aim of the R&D is the innovation of the cables formulations

The new horizons of our R&D will be focused on the use of new additives, enhancing further the performances of cables formulations

CONCLUSIONS

Conclusions

The aim of the R&D is the innovation of the cables formulations

The new horizons of our R&D will be focused on the use of new additives, enhancing further the performances of cables formulations

CONCLUSIONS

References[1] Two-Stage Pyrolysis Model of PVC, Wu, C.-H., et al., Canadian J. Chem. Eng. 72, 644-650 (1994).

[4] A Thermal Analysis of the Production of Anhydrous MgCl2:G. J. Kipouros, Donald R. SadowayJournal of Light Metals: Volume 1, Issue 2, 29 May 2001, Pages 111-117

[2] Flame and Smoke Retardants in Vinyl Chloride Polymers – Commercial Usage and Current DevelopmentsEdward D. Weil, Sergei Levchik and Paul MoyJournal of Fire Sciences 2006; 24; 211

[3] Fire retardant action of mineral fillers.Hull, T Richard, Witkowski, Artur and Hollingbery, Luke (2011) Polymer degradation and Stability, 96 (8). pp. 14621469.

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Cable Group Italy

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The project class B2ca�How formulations can influence the PVC cables fire behaviorHow formulations can influence the PVC cables fire behaviorCables Group ItalyB2ca PROJECT���1) Evaluation of the cables on the market before CPR����1) Evaluation of the cables on the market before CPR�������1) Evaluation of the cables on the market before CPR�2) Lab scale testsSlide Number 92) Lab scale tests:2) Lab scale tests:2) Lab scale tests:2) Lab scale tests:2) Lab scale tests:3) Tests on cables3) Tests on cables��FIRE PERFORMANCES:OLD AND NEW CABLES���FIRE PERFORMANCES:OLD AND NEW CABLES��FOCUS ON SMOKE ACIDITYTo understand the differences b/w the two standards we need to introduce the theory of acid scavenging for the reduction of smoke acidityACID SCAVENGING THEORYAcid scavenging theory: inert substanceSlide Number 23Acid scavenging theory: efficient ASEN 60754-1: used before CPREN 60754-2: a.t. CPRDifferences in numbersRelationship b/w pH and conductivityThe importance of R&D in PVCConclusionsConclusionsReferencesTHANK YOU