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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.
THANK YOUP VC F O R U M I TA L I A : CA B L E S G R O U P
PVC forum:www.pvcforum.it
Cable Group Italy
http://www.pvcforum.it/
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