Composite Flame Retardant and Smoke Suppressing Surfacing Mat

1
Composite Flame Retardant and Smoke Suppressing
Surfacing Mat

• John Rowen
• Fire Smoke Toxicity
• SAMPE 2003 Session 7E

Avtec Industries 9 Kane Industrial Drive Hudson,
MA 01749
2
Introduction

• This presentation will highlight the development
  and results of Avtecs fire retardant and smoke
  suppressing surfacing mat which is based on its
  core technology TSWB over a period of two years.

3
Thermashield

• Avtecs Thermashield Fire Retardant Coating is a
  tough, solvent based intumescent/ceramic coating.
• This coating composition is approximately 50
  of Avtecs TSWB Polymeric Fire Retardant
  Additive and 50 binders and fillers. TSWB is a
  non-brominated, dry powder composition.

4
TSWB

• FRP/composite materials can benefit from TSWB
  with regard to fire, smoke and toxicity issues
  due to its chemical reaction mechanisms upon
  exposure to open flame or high radiant heat.
• ASTM test results demonstrate the effectiveness
  of the additive as follows

5
ASTM E-162

• The results from this test were obtained from
  cored vinyl ester glass reinforced laminate
  specimens cured in a press and coated with a 63
  mil thick layer.
• This test, the Standard Method of Test for
  Surface Flammability of Materials Using a Radiant
  Heat Energy Source, is to determine the relative
  surface flammability performance of various
  materials under specific test conditions when
  using a radiant heat source. The results are
  recorded as a Flame Spread Index.

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ASTM E-162

• The Flame Spread Index (Is) is calculated by
  multiplying the Flame Spread Factor (Fs), the
  speed at which the flame front burns down the
  specimen, times the Evolution of Heat Factor (Q),
  determined by the maximum temperature developed
  in the stack above the burning sample as a result
  of the burning characteristics of the material
  under test.
• NFPA No. 101 classifies
• Class A (I) Flame spread 0 to 25
• Class B (II) Flame spread 26 to 75
• Class C (III) Flame spread 76 to 100
• As indicated here, the test results show the
  laminate panel attained a Class A (I) Flame
  spread.

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ASTM E-662

• This test, The Standard Test Method for Specific
  Optical Density of Smoke Generated by a Solid
  Material, is to determine the quantity of smoke
  generated by solid materials and assemblies in
  thicknesses up to and including one inch.
• The test is based on the attenuation (i.e.
  change in the concentration) of a light beam by
  smoke accumulating within a closed chamber.
  Results are expressed in terms of specific
  optical density, which is derived from measuring
  optical density as absorbance within the chamber.
  
• The photometric scale used to measure smoke by
  this method is similar to the optical density
  scale for human vision.

8
ASTM E-662

• The test specimens were composite 5/8 thick
  balsa wood cored vinyl ester laminates fabricated
  by the SCRIMP process with 1/16 TSWB surface
  coating on one side. The test method protocol
  specifies an electrically heated radiant heat
  source for the non-flaming exposure of the test,
  and a row of air-propane flamelets to constitute
  the flaming combustion exposure. The test data
  and results are illustrated below

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BSS 7239 Toxic Gas Analysis

• The following gas analysis was made after 4
  minutes of exposure to 2.5 kw/cm² and in the
  flaming mode. Colorimetric Gas Detection Tubes
  were used in the toxic gas analysis. The results
  are as follows

Ambient Temperature 47ºF, Relative Humidity
0.65, Bar. Pressure 29.91 in. Hg 1 Specimen
wgt. 49.7g, 2 Specimen wgt. 52.6g
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Bromine Content

• This test was performed by Dr. David K. Ryan on
  Apr, 6, 2001 at the Dept. of Chemistry of
  UMASS/Lowell.
• TSWB was analyzed with a Second Ion Mass
  Spectrometer. Careful counting of the bromine
  ions resulted in a measured total trace
  background bromine content of 25.0 ppm by
  weight(µg/g).

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Pultrusion

• Pultrusion Building Materials are gaining greater
  acceptance and use in the construction industry.
  It was envisioned an inter-laminate surface
  coating of the TSWB composition could assist
  engineers and fabricators in their efforts to
  meet regulatory life safety code requirements
  such as ASTM E-84 Class A(1).
• It was theorized TSWB could simply be
  integrated and affixed to a pultrudable,
  non-combustible glass surfacing fabric. A glass
  rich side could be pulled against the die in a
  standard fashion, while a TSWB rich side would
  be forced out and through the fabric ensuring
  complete wet-out.

12
Generation 1

• This prototype was a non-woven, mil-spec fabric
  with TSWB held in place with a solvent based
  adhesive which contributed little in the way of
  fuel load and smoke contribution.
• FRP sheets were fabricated informally by hand
  using commodity materials.

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Generation 1

• Upon exposure to a torch flame, the laminate
  demonstrated excellent fire retarding and smoke
  suppressing characteristics.
• This image is a photograph of an example laminate
  upon exposure to a propane torch

14
Generation 2

• This improved version employed a 20mil glass
  Pultrusion mat produced by Hollinee, TSWB and
  the solvent based spray adhesive as the binder.
• This combination provided an improved
  construction and enabled Avtec to manufacture
  better hand fabricated panels, as well as, long
  tapes that could be easily pultruded. The
  following images are of flat pultruded bar 2 x
  .25 before and during a fire load.

15
Generation 2
16
Generation 3

• Due to VOC and HAP issues and regulations, the
  solvent sprayed adhesive binder was replaced by a
  solid hot melt adhesive system which could be
  pre-blended with the TSWB prior to application
  to the surfacing mat.
• The blend was metered onto the fabric, heated,
  cooled and wound into rolls.
• Modifications were made as investigation and
  refinement in both binder technology and
  processing equipment became available.

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Generation 4

• The uniformity of the fire retardant mat,
  although still in development due to small voids
  and excessive graininess, was acceptable enough
  for full scale fabrication and testing to
  determine the criteria and specification
  requirements for a commercially available
  product.
• The product was first pultruded in a 36 x .25
  flat sheet comprised of brominated polyester
  resin.

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Generation 4

• The results of an E-84 test on the laminate with
  the FR mat were compared with the identical
  laminate with a polyester surfacing veil. The
  results were as follows

Glass Reinforced / Iso-polyester / Bromine
Antimony Laminate
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Generation 4

• The E-84 test results, although illustrating the
  positive effectiveness of the concept, indicated
  a thinner, denser construction was needed with
  better uniformity.
• The TSWB needed to be applied as a liquid,
  mimicking Thermashield.

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Generation 5

• The ongoing binder investigation led to a
  non-toxic, water based adhesive polymer which
  allowed the fabric to be produced such that it
  could be easily incorporated into a laminate and
  provide the uniform coverage of a paint.
• Over several months, a series of panels were
  fabricated by vacuum bagging and tested by Cone
  Calorimeter to investigate the effectiveness of
  the FR fabric with regard to peak heat, smoke
  generation, ect.

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Cone Calorimeter Results 1
22
Generation 5

• Additional panels were fabricated by vacuum
  bagging, and, flat sheet was pultruded employing
  the FR mat.
• These specimens were Cone tested to verify and
  average the results of the Glass Out / TSWB In
  orientation.

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Cone Calorimeter Results 2
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Generation 5

• Visually, a dramatic difference can be seen
  between a pultruded brominated placard and a
  pultruded placard containing TSWB after exposure
  to heat.
• With a brominated fire retardant package, all
  that remains is the reinforcement.
• With TSWB as the fire retardant package, a
  cementitious structure with very good basket
  strength remains, mechanically bonded to the
  reinforcements.

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Cone Calorimeter Placards
Bromine Placard
TSWB Placard
Before
After
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Generation 5

• Four sections of the pultruded flat sheets were
  sent to Southwest Research Institute for ASTM
  E-84 test evaluation.
• Class(1) Flame Spread Index (FSI) and Class A
  Smoke Development Index(SDI) were achieved.
• The results are as follows

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ASTM E-84 Results