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Intumescent coating surface temperature measurement in a cone calorimeter using laser-induced phosphorescence

Omrane, Alaa LU ; Wang, Y. C.; Göransson, Ulf LU ; Holmstedt, Göran LU and Aldén, Marcus LU (2007) In Fire Safety Journal 42(1). p.68-74
Abstract
Intumescent coating acts as a thermal barrier for construction materials during fire hazards. The coating has the ability to expand by a factor of 40 or more during heat exposure. However, due to its fragile consistence, no physical or optical measurement technique has previously been able to measure the coating surface temperature during expansion. This is undesirable since without accurate information about the coating surface temperature, it will always be difficult to fully understand the heat transfer processes from the fire exposure to the coating and within the coating. Thermographic phosphor technique makes it possible to reliably measure intumescent coating surface thermometry. This paper presents the results of an experimental... (More)
Intumescent coating acts as a thermal barrier for construction materials during fire hazards. The coating has the ability to expand by a factor of 40 or more during heat exposure. However, due to its fragile consistence, no physical or optical measurement technique has previously been able to measure the coating surface temperature during expansion. This is undesirable since without accurate information about the coating surface temperature, it will always be difficult to fully understand the heat transfer processes from the fire exposure to the coating and within the coating. Thermographic phosphor technique makes it possible to reliably measure intumescent coating surface thermometry. This paper presents the results of an experimental study using this technique. It compares experimental results with predictions of a calculation model for measurements made inside a cone calorimeter in well-controlled conditions. The coating was applied to steel plates having different thickness, in layers of 1000 g/m(2) by means of a brush. Thermographic phosphor particles were seeded on the surface of the coating. The coated plate was placed in a non-standard electric cone calorimeter, which was calibrated to give a constant radiant heat flux of 50 kW/m(2), measured by a Gardon-type Medtherm heat flux meter at a height of 40 mm from the surface of the coating before expansion, being about the expected position after the intumescent coating had fully expanded. The third harmonic generation of a pulsed Nd:YAG laser at 355 nm was used to excite the phosphor particles. A photomultiplier detector monitored the subsequent emission and an ICCD camera was used to measure the expansion rate of the intumescent coating. A comparison between measurement results using this technique and predictions of a model that adequately describes the heat transfer condition of the test setup shows that the measured and predicted surface temperatures were generally in good agreement. The inaccuracy in the predicted results is due to the uncertainty over the emissivity value of the intumescent coating surface. The results of this study clearly indicate that thermographic phosphor technique is promising. (C) 2006 Elsevier Ltd. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
intumescent coating, thermographic phosphor, thermometry, fire protection, experiment technique, cone calorimeter, laser technology, surface temperature
in
Fire Safety Journal
volume
42
issue
1
pages
68 - 74
publisher
Elsevier
external identifiers
  • wos:000243588800006
  • scopus:37849186590
ISSN
0379-7112
DOI
10.1016/j.firesaf.2006.08.006
language
English
LU publication?
yes
id
3e00fde5-9b3b-40ce-886c-74352e1cb317 (old id 677392)
date added to LUP
2007-12-17 08:39:12
date last changed
2017-07-09 04:24:18
@article{3e00fde5-9b3b-40ce-886c-74352e1cb317,
  abstract     = {Intumescent coating acts as a thermal barrier for construction materials during fire hazards. The coating has the ability to expand by a factor of 40 or more during heat exposure. However, due to its fragile consistence, no physical or optical measurement technique has previously been able to measure the coating surface temperature during expansion. This is undesirable since without accurate information about the coating surface temperature, it will always be difficult to fully understand the heat transfer processes from the fire exposure to the coating and within the coating. Thermographic phosphor technique makes it possible to reliably measure intumescent coating surface thermometry. This paper presents the results of an experimental study using this technique. It compares experimental results with predictions of a calculation model for measurements made inside a cone calorimeter in well-controlled conditions. The coating was applied to steel plates having different thickness, in layers of 1000 g/m(2) by means of a brush. Thermographic phosphor particles were seeded on the surface of the coating. The coated plate was placed in a non-standard electric cone calorimeter, which was calibrated to give a constant radiant heat flux of 50 kW/m(2), measured by a Gardon-type Medtherm heat flux meter at a height of 40 mm from the surface of the coating before expansion, being about the expected position after the intumescent coating had fully expanded. The third harmonic generation of a pulsed Nd:YAG laser at 355 nm was used to excite the phosphor particles. A photomultiplier detector monitored the subsequent emission and an ICCD camera was used to measure the expansion rate of the intumescent coating. A comparison between measurement results using this technique and predictions of a model that adequately describes the heat transfer condition of the test setup shows that the measured and predicted surface temperatures were generally in good agreement. The inaccuracy in the predicted results is due to the uncertainty over the emissivity value of the intumescent coating surface. The results of this study clearly indicate that thermographic phosphor technique is promising. (C) 2006 Elsevier Ltd. All rights reserved.},
  author       = {Omrane, Alaa and Wang, Y. C. and Göransson, Ulf and Holmstedt, Göran and Aldén, Marcus},
  issn         = {0379-7112},
  keyword      = {intumescent coating,thermographic phosphor,thermometry,fire protection,experiment technique,cone calorimeter,laser technology,surface temperature},
  language     = {eng},
  number       = {1},
  pages        = {68--74},
  publisher    = {Elsevier},
  series       = {Fire Safety Journal},
  title        = {Intumescent coating surface temperature measurement in a cone calorimeter using laser-induced phosphorescence},
  url          = {http://dx.doi.org/10.1016/j.firesaf.2006.08.006},
  volume       = {42},
  year         = {2007},
}