Fire Technology

, Volume 53, Issue 4, pp 1569–1587 | Cite as

Variation of Intumescent Coatings Revealing Different Modes of Action for Good Protection Performance

  • Michael Morys
  • Bernhard Illerhaus
  • Heinz Sturm
  • Bernhard Schartel


Thermal insulation and mechanical resistance play a crucial role for the performance of an intumescent coating. Both properties depend strongly on the morphology and morphological development of the foamed residue. Small amounts (4 wt%) of fiberglass, clay and a copper salt, respectively, are incorporated into an intumescent coating to study their influence on the morphology and performance of the residues. The bench scale fire tests were performed on 75 × 75 × 2 mm3 coated steel plates according to the standard time–temperature curve in the Standard Time Temperature Muffle Furnace+ (STT Mufu+). It provided information about foaming dynamics (expansion rates) and thermal insulation. Adding the copper salt halved the expansion height, whereas the clay and fiberglass change the height of the residue only moderately. The time to reach 500°C was improved by 31% for clay and 15% for the other two fillers. Nondestructive micro computed tomography is used to assess the inner structure of the residues. A transition of the residue from a black, carbonaceous foam with closed cells into an inorganic, residual open cell sponge occurs at high temperatures. This transition is due to a loss of carbon; the change in microstructure is analyzed by scanning electron microscopy. Additional mechanical tests are performed and interpreted with respect to the results of the morphology analysis. Adding clay or copper salt improved the mechanical resistance tested by a factor 4. The additives significantly influence the thickness and foaming dynamics as well as the inner structure of the residues, whereas their influence on insulation performance is moderate. In conclusion, different modes of action are observed to achieve similar insulation performance during the fire test.


Intumescence Coating Bench scale fire testing Computed tomography Fire resistance 



The authors are grateful to Dr. Futterer and David García Martínez of Chemische Fabrik Budenheim for providing the intumescent coatings. Michael Schneider and Tobias Kukofka from the BAM workshop are acknowledged for their work in manufacturing the setup. Dr. Andreas Staude and Dr. Dietmar Meinel are acknowledged for their support during the μ-CT measurement.


  1. 1.
    Vandersall H (1971) Intumescent coating systems, their development and chemistry. J Fire Flammabil 2(2):97–140Google Scholar
  2. 2.
    Bourbigot S, Le Bras M, Duquesne S, Rochery M (2004) Recent advances for intumescent polymers. Macromol Mater Eng 289(6):499–511. doi: 10.1002/mame.200400007 CrossRefGoogle Scholar
  3. 3.
    Alongi J, Han ZD, Bourbigot S (2015) Intumescence: tradition versus novelty. A comprehensive review. Prog Polym Sci 51:28–73. doi: 10.1016/j.progpolymsci.2015.04.010 CrossRefGoogle Scholar
  4. 4.
    Duquesne S, Magnet S, Jama C, Delobel R (2004) Intumescent paints: fire protective coatings for metallic substrates. Surf Coat Technol 180–181:302–307. doi: 10.1016/j.surfcoat.2003.10.075 CrossRefGoogle Scholar
  5. 5.
    Weil ED (2011) Fire-protective and flame-retardant coatings—a state-of-the-art review. J Fire Sci 29(3):259–296. doi: 10.1177/0734904110395469 CrossRefGoogle Scholar
  6. 6.
    Saxena NK, Gupta DR (1990) Development and evaluation of fire retardant coatings. Fire Technol 26(4):329–341. doi: 10.1007/bf01293077 CrossRefGoogle Scholar
  7. 7.
    Hörold A, Schartel B, Trappe V, Gettwert V, Korzen M (2015) Protecting the structural integrity of composites in fire: intumescent coatings in the intermediate scale. J Reinf Plast Compos 34(24):2029–2044. doi: 10.1177/0731684415609791 CrossRefGoogle Scholar
  8. 8.
    Hassan MA, Kozlowski R, Obidzinski B (2008) New fire-protective intumescent coatings for wood. J Appl Polym Sci 110(1):83–90. doi: 10.1002/app.28518 CrossRefGoogle Scholar
  9. 9.
    Rhys JA (1980) Intumescent coatings and their uses. Fire Mater 4(3):154–156. doi: 10.1002/fam.810040308 CrossRefGoogle Scholar
  10. 10.
    Landucci G, Molag M, Reinders J, Cozzani V (2009) Experimental and analytical investigation of thermal coating effectiveness for 3 m3 LPG tanks engulfed by fire. J Hazard Mater 161(2–3):1182–1192. doi: 10.1016/j.jhazmat.2008.04.097 CrossRefGoogle Scholar
  11. 11.
    Droste B (1992) Fire protection of LPG tanks with thin sublimation and intumescent coatings. Fire Technol 28(3):257–269. doi: 10.1007/bf01857695 CrossRefGoogle Scholar
  12. 12.
    Schuff W, Clar C, Kühnel P, Tramm H (1934) Feuersichere Überzüge ergebendes Anstrichmittel. Germany PatentGoogle Scholar
  13. 13.
    Anderson CE, Dziuk J, Mallow WA, Buckmaster J (1985) Intumescent reaction-mechanisms. J Fire Sci 3(3):161–194. doi: 10.1177/073490418500300303 CrossRefGoogle Scholar
  14. 14.
    Anderson CE, Ketchum DE, Mountain WP (1988) Thermal-conductivity of intumescent chars. J Fire Sci 6(6):390–410. doi: 10.1177/073490418800600602 CrossRefGoogle Scholar
  15. 15.
    Camino G, Costa L, Martinasso G (1989) Intumescent fire-retardant systems. Polym Degrad Stab 23(4):359–376. doi: 10.1016/0141-3910(89)90058-x CrossRefGoogle Scholar
  16. 16.
    Camino G, Costa L, Trossarelli L (1984) Study of the mechanism of intumescence in fire retardant polymers: part I—thermal degradation of ammonium polyphosphate-pentaerythritol mixtures. Polym Degrad Stab 6(4):243–252. doi: 10.1016/0141-3910(84)90004-1 CrossRefGoogle Scholar
  17. 17.
    Mesquita L, Piloto P, Vaz M, Pinto T (2009) Decomposition of intumescent coatings: comparison between a numerical method and experimental results. Acta Polytech 49(1):60–65Google Scholar
  18. 18.
    Wang G, Yang J (2011) Influences of glass flakes on fire protection and water resistance of waterborne intumescent fire resistive coating for steel structure. Prog Org Coat 70(2–3):150–156. doi: 10.1016/j.porgcoat.2010.10.007 CrossRefGoogle Scholar
  19. 19.
    Wang Z, Han E, Ke W (2006) Effect of nanoparticles on the improvement in fire-resistant and anti-ageing properties of flame-retardant coating. Surf Coat Technol 200(20–21):5706–5716. doi: 10.1016/j.surfcoat.2005.08.102 CrossRefGoogle Scholar
  20. 20.
    Staggs J (2010) Thermal conductivity estimates of intumescent chars by direct numerical simulation. Fire Saf J 45(4):228–237CrossRefGoogle Scholar
  21. 21.
    Cirpici BK, Wang YC, Rogers B (2016) Assessment of the thermal conductivity of intumescent coatings in fire. Fire Saf J 81:74–84. doi: 10.1016/j.firesaf.2016.01.011 CrossRefGoogle Scholar
  22. 22.
    Li G-Q, Zhang C, Lou G-B, Wang Y-C, Wang L-L (2012) Assess the fire resistance of intumescent coatings by equivalent constant thermal resistance. Fire Technol 48(2):529–546. doi: 10.1007/s10694-011-0243-8 CrossRefGoogle Scholar
  23. 23.
    Wang L, Dong Y, Zhang C, Zhang D (2015) Experimental study of heat transfer in intumescent coatings exposed to non-standard furnace curves. Fire Technol 51(3):627–643. doi: 10.1007/s10694-015-0460-7 CrossRefGoogle Scholar
  24. 24.
    Reshetnikov IS, Yablokova MY, Potapova EV, Khalturinskij NA, Chernyh VY, Mashlyakovskii LN (1998) Mechanical stability of intumescent chars. J Appl Polym Sci 67(10):1827–1830. doi: 10.1002/(sici)1097-4628(19980307)67:10<1827::aid-app16>;2-t CrossRefGoogle Scholar
  25. 25.
    Norgaard KP, Dam-Johansen K, Catala P, Kiil S (2013) Investigation of char strength and expansion properties of an intumescent coating exposed to rapid heating rates. Prog Org Coat 76(12):1851–1857. doi: 10.1016/j.porgcoat.2013.05.028 CrossRefGoogle Scholar
  26. 26.
    Naik AD, Duquesne S, Bourbigot S (2016) Hydrocarbon time-temperature curve under airjet perturbation: an in situ method to probe char stability and integrity in reactive fire protection coatings. J Fire Sci. doi: 10.1177/0734904116658049 Google Scholar
  27. 27.
    Bugajny M, Bras ML, Bourbigot S (1999) New approach to the dynamic properties of an intumescent material. Fire Mater 23(1):49–51. doi: 10.1002/(sici)1099-1018(199901/02)23:1<49::aid-fam668>;2-d CrossRefGoogle Scholar
  28. 28.
    Morys M, Illerhaus B, Sturm H, Schartel B (2016) Revealing the inner secrets of intumescence: Advanced standard time temperature oven (STT Mufu +)—μ-computed tomography approach. Fire Mater (submitted)Google Scholar
  29. 29.
    Bailey C (2004) Indicative fire tests to investigate the behaviour of cellular beams protected with intumescent coatings. Fire Saf J 39(8):689–709. doi: 10.1016/j.firesaf.2004.06.007 CrossRefGoogle Scholar
  30. 30.
    Dai XH, Wang YC, Bailey CG (2009) Effects of partial fire protection on temperature developments in steel joints protected by intumescent coating. Fire Saf J 44(3):376–386. doi: 10.1016/j.firesaf.2008.08.005 CrossRefGoogle Scholar
  31. 31.
    Jimenez M, Duquesne S, Bourbigot S (2006) High-throughput fire testing for intumescent coatings. Ind Eng Chem Res 45(22):7475–7481. doi: 10.1021/ie0608410 CrossRefGoogle Scholar
  32. 32.
    Jimenez M, Duquesne S, Bourbigot S (2006) Intumescent fire protective coating: toward a better understanding of their mechanism of action. Thermochim Acta 449(1–2):16–26. doi: 10.1016/j.tca.2006.07.008 CrossRefGoogle Scholar
  33. 33.
    Jimenez M, Duquesne S, Bourbigot S (2006) Multiscale experimental approach for developing high-performance intumescent coatings. Ind Eng Chem Res 45(13):4500–4508. doi: 10.1021/ie060040x CrossRefGoogle Scholar
  34. 34.
    Bartholmai M, Schartel B (2007) Assessing the performance of intumescent coatings using bench-scaled cone calorimeter and finite difference simulations. Fire Mater 31(3):187–205. doi: 10.1002/Fam.933 CrossRefGoogle Scholar
  35. 35.
    Bartholmai M, Schriever R, Schartel B (2003) Influence of external heat flux and coating thickness on the thermal insulation properties of two different intumescent coatings using cone calorimeter and numerical analysis. Fire Mater 27(4):151–162. doi: 10.1002/Fam.823 CrossRefGoogle Scholar
  36. 36.
    Schartel B, Hull TR (2007) Development of fire-retarded materials—interpretation of cone calorimeter data. Fire Mater 31(5):327–354. doi: 10.1002/Fam.949 CrossRefGoogle Scholar
  37. 37.
    Amir N, Abd Majid AA, Ahmad F (2016) Effects of hybrid fibre reinforcement on fire resistance performance and char morphology of intumescent coating. In: Karim ZAA, Baharudin ZH, Basrawi MF, Rahman MM, Noor MM (eds) Utp-ump symposium on energy systems 2015, vol 38. MATEC Web of Conferences. doi: 10.1051/matecconf/20163803001
  38. 38.
    Amir N, Ahmad F, Megat-Yusoff PSM (2012) Char strength of wool fibre reinforced epoxy-based intumescent coatings (FRIC). In: Abdullah MMA, Jamaludin L, Razak RA, Yahya Z, Hussin K (eds) Advanced materials engineering and technology, vol 626. Advanced Materials Research, pp 504–508. doi: 10.4028/
  39. 39.
    Aziz H, Ahmad F, Yusoff P, Zia-Ul-Mustafa M (2014) Effect of kaolin clay and alumina on thermal performance and char morphology of intumescent fire retardant coating. In: Karuppanan S, Karim ZAA, Ovinis M, Baheta AT (eds) Icper 2014—4th international conference on production, energy and reliability, vol 13. MATEC Web of ConferencesGoogle Scholar
  40. 40.
    Fan F-Q, Xia Z-B, Li Q-Y, Li Z (2013) Effects of inorganic fillers on the shear viscosity and fire retardant performance of waterborne intumescent coatings. Prog Org Coat 76(5):844–851. doi: 10.1016/j.porgcoat.2013.02.002 CrossRefGoogle Scholar
  41. 41.
    Kahraman HT, Gevgilili H, Pehlivan E, Kalyon DM (2015) Development of an epoxy based intumescent system comprising of nanoclays blended with appropriate formulating agents. Prog Org Coat 78:208–219. doi: 10.1016/j.porgcoat.2014.09.002 CrossRefGoogle Scholar
  42. 42.
    Ullah S, Ahmad F, Shariff AM, Bustam MA (2014) Synergistic effects of kaolin clay on intumescent fire retardant coating composition for fire protection of structural steel substrate. Polym Degrad Stab 110:91–103. doi: 10.1016/j.polymdegradstab.2014.08.017 CrossRefGoogle Scholar
  43. 43.
    Duquesne S, Bachelet P, Bellayer S, Bourbigot S, Mertens W (2013) Influence of inorganic fillers on the fire protection of intumescent coatings. J Fire Sci 31(3):258–275. doi: 10.1177/0734904112467291 CrossRefGoogle Scholar
  44. 44.
    Li H, Hu Z, Zhang S, Gu X, Wang H, Jiang P, Zhao Q (2015) Effects of titanium dioxide on the flammability and char formation of water-based coatings containing intumescent flame retardants. Prog Org Coat 78:318–324. doi: 10.1016/j.porgcoat.2014.08.003 CrossRefGoogle Scholar
  45. 45.
    CEN (1999) EN 1363-1: 1999-10: Feuerwiderstandsprüfungen–Allgemeine AnforderungenGoogle Scholar
  46. 46.
    Muller M, Bourbigot S, Duquesne S, Klein R, Giannini G, Lindsay C, Vlassenbroeck J (2013) Investigation of the synergy in intumescent polyurethane by 3D computed tomography. Polym Degrad Stab 98(9):1638–1647. doi: 10.1016/j.polymdegradstab.2013.06.018 CrossRefGoogle Scholar
  47. 47.
    Brehme S, Schartel B, Goebbels J, Fischer O, Pospiech D, Bykov Y, Döring M (2011) Phosphorus polyester versus aluminium phosphinate in poly(butylene terephthalate) (PBT): flame retardancy performance and mechanisms. Polym Degrad Stab 96(5):875–884. doi: 10.1016/j.polymdegradstab.2011.01.035 CrossRefGoogle Scholar
  48. 48.
    Müller P, Morys M, Sut A, Jäger C, Illerhaus B, Schartel B (2016) Melamine poly(zinc phosphate) as flame retardant in epoxy resin: decomposition pathways, molecular mechanisms and morphology of fire residues. Polym Degrad Stab 130:307–319. doi: 10.1016/j.polymdegradstab.2016.06.023 CrossRefGoogle Scholar
  49. 49.
    Goebbels J, Illerhaus B, Onel Y, Riesemeier H, Weidemann G (2004) 3D-computed tomography over four orders of magnitude of X-ray energies. In: 16th world conference on nondestructive testing, Montreal, CanadaGoogle Scholar
  50. 50.
    DIN (1994) DIN 4102 Teil 4 Brandverhalten von Baustoffen und BauteilenGoogle Scholar
  51. 51.
    Sturm H, Schartel B, Weiß A, Braun U (2012) SEM/EDX: advanced investigation of structured fire residues and residue formation. Polym Testing 31 (5):606–619. doi: 10.1016/j.polymertesting.2012.03.005 CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2017

Authors and Affiliations

  • Michael Morys
    • 1
  • Bernhard Illerhaus
    • 1
  • Heinz Sturm
    • 1
  • Bernhard Schartel
    • 1
  1. 1.Bundesanstalt für Materialforschung und –prüfung (BAM)BerlinGermany

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