THE MOTORWAY THAT CAUGHT FIRE

EXPANDED POLYSTYRENE (EPS) VOID FORMERS WERE INTRODUCED IN GREAT BRITAIN ABOUT 15 YEARS AGO FOR THERMAL INSULATION OF BRIDGE DECKS. REDUCED COSTS AND IMPROVED PROCESSING TECHNIQUES OPENED UP ITS USE AS A VOID FORM MATERIAL IN THE LATE 1960'S. IN APRIL 1972 A POTENTIAL DRAWBACK TO EPS WAS DISCOVERED WHEN A FIRE WAS DELIBERATELY SET IN SEVERAL OF 200 EPS CYLINDERS UNDER A LENGTH OF REINFORCED CONCRETE RAMP. THE TEMPERATURE OF THE BURNING CYLINDERS, OF WHICH ONLY 60 ESCAPED DESTRUCTION, WAS BETWEEN 800 AND 1200 C. ALTHOUGH THE FIRE BURNED FOR ONLY 15--20 MINUTES, THE OVERHEAD CONCRETE SPALLED TO A DEPTH OF 1.5 INCHES. LOAD TESTS AND REPAIR PROCEDURES FOR THE CONCRETE ARE DESCRIBED. IN ADDITION, A TEST PROGRAM FOR EPS IGNITION WAS UNDERTAKEN. IT WAS DETERMINED THAT THE MATERIAL WILL NOT IGNITE BELOW 450 C, AND THAT ONCE PLACED AND SURROUNDED BY CONCRETE THERE IS INSUFFICIENT OXYGEN PRESENT IN THE CELLULAR STRUCTURE TO SUPPORT COMBUSTION OF THE STYRENE. HOWEVER, THERE IS DANGER OF FIRE DURING THE PLACING OPERATION ITSELF. IT WAS DETERMINED THAT LOW HEAT-CAPACITY, NONFLAMING SOURCES SUCH AS LIGHTED CIGARETTS AND SPARKS FROM OXYACETYLENE CUTTING DID NOT IGNITE THE MATERIAL. HIGH HEAT-CAPACITY, NONFLAMING SOURCES, SUCH AS DENSE CLOUDS OF SPARKS OR LARGE MOLTEN PIECES OF METAL RESULTED IN EPS SHRINKAGE FROM THE HEAT SOURCE; AFTER SEVERAL MINUTES, LOCALIZED BURNING OCCURRED. NAKED FLAMES, RANGING FROM A SHIELDED MATCH TO A BLOWTORCH, DO CAUSE IGNITION. WATER, DRY POWDER, AND BCF EXTINGUISHERS ARE ALL EFFECTIVE IN BRINGING THE FIRE UNDER CONTROL VERY RAPIDLY. ON THE BASIS OF THE TESTS, PRECAUTIONS ARE RECOMMENDED FOR THE STORAGE AND PLACING OF EPS VOID FORMERS.

Media Info

  • Features: Photos;
  • Pagination: p. 32-5
  • Serial:
    • Concrete (London)
    • Volume: 6
    • Issue Number: 9
    • Publisher: CONCRETE SOCIETY
    • ISSN: 0010-5317

Subject/Index Terms

Filing Info

  • Accession Number: 00215582
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 17 1973 12:00AM