Page 48 - UL_Report On_Part 1

39 IITGN-UL/Façade
Event11: Time: 18:41:57: (4.95 min)
Three glass panels fall (in intact form) from the aluminium frame of ground floor façade due to failure of binder gel and expansion of the cladding
aluminium frame. This enhances the ventilation conditions within the compartment thereby increasing the temperature within. Maximum temperature
at roof level near façade is around 740°C, much higher than the melting point of aluminium i.e., 660°C. This has caused melting of aluminium cladding
framework and falling of glass façade panel.
Maximum temperature at first floor roof level has reached around 190°C, whereas near steel beam it is around 19°C.
Event12: Time: 18:42:27: (5.45 min)
Maximum temperature at roof level is around 760°C and temperature at base level is about 275°C for ground floor level. TC 34 placed near steel beam had
started showing increase in temperature. Temperature recorded near steel beam is around 60°C. Cement boards are still in intact position providing
protection against fire.
Curtains at first floor level are completely engulfed in flames. Fire has penetrated through opening of one glass panel thereby forcing the upper and side
panels to fall by distorting the aluminium frame. Glass panels again come out in intact form from first floor level and shatter after falling on the ground.
Ventilation inside the compartment at first floor level increased thereby allowing gust of fresh air to enhance the fire. Temperature at roof level near
façade is around 280°C.
Second floor temperatures at roof level are around 38°C.
Event13: Time: 18:43:30: (6.5 min)
Roof level temperature at ground floor level has reduced to 670°C. At first floor level, ACP sheets have easily caught fire and allow the inner insulation
polymer to be exposed to fire and subsequently initiated a small secondary fire at the ground level outside the building. Maximum temperature inside the
compartment is around 340°C and near steel beam is around 20°C. Fire load present within the compartment such as wooden crib, table, etc. has not
caught fire. Temperatures at second floor level are around 48°C, but fire has not yet propagated to second floor level.
Event14: Time: 18:47:30: (10.5 min)
Ground floor base level temperatures are constant for about 3 minutes since the past event. Maximum roof temperature is around 816°C whereas
thermocouple tree is showing temperature around 470°C. TC 34 near steel beam has reached temperature of 120°C which indicates that cement board
might have failed locally at this time. Flashover has occurred during this time interval at ground floor level. Aluminium cladding framework has melted
completely on one side where wooden crib was placed.
40 IITGN-UL/Façade
Temperatures are constant at first floor roof level around 300 - 350°C since the last event and have started to increase after 18:47:00. All ACP sheets and
glass panels at first floor level are dismantled out of the aluminium cladding due to the frame distortion and expansion. Ventilation conditions have
changed drastically inside the compartment allowing fresh air to enhance the fire conditions which results in rise in the temperature after 18:47:00.
Wooden crib has caught fire but table placed near it has still not started to burn. Maximum temperature is recorded by left side thermocouple tree (TL4)
placed near wooden crib of about 307°C. Temperature near steel beam is around 36°C, indicating no damage to the cement boards up to this time. Second
floor roof level temperature is about 54°C.
Event15: Time: 18:48:37: (11.62 min)
Temperatures within ground floor compartment have started to reduce as entire fuel within the compartment has been consumed. Maximum roof
temperature was recorded at 710°C and near steel beam it was about 150°C.
Local failure of cement board has occurred at first floor level. This can be seen through sudden increment in the temperature profile of TC 56 and TC 68 from
this time instant. Wooden table besides crib has also caught fire thereby increasing the temperature of the compartment to around 400°C.
Event16: Time: 18:53:40: (16.67 min)
Ground floor fire has died out due to inadequacy of fuel. Maximum temperature is about 305°C. Maximum temperature reached near steel beam was
around 226°C before it began to reduce (maximum steel temperature of 226°C indicates negligible fire damage to the structural beams). Post fire survey
showed that cement board covering the TC 34 near steel beam had not failed but local failure of the boards led to the increment of temperature.
Flashover occurs at first floor level during this time interval. Maximum roof temperature is around 675°C, whereas peak temperatures recorded by
thermocouple trees (TL4) and (TR4) are around 590°C and 575°C. As temperature within the compartment went above melting point of aluminium, certain
portion of aluminium cladding framework fell out from first floor level. Major failure of cement board has taken place, exposing the thermocouple TC 68
near the steel beam. Temperatures near steel beam rapidly started to rise from 220°C and reached up to 510°C from this time instant. Fire has still not
propagated to second floor level and recorded maximum temperature within the compartment is around 56°C.
Event17: Time: 18:55:33: (18.55 min)
Fire propagats to second floor level through curtains. Temperatures at second floor level are around 226°C near façade and near partition wall it is about
140°C.
Event18: Time: 18:58:50: (21.83 min)
Fire extinguishing operations begin.
In brief, the timeline of events is presented in the Table 4