Investigation Of Effects Of Two Flame Retardants On The Fire Characterisit Ics Of Flexible Poly Ether Foam

3.3.3    Determinati on of Ignition – time
The sample was clamped vertically at constant distance between its base and a small cigarette lighter. Ignition time was recorded as the interval between striking the lighter and a visually perceptible flame on the sample.
3.3.4    Det ermination of Flame propagation
The sample was clamped vertically and was ignited at the base in a draught – free room. The distance traveled at a stipulated time interval by the char front was measured. The rate of the flame propagation was calculated as the vertical distance transversed per second.
Flame propagation rate (cm/s) = distance moved by char front (cm) /Time (s)
3.3.5    Determination of Flame duration
This simple test is a measure of the sustainability of combustion, which is a manifestation of pyrolytic and oxidative reaction going on at combustion. Sample was again clamped vertically in a room with no air current, ignited at the base. The flame duration time is the time lapse between the onset of combustion or ignition and se lf extinguishment.
3.3.6    Determination of   Percentage char formation
The percentage char formation was carried out at NAFDAC laboratory, Agulu, Anambra state. The sample was crushed into pieces and weighed, after which it was kept in a crucible with a lid . This was then placed into a carbolite muffle furnace of the type AAF11/18, and serial No: 20 – 501901 at 700˚C. The crucible with its contents were periodically cooled and weighed at 20mins interval until constant weight was obtained.
The % char formed was determined using the expression.
Char (% )    =    Weight of material after burning /  weight of material before burning          x    100/1