(i) Moisture. On heating moisture content of lubricating oil forms steam. It may prevent the oil vapour from igniting and hence raise the flash point.
(ii) Low molecular weight constituents. They tend to decrease the flash point.
(iii) Contamination with small amount of volatile organic compounds. Because of their presence , irregular flashes can be observed below the true flash point of a lubricating oil. It is called "Freaky" flash point.
(iv) Experimental factors. Frequency of application of test flame, rate of heating , rate of strirring, size of test flame, time of opening the shutter and determination of open cup or closed cup method, all affect the value of flash or fire point of a lubricating oil.
Tags
lubricants