When determining the fire hazard characteristics of liquids and solids, abnormal situations may arise in which the use of standard techniques is either ineffective or impossible. Four such situations are considered in this paper for testing of heterogeneous liquids, solvents with low flash point and thermally unstable powders. The special test algorithm was proposed for determination of the flash point of a heterogeneous mixs of solvents. It includes preparing the emulsion, dividing it into 5 batches, holding them at room temperature until the emulsion is completely destroyed, carefully filling the crucible and conducting tests without mixing. The standard drip method according to GOST 12.1.044 turns out to be unsuitable for experimentally finding the auto-ignition temperature of heterogeneous liquid mixs. The special crucible furnace device has been developed to solve this problem. The increase of the sample volume and the using of the above described sample preparation allows determining the auto-ignition temperature of heterogeneous liquids in the developed apparatus with high precision. there is no method for determining the flash point of liquids with negative values in modern regulatory documents. To solve this problem, a technique and low-budget installation based on the Holde method and the widely used Russian TVZ device has been proposed. This approach can be used for a wide range of low-boiling and highly volatile liquids. It is shown that the “STS” installation for determining the auto-ignition temperature with an additional external ignition source can also be used to establish the ignition temperature of thermally unstable organic powders.