ESTIMATION OF THE RATIO OF THE REQUIRED MINIMUM FIRE PROTECTION THICKNESS OF STEEL STRUCTURES UNDER DIFFERENT NOMINAL FIRE TEMPERATURE-TIME CURVE

Abstract

Given the lack of certainty and practical significance of the data on the
relationship between the required minimum thickness of fire protection systems for steel
structures under different nominal fire temperature-time curve, research aimed at
further improving and developing methods for assessing this thickness at different levels
of thermal exposure, reflecting different fire scenarios, as well as methods for

determining this relationship, is currently relevant. The purpose of the study was to
substantiate a method for determining this ratio, suitable for obtaining reliable results
for the evaluation of passive and reactive fire protection systems for steel structures. To
achieve this goal, the task was set to substantiate the components of this method and its
procedures.
The essence of the method proposed in this paper is to test a set of loaded and
unloaded structures at a standard temperature-time curve, determine the thermal
properties of the fire protection material used, calculate the required minimum fire
protection thickness for different nominal temperature-time curve and the ratio between
these thicknesses based on the data obtained on these properties. This method employs
a number of procedures, some of which are standardized and some of which are not.
The standardized procedures include procedures for selecting and testing structural
specimens, adjusting the time intervals until design temperatures are reached due to
differences in test specimen parameters and "adhesion" values, and selecting the range
and parameters of steel structures to determine the required minimum fire protection
thickness. Non-standardized procedures are used to adjust the time intervals for loaded
structures and short structures for comparison, which were heated during different
tests, as well as procedures for determining the thermal properties of the fire protection
material and calculating the required minimum thickness of fire protection. The
rationale for using these procedures in the proposed method is given.