Breaking into a building for the purpose of theft, sabotage or murder is a problem that is solved for centuries. To prevent these unwanted problems, security barriers have come into use, the purpose of which is to prevent unauthorized entry persons into a building or premises. In the past, they used to be secured mainly by security barriers often replaced or combined with various electrical systems. This article will test security grilles, which are one of the oldest security barriers. Security grilles can be of different design. They differ not only in the material from which they are made, but also in many other parameters such as the arrangement of the individual bars of the bars, their diameters or the attachment of the bars. All this is reflected in their price. This study examines the effect of the hardness of the material from which the safety bars are made on their delay time. The results of the study confirmed that the hardness of the material has a significant effect on the delay time.