<p>The present paper describes the influence of various types of expandable graphite on the fire-retardant properties of intumescent coating based on PVC binder. The optimal content of the expandable graphite required to achieve maximum fire protection efficiency was determined by incorporation of different amount of expandable graphite (5%, 11%, 18%, 22.5%, and 28%) to the intumescent fire-retardant coatings. The degree of expansion and fire protection efficiency of coatings were measured. TGA was performed to investigate the obtained coatings. The coatings were applied to steel I-beams and subjected to a standard fire test to assess their fire protection efficiency in terms of time. The use of expandable graphite derived from graphite nitrate and graphite bisulfate, along with their modifications with phosphorus(V) oxide as intumescent agents in fire-retardant PVC compositions, exhibited varying effects on the thermal behavior of the coatings. The test results revealed that coatings based on expandable bisulfate graphite demonstrated a higher degree of expansion and superior fire-retardant properties compared to those based on expandable nitrate graphite. Additionally, the presence of P₂O₅ in the expandable graphite formulation acted as an anti-oxidizing agent, contributing to an increase in non-combustible residue when exposed to heat, and consequently enhancing the overall fire-retardant efficiency of the coatings.</p>