Fire Protection of Steel Structures with Epoxy Coatings under Cryogenic Exposure

Marina Gravit,Daria Shabunina,Boris Klementev

doi:10.3390/buildings11110537

Abstract

Cases of fire with highly flammable, combustible liquids and combustible gases with high potential heat emission at oil and gas facilities are assumed to develop as a hydrocarbon fire, which is characterized by the temperature rising rapidly up to 1093 ± 56 °C within five minutes from the test start and staying within the same range throughout the test, as well as by overpressure being generated. Although various fireproof coating systems are commonly used to protect steel structures from high temperatures, a combination of fire protection and cryogenic spillage protection, i.e., protection from liquefied natural gas (LNG), is rather an international practice novelty regulated by standards ISO 20088. Thanks to their outstanding features, i.e., ability to sustain chemical and climatic impact, these epoxy-based materials are able to ensure positive fireproof performance for steel structures in the case of potential cryogenic impact. The article discusses tests on steel structures coated with epoxy fireproof compounds, specifically PREGRAD-EP, OGRAX-SKE and Chartek 2218. The test records show the time from the start of cryogenic exposure to the said sample reaching the limit state, as well as the time from the start of heat impact to the sample reaching the limit state in case of hydrocarbon fire temperature.

Highlights

The oil and gas industry is one of the global economy’s leading and most challenging branches, and is of critical importance [1]
According to the test results, it was found that sample no. 2, with its dry layer thickness of 22.5 mm applied on a square cross-section steel pipe (100 × 100 × 8 mm) and with a section ratio of 134 mm−1, ensured fire protection performance under hydrocarbon fire for at least 120 min after 10 min of cryogenic impact on the sample fully immersed in liquid nitrogen
No blistering, peeling or other visible defects were found on the fireproof coating after the cryogenic exposure

Summary

Introduction

The oil and gas industry is one of the global economy’s leading and most challenging branches, and is of critical importance [1]. The following temperature cases are stipulated to be used for standardized structural fire tests: “standard” (cellulosic) fire; external, slow heating; and hydrocarbon fire [9]. Steel structures in a fire or blast emergency scenario in oil and gas facilities suffer high-temperature and overpressure impact corresponding to the hydrocarbon fire case. The steel structure strength becomes drastically lower within the range of 400–600 ◦ C, while in case of applied load, the unprotected structure almost immediately loses its stability [13]. For this reason, structures that can withstand, e.g., higher temperatures and blast shockwaves, are protected with fireproofing, must be used at hazardous facilities

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Conclusion