buildings Article Fire Resistance of Steel Structures with Epoxy Fire Protection under Cryogenic Exposure Marina Gravit 1 , Boris Klementev 2 and Daria Shabunina 1, *   Citation: Gravit, M.; Klementev, B.; Shabunina, D. Fire Resistance of Steel Structures with Epoxy Fire Protection under Cryogenic Exposure. Buildings 2021, 11, 537. https://doi.org/ 10.3390/buildings11110537 Academic Editor: Francisco Lopez Almansa Received: 3 October 2021 Accepted: 11 November 2021 Published: 14 November 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Civil Engineering Institute, Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia; marina.gravit@mail.ru 2 Department of Expertise, LLC “Arctic LNG 2”, 117393 Moscow, Russia; zeugmas@icloud.com * Correspondence: d.shabunina00@gmail.com 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. Keywords: steel structure; oil and gas facilities; liquefied natural gas (LNG); cryogenic spillage protection; passive fire protection (PFP); epoxy syntactic materials; hydrocarbon fire 1. Introduction The oil and gas industry is one of the global economy’s leading and most challenging branches, and is of critical importance [1]. In most cases, energy economy assets and facilities (buildings, structures and equipment) are deemed higher hazard sources as such process facilities imply handling and storing considerable volumes of combustible and explosive substances, and non-compliance with the relevant safety rules may entail fire, explosion and/or spillage [2–6]. The major and most severe incidents at Piper Alpha, the North Sea, (6 July 1988) and Deepwater Horizon (20 April 2010) proved that the standards adopted in the oil production industry should be improved [7,8]. 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. During the several minutes when the fire starts, the temperature reaches 1000 ◦ C and higher [10–12]. 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. Standards such as EN 1473 and NFPA 59A [14,15] or industrial standards of the major oil and gas companies stipulate that the steel structures being part of equipment, process units and piperacks related to processing/storing liquefied natural gas (LNG), shall be Buildings 2021, 11, 537. https://doi.org/10.3390/buildings11110537 https://www.mdpi.com/journal/buildings