## 2 Fire-Resistance Performance of A60 BPP
### Transient Heat Transfer Analysis and Fire Test
As shown in Figure 6, the temperature results of the A60 BPP measured in the unexposed ambient domain were distributed in the range of 20 \({}^{\circ}\)C to 313 \({}^{\circ}\)C, while in the exposed furnace domain, they were distributed in the range of 330 \({}^{\circ}\)C to 892 \({}^{\circ}\)C. Based on the numbers represented in Figure 4 and Table 1, the maximum temperature results on the body of the A60 BPP in the unexposed ambient domain were measured as 172.4 \({}^{\circ}\)C at #1, 76.6 \({}^{\circ}\)C at #2, 170.0 \({}^{\circ}\)C at #3 and 58.4 \({}^{\circ}\)C at #4, respectively. It was found that the temperature result of the newly devised A60 BPP from the transient heat transfer analysis satisfied the fire-resistance temperature limit for the A60 class apparatus regulated in the FTP code. In order to verify the transient heat transfer analysis result, the fire test specimen was manufactured in accordance with the FTP code in the same way as the analysis model, and the test was carried out according to the international fire-resistance test procedure specified in ISO [10]. The vertical furnace, which is used for the verification of fire-resistance performance of the A60 BPP, is a facility that tests the A-class vertical  
Figure 6: Temperature distribution contour results (unit: \({}^{\circ}\)C). fire protection apparatus installed at the vertical bulkhead compartment in ships and offshore plants. The effective heating area of the vertical furnace is 3000 mm \(\times\) 3000 mm. The fire test temperature inside the furnace is controlled according to the furnace control temperature curve of Equation (1) through the flame from burners installed on the lower side of the furnace. The fire test time is adjusted according to the fire-resistance class. The vertical furnace facility and the test configuration used for the fire test of A60 BPP are shown in Figure 7.  
As shown in Figure 7b, the temperatures of the fire test for A60 BPP were measured at the same locations as the transient heat transfer analysis. The measurement results from the fire test are represented in Table 2 in comparison to the transient heat transfer analysis results. As represented in Table 2, the minimum error between the transient heat transfer analysis and the fire test of A60 BPP was 3.2% at the #1 measurement location, and the maximum error was 14.0% at #2, respectively. The average error at all measurement locations was 7.8%, and it was also found that the temperature variation characteristics according to the design specifications such as A60 BPP length, diameter, and material type were coincident in both the transient heat transfer analysis and the verification test. Considering the transient heat transfer analysis for the 60 min fire test, it was confirmed that the accuracy of the analysis result was verified. Since the transient heat transfer analysis method adopted in this study was confirmed to be adequate for the evaluation of the fire-resistance design of the A60 BPP, meta-model generation and approximate optimization with discrete design variables were carried out for the minimum weight design based on the transient heat transfer analysis.