She pulled up the feed. A gasket on a 4-inch line was weeping, then spraying. Propane. The wind was blowing southeast — directly toward the old building.
Then she leaned back, listening to the positive pressure system hum.
She watched the old control room camera as the emergency shutdown valves closed remotely. A cloud formed — colorless, invisible on IR. But she knew it was there. And she knew: six months ago, she would have been standing in that cloud's path, in a building with a two-inch concrete wall and no overpressure rating. api rp 752 pdf
So last Monday, they rolled in a portable operations module — a white double-wide with blast-rated walls and a separate HVAC. They parked it 600 feet west, behind the sulfur pit berm. Mara’s supervisor called it "the bunker." The crew called it "Fort Anxiety."
It was the map.
The new risk assessment had reclassified Building 43 as a — too close, too exposed. According to Section 5.4 of the 752 PDF, they had to either relocate personnel or retrofit for blast overpressure. Retrofitting cost millions. Relocating cost a trailer.
At 2:17 a.m., Mara sat in the new module, watching six screens showing the old control room, dark and silent. The only sound was the hiss of breathing air — positive pressure to keep out toxic vapors. She pulled up the feed
Outside, the vapor cloud dissipated. Inside the old control room, a single monitor still glowed — showing the bunker, safe and distant, where the shift lived on. Based on real-world guidance from API RP 752 (3rd Edition), which emphasizes risk evaluation, building siting studies, and mitigation for existing occupied buildings in process plants.