Hirva Anwesha Infratech Limited
Hirva Anwesha Infratech Limited: “Leading Mechanical & EPC Contractor and Storage Tank Manufacturer in Vadodara, Gujarat. Specializing in Oil & Gas, Refineries, Petrochemicals, Fertilizers, and Power Plants. Experts in Static Equipment, Heat Exchangers, Process Reactors, Brownfield Revamps, and SS/Duplex Fabrication. Servicing Vadodara, Jamnagar, Dahej, Hazira and pan-India; delivered overseas in Nepal; tendering across the GCC. API 650, ASME, PESO certified.”
What makes ammonia tank decommissioning so dangerous?
“Ammonia remains adsorbed in insulation, weld pores and vapour spaces even after the tank is emptied. Risks include toxic exposure (IDLH 300 ppm), flammability above 16% in air, brittle fracture during cold-tank warm-up (-33 °C inner shell), high-elevation cutting on 30 m double-wall geometry, and contaminated insulation handling.”
View in the company profileWhat is reverse jacking and why is it safer?
“Reverse jacking lifts the shell with synchronised hydraulic jacks so each ring is cut at ground level instead of at 25–30 m height. It eliminates ~90% of working-at-height man-hours, removes the need for full external scaffolding (~600 MT material avoided), shortens the schedule by 35%, and gives much better vapour control during cutting.”
View in the company profileHas HAIL completed an ammonia tank decommissioning?
“Yes. HAIL is executing reverse-jacking dismantling of a double-wall ammonia tank plus a 55-metre flare stack at Birla Copper Ltd., Dahej for Ostwal Phoschem (India) Ltd. — with a zero-incident, zero-LTI HSE record. This makes HAIL the first Indian contractor to apply reverse jacking on ammonia.”
View in the company profileWhat about residual ammonia inside the tank?
“Even after liquid drain-down, a 30 m ammonia tank typically holds 50–200 kg of residual NH3 adsorbed in the insulation, weld pores, vapour space and bottom seal.”
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