The most demanding tank decommissioning job in India
Decommissioning an ammonia storage tank is fundamentally different from dismantling a fuel or water tank. Ammonia is toxic at low ppm, flammable in concentration, deeply adsorbed into insulation and weld pores, and the cold inner shell is at risk of brittle fracture during uncontrolled warm-up. A double-wall tank adds 30 metres of working-at-height to every cut. There are very few contractors in India qualified to carry that risk — HAIL is the first to do it with reverse jacking, executed at Birla Copper Ltd., Dahej for Ostwal Phoschem (India) Ltd.
Our reverse-jacking method — why it is safer
Conventional dismantling cuts shell rings from the top down, with crews working at 25—30 m height for weeks. Reverse jacking inverts the sequence: hydraulic jacks lift the entire shell while each ring is cut and removed at ground level. The result:
- 90% reduction in working-at-height — the riskiest activity is eliminated.
- No full-tank scaffolding — material and erection time saved.
- Faster schedule — parallel cutting and rigging at ground level.
- Better cold-tank control — slow, monitored warm-up rather than cut-as-you-warm.
- Cleaner waste handling — insulation and contaminated debris contained at ground level.
Step-by-step decommissioning procedure
- Aged-plant safety study & HAZOP. Independent walk-down, design review, register of identified hazards, mitigation matrix and approved method statement.
- Isolation & positive disconnection. All process lines isolated, blinded and tagged. Power and instrument loops de-energised.
- Drain-down, flushing & warm-up. Residual ammonia removed via controlled drain. Water flushing, slow warm-up to ambient with vapour to scrubber.
- Nitrogen purging. Multiple N— purge cycles until vapour-space ammonia is below safe threshold (verified by gas detector at multiple elevations).
- Scrubber-controlled venting. Any released vapour passes through a water/acid scrubber before atmospheric release; continuous downwind monitoring.
- Outer shell removal. Cold cutting (no hot work) of outer shell; perlite/insulation extracted, bagged and disposed under HW manifest.
- Reverse jacking of the inner shell. Hydraulic jacks lift the inner tank; each ring is cut at ground level and removed by crane.
- Bottom plate & foundation handover. Bottom plate cut and removed; foundation surveyed and handed over per the agreed end-state (clear, capped or remediated).
- Scrap segregation, transport & final certificate. Ferrous and non-ferrous scrap segregated, weighed, transported under manifest. Final HSE close-out with photos and certificate of safe handover.
Active reference — Birla Copper Ltd., Dahej
Client
Ostwal Phoschem (India) Ltd. — for Birla Copper facility, Dahej, Gujarat.
Scope
Complete dismantling of a double-wall ammonia tank, plus 55-metre flare stack. Aged-plant safety study, HAZOP, engineered dismantling procedure, reverse jacking, transport and safe disposal.
HSE record
Zero major incidents; continuous downwind ammonia monitoring; HSSE-trained crew with cranes, man lifts and full scaffolding capacity.
Status
Ongoing, with milestone-by-milestone client sign-off.
Equipment we deploy
- Owned 200 MT, 100 MT, 50 MT and 20 MT cranes.
- Hydraulic jacking sets and synchronised jacking control.
- Cold cutting tools (band saw, magnetic drill, abrasive saw — no hot work in vapour zones).
- Mobile nitrogen banks and pre-engineered scrubber skid.
- Multi-gas detectors, area monitors and ammonia-specific PPE.
- Man lifts, scissor lifts and certified scaffolding.
Why HAIL for ammonia decommissioning
- India's first reverse-jacking ammonia dismantle — a documented, audited methodology.
- HSSE-trained core team with refinery/chemical-plant decommissioning experience.
- Single-point contractor — engineering, jacking, cutting, transport, disposal under one PO.
- Owned crane fleet eliminates rental risk.
- Consortium with RINA Consulting for independent design/risk verification.
Why ammonia tank decommissioning is uniquely dangerous
Ammonia (NH—) is one of the most hazardous chemicals an Indian process plant stores. At its boiling point of —33 ×C it is a refrigerated liquid; at room temperature, a corrosive toxic gas. The decommissioning of an ammonia tank introduces three failure modes that conventional tank dismantling does not face:
| Hazard | What happens | HAIL mitigation |
|---|---|---|
| Toxic exposure | Ammonia at 300 ppm is immediately dangerous to life. IDLH is 300 ppm; OSHA PEL is 50 ppm for 8 hr. | N— purging until residual NH— < 25 ppm verified at multiple elevations. Continuous downwind monitoring during entire dismantling. |
| Flammability | NH— is flammable above 16% concentration in air. Hot work without verified gas-free conditions can cause vapour-cloud explosion. | Cold cutting only (band saw, abrasive saw, magnetic drill) until written gas-free permit issued by HSE manager. |
| Cold-tank brittle fracture | The inner shell at —33 ×C has reduced fracture toughness. Sudden warming or impact cuts can initiate brittle fracture, releasing residual ammonia uncontrolled. | Slow controlled warm-up over 5—7 days. Vapour to scrubber. Continuous shell temperature monitoring at 16 thermocouple points. |
| Insulation contamination | Perlite/foam-glass insulation between inner and outer shells absorbs ammonia and water over 20+ years of service. Crushing or cutting releases toxic dust. | Bagged extraction with HEPA filters, hazardous-waste manifest, transport to authorised TSDF (Treatment Storage Disposal Facility). |
| Working at 30 m height | Conventional top-down cutting requires crews at 25—30 m for weeks, with full external scaffolding. | Reverse jacking — eliminates 90% of working-at-height by cutting at ground level after lifting the shell hydraulically. |
Reverse jacking vs conventional dismantling — comparison
Below is a head-to-head comparison from our Birla Copper Dahej execution data versus a conventional top-down dismantle of a similar 30 m ammonia tank we previously evaluated:
| Parameter | Conventional top-down | HAIL reverse jacking |
|---|---|---|
| Working-at-height man-hours | ~14,000 hours | ~1,400 hours (90% reduction) |
| Full external scaffolding required | Yes (~600 MT material) | No (jacking platform only) |
| Total schedule (single tank) | 26—32 weeks | 16—20 weeks (35% faster) |
| Crane mobilisation requirement | 200—300 MT crawler | 100 MT crawler + 50 MT support |
| Vapour control during cutting | Cuts at elevation — vapour drift risk | Cuts at ground — easier scrubber capture |
| Insulation handling | Insulation falls during cuts — dust risk | Insulation extracted in controlled way at ground |
| HSE risk profile | High | Significantly lower |
Pre-mobilisation deliverables — what we issue before any crew arrives
An ammonia tank dismantle must be paper-perfect before metal is touched. Below is the complete document set HAIL issues to the client and statutory authorities prior to mobilisation:
- Aged-Plant Safety Study (APSS). Independent walk-down by senior dismantling engineer, structural fitness assessment, hazard register with severity/frequency rating, photographic dossier.
- HAZOP & HAZID worksheets. Conducted by 6-person team (HAIL + client + independent chair). Every node assessed for deviation, cause, consequence, safeguards, recommendations.
- Method Statement (RAMS). Risk Assessment + Method Statement for each work pack — drain-down, flushing, warm-up, purging, cutting, jacking, transport.
- Job Safety Analysis (JSA). Per task. Lists every step, hazard, control, PPE, permit. Signed by crew before each shift.
- Permit-to-Work (PTW) framework. Hot work, cold work, working at height, confined space, lifting permits — all integrated with client's PTW system.
- Emergency Response Plan (ERP). Ammonia release scenarios, downwind evacuation zones, scrubber failure, fire, medical (ammonia exposure).
- Lift study & rigging plan. 3D crane geometry, ground-bearing capacity check, outrigger pad design, sling/shackle take-off.
- Waste handling & disposal plan. CPCB / GPCB authorised TSDF, manifest format, scrap segregation matrix, ferrous/non-ferrous tracking.
- Mobilisation organogram. Site Manager, HSE Lead, Quality Lead, jacking specialist, dismantling crew, scrubber operators, riggers — with CVs and certifications.
- Insurance & bonds. Workmen's Compensation, Public Liability, CAR (Contractor's All Risk), Performance Bond.
Birla Copper Ltd. Dahej — the project that made HAIL India's first reverse-jacking ammonia contractor
In 2025 HAIL was awarded — on a competitive bid for Ostwal Phoschem (India) Ltd. — the dismantling of the ammonia storage facility at Birla Copper Ltd., Dahej. The scope included:
- One double-wall ammonia storage tank — inner shell SA 333 Gr.6 LTCS, outer shell SA 516 Gr.70 carbon steel, perlite-insulated annular space, ~30 m diameter × 30 m height, original commissioning 1990s.
- One 55-metre flare stack — guyed structure, dismantled by sectional cut-down with controlled lowering.
- Associated piping & instrumentation — N— purge piping, scrubber connections, vapour return lines.
- Civil clearance — foundation hand-over to client per agreed end-state.
What made the project a first in India: HAIL was the only contractor to bid the job using reverse jacking rather than conventional top-down cutting. This approach was approved by Birla Copper's safety review board after independent verification of the lift study by a third-party consulting firm. The execution achieved:
- Zero Lost Time Incident (LTI) and zero recordable medical case throughout execution.
- Zero ammonia release above detection threshold during purging or cutting.
- Schedule of approximately 18 weeks vs. ~28-week baseline for conventional dismantle.
- ~85% scrap recovery (ferrous), all transported under hazardous-waste manifest.
This single project established HAIL as the reference Indian contractor for ammonia tank decommissioning. It is the case study we offer for technical due diligence by clients planning similar shutdowns at GSFC, GNFC, IFFCO, RCF, NFL, KRIBHCO, Coromandel, Deepak Fertilisers and other Indian fertiliser / ammonia operations.
Equipment we deploy on an ammonia decommissioning
| Category | Equipment | Purpose |
|---|---|---|
| Cranes | 200 MT, 100 MT, 50 MT, 20 MT crawler / hydraulic | Sphere/shell lifting, rigging, scrap handling |
| Jacking | Hydraulic jacking sets with synchronised PLC control | Reverse-jacking the inner and outer shells |
| Cold cutting | Band saw, magnetic drill, abrasive saw, hydraulic shears | No spark / no flame in vapour-zone areas |
| Hot cutting (after gas-free certification) | Plasma, oxy-fuel | Final scrap reduction at lay-down area |
| Nitrogen system | Mobile N— banks (cryogenic dewars + vaporiser) | Inerting of inner shell |
| Scrubber | Pre-engineered water/acid scrubber skid | Capture residual NH— vapour during venting |
| Gas detection | Multi-gas + ammonia-specific area monitors, personal monitors | Continuous downwind & in-shell monitoring |
| PPE | SCBA (self-contained breathing apparatus), Level B chemical suits, ammonia-resistant gloves | Crew protection during entry/cutting |
| Access | Man lifts, scissor lifts, certified scaffolding (minimal) | Limited high-elevation work |
| Communication | Hard-wired plus intrinsically safe radios | Crew coordination in vapour zones |
Cost & schedule guide for ammonia tank decommissioning
Each ammonia decommissioning is unique to tank geometry, residual product condition, insulation state, plot constraints and statutory framework. As a budgetary indication based on our reference data:
- Single double-wall ammonia tank, ~25—30 m diameter: typical contract value —4—8 Crore, schedule 16—22 weeks from mobilisation to foundation handover.
- Single-containment ammonia tank, 10—18 m diameter: —2—4 Crore, schedule 10—14 weeks.
- Add a flare stack (40—60 m): —50—90 Lakh, in parallel with main dismantle.
- Add associated piping, control room, transformers, etc.: —30—80 Lakh depending on scope.
The fastest cost-saver is procurement timing. A 6-week pre-mobilisation engineering window (HAZOP, lift study, scrubber design) avoids the much larger schedule cost of mobilising twice. We strongly advise client + HAIL pre-FEED engagement before tendering.
Industries & clients who need ammonia decommissioning
Ammonia storage is found at every fertiliser plant, several copper smelters, refrigeration warehouses and a number of large dairy / cold-chain operations. As Indian assets built in the 1980s—1990s reach end-of-life, decommissioning demand is accelerating. HAIL targets:
- Fertiliser industry: GSFC Vadodara, GNFC Bharuch, IFFCO Kalol/Phulpur/Aonla, KRIBHCO Hazira, RCF Trombay/Thal, NFL Vijaipur/Nangal/Bathinda, Chambal Fertilisers Gadepan, Coromandel International Visakhapatnam, Deepak Fertilisers Taloja, Yara India.
- Petrochemical: Reliance Hazira / Jamnagar, IOCL Panipat, BPCL Kochi, GAIL Pata, Haldia Petrochemicals.
- Copper / metals: Birla Copper Dahej, Hindustan Copper Ghatsila, Vedanta Sterlite Tuticorin (when re-opened).
- Cold chain & food: Snowman Logistics, ColdEX, Future Supply Chain, ITC food processing units with ammonia refrigeration.
Frequently asked questions
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. A documented HAZOP-led procedure with N— purging, controlled warm-up and scrubber venting is mandatory.
What 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.
Has 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.
What does the decommissioning scope include?
Aged-plant safety study, HAZOP, isolation & positive disconnection, drain-down, water flushing, slow warm-up, nitrogen purging, scrubber-controlled venting, sectional cold cutting, reverse jacking of inner and outer shells, insulation extraction and disposal, sectional dismantle, scrap segregation, transport under hazardous-waste manifest, and final certificate of safe handover.
Do you also dismantle flare stacks and cold-boxes?
Yes. At Birla Copper Dahej we are dismantling a 55-metre flare stack alongside the ammonia tank. We also dismantle cold-boxes, reactors, columns, pipe racks, and full process trains under the same HSSE plan — often in parallel to compress overall shutdown duration.
How much does it cost to dismantle an ammonia tank?
For a typical 25—30 m diameter double-wall ammonia tank: contract value —4—8 Crore, schedule 16—22 weeks. Single-containment 10—18 m tanks: —2—4 Crore, 10—14 weeks. Adding a 40—60 m flare stack: —50—90 Lakh in parallel. Final price depends on insulation condition, residue, plot constraints and statutory framework.
How long does ammonia decommissioning take?
16—22 weeks for a typical double-wall tank from mobilisation to foundation handover. Pre-mobilisation engineering (HAZOP, lift study, scrubber design) takes an additional 4—6 weeks. Conventional top-down dismantle takes 26—32 weeks — reverse jacking is ~35% faster.
What is HAZOP and why is it mandatory before ammonia dismantling?
HAZOP (Hazard and Operability Study) is a structured risk review where a team of dismantling engineers, plant operators and safety experts go through every step of the procedure node-by-node, identifying possible deviations, causes, consequences and required safeguards. For ammonia work it is statutorily mandatory under PESO and CCOE regulations and must be conducted before any work begins.
What about residual ammonia inside the tank?
Even after liquid drain-down, a 30 m ammonia tank typically holds 50—200 kg of residual NH— adsorbed in the insulation, weld pores, vapour space and bottom seal. We remove this through phased water flushing, controlled warm-up to ambient over 5—7 days with vapour to scrubber, and multiple N— purge cycles until residual concentration is verified below 25 ppm at multiple elevations.
How do you handle the perlite / foam-glass insulation?
The insulation between inner and outer shells absorbs ammonia and water over decades of service. We extract it in a controlled sequence: vacuum extraction at the top of the annular space, bagged collection with HEPA filters, hazardous-waste manifest, transport to authorised TSDF (Treatment Storage Disposal Facility) with CPCB / GPCB authorisation. Crew wear Level B chemical suits during extraction.
What documents do you provide before mobilisation?
Aged-Plant Safety Study (APSS), HAZOP & HAZID worksheets, RAMS Method Statement per work pack, JSA per task, Permit-to-Work framework integrated with client, Emergency Response Plan, lift study with rigging plan, waste handling & disposal plan, mobilisation organogram with crew CVs, and full insurance & bond certificates.
Which Indian fertiliser plants typically need ammonia decommissioning?
Most Indian fertiliser plants built in the 1980s—1990s have ammonia storage approaching end-of-life: GSFC Vadodara, GNFC Bharuch, IFFCO Kalol/Phulpur/Aonla, KRIBHCO Hazira, RCF Trombay/Thal, NFL Vijaipur/Nangal/Bathinda, Chambal Fertilisers Gadepan, Coromandel International Visakhapatnam, Deepak Fertilisers Taloja, Yara India. We also serve copper smelters and large cold-chain warehouses with ammonia refrigeration.
Can you decommission an ammonia tank inside an operating fertiliser plant?
Yes. We have specialised in live-plant work — most ammonia tanks need to be dismantled while the rest of the fertiliser unit continues to operate. We coordinate with plant operations, isolate utilities, manage downwind monitoring, and execute under strict client PTW. Birla Copper Dahej was executed adjacent to live operations.
Do you handle the ammonia drain-down and disposal too?
Yes — typically the client will have flared off or transferred the bulk liquid ammonia before our scope starts. If residual liquid remains, we manage controlled drain-down to a holding system, neutralisation with dilute acid (under HAZOP-approved procedure), and final disposal via authorised handler.
What insurance & bonds do you carry for hazardous decommissioning?
Workmen's Compensation Insurance covering all crew, Public Liability Insurance with adequate cover for third-party damage, Contractor's All Risk (CAR) Insurance for the duration of the project, and Performance Bond / Bank Guarantee as required by client tender. Specific cover values are scaled to project value and risk profile.
What scrap recovery do you achieve?
Typically ~85% scrap recovery on the ferrous content (carbon steel outer shell, structural). The inner shell is LTCS — separated and transported separately due to potential ammonia adsorption history. All scrap moves under client manifest with weighbridge tickets and TSDF receipts where applicable.
Why is HAIL the right contractor for ammonia decommissioning in India?
(1) India's first reverse-jacking ammonia dismantle — documented, audited HSE methodology. (2) Active reference at Birla Copper Dahej with zero-incident record. (3) Owned crane fleet (200/100/50/20 MT) — no rental dependency. (4) Single-point contractor for engineering, jacking, cutting, transport and disposal. (5) RINA Consulting consortium for independent design assurance. (6) Pre-engineered scrubber + N— system available for rapid mobilisation. No other Indian contractor combines all five.