Hazard Studies & Risk Assessment

Facility Siting Studies

Occupied building risk assessment and siting optimisation per API 752/753

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What this study delivers

Facility Siting
Studies

Facility Siting Studies (FSS) assess the risk to personnel in occupied buildings on process industry sites from fire, explosion, and toxic release events. The study determines whether buildings are appropriately sited and constructed, and recommends upgrades where occupant risk exceeds tolerable levels.

Facility Siting Studies — Overview
Study execution

How the study is executed

A structured, facilitated process — from scope definition through close-out — producing defensible, actionable outputs.

Building Inventory & Occupancy Profiling

Compile building register with classification (permanent/portable/tent per API RP 752/753/756), structural type (brick/modular/BRM), occupancy (peak persons, occupied hours, staff vs contractor), and GPS coordinates; cross-map to site layout and process-unit proximity.

Explosion Source Term & Overpressure Basis

Select VCE / BLEVE scenarios from FERA / CDM study per unit; apply Multi-Energy, Baker-Strehlow-Tang, or FLACS overpressure modelling; calculate side-on overpressure, duration, and positive impulse at each building location.

Building Damage & Personnel Vulnerability

Apply ASCE Petrochemical Energy Committee fragility curves per structural type (brick, portal frame, modular) to derive damage state (minor/moderate/major/collapse); calculate personnel fatality and injury probabilities per Pietersen / Stephens probit functions.

Thermal Radiation & Toxic Infiltration Assessment

Calculate thermal dose at each building from pool fire / jet fire / fireball scenarios; assess skin burn, structural ignition, and HVAC-driven toxic infiltration to AEGL-2 / SLOT; determine shelter-in-place viability per air-change rate and exposure duration.

Building Risk Ranking & Tolerability Assessment

Calculate IRPA and PLL per building; plot against API RP 752 tolerability criteria (TRIR < 1×10⁻³ for workers); rank buildings by risk level; identify buildings above tolerable threshold requiring upgrade action.

Upgrade Options Appraisal & Action Plan

Appraise options per building — BRM (Blast-Resistant Module), structural reinforcement, relocation, demolition, occupancy reduction; develop cost-benefit basis; issue priority-ranked action plan with timeline, risk-reduction quantification, and 5-year re-assessment trigger matrix.

Facility Siting Studies — Scope
Study scope

What the study covers in full

Building inventory and occupancy data collection
Explosion overpressure assessment per API 752 methodology
Fire and toxic exposure consequence modelling per building location
Structural vulnerability assessment: brick, modular, blast-resistant
Occupied Building Risk Assessment (OBRA) per API 753
Risk tolerance criteria application and building risk ranking
Upgrade options: blast-resistant modular buildings, relocation, occupancy reduction
Action prioritisation by risk level and occupant count
Why it matters

Outcomes of Facility Siting Studies

Blast & Fire Exposure Reduction
  • Protects control room, administration, and temporary workers from explosion
  • Identifies buildings at unacceptable risk for priority action
  • Prevents fatalities from structural collapse in blast events
  • Documents tolerable risk basis for each occupied building
API 752 / 753 / OSHA PSM Defence
  • OSHA PSM PHA element — occupied building consideration
  • API 752 and 753 methodology compliance
  • CCPS Facility Siting guidance implementation
  • Post-Buncefield and Texas City regulatory focus compliance
Occupancy & SIMOPS Risk Management
  • Identifies whether muster points and control rooms are adequately located
  • Supports contractor and temporary workforce siting decisions
  • Provides basis for safe working population limits in at-risk areas
  • Informs SIMOPS occupancy restrictions
BRM & Retrofit Cost Targeting
  • Early identification of at-risk buildings prevents costly post-incident litigation
  • Risk-prioritised upgrade programme avoids blanket replacement costs
  • Blast-resistant building specification prevents over-engineering
  • Documents due diligence for insurance and legal purposes
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