PHA is a required PSM/RMP element (29 CFR 1910.119(e), 40 CFR 68.67) and must be revalidated every five years.
Methodology selection matters: HAZOP, What-If, FMEA, and Checklist each serve different process types and risk profiles. Aggie Safety selects and facilitates the right one for your facility.
LOPA (Layer of Protection Analysis) quantifies risk reduction from independent protection layers — bridging the gap between a qualitative HAZOP and a full quantitative risk assessment.
Facility Siting studies evaluate whether occupied buildings near process hazards are adequately protected from blast, fire, and toxic release scenarios.
PHAST (DNV consequence modeling software) allows Aggie Safety to model toxic, flammable, and explosion consequences quantitatively — supporting RMP off-site consequence analysis, facility siting, and emergency planning.
Root Cause Analysis (RCA) applied after incidents or near-misses prevents recurrence by identifying systemic failures, not just the triggering event.
Aggie Safety delivers the full spectrum of PHA and process risk services. Each study is scoped to the specific methodology, process type, and regulatory context your facility requires. Below is what each service covers and when it applies.
A Hazard and Operability Study (HAZOP) is the most rigorous and widely used PHA methodology for continuous process systems — pipelines, reactors, distillation columns, heat exchangers, and similar equipment. It uses a structured set of guidewords (No, More, Less, Reverse, Other Than, As Well As, Part Of) applied systematically to each node of the process to generate deviation scenarios.
Aggie Safety facilitates HAZOPs using up-to-date P&IDs, operating procedures, and process safety information. Our team brings working process knowledge to the table — not just facilitation mechanics. For a HAZOP to produce actionable findings, the facilitator needs to understand the chemistry and thermodynamics well enough to recognize which deviations are credible and which consequences are realistic. That is what 20-plus years of process engineering experience provides.
HAZOP outputs include: identified hazards and consequences, existing safeguards, identified gaps, and recommendations with assigned owners and due dates — formatted to satisfy PSM/RMP documentation requirements and internal insurance audits.
Applicable standards: OSHA 29 CFR 1910.119(e), 40 CFR 68.67 (RMP), IEC 61882 (HAZOP standard), API RP 14C (for offshore/onshore gas facilities).
What-If analysis is a structured brainstorming method that asks "What if this specific deviation or failure occurred?" across defined areas of a process. It is less rigorous than a full HAZOP but faster and well-suited for batch processes, simpler operations, facilities with limited P&ID documentation, or initial-phase hazard screening before detailed engineering is complete.
Aggie Safety conducts What-If studies as standalone engagements or as part of a combined PHA approach where some process sections warrant HAZOP depth and others are adequately addressed with What-If. We document all scenarios, consequences, existing safeguards, and recommendations in a format that meets PSM/RMP requirements.
What-If is also commonly used for Management of Change (MOC) reviews when a process modification is too significant for a simple checklist but does not justify a full node-by-node HAZOP.
LOPA is a semi-quantitative risk assessment technique applied to high-consequence scenarios identified during a HAZOP or What-If study. Where a HAZOP identifies that a scenario is hazardous and that safeguards exist, LOPA answers the question: are those safeguards sufficient?
The method assigns initiating event frequencies and calculates Independent Protection Layer (IPL) credit for each safeguard -- considering demand rate, probability of failure on demand (PFD), and conditional modifiers -- to determine the mitigated event frequency. That frequency is then compared against a target risk tolerance (typically expressed as a maximum tolerable frequency for fatality scenarios, process demands, or environmental releases).
LOPA results directly drive Safety Instrumented System (SIS) requirements. When LOPA shows that existing layers are insufficient, the gap is typically addressed through a Safety Instrumented Function (SIF) designed to IEC 61511 / ISA 84.00.01, with a specified Safety Integrity Level (SIL). Aggie Safety can scope and support SIL determination as part of the LOPA engagement.
Applicable standards: IEC 61511 / ISA 84.00.01 (SIS), CCPS Layer of Protection Analysis: Simplified Process Risk Assessment, OSHA 29 CFR 1910.119.
Root Cause Analysis is the systematic investigation of an incident, near-miss, or repeated equipment failure to identify the underlying systemic causes -- not just the immediate trigger. OSHA PSM requires incident investigation within 48 hours of an event and documentation of root causes, corrective actions, and communication to affected personnel (29 CFR 1910.119(m)).
Most process incidents are not caused by a single failure. They result from the combination of a physical failure, a procedural gap, and an organizational factor that allowed the failure mode to go undetected or uncorrected. RCA methods used by Aggie Safety include:
RCA deliverables include: timeline of events, identified root and contributing causes, corrective and preventive actions (CAPAs) with owners and due dates, and a lessons-learned summary for communication to affected employees -- formatted to satisfy PSM incident investigation requirements.
A Facility Siting Study evaluates whether occupied structures -- control rooms, administrative buildings, maintenance shops, break rooms -- are located at safe distances from process equipment that could release hazardous energy in an accident scenario. It is a required component of Process Safety Information under PSM (29 CFR 1910.119(d)) and is typically triggered or updated by a PHA, a significant process expansion, or an MOC involving new building construction or occupancy changes.
The primary hazard scenarios evaluated in a facility siting study are:
Aggie Safety conducts facility siting studies using consequence modeling (PHAST, described below) to quantify hazard distances and compares results against accepted risk criteria from API RP 752 (Management of Hazards Associated with Location of Process Plant Permanent Buildings) and API RP 753 (Management of Hazards Associated with Location of Process Plant Portable Buildings).
Where a building is identified as inadequately sited, Aggie Safety provides risk reduction options: relocation, blast-rated construction upgrades, occupancy reduction, or administrative controls to limit personnel exposure during high-hazard operations.
PHAST (Process Hazard Analysis Software Tool) is DNV's industry-standard consequence modeling software, used by major oil companies, chemical manufacturers, and regulators worldwide. Aggie Safety uses PHAST to model the physical consequences of accidental releases of hazardous substances -- providing the quantitative foundation for facility siting decisions, RMP off-site consequence analysis, emergency response planning, and LOPA scenario frequency calibration.
PHAST modeling capabilities used by Aggie Safety include:
PHAST output directly supports EPA RMP worst-case and alternative release scenario analysis under 40 CFR Part 68, Subpart B. Aggie Safety uses PHAST in conjunction with site-specific meteorological data, release inventory data, and realistic failure scenarios to produce defensible, code-compliant consequence analysis reports.
| Methodology | Best Suited For | Key Output | Regulatory Basis |
|---|---|---|---|
| HAZOP | Continuous processes with defined P&IDs: refineries, chemical plants, gas processing units | Deviation scenarios, consequences, safeguards, and recommendations for each process node | OSHA 29 CFR 1910.119(e); 40 CFR 68.67; IEC 61882 |
| What-If | Batch processes, simpler operations, MOC reviews, early-phase hazard screening | Scenario list with consequences, safeguards, and recommendations | OSHA 29 CFR 1910.119(e); 40 CFR 68.67 |
| LOPA | High-consequence scenarios identified in HAZOP/What-If needing quantified IPL adequacy assessment | Mitigated event frequency vs. target; SIL requirements for safety instrumented functions | IEC 61511 / ISA 84.00.01; CCPS LOPA guidelines |
| Root Cause Analysis | Post-incident or near-miss investigation; repeat equipment failures | Root and contributing causes; corrective/preventive actions; lessons-learned report | OSHA 29 CFR 1910.119(m); 40 CFR 68.81 |
| Facility Siting | Process expansions, new occupied building placement, PSI documentation, MOC involving occupancy | Hazard distances; building risk assessment; risk reduction recommendations | API RP 752 / 753; OSHA 29 CFR 1910.119(d) |
| PHAST Consequence Modeling | RMP off-site consequence analysis, facility siting, emergency planning, LOPA scenario calibration | Toxic dispersion, flammable/explosion/fire consequence distances; RMP-compliant analysis report | 40 CFR Part 68 Subpart B (RMP); API RP 752 |
We review your facility type, process descriptions, existing PSM/RMP status, and what triggered the study need — initial PHA, five-year revalidation, MOC, post-incident, or new construction. We confirm the appropriate methodology and estimate study scope.
Aggie Safety reviews your Process Safety Information package: P&IDs, PFDs, cause-and-effect diagrams, equipment datasheets, operating procedures, prior PHA reports, and incident history. We identify gaps in documentation before the study begins — documentation gaps during a PHA session waste expensive facilitated time.
We facilitate structured sessions with your operations, engineering, and maintenance teams. Aggie Safety leads the methodology while your team provides the facility-specific knowledge. Sessions are conducted on-site or remotely depending on scope and preference.
All scenarios, consequences, safeguards, and recommendations are documented in real time. You receive a draft report for review — including a recommendation register with suggested action owners and suggested target completion dates.
Final PHA report is issued following your review comments. Aggie Safety can support ongoing recommendation closure tracking and can assist with PSM documentation updates (P&ID markups, procedure revisions, MOC documentation) arising from the study.
Sumit Anand, PE, brings 20-plus years of direct oil and gas, petrochemical, and gas processing experience to every PHA facilitation. He holds a master's degree in chemical engineering with a research focus in process safety and spent his career at companies including CITGO, KBR, and BASF before founding Aggie Safety's process safety practice. PHA facilitation is only as good as the facilitator's ability to recognize credible scenarios. That comes from having designed, troubleshot, and operated the kinds of systems being analyzed not from running software or reading guideword lists.
PHA findings do not exist in isolation. They connect to PSM program elements: mechanical integrity, operating procedures, MOC, training, and emergency response. Aggie Safety's team holds the full PSM/RMP picture, so recommendations from a PHA are integrated into your compliance program rather than handed off as a disconnected list.
Many Houston PHA consultants can facilitate a HAZOP. Very few can also run PHAST consequence models and integrate those results into the hazard analysis. Aggie Safety does both, which means facility siting evaluations and RMP consequence analyses are conducted by the same team that understands your process, not outsourced to a separate modeling group.
A five-year HAZOP revalidation for a small specialty chemical facility looks very different from an initial PHA for a new gas processing unit. We scope every engagement to what your facility actually needs, not a standard package that may be more or less than what the project requires.
On-site PHA facilitation is available throughout Greater Houston, including Baytown, Pasadena, Deer Park, Texas City, Freeport, and the broader Gulf Coast industrial corridor. For full team credentials, visit our About Us page.
Engineering work we have done in last few years
