Process Safety

Process safety focuses on preventing, mitigating, and learning from unplanned releases of hazardous energy or materials. In industrial facilities, Safety Instrumented Systems (SIS) are often a key layer of protection—designed to detect predefined unsafe conditions and automatically drive a process to a safe state when setpoints are exceeded.

PSM is a management framework used to control hazards associated with highly hazardous chemicals and complex industrial processes. In the U.S., many facilities follow OSHA’s Process Safety Management standard (29 CFR 1910.119) along with recognized and generally accepted good engineering practice (RAGAGEP). PSM is not a one-time effort—it requires ongoing implementation, verification, and continuous improvement throughout the life of a process.

An SIS is an independent protective layer that performs one or more Safety Instrumented Functions (SIFs) to reduce risk. A typical SIF includes sensors, logic solving, and final elements (such as shutdown valves) designed to take the process to a safe state. SIS design is intentionally independent of the Basic Process Control System (BPCS) so the protection remains effective even if the control layer is compromised.

In IEC 61511’s safety lifecycle, risk assessment is a foundational early step. A PHA, required by OSHA 1910.119, is part of the first stage of the safety lifecycle and is a structured method for identifying process hazards, understanding risk, and defining safeguards. HAZOP (Hazard and Operability Study) is one of the most common PHA techniques but other methods include Checklists, What-Ifs, HazIDs, and LOPAs. (Layers of Protection Analysis). PHAs are typically performed for new projects, major modifications (management of change), and legacy systems—then revalidated every five (5) years to confirm safeguards still match real plant conditions.

LOPA (Layers of Protection Analysis) is a semi-quantitative method used to evaluate whether existing safeguards reduce risk to a tolerable level. It helps teams validate the effectiveness and independence of protection layers and can be used to determine the risk reduction needed for a Safety Instrumented Function—informing SIF selection and Safety Integrity Level (SIL) targets and calculations.

A HAZOP is a qualitative method of defining what hazards are present in a process, the causes, how likely they are to occur, and how severe they could be (i.e. the overall risk). Protections against these scenarios are usually identified. LOPA is a semi-quantitative, closer look at those protections which will reveal shortcomings (see the section on “What is LOPA, and how does it relate to SIL?”). Normally both should be used for a complete evaluation of the process.

FSA’s are an independent back-check to be sure that all hazardous scenarios (especially the new recommendations identified in a LOPA) are being addressed adequately and properly. There are five stages which occur throughout the Safety Lifecycle, and address different required information.

Cyber assessments are required by the 61511 standard. A common phrase is “if it isn’t secure it isn’t safe” because cyber incidents can be another cause of a hazardous scenario.

Our Team designs and implements safety systems for a wide range of process and industrial environments, including refining, petrochemicals, chemicals, oil & gas, and manufacturing.

We typically start with a short scoping conversation to understand your process, constraints, and goals (risk reduction, compliance, modernization, training, etc.). From there, we can propose an assessment or workshop and provide a roadmap for improvement. Helpful starting information may include P&IDs, process safety information, prior PHA/LOPA documentation, SRS and cause-and-effect documentation, operating/proof test procedures, and SIS platform details.

Yes. We offer training such as Process Safety for the Non-Process Safety Engineer, which introduces core concepts like layers of protection (LOPA) and how changes or missed maintenance can increase risk. We also provide customized PSM training and can support TÜV Rheinland certification courses facilitated by authorized providers.

Our process safety work is led by specialists who are trained and qualified in functional safety, including TÜV Rheinland-certified Functional Safety Engineers. The Team includes process, electrical/instrumentation, and control system professionals, and members actively participate in industry standards committees, bringing practical experience and current best practices to each engagement.

Our Specialists have experience across a range of SIS technologies, including HIMA; Schneider Triconex; Emerson DeltaV SIS; Rockwell GuardLogix; Honeywell Safety Manager and FSC; Yokogawa ProSafe; and Siemens safety platforms (including legacy systems). We also support Burner Management Systems (BMS).

Yes. We can assess existing SIS implementations, identify risk and compliance gaps, and recommend practical improvements. This may include reviewing documentation (SRS and procedures), confirming field device suitability, validating proof test intervals and methods, supporting modernization or platform changes, and helping verify that safeguards perform as intended over the system’s operating life.

We support the full safety lifecycle—from early risk assessment through long-term sustainment. Typical services include PHA/HAZOP and LOPA facilitation; gap analysis and SIF conceptual design; SIL calculations and Safety Requirements Specifications (SRS); SIS logic solver programming and commissioning support; periodic proof-testing procedures; Functional Safety Assessments (FSA); alarm rationalization; and customized PSM/process safety training.

Our Team supports clients using commonly applied standards and requirements, including OSHA PSM (29 CFR 1910.119), IEC 61508, and IEC 61511 (ANSI/ISA 61511). Depending on the facility and scope, we also support related requirements and good practices such as applicable NFPA standards and EPA Risk Management Program (40 CFR Part 68).

Hargrove Teammates are voting members on the following committees: NFPA 85, ISO 5133 for Fired Equipment, American Technical Committee TC-56 for the IEC 61882 HAZOP Application Guide, ISA Alarm Management committee ISA 18.2, and the ISA Non-SIS IPL committee 84.91.03.