Hazard studies

TÜV Rheinland provides a range of hazard studies or PHA studies during projects, from the early R&D phase through to early stages of operation, and can assist clients to identify the appropriate approach for a specific project.

The studies include:

Inherent safety

Development chemists and engineers work to eliminate or minimise the effects from hazards to reduce the reliance on ‘add-on’ safety measures. The methodology provides a demonstration of a structured hierarchical approach, as required by some regulators and gives maximum benefit at the pre-FEED stage.

Hazard study 1

Checklist-based study at start of process development to ensure an adequate understanding of project, processes and materials to address SHE issues effectively, define what other PHA studies are needed, prompt contact with the regulatory bodies who may place restrictions on project, and so avoid any expensive delays at a later date.

Hazard Identification (HAZID) / hazard study 2

Guideword-based and consequence led study of the preliminary PFD’s, on a system by system basis to identify significant hazards. If hazards cannot be eliminated, specify safety measures are needed and carry out risk assessments to ensure risk is reduced to an acceptable level.

Hazard and Operability Analysis (HAZOP) / hazard study 3

Detailed and systematic study of process design and outline operating procedures, using guideword based deviation analysis and based on P&IDs and procedures. The study will identify hazards or operability problems and make recommendations to allow the design to be finalised.

Hazard studies 4 / 5 (PSSR)

Checklist-based studies prior to construction handover, designed to ensure plant has been installed as designed and has incorporated any features from earlier studies. Provides an opportunity to review the facilities for workplace aspects of SHE protection.#

Hazard study 6

Checklist-based study to review early operation and ensure the level of safety developed during the plant design is still appropriate.

Retrospective hazard review

Retrospective hazard review is a team based hazard identification and risk assessment technique that enables continuous improvement in process safety for existing major hazard facilities.

The review has a structured system-by-system (PHR) or line-by-line (HAZOP) approach focusing on hazardous events with the potential to cause significant harm to people, the environment or the business / reputation.

Retrospective Hazard Reviews have been used to meet regulatory or company requirements for the periodic revalidation of Process Hazard Analysis (PHA). PHR takes a higher level and more time efficient approach focussing on loss of containment and release of energy events. HAZOP studies may be required in order to revalidate the process design and operation if required by companies wanting re-assurance that all aspects have been considered.

Reviews produce risk based recommendations building on the operational experience of the team and targeted towards areas of real concern. These include verification of critical safeguards such as pressure relief and safety instrumented systems, plus design checks or essential improvements to hardware or operating / maintenance / inspection procedures.

To assist with effective follow-up to these reviews, TÜV Rheinland provides an action close-out service. This includes any further assessment needed to convert recommendations into specific actions, plus an option for full management of the action plan through to effective close-out and realisation of the benefits.

LOPA / SIL

TÜV Rheinland has a team of professional consultants who have proven engineering skills in all matters relating to the approach and determination of appropriate target Safety Integrity Levels (SIL) for Safety Instrumented Functions (SIFs).

Within the IEC 61508 / 61511 standards, the SIL is a fundamental means of specifying the safety integrity requirements of a SIF.

SIL Determination is an assessment of the risk reduction required from SIFs to give a sufficiently low level of risk in relation to a specific hazardous event. TÜV Rheinland has a highly structured approach to SIL determination that is recorded on TÜV Rheinland’s TRAC software tool.

TÜV Rheinland recommends the use of Layer of Protection Analysis (LOPA) for SIL Determination. A calibrated risk graph can also be used for initial screening of simple low consequence scenarios where the required risk reduction is likely to be in the ‘unclassified’ range or even not required at all.

For complex scenarios or those potentially involving high levels of instrumented risk reduction, a quantified hazard analysis would be the approach of choice, and TÜV Rheinland can provide this support when required.

Quantitative Risk Assessment (QRA)

TÜV Rheinland can carry out a numerical analysis of the impact of plant hazards on site personnel and local public.

The data generated enables risks to be benchmarked against internationally recognized guidance on tolerable risk levels for employees and public. The assessment also provides a basis for the appropriate level of control to be implemented in the most cost effective way.

Major plant hazards come from toxic gas release, fire and explosions. Detailed consequence analysis of each source, including blast modelling, thermal radiation profiles for fires and gas dispersion modelling that applies data relating to the impact of concentrations of toxic gas (see gas dispersion modelling and gas & vapour explosions below) enables calculation of risk levels around the plant and individual items of equipment.

Individual risk contours can be generated that show the risk to individuals working on the plant and also to people living in the local area.

Electrostatic

Current legislation changes, major insurers and major operators require formal fire risk assessments.

We offer management systems which not only comply with these needs, but are also cost effective in the long term.

We offer comprehensive fire safety management support - starting either at the design stage or by reviewing existing systems. This service is underlined by an approach that first identifies the main process fire hazards associated with particular operations and then determines that most appropriate means for control of the associated fire risks.

TÜV Rheinland technical engineering consultancy has knowledge of the different types of process fire hazards and escalation potentials including consequence modeling. TÜV Rheinland technical engineering consultancy using its Process Hazard Assessment skills and expertise has also developed a semi quantified process fire risk assessment methodology and can advise on the most appropriate fire protection measures, ranging from area classification and ignition control, including DSEAR / ATEX compliance, through detection, control, mitigation and emergency response.

TÜV Rheinland technical engineering consultancy also realize that some unique process fire hazards require unique fire measures.

Consequence modelling

Companies carrying out risk assessments relating to major accident hazards in the process industries have a requirement to estimate the extent and severity of hazardous events.

These cover releases of flammable or toxic materials with the potential to cause harm to people or the environment. The mechanisms of release may include vessel explosions, leaks and major fractures, vapour cloud explosions or process upsets such as flaring resulting in thermal radiation hazards or blast overpressure hazards.

TÜV Rheinland has expertise in assisting clients in identifying credible hazardous events, establishing the consequences of the releases using appropriate software tools including DNV’s PHAST and TNO GAMES, thereby determining the hazard ranges, be it thermal radiation, blast overpressure or toxic effects.

Potential on-site and off-site impact of the releases are analysed against the location of the hazard. Consequence assessment is used for various types of study, typically regulatory driven such as COMAH safety reports or Occupied Building Risk Assessments (OBRA), in addition to other forms of risk assessments such as Quantitative Risk Assessment (QRA), incident investigation, proposed plant modifications and as part of hazard study action close out.

Environmental risk

TÜV Rheinland offers a complete range of services to carry out occupied building (facility siting) risk assessment.

This will identify what, if any, improvements to buildings are required, and demonstrate the basis of safety for the occupied building in accordance with CIA (UK) and API (US) guidelines.

The services include; modelling the hazardous effects of fire, explosion and toxic gas releases, assessment of the hazardous effects on buildings of different construction types, quantification of the risks to building occupants and developing improvements to eliminate or mitigate risks to an acceptable level.

TÜV Rheinland has a range of services that can help you understand, and then improve, the human factors that impact the way your business operates.

We are able to assess the interactions between the individual, the organization and the job, through one or more of the following areas:

• Alarm handling
• Competence assurance
• Control room design
• Emergency response
• Human factors in accident investigation
• Identifying human failures
• Maintenance error
• Managing fatigue risks
• Organisational change and transition management
• Reliability and usability of procedures
• Safety critical communications
• Safety culture and improving behaviours

TÜV Rheinland has a background of human-centered engineering and its dedicated human factors team brings together expertise in operational organisation and culture, competency assessment, HMI design, alarm management, ergonomics, and control room architectural consultancy.

Our human factors consultants bring a practical approach, operational experience, technical ability and proven techniques to solve your human factors problems.