P&ID Hazard Assessment

When used in the early design phase, hazard assessment review techniques uncover necessary changes that can be made at minimum cost. Later, errors may be extremely costly to correct.

Almost without exception a representative of the owner/operator/client must be present at every review meeting. Other interested organizations include process, designs, maintenance, operations, safety, reservoir engineering, plant or drilling foremen, area superintendent, other management, etc.

Hazard assessment may also include mitigation and abatement techniques such as the Hazard and Operability Study, Failure Mode and Effects Study, Fault Tree Analysis, SAFE charts, Blast Effect Analysis, Atmospheric Dispersion Study, Radiant Heat Study, etc. These can be quite costly, particularly when full documentation is required. They are used when mandated by federal, state or local laws and regulations or as judged appropriate by the responsible manager.

California and New Jersey have passed legislation requiring the application of these techniques to plant processes and equipment for stipulated toxic or flammable materials whose catastrophic release could impact the general population (see API RP 14C, Analysis, Design, Installation, and Testing of Basic Surface Safety Systems for Offshore Production Platforms). AIChE has published “Vapor Cloud Dispersion,”

“Vapor Release Mitigation,” “Guideline for Safe Storage and Handling of High Toxic Hazard Materials,” and “Hazard Evaluation Procedures.” The Hazard and Operability Study covered in “Hazard Evaluation Procedures” has been accepted by the EPA as definitive. Future publications planned are: “Quantitative Risk Assessment” and “Guidelines for Process Control.”

Because of the many safe design practices built into Company standards and procedures, these AIChE Procedures—and their reporting requirements—may be found to be unnecessarily formal and lengthy. Modification and shortening should be considered if the full procedure is not legally mandated.

The AIChE guidelines do not define what level of risk is acceptable, and this is a complex subject affected by conditions peculiar to a facility such as closeness to a population, amounts and types of materials involved, and regulatory emission limits. A guideline recommending “applicable projects, techniques, sources of help, references,
suitable consultants, waiver procedures, and other appropriate guidance to operating company personnel” is under consideration by the Hazard Assessment Steering Committee. Contact HE&LP for an update.