A. Site Assessment

The critical system site assessment is conducted to determine the risk associated with the operation of process units, and to evaluate the design, operation and maintenance of existing safety instrumented systems (SIS). The assessment involves the following:

on-site surveys of operating units,
reviews of available documentation (operating and maintenance procedures, P&IDs, process safety management documentation, etc.),
examination of process hazards analysis results, and
discussions with plant personnel concerning operating history.

Current national and international standards are utilized to benchmark the facility’s risk exposure. Conformance to IEC 61511 and/or ANSI/ISA S84.01-2003 is reviewed. For systems designed and constructed prior to the issuance of the new standards, an evaluation of the design, maintenance and testing records for safe operation provides a basis for decision-making regarding the adequacy of the existing SIS (i.e. Grandfather clause in the U.S).

Recognizing the importance of process uptime and the detrimental impact of spurious trips on operating costs as well as on safety, recommendations are made to improve reliability.

The PCS report lists site findings with recommendations for compliance with the company’s objectives concerning Safety and Reliability, including conformance to applicable national and international standards in the area of:

Design and architecture
Safety Availability issues
Reliability (spurious trip) issues
Support systems
Installation
Validation
Testing and Maintenance
Auditing
Hardware issues
Software issues
Security
Human-Machine-Interface
Management of Change issues
Competence requirements

The site assessment provides management with a basis for prioritized capital spending by providing specific recommendations for risk reduction and reliability improvement. It demonstrates to, insurers, regulatory agencies, company personnel and to the public that a serious plan has been established to address safety and reliability issues.

Site Assessment
Inputs:	Deliverables:
On-site survey of operating units Process design drawings P&ID / Electrical Drawings Process HAZOP/PHA Operating History Maintenance and test procedures Maintenance and test records	Standards compliance Safety availability issues Reliability issues Testing and maintenance issues Procedures issues Competence requirements Risk exposure Improvements recommendations