For refrigeration systems containing or capable of containing more than 10,000 pounds of ammonia, the following items are required for OSHA’s Process Safety Management standards and for EPA’s Risk Management Plan regulations. Rigid interpretation is applied by both governing agencies.
For refrigeration systems containing less than 10,000 pounds of ammonia, the following items are required for OSHA’s and EPA’s interpretation of the General Duty Clause of the 1991 Clean Air Act. This Clause requires all facility operators using or storing extremely hazardous substances (the list includes anhydrous ammonia) to take all necessary and appropriate actions to protect employees from and to prevent off site releases of anhydrous ammonia. Following an ammonia accident resulting in an ammonia release, the investigating state and federal agencies may determine that without the following, the operator did not perform their General Duties to prevent accidental release of ammonia. A less rigid interpretation may be applied by both governing agencies.
Employee Participation includes employee awareness for employees not directly involved with the process. Participation includes knowing the hazards, the safety rules, warning signs, and evacuation procedures. All employees have rights to access the PSM Program. Involved employees participate directly in every phrase of the PSM program, including conducting the PHA, developing or reviewing operating procedures, reviewing incident investigations, and conducting mechanical integrity and compliance audits. Process Safety Information includes a wide variety of books, manuals, and process information. These must be available to employees that operate, maintain, or repair the ammonia equipment and piping. There are three major categories of required information: ammonia data such as MSDS, safety information, first aid, chemical properties, IIAR safety bulletins, etc.; process information such as piping & instrumentation diagrams, block flow diagram, mass flow balance, design codes and standards, pressure safety relief settings, safety system/devices, ventilation system design, operating procedures, safe operating limits, and ramification of process deviation; and process equipment information such as equipment specifications, electrical classifications, materials of construction, installation manuals, and the manufacturer's operating and maintenance manuals.
Process Hazard Analyses are performed using the "What-if" technique. Hazard analyses address the ammonia hazards, system engineering and administrative controls, consequences of failure of engineering and administrative controls, safety reviews of ammonia equipment and facility locations, human factors, and a qualitative evaluation of the possible safety and health impact. The results of the PHA were prioritized and incorporated into a PHA Findings Report for follow-up as a corrective action log. This is required every five years and following major changes.
Standard Operating Procedures are provided for each compressor, condenser, ammonia vessel and oil pot, and evaporator. Program includes general information such as objectives, hazards, location, safety equipment needed, Piping & Instrumentation Diagrams, task flow diagrams, and step-by-step procedures with specific warnings and comments. The SOPs cover different phases of operations such as: initial startup; normal, temporary and emergency operations; emergency shutdowns; and startup following a shutdown. Procedures are also required for ammonia-area access, opening ammonia equipment, confined spaces, and lockout/tag-out.
Training is for all employees to be aware of program and emergency procedures and for employees who are involved with anhydrous-ammonia system. Employees involved in operating and maintaining the ammonia systems must be properly trained, at a minimum, in understanding the MSDS, routine refrigeration system operations, emergency refrigeration system operations, emergency and normal refrigeration safety practices, and, if appropriate, the individual's role in the emergency response plan. Involved employees must also participate in selecting training programs.
Contractors Qualifications ensures that contractors and their employees are fully aware of the potential dangers involved with the ammonia system. Contractors must understand their responsibility and train their people. The facility owner or operator shall consider the contractor’s safety record and records in considering the acceptability of the contractors.
Pre-Startup Reviews are required on all new or modified equipment/systems. This safety checklist involves process safety information, process hazard analysis, training, safety procedures, operating procedures, and verification that construction and equipment are in accord with the design specifications prior to the installation or prior to introducing ammonia into the new equipment. Mechanical Integrity program is to ensure that the equipment is maintained in good working condition. Records are required for routine checks, preventive maintenance, and for repairs. Mechanical integrity audits and periodic testing shall be performed on all compressors, condensers, evaporators, pressure vessels, piping system, relief and vent systems and devices, emergency shutdown systems, controls, and pumps.
Hot Work Permits protect against fire, explosion and other dangers resulting from hot work. Permits must be obtained before any work is done on or around the ammonia system and in any area that might adversely affect the any area containing ammonia equipment or piping. The Maintenance Supervisor reviews and issues the permits to insure all fire prevention and protection rules are met.
Management of Change procedures require all changes (even "replacement in kind") be reviewed to see if there is a possible negative effect on the safety of the ammonia system. This review addresses the technical basis for the change, the impact on safety and health, modifications to operating procedures, changes required for documenting process safety information, and authorization requirements for the proposed change. Employees affected by the change are informed of the change and trained in the proper procedures before startup.
Incident Investigations shall be performed any time there is an incident which resulted in, or which could reasonably have resulted in, a catastrophic release of ammonia. The purpose is to gain information that could prevent further accidents and to identify weaknesses in the emergency response plan that need to be addressed. Investigations are initiated promptly using a trained team. The findings and recommendations will be studied, appropriate corrective action taken, and documentation maintained.
Emergency Response Plan identifies emergency situations, facility evacuation routes and procedures, emergency equipment, alarm procedures, and duties of emergency personnel. This facility has a comprehensive emergency response plan that is provided to the local fire department and the Local Emergency Planning Committee.
Compliance Audits insure that all other PSM program elements are followed. It is an independent audit performed at least every three years. The results of the audit are prioritized, incorporated into a report, and a corrective action log is required for follow-up.
Risk Management Plan identifies various ammonia release scenarios and their potential affect on the environment, neighboring populations, and public gathering places. It communicates this information to the local, state, and federal emergency response authorities.