Dove Creek Gas Plant - Executive Summary |
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Questar Gas Management Company Risk Management Plan Executive Summary Dove Creek Gas Plant Accidental Release Prevention and Response Policies Questar Gas Management Company has a long standing commitment to worker and public safety. This commitment is demonstrated by the resources invested in accident prevention, such as training personnel and considering safety in the design, installation, operation, and maintenance of our processing plants. Our policy is to implement reasonable controls to prevent foreseeable releases of regulated substances. However, if a release does occur, plant personnel will respond to contain and control the release. Description of the Stationary Source and Regulated Substances The Dove Creek Gas Plant is located approximately 1.75 miles east of the town of Dove Creek, Colorado. The plant operates a low temperature, liquid separation process for the production of "Y-grade" natural gas liquids (NGLs). These liquids are made-up of propanes, butanes , and heavier hydrocarbons. Additionally, dehydrated natural gas (methane, ethane) is produced at the facility. All of these substances are regulated substances for purposes of risk management planning. Offsite Consequence Analysis Results The worst-case scenario (WCS) associated with regulated substances in Program Level 1 processes at the plant is a catastrophic failure of a 30,000 gallon NGL storage tank. This results in a release of the entire contents of the largest tank (134,730 pounds of Y-grade NGLs) over a 10-minute period. The resulting vapor-cloud explosion generates a 1 psig over-pressure endpoint approximately 0.4 miles from the center of the plant. Although QGMC has numerous controls in place to prevent such a release and to manage their consequences, no credit for administrative controls or passive mitigation measures were taken into account in evaluating this scenario. The Alternative Release Scenario (ARS) for this facility is also a vapor cloud explosion resulting from the release of Y-grade NGLs from ..................... The release is expected to be isolated by the safety controls and/or operators within xx minutes (active mitigation). The maximum distance to the 1 psig over-pressure endpoint for this event is 0.xx miles. This event was selected as being a practical scenario for use in emergency planning and response. General Accidental Release Prevention Program The following is a summary of the accident prevention program in place at the plant. Although the plant is not subject to the Occupational Safety and Health Administration's (OSHA's) Process Safety Management (PSM), the plant follows a program similar to PSM in order to comply with the requirements of the Risk Management Plan regulations. Employee Participation The Dove Creek Gas Plant encourages employees to participate in all facets of process safety management and accident prevention. Examples of employee participation range from updating and compiling technica l documents and chemical information to participating as members of a process hazard assessment (PHA) team. Process Safety Information The Dove Creek Plant keeps a variety of technical documents that are used to help maintain safe operation of the process. These documents address chemical properties and associated hazards, limits for key process parameters and specific chemical inventories, and equipment design basis/configuration information. The documents are available to plant employees. Chemical-specific information, including exposure hazards and emergency response considerations, is provided in the material safety data sheets (MSDSs). For specific process areas, the plant has documented safety related limits for specific process parameters (e.g., temperature, level, pressure). The plant ensures that the process is maintained within these limits using process controls and monitoring instruments, highly trained personnel, and protective instrument systems (e.g., automated shutdown systems). The plant also maintains numerous technical documents that provide information about the design and construction of the process equipment. The information includes materials of construction, design pressure and temperature ratings, and electrical rating of equipment. This information in combination with procedures and trained personnel provides a basis for inspection and maintenance activities as well as for evaluating proposed process and facility changes. Process Hazard Assessment (PHA) The Dove Creek Plant has a comprehensive program to help ensure that hazards associated with the various processes are identified and controlled. Within this program, each process is systematically examined to identify hazards and ensure that adequate controls are in place to manage these hazards. The ABC gas plant primarily uses the hazard and operability (HAZOP) analysis technique to perform these evaluations. HAZOP analysis is recognized as one of the most systematic and thorough hazard evaluation techniques. The analyses are conducted using a team of people who have operating and maintenance experience as well as engineering expertise. This team identifies and evaluates hazards of the process as well as accident prevention and mitigation measures, and the team makes suggestions for additional prevention and/or mitigation measures when the team believes such measures are necessary. The PHA team findings are forwarded to local and corporate management for resolution. Implementation of mitigation options in response to PHA findings is based on a relative risk ranking assigned by the PHA team. This ranking helps ensure that potential accident scenarios assigned the highest risk receive immediate attention. All approved mitigation options in response to PHA team findings are tracked until they are completed. The final resolution of each finding is documented and retained. To help ensure that the process controls and/or process hazards do not event ually deviate significantly from the original design safety features, the plant periodically updates and revalidates the hazard analysis results. These periodic reviews are conducted at least every five years and will be conducted at this frequency until the process is no longer operating. The results and findings from these updates are documented and retained. Once again, the team findings are forwarded to management for consideration, and the final resolution of the findings is documented and retained. Operating Procedures The ABC gas plant maintains written procedures that address various modes of process operations, such as (1) unit startup, (2) normal operations, (3) temporary operations, (4) emergency shutdown, (5) normal shutdown, and (6) initial startup of a new process. These procedures can be used as a reference by experienced operators and provide a basis for consistent training of new operators. These procedures are periodically reviewed and annually certified as cu rrent and accurate. The procedures are kept current and accurate by revising them as necessary to reflect changes made through the management of change process. In addition, the ABC gas plant maintains a Key Process Parameter Document that provides guidance on how to respond to upper or lower limit exceedances for specific process or equipment parameters. This information, along with written operating procedures, is readily available to operators in the process unit and for other personnel to use as necessary to safely perform their job tasks. Training To complement the written procedures for process operations, the ABC gas plant has implemented a comprehensive training program for all employees involved in operating a process. New employees receive basic training in gas plant operations if they are not already familiar with such operations. After successfully completing this training, a new operator is paired with a senior operator to learn process-specific duties and tasks. After operators demonstrate (e.g., through tests, skills demonstration) having adequate knowledge to perform the duties and tasks in a safe manner on their own, they can work independently. In addition, all operators periodically receive refresher training on the operating procedures to ensure that their skills and knowledge are maintained at an acceptable level. This refresher training is conducted at least every three years. All of this training is documented for each operator, including the means used to verify that the operator understood the training. Contractors The ABC gas plant uses contractors to supplement its work force during periods of increased maintenance or construction activities. Because some contractors work on or near process equipment, the gas plant has procedures in place to ensure that contractors (1) perform their work in a safe manner, (2) have the appropriate knowledge and skills, (3) are aware of the hazards in their workplace, (4) understand what they should do in the event of an emergency, (5) understand and follow site safety rules, and (6) inform gas plant personnel of any hazards that they find during their work. This is accomplished by providing contractors with (1) a process overview, (2) information about safety and health hazards, (3) emergency response plan requirements, and (4) safe work practices prior to their beginning work. In addition, the ABC gas plant evaluates contractor safety programs and performance during the selection of a contractor. Gas plant personnel periodically monitor contractor performance to ensure that contractors are fulfilling their safety obligations. Pre-startup Safety Reviews (PSSRs) The ABC gas plant conducts a PSSR for any new facility or facility modification that requires a change in the process safety information. The purpose of the PSSR is to ensure that safety features, procedures, personnel, and equipment are appropriately prepared for startup prior to placing the equipment into s ervice. This review provides one additional check to make sure construction is in accordance with the design specifications and that all supporting systems are operationally ready. The PSSR review team uses checklists to verify all aspects of readiness. A PSSR involves field verification of the construction and serves a quality assurance function by requiring verification that accident prevention program requirements are properly implemented. Mechanical Integrity The ABC gas plant has well-established practices and procedures to maintain pressure vessels, piping systems, relief and vent systems, controls, pumps and compressors, and emergency shutdown systems in a safe operating condition. The basic aspects of this program include: (1) conducting training, (2) developing written procedures, (3) performing inspections and tests, (4) correcting identified deficiencies, and (5) applying quality assurance measures. In combination, these activities form a system that maintains the me chanical integrity of the process. Maintenance personnel receive training on (1) an overview of the process, (2) safety and health hazards, (3) applicable maintenance procedures, (4) emergency response plans, and (5) applicable safe work practices to help ensure that they can perform their jobs in a safe manner. Written procedures help ensure that work is performed in a consistent manner and provide a basis for training. Inspections and tests are performed in a consistent manner and provide a basis for training. Inspections and tests are performed to help ensure that equipment functions as intended and to verify that equipment is within acceptable limits (e.g., adequate wall thickness for pressure vessels). If a deficiency is identified, employees will correct the deficiency before placing the equipment back into service (if possible), or a management of change team will review the use of the equipment and determine what actions are necessary to ensure the safe operation of the eq uipment. Another integral part of the mechanical integrity program is quality assurance. The ABC gas plant incorporates quality assurance measures into equipment purchases and repairs. This helps ensure that new equipment is suitable for its intended use and that proper materials and spare parts are used when repairs are made. Safe Work Practices The ABC gas plant has long-standing safe work practices in place to help ensure worker and process safety. Examples of these include (1) control of the entry/presence/exit of support personnel, (2) a lockout/tagout procedure to ensure isolation of energy sources for equipment undergoing maintenance, (3) a procedure for safe removal of hazardous substances before process piping or equipment is opened, (4) a permit and procedure to control spark-producing activities (i.e., hot work), and (5) a permit and procedure to ensure that adequate precautions are in place before entry into a confined space. These procedures (and others), along with training of affected personnel, form a system to help ensure that operations and maintenance activities are performed safely. Management of Change The ABC gas plant has a comprehensive system to manage changes to all covered processes. This system requires that changes to items such as process equipment, chemicals, technology (including process operating conditions), procedures, and other facility changes be properly reviewed and authorized before being implemented. Changes are reviewed to (1) ensure that adequate controls are in place to manage any new hazards and (2) verify that existing controls have not been compromised by the change. Affected chemical hazards information, process operating limits, and equipment information, as well as procedures, are updated to incorporate these changes. In addition, operating and maintenance personnel are provided any necessary training on the change. Incident Investigation The ABC gas plant promptly investigates all incidents that resul ted in, or reasonably could have resulted in, a fire/explosion, toxic gas release, major property damage, environmental loss, or personal injury. The goal of each investigation is to determine the facts and develop corrective actions to prevent a recurrence of the incident or a similar incident. The investigation team documents its findings, develops recommendations to prevent a recurrence, and forwards these results to gas plant management for resolution. Corrective actions taken in response to the investigation team's findings and recommendations are tracked until they are complete. The final resolution of each finding or recommendation is documented, and the investigation results are reviewed with all employees (including contractors) who could be affected by the findings. Incident investigation reports are retained for at least five years so that the reports can be reviewed during future PHAs and PHA revalidations. Compliance Audits To help ensure that the accident preventio n program is functioning properly, the ABC gas plant periodically conducts an audit to determine whether the procedures and practices required by the accident prevention program are being implemented. Compliance audits are conducted at least every three years. Both hourly and staff personnel participate as audit team members. The audit team develops findings that are forwarded to gas plant management for resolution. Corrective actions taken in response to the audit team's finding are tracked until they are complete. The final resolution of each finding is documented, and the two most recent audit reports are retained. CHEMICAL-SPECIFIC PREVENTION STEPS The processes at the ABC gas plant have hazards that must be managed to ensure continued safe operations. The following is a description of existing safety features applicable to prevention of accidental releases of regulated substances in the facility. Universal Prevention Activities The accident prevention program summarized previously is applied to all RMP-covered processes at the ABC gas plant. Collectively, these prevention program activities help prevent potential accident scenarios that could be caused by equipment failures and human errors. Specialized Safety Features The ABC gas plant has safety features on many units to help (1) contain/control a release, (2) quickly detect a release, and (3) reduce the consequences of (mitigate) a release. The following types of safety features are used in the covered processes: Release Detection Hydrocarbon detectors with alarms Release Containment/Control Process relief valves that discharge to a flare to capture and incinerate episodic releases. Valves to permit isolation of the process (manual or automated) Automated shutdown systems for specific process parameters (e.g., high temperature) Curbing or diking to contain liquid releases Redundant equipment and instrumentation (e.g.,uninterruptible power supply for process control system, backup firewater pump) Atmospheric relief devices Release Mitigation Fire suppression and extinguishing systems Deluge system for specific equipment Trained emergency response personnel Personal protective equipment (e.g., chemical protective clothing, self-contained breathing apparatus) Blast-resistant buildings to help protect control systems and personnel FIVE-YEAR ACCIDENT HISTORY The ABC gas plant has an excellent record of accident prevention over the past five years. There has been a decreasing trend in the frequency of accidental releases. Except for an incident involving a release of H2S in 1995 (resulting in evacuation of several homes), none of the incidents that have occurred in the past five years resulted in offsite effects. We investigate every incident very carefully to determine ways to prevent similar incidents from recurring. The following table is a summary of the number of incidents that have occurred during the past five yea rs. 1995 1996 1997 1998 1999 Number of RMP Events with Onsite Effects 5 3 4 2 0 Number of RMP Events with Offsite Effects 1 0 0 0 0 EMERGENCY RESPONSE PROGRAM INFORMATION The ABC gas plant maintains a written emergency response program, which is in place to protect worker and public safety as well as the environment. The program consists of procedures for responding to a release of a regulated substance, including the possibility of a fire or explosion if a flammable substance is accidentally released. The procedures address all aspects of emergency response including proper first aid and medical treatment for exposures, evacuation plans and accounting for personnel after an evacuation, notification of local emergency response agencies and the public if a release occurs, and postincident cleanup and decontamination requirements. In addition, the plant has procedures that address maintenance, inspection, and testing of emergency response equipment, as well as instructions that a ddress the use of emergency response equipment. Employees receive training in these procedures as necessary to perform their specific emergency response duties. The emergency response program is updated when necessary based on modifications made to gas plant processes or other ABC gas plant facilities. The emergency response program changes are administered through the MOC process, which includes informing and/or training affected personnel in the changes. The overall emergency response program for the ABC gas plant is coordinated with the Anywhere, U.S.A., local emergency planning committee (LEPC). This coordination includes periodic meetings of the committee, which includes local emergency response officials, local government officials, and industry representatives. The ABC gas plant has around-the-clock communications capability with appropriate LEPC officials and emergency response organizations (e.g., fire department). This provides a means of notifying the public of an inc ident, if necessary, as well as facilitating quick response to an incident. In addition to periodic LEPC meetings, the ABC gas plant conducts periodic emergency drills that involve the LEPC and emergency response organizations, and the gas plant provides annual refresher training to local emergency responders regarding the hazards of regulated substances in the gas plant. PLANNED CHANGES TO IMPROVE SAFETY The ABC gas plant resolves all findings from PHA's, some of which result in modifications to the process. The following types of changes are planned over the next few years in response to PHA, safety audit, and incident investigation findings: Decrease in the amount of chlorine stored on site for cooling water chemical treatment Upgraded process control system to use distributed computerized control system Hydrocarbon release detection system in the liquefied petroleum gas (LPG) loading rack area Revisions to personnel training programs Revised written opera ting procedures in the amine treatment area Upgraded fire protection system in the separation/dehydration area New vibration monitoring program for gas compressors |