Lilac Street Repump Station - Executive Summary |
|
RISK MANAGEMENT PLAN (RMP) EXECUTIVE SUMMARY RELEASE PREVENTION POLICY There are five separate facilities at Seacoast Utility Authority (SUA) that store chlorine in amounts exceeding the threshold quantities listed in the Environmental Protection Agency's (EPA) Title 40 CFR Part 68.130. The management of SUA is committed to maintaining as well as improving the safety of each process that involves the use of chlorine. Evidence of this policy is clearly visible based on the history of improvements made to the chlorination processes at SUA. Examples of improvements are described later in this summary. EMERGENCY RESPONSE PROGRAM SUA maintains a written Emergency Response Program (ERP) in the SUA Emergency Operations Plan Manual. The ERP was developed to provide a prompt response to the release of chlorine gas while preserving the safety of the plant operators and the surrounding community. The intent of the plan is to provide treatment plant operators a concise procedure regarding re sponse to a release of chlorine gas regardless of the magnitude. The Plan is divided into two scenarios, which relate to the severity of the release: minor leaks and major leaks. Minor leaks are handled by the plant operators on duty while major leaks are handled by the local Hazardous Material Response Team. GENERAL ACCIDENTAL RELEASE PREVENTION The chlorine is used for disinfection of water and is contained in steel cylinders which hold one (1) ton of chlorine each. Each location has a RMP written specifically for it. The Programs Coordinator developed the RMP with assistance from the Chief Operator in charge of the subject facility, the facility's Department Manager, the Operations Director, and an Operator from another SUA facility that has a chlorination process in use. The five positions listed here made up the Process Hazard Analysis Team who used the EPA approved method titled "What If/Checklist" to analyze each process. Meetings were held at each facility to complete a Proc ess Hazard Analysis (PHA) using the combined knowledge of the PHA team, process safety information and site inspection. Follow-up correspondence between the PHA team members and review and input by process operators was also used to gain a complete understanding of areas that could be improved to make the process as fail-safe as possible. The five facilities at SUA that use chlorine have essentially the same type of equipment and arrangement to carry out the chlorination process. The chlorine is fed from the cylinder through a pressure-to-vacuum regulator then piped to a chlorinator followed by an injector which provides the vacuum to pull the chlorine from the cylinder into solution with potable water. This chlorine and water solution is then piped to one or more dosing points. Two of the five facilities are not manned 24 hours per day but are checked by the plant operators regularly throughout the day and night. All five facilities at SUA are equipped with a chlorine gas detector w hich constantly samples the air around the chlorine cylinder storage areas. If chlorine is present in the air an alarm sounds alerting the plant operators to begin the emergency response procedure. Every step in the chlorination process was analyzed to determine what could be done to make the process safer. The steps include: 7 delivery of the cylinders, 7 unloading the cylinders, 7 moving the cylinders into position for use, 7 connection of the pressure-to-vacuum regulator to the cylinder to dispense the chlorine, 7 inspection and maintenance of the pressure-to-vacuum regulator and 7 disconnecting the regulator from the cylinder. Also, inspection and maintenance schedules for the tubing, valves, piping, chlorinators, chlorine gas detectors, ventilation equipment and injectors were verified or established. RELEASE SCENARIOS A worst case release scenario at any of the facilities owned by SUA would be the total unmitigated release of the contents of a single one ton container of chlorine due to damage sustained (cracked, punctured, etc.) to the container. An alternative release scenario would be the failure of the chlorine cylinder valve or valve seal causing the chlorine to be released at 0.25 pounds per second for a one hour time period. Emergency response procedures would entail installation by the local hazardous materials response team of a valve repair kit which would stop the release. Chlorine is stored under pressure in the aforementioned steel cylinders. Chlorine gas is dispensed from a cylinder by opening a valve that will allow chlorine gas to be piped to a chlorinator which is used to control the amount of chlorine used per day. To eliminate the part of the system that operates under pressure a pressure-to-vacuum regulator is used. Since it is the pressure that would in most cases cause chlorine to be released SUA has obtained equipment that will allow the regulator to be attached directly to the valve on the cylinder thereby minimizing the amo unt of the system that operates under pressure. The pressure-to-vacuum regulator provides another safety feature in that it will not allow chlorine gas to flow unless a constant vacuum is applied to the outlet end of the regulator. The vacuum is applied to the regulator by an injector located just after the chlorinator. This means the pipe carrying the chlorine gas to the chlorinator is under constant vacuum which pulls the chlorine gas through the chlorinator. If the pipe or chlorinator is broken there will not be a release of chlorine gas, instead the vacuum to the regulator would be lost causing it to close thus stopping the flow of chlorine gas. Attaching a pressure-to-vacuum regulator directly to the cylinder valve is a great improvement over alternate methods, making the entire chlorination process safer. FIVE YEAR ACCIDENT HISTORY In the past five years there has not been a release of chlorine gas at any SUA facility that has caused injury to employees or resulted in conc entrations exceeding those listed in Appendix A to part 68 (0.0087 mg/l) to extend offsite. PLANNED CHANGES TO IMPROVE SAFETY The PHA revealed numerous areas and items where improvements will be made. Examples of the improvements include: 7 written cylinder receiving procedure - completed 8/14/98 7 improved access for emergency vehicles - completed 9/11/98 7 additional self contained air pack location - completed 3/16/99 7 use of wheel chocks for delivery truck - completed 11/17/98 7 new fire extinguisher location - completed 3/15/99 7 improve lighting - completed 7/1/98 7 revised hurricane plan - completed 10/20/98 7 written cylinder change procedure - completed 8/14/98 7 enlargement of cylinder storage area - completed 4/30/98 |