Nikkiso Cryo, Inc. - Executive Summary |
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EXECUTIVE SUMMARY THE ACCIDENTAL RELEASE PREVENTION AND EMERGENCY RESPONSE POLICIES AT THE FACILITY The facility complies with NFPA requirements for LNG and LPG storage. It also complies with State of Nevada's Chemical Accident Prevention Program (CAPP). It is the facility's policy to adhere to all applicable federal, state, and local laws and regulations. The facility's system is designed, installed, maintained, and operated to utilize current technology, safety, and control devices to ensure effective and safe operation, emergency shutdown, and fire prevention and fire fighting, etc. The facility has developed its own emergency response procedure/plan, and has trained the personnel. THE FACILITY AND THE REGULATED SUBSTANCES HANDLED The facility is owned and operated by Nikkiso Cryo, Inc. It is a pump testing facility, using refrigerated liquefied natural gas (LNG) OR refrigerated liquefied petroleum gas (LPG, i.e. refrigerated liquid propane OR refrigerated liquid butane) as pump t esting medium. The on-site liquid is stored in two horizontal cylindrical tanks. The system consists of two cryogenic storage tanks for refrigerated testing fluid, two storage tanks for liquid nitrogen (used for cooling and purging, a non-regulated substance), two (2) pump test vessels, a re-circulation vessel, two transfer pumps, associated piping, valves, heat exchangers, control system, etc. IT SHOULD BE NOTED that the facility could have ONLY ONE regulated substance on-site AT ANY GIVEN TIME, due to the fact that the facility has only one system set which can handle only one testing fluid at a time. The regulated substance handled is either methane which is the major component of LNG, OR propane, OR butane. After completion of each test the testing fluid is transported away from the facility, and the system is purged with nitrogen in preparation for the next test. Methane, propane, and butane are all non-toxic, flammable, and clean burning gases. The maximum allowed inventory at th e facility is: 78,486 lbs. of LNG, OR 108,104 lbs. of refrigerated liquid propane, OR 110,918 lbs. of refrigerated liquid butane. THE WORST-CASE RELEASE SCENARIO AND THE ALTERNATIVE RELEASE SCENARIO By using EPA's 40CFR68 and OCA Guidance, it is determined that the worst-case release scenario is failure of one of the two storage tanks (the largest vessels at the facility, each has gross capacity of 13,848 gallons) when it has the maximum allowed inventory by written operating procedure (80% of gross capacity, i.e. 11,078 gallons or 39,243 lbs of LNG), resulting in an assumed vapor cloud explosion involving the quantity of 926.7 lbs. which evaporates in 10 minutes from the liquid pool in the spill containment sump which limits the exposed surface area of the pool to 450 square feet and thus reduces the evaporate/release rate to 92.67 lbs./minute. The resulting distance to the endpoint of 1 psi overpressure (TNT equivalency method) is 0.081 miles and extends offsite. The facility is loc ated in an industrial park. Within the circle with a radius of 0.081 miles there are no residences, but other public receptors such as employees in the neighboring facilities. The maximum total number of the public population within the circle is 85. It should be noted that no explosion of unconfined methane vapor cloud has ever happened, nor is it considered a credible accident. Based on LNG industry experience and by using EPA's 40CFR68 and OCA Guidance, it is determined that the alternative release scenario is a leak in the system, resulting in a liquid pool in the spill containment sump as described in the worst-case release scenario above. The liquid evaporates to form a vapor cloud which ignites to form a vapor cloud fire burning back to the pool to a reduced size of pool fire. It is conservatively assumed that the liquid in the pool is enough to cover the containment surface and the depth of the pool is more than 1 cm. The liquid amount in a pool of 450 square feet by 1 cm deep is about 390 lbs. Manual emergency shutdown is expected to limit the quantity of leakage. A smaller leakage leads to a smaller vapor cloud which disperses faster to below Lower Flammable Limit (LFL). The evaporating/release rate is calculated by using the containment surface area of 450 square feet and wind speed of 3.0 meter/second. The result is 159.13 lbs./minute. Because the release duration does not need to be considered for estimating vapor cloud fire distances, the liquid amount in the pool does not make any difference in the result of such estimating. By using the tables in OCA Guidance the distance to the endpoint of LFL is estimated as 0.06 miles. The public population situation is essentially the same as that in the worst-case release scenario. THE GENERAL ACCIDENTAL RELEASE PREVENTION PROGRAM AND CHEMICAL-SPECIFIC PREVENTION The facility complies with the CAPP of State of Nevada. It also complies with all the applicable state and local codes and regulations. It is designe d, installed, and maintained in accordance with NFPA and state law. The facility has and adheres to its detailed operating procedures including safety checks during operation and other written procedures on safety, employee training, maintenance, etc. THE FIVE-YEAR ACCIDENT HISTORY The facility has never had an accident involving LNG or LPG or the vapors from either that caused deaths, injuries, property or environmental damage, evacuations, or sheltering in place. THE EMERGENCY RESPONSE PROGRAM The facility has emergency response procedures in its own "Emergency Response Plan", although it does not have an emergency response program as defined by EPA's Risk Management Program because employee responding action is not required. All the emergency response procedures were reviewed/updated in May 2000. The personnel have been trained to follow the procedures when an emergency situation occurs. The most recent emergency response training for the facility's employees was done in May 2000. It is the facility's policy to immediately call the Clark County Fire Department in case of flammable gas release or fire. The Fire Department is familiar with the process and experiences in fighting hydrocarbon-fuel fires. The local Fire Department and/or EMS will be contacted as needed. PLANNED CHANGES TO IMPROVE SAFETY None. |