Section 112.46 - Sumps and Grading(1) Grading, drainage, impounding systems, and separation distances shall be provided to the extent determined practicable by the operator, consistent with good engineering practice, at plants existing as of September 14, 1990, and at all plants constructed after September 14, 1990, to ensure that accidental hazardous liquid spills from the following areas do not endanger other areas, adjacent property, or enter navigable waterways:(a) liquefaction and other process areas;(c) cargo transfer system areas;(d) tank truck or tank car parking areas; and(e) areas for handling or storing portable containers.(2) Each LNG cargo transfer station shall have an associated sump to contain spilled liquid. A system of trenches shall be used to conduct spilled liquid from the transfer station. (a) The sump volume shall be at least 10,000 gallons for transfer stations designed to handle one or two trucks. The sump volume shall be at least 15,000 gallons for transfer stations handling three or more trucks.(b) The sump shall be located so as to minimize the vapor concentration and thermal radiation at the transfer station and plant boundaries. A truck station sump shall be so located that the thermal radiation from a fire may not exceed 3,700 Btu/sq. ft./hour at an LNG storage tank.(3) When determined by the operator to be practicable, each diked storage tank area shall have a sump and trenches to reduce the vaporization and thermal radiation from a ten-minute spill. The spill rate shall be determined according to the following formula: Click to view image
where:
q = Liquid flow rate, cubic feet per minute
d =Diameter of largest tank penetration below LNG liquid level (expressed in inches); and
h = Maximum liquid height above the penetration (expressed in feet).
Amended by Mass Register Issue 1432, eff. 12/11/2020.