Filling of tanks-TB/ALL.

§ 38.15–1 Filling of tanks—TB/ALL. (a) Refrigerated and semirefrigerated tanks shall be filled so that there is an outage of at least 2 percent of the volume of the tank at the temperature corresponding to the vapor pressure of the cargo at the safety relief valve setting. A reduction in the required outage may be permitted by the Commandant when warranted by special design considerations. Normally then, the maximum volume to which a tank may be loaded is: V L = 0.98 d r V/d L where: V L = maximum volume to which tank may be loaded. V = volume of tank. d r = density of cargo at the temperature required for a cargo vapor pressure equal to the relief valve setting. d L = density of cargo at the loading temperature and pressure. (b) Nonrefrigerated tanks shall be filled so that their filling densities shall not exceed the ratios indicated in table 38.15–1(b). (c) The “filling density” is defined as the percent ratio of the weight of the gas in a tank to the weight of water the tank will hold at 60 °F. Table 38.15–1( b )—Maximum Permissible Filling Densities for Tanks Operating At or Near Ambient Temperature Specific gravity at 60 °F. Maximum permitted filling density Unlagged tanks—water capacity 1,200 gal. and under Over 1,200 gal. Lagged tanks—all capacities 0.473–0.480 38 41 42 0.481–0.488 39 42 43 0.489–0.495 40 43 44 0.496–0.503 41 44 45 0.504–0.510 42 45 46 0.511–0.519 43 46 47 0.520–0.527 44 47 48 0.528–0.536 45 48 49 0.537–0.544 46 49 50 0.545–0.552 47 50 51 0.553–0.560 48 51 52 0.561–0.568 49 52 53 0.569–0.576 50 53 54 0.577–0.584 51 54 55 0.585–0.592 52 55 56 0.593–0.600 53 56 57 0.601–0.608 54 57 58 0.609–0.617 55 58 59 0.618–0.626 56 59 60 0.627–0.634 57 60 61 Note: Increase in filling densities to provide for seasonal changes may be considered by the Commandant upon presentation of factual evidence that safe operation can be effected.