(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: VL = 0.98dr V/dL where: VL = maximum volume to which tank may be loaded.V = volume of tank.dr = density of cargo at the temperature required for a cargo
vapor pressure equal to the relief valve setting.dL = 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------------------------------------------------------------------------
Maximum permitted filling density
-------------------------------------------
Unlagged tanks--water capacity
Specific gravity at 60 F. -------------------------------- Lagged
1,200 gal. and Over 1,200 tanks--all
under gal. capacities------------------------------------------------------------------------0.473-0.480................. 38 41 420.481-0.488................. 39 42 430.489-0.495................. 40 43 440.496-0.503................. 41 44 450.504-0.510................. 42 45 460.511-0.519................. 43 46 470.520-0.527................. 44 47 480.528-0.536................. 45 48 490.537-0.544................. 46 49 500.545-0.552................. 47 50 510.553-0.560................. 48 51 520.561-0.568................. 49 52 530.569-0.576................. 50 53 540.577-0.584................. 51 54 550.585-0.592................. 52 55 560.593-0.600................. 53 56 570.601-0.608................. 54 57 580.609-0.617................. 55 58 590.618-0.626................. 56 59 600.627-0.634................. 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.