46 CFR 38.15-1 - Filling of tanks

View all text of Subpart 38.15 [§ 38.15-1 - § 38.15-20]

§ 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:

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

Specific gravity at 60 °F.	Maximum permitted filling density			Unlagged tanks—water capacity		Lagged tanks—all capacities	1,200 gal. and under	Over 1,200 gal.	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.