SECTION
12 Liquid Volume Tables and Temperature Correction Factors
Appendix F Liquid Volume Tables, Computations and Graphs This appendix is not a part of the requirements of this NFPA document but is included for informational purposes only.
F.1 Scope.
F.1.1 Application. This appendix explains the basis
for Table 4.4.2.1, includes the LP-Gas liquid volume temperature correction table, Table F.3.3, and describes its use. It also explains the methods of making liquid volume computations to determine the maximum permissible LP-Gas content of containers in accordance with Tables 4.4.2.2(a), (b), and (c).
F.2 Basis for Determination of LP-Gas Container Capacity. The basis for determination of the maximum permitted filling limits shown in Table 4.4.2.1 is the maximum safe quantity that will assure that the container will not become liquid full when the liquid is at the highest anticipated temperature. F.2.1 For portable containers built to DOT specifications and other aboveground containers with water capacities of 1200 gal (4.5 m3) or less, this temperature is assumed to be 130°F (54°C). F.2.2 For other aboveground uninsulated containers with water capacities in excess of 1200 gal (4.5 m3), including those built to DOT portable or cargo tank specifications, this temperature is assumed to be 115°F (46°C). F.2.3 For all containers installed under ground, this temperature is assumed to be 105°F (41°C).
(2) If the container is not equipped with a well, but is essentially empty of liquid prior to loading, the temperature of the liquid in the container from which liquid is being withdrawn can be used. Otherwise, a thermometer can be inserted in a thermometer well or other temperature-sensing device installed in the loading line at a point close to the container being loaded. Read temperatures at intervals during trans fer and averaging. [See F.3.2(c).] (3) A suitable liquid should be used in thermometer wells to obtain an efficient heat transfer from the LP Gas liquid in the container to the thermometer bulb. The liquid used should be noncorrosive and should not freeze at the tem-peratures to which it will be subjected. Water should not be used. F.3.3 The volume observed or measured is corrected to 60....F (16....C) by use of Table F.3.3. The column headings, across the top of the tabulation, list the range of specific gravities for the LP-Gases. Specific gravities are shown from 0.500 to 0.590 by 0.010 increments, except that special columns are inserted for chemically pure propane, isobutane, and normal butane. To obtain a correction factor, follow down the column for the specific gravity of the particular LP-Gas to the factor corresponding with the liquid temperature. Interpolation between the specific gravities and temperatures shown can be used if necessary.
appendices
F.3 Liquid Volume Correction Table. Correction of observed volume to standard temperature condition (60°F and equilibrium pressure). F.3.1 The volume of a given quantity of LP-Gas liquid in a container is directly related to its temperature, expanding as temperature increases and contracting as temperature decreases. Standard conditions, often used for weights and measures purposes and, in some cases, to comply with safety regulations, specify correction of the observed volume to what it would be at 60°F (16°C). F.3.2 To correct the observed volume to 60°F (16°C), the specific gravity of LP-Gas at 60°F (16°C) in relation to water at 60°F (16°C) (usually referred to as “60°/60°F”) and its average temperature must be known. The specific gravity normally appears on the shipping papers. The average liquid temperature can be obtained as follows: (1) Insert a thermometer in a thermometer well in the container into which the liquid has been transferred, and read the temperature after the completion of the transfer. [see F.3.2(c) for proper use of a thermometer].
* This section is an excerpt from the NFPA 58 Liquified Petroleum Gas Code — 2001 Edition
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