Standard Method for Calibration of Tank Cars - API Ballotsballots.api.org/copm/colm/ballots/docs/Std2554_e2_COLM_9_17.pdf · Standard Method for Calibration of Tank Cars 4 1 Introduction

Standard Method for Calibration of Tank Cars API STANDARD 2554 SECOND EDITION, XXXXXX 2017 COMMITTEE DRAFT This document is not an API Standard; it is under consideration within an API technical committee but has not received all approvals required to become an API Standard. It shall not be reproduced or circulated or quoted, in whole or in part, outside of API committee activities except with the approval of the Chairman of the committee having jurisdiction and staff of the API Standards Dept. Copyright API. All rights reserved.

Standard Method for Calibration of Tank Cars 2

Contents 1 Introduction ................................................................................................................................ 4

2 Scope ........................................................................................................................................ 4

3 Normative References .............................................................................................................. 4

4 Definitions, Symbols, and Abbreviations ................................................................................... 4

4.1 Definitions .................................................................................................................................. 4

4.2 Symbols ..................................................................................................................................... 5

4.3 Abbreviations ............................................................................................................................. 6

5 Determining the Grouping of Cars that Share a Calibration Table ........................................... 7

5.1 General ...................................................................................................................................... 7

5.2 Criteria ....................................................................................................................................... 7

6 Procedure for Determining Shell-Full Location ......................................................................... 7

7 Procedure for Calibrating Tank Cars ........................................................................................ 9

7.1 General ...................................................................................................................................... 9

7.2 Water Gauge Procedure for Total Capacity .............................................................................. 9

7.2.1 Preparation ................................................................................................................................ 9

7.2.2 Filling the Car Tank ................................................................................................................. 10

7.3 Water gauge procedure for Incremental Capacity Table ........................................................ 10

7.3.1 Preparation .............................................................................................................................. 10

7.3.2 Incremental Gauging ............................................................................................................... 11

7.4 Metering Procedure Adaptation of the Water Gauge Procedure ............................................ 12

8 Procedures for Calibrating Pressure Tank Cars ..................................................................... 12

8.1 General .................................................................................................................................... 12

8.2 Preparation for Calibrating ...................................................................................................... 12

8.3 Modification to Water Gauge Procedure for Pressure Tanks ................................................. 12

9 Calibrating Nonpressure Tank Cars by External Strapping Procedure .................................. 13

9.1 General .................................................................................................................................... 13

9.2 Measurement Steps ................................................................................................................ 14

9.3 Recording of Data ................................................................................................................... 15

10 Calculation of Tank Volume .................................................................................................... 15

10.1 General Considerations .......................................................................................................... 15

10.2 Calculation of Tank Volume Using the Geometric Method ..................................................... 16

10.3 Calculation of Tank Volume Using the Finite Element Method ............................................... 19

10.3.1 General Approach and Considerations ................................................................................... 19

10.3.2 Tank Slope .............................................................................................................................. 20

10.3.3 Section Lengths....................................................................................................................... 20

10.3.4 Slice Radius ............................................................................................................................ 21

10.3.5 Apparent Fluid Level ............................................................................................................... 21

10.3.6 Slice Area and Volume ............................................................................................................ 22

3 This document is not an API Standard; it is under consideration within an API technical committee but has not received all approvals required to become an API Standard. It shall not be reproduced or circulated or quoted, in whole or in part, outside of API committee activities except with the approval of the Chairman of the committee having jurisdiction and staff of the API Standards Dept. Copyright API. All rights reserved. 10.3.7 Completion of the Table .......................................................................................................... 24

10.4 Calculation of Volumes from Water Gauge Methods .............................................................. 24

10.5 Structure of the Calibration Table ........................................................................................... 25

10.6 Required Elements .................................................................................................................. 25

10.7 Rounding of Volumes .............................................................................................................. 25

Annex A. Annex Design and Construction of Gauge Plants - Informative ............................................. 27

A.1 Design and Construction of Gauge Plants for the Water gauge procedure ........................... 27

A.2 Calibration of Water Gauge Plants .......................................................................................... 28

Annex B. Data Forms - Informative ........................................................................................................ 31

Annex C. Calculated Examples – Informative......................................................................................... 33


1 Introduction

Rail tank cars serve both the purposes of secure and safe transportation of petroleum and petrochemical materials and as measurement devices for those contents. This document addresses the development and standardization of the capacity charts used for those measurements. The actual determination of volume of material contained in a railcar is addressed in API Manual of Petroleum Measurement Stand-ards Chapter 3, Section 2.

2 Scope

This standard describes the procedures required to produce a calibration table for a rail tank car. The calibration table produced may also be applied to dimensionally similar railcars within the limits set forth in this standard. Both pressure and nonpressure containing railcars are addressed though some calibration methods are not applicable to both types.

3 Normative References

MPMS Chapter 2.2E/ISO 12917-1:2002 Petroleum and Liquid Petroleum Products—Calibration of Hori-zontal Cylindrical Tanks—Part 1: Manual Methods (ANSI/API MPMS 2.2E)

MPMS Chapter 4.9.1 Methods of Calibration for Displacement and Volumetric Tank Provers, Part 1—Introduction to the Determination of the Volume of Displacement and Tank Provers

MPMS Chapter 4.9.2 Methods of Calibration for Displacement and Volumetric Tank Provers, Part 2—Determination of the Volume of Displacement and Tank Provers by the Waterdraw Method of Calibra-tion

4 Definitions, Symbols, and Abbreviations

4.1 Definitions

4.1.1

Class

Class is the grouping of rail cars considered to be dimensionally similar enough to use a single common calibration table.

4.1.2

Class exemplar

Class exemplar is the specific rail car or its calibration table that is chosen to represent any rail car in the same class.

5 This document is not an API Standard; it is under consideration within an API technical committee but has not received all approvals required to become an API Standard. It shall not be reproduced or circulated or quoted, in whole or in part, outside of API committee activities except with the approval of the Chairman of the committee having jurisdiction and staff of the API Standards Dept. Copyright API. All rights reserved.

4.1.3

Finishing tanks

Finishing tanks are calibrated measures intended to measure smaller quantities using a cali-brated volume and a level measurement.

4.1.4

Gauging tanks

Measuring tanks

Gauging tanks are calibrated measures used for the determination of rail car tank volume, usually calibrated as to-deliver and without intermediate volume measuring capability

4.1.5

Shell-Full

Shell-Full is the point or level at which additional liquid volume cannot be added to the level tank that uniformly increases the liquid level across the entire free surface of the liquid. The creation of an air pocket generally sets it.

4.2 Symbols

A is the area of the flooded cross-section at the level h

d is the cross-sectional diameter dimension of the tank as measured in sections 7, 8, or 9.2 in cm (inches).

E is the full depth of the head in cm (in.) as measured

H is the dimensionless ratio of the liquid height to the radius

h is the fluid height as measured at the center of the tank in cm (in.)

hs is the fluid height in a finite element slice in cm (in.)

hs,center is the fluid height in a finite element slice within the center section of the tank in cm (in.)

hs,head is the fluid height in a finite element slice within the head section of the tank in cm (in.)

k is the distance above the centerline and increasing towards the top of the tank in cm (in.)


L is the average length of the half tank as measured in cm (in.)

Lcenter is the length of the center section in cm (in.)

Lcylinder is the length of the cylinder section in cm (in.)

n is the distance below the midline and increasing towards the bottom of the tank in cm (in.)

R is the radius of the main cylinder of the tank in cm (in.)

Rs is the radius of a slice in cm (in.)

Rs,head is the radius of the slice within the elliptical head in cm (in.)

s is the average slope of the tank from the lowest point to the end of the cylindrical section in cm (in.). Other than a slope of zero, all slopes are related to the distance over which they are measured.

V50 is the volume of the tank with the liquid level at the vertical midline in cm3 (in.3)

Vcylinder is the volume of the cylinder at level h in cm3 (in.3)

Vh is the total volume of the tank at level h in cm3 (in.3)

Vhead is the volume of the head at level h in cm3 (in.3)

Vk is the volume to be estimated bounded by the tank midline and the plane n increment away from the midline

Vn is the volume bounded by the tank midline plane and the plane n increment below centerline

x is the distance from the end of the previous section to the center of the slice in cm (in.)

xcenter is the distance from the center of the tank to the center of the slice

α is the segment included angle in radians

θ is the angle of the tank slope in radians

4.3 Abbreviations

gpm gallons per minute

ICC Interstate Commerce Commission (USA)

NIST National Institute of Standards and Technology


5 Determining the Grouping of Cars that Share a Calibration Table

5.1 General

Tank cars are typically built using common designs, many tank cars from the same drawings, with the same dimensions. It is acceptable under this standard to apply the same calibration table to rail cars that meet certain criteria for dimensional similarity. These cars shall be considered in the same “class” and use a table that was developed from a single tank car of the class.

The table may be labeled and presented as for a list of cars including the specific car or it may be labeled as for the specific car at the owner’s preference.

To provide an entire outage table, one exemplar car of each class shall be water gauged to show the volume held for each increment from the bottom to the top of the tank. The table calculation procedures in section Error! Reference source not found. shall be followed using the measurements obtained. The calculated table may be used as the calibration table for any member the class of cars represented by the exemplar tank gauged.

This section does not to prohibit the development of a calibration table for a single rail tank car regardless of class similarities if preferred by the owner.

5.2 Criteria

For rail tank cars to be considered eligible to be of the same class and use a common calibration table they shall meet all the following criteria:

1) The tank shall have a contained volume at the shell-full level within +/- 0.1 % of the class exem-plar.

2) The diameter of the tank in the vertical dimension at the shell-full point shall round to the same one-half cm (one-quarter in.) of the class exemplar.

3) The tank shall have a slope within +/- 5% of the slope of the class exemplar. For example, if the class exemplar’s slope is 4 inches in 200 inches (2%), the acceptable range of cars in the class would have slopes from 3.8 to 4.2 inches rise in 200 inches inclusive (i.e. 1.9% to 2.1% )

6 Procedure for Determining Shell-Full Location


The reference point for gauging tank cars that sets the maximum capacity of a tank car is the point referred to as “shell-full”. At that point, additional liquid volume cannot be added to the level tank that uniformly increases the liquid level across the entire free surface of the liquid. Depending on the configuration of the tank, this could be set either by the overflow of the nozzle or by the potential isolation of an air pocket of any size. Manual venting of a contained pocket does not change the shell-full point, though a permanent vent hole might. The shell-full capacity of several potential configurations are shown in Figure 1.

Shell-full refers to the liquid volume at the transition point at which air or vapor becomes entrapped in a

Figure 1 Shell Full Capacity of Tank Cars

9 This document is not an API Standard; it is under consideration within an API technical committee but has not received all approvals required to become an API Standard. It shall not be reproduced or circulated or quoted, in whole or in part, outside of API committee activities except with the approval of the Chairman of the committee having jurisdiction and staff of the API Standards Dept. Copyright API. All rights reserved. location that is not in direct communication with all top fittings.

7 Procedure for Calibrating Tank Cars

7.1 General

The volume capacity of tank car tanks shall be determined in one of the two following ways:

(1) By filling the tank with a quantity of water measured by discharge from calibrated tank or tanks (water gauge procedure).

(2) By computing the volume from external measurements of the tank and deducting for the thickness of walls, etc. ("strapping" procedure). The strapping procedure is used prior to any insulation being applied.

The procedure is described for calibrating single-compartment tank car tanks. The same procedure is applicable to multiple-compartment tank cars by considering each compartment individually as a sin-gle-compartment tank.

The calibration procedures outlined herein require that the interior surface of the tank be clean and free from any foreign substance such as the residue of commodities adhering to the bottom and sides of the tank—dirt, rust, and the like. Examination and inspection of a tank car may indicate the need for thorough cleaning if the correct established capacity is to be assured.

The capacity of the car to be gauged shall be determined as it stands on a level track. Before gauging commences, it is important that the gauge track be checked to ascertain that it is level.

Tank cars modified or damaged to the extent that the capacity is changed should be recalibrated; and the new capacity should be reported in accordance with instructions in Freight Tariff No. 500 for nonpressure cars or Freight Tariff No. 300 for pressure cars, latest issue and supplements thereto, issued under ICC authority for United States, Canadian, and Mexican railroads.

7.2 Water Gauge Procedure for Total Capacity

7.2.1 Preparation

The procedure is described for calibrating single-compartment tank car tanks. The same procedure is applicable to multiple-compartment tank cars by considering each compartment individually as a sin-gle-compartment tank.

In hot weather, tank car tanks shall be cooled by spraying the outside with water before gauging. Do not gauge tanks on windy days nor in freezing weather. Use only clean water at a temperature as near 60 F as practicable.

If present, the bottom outlet valve of the tank car shall be thoroughly cleaned and put in good condition.

All gauging tanks shall be examined to make certain that they are perfectly clean. A check shall be made to ascertain that the scale behind the gauge glass on the finishing tank is tight and in its proper position. When gauging tanks become nearly empty, they shall be watched for sediment. If any sediment is present, the water shall be stirred thoroughly to carry it away. The operators shall examine all valves on the gauging tanks to see that none are leaking. If any of the valves leak, they shall be repaired or renewed.

A pail shall be placed under the valve in such a position that it will catch any leakage. When water is first emptied into the car tank, the tank car outlet valve shall be examined, if it leaks more than 20 drops per


minute, the water shall be drained from the car tank and the valve repaired before proceeding. If any dripping occurs, the leaked water shall be collected in the pail and returned to the car tank before each level measurement is made. Throughout the operation, the outlet valve shall be watched carefully to see that leakage does not become excessive.

If preferred, the valve cap may be screwed on (a tight gasket being used). However, if this is done, the outlet leg shall be filled with water and the valve closed. Any surplus water left in the car from this operation shall be removed by wiping.

7.2.2 Filling the Car Tank

Starting with the clean empty car tank, drain water into the tank from the gauging tanks. The initial plan must ensure that any gauging tank drained into the car will be able to drain completely without raising the liquid level above the shell-full point. Each gauging tank used shall be separately drained into the car tank, 5 min being allowed for draining after the tanks have become empty. To avoid error or duplication in tallying the number of gauging tanks emptied into the car tank, a record shall be made immediately after the valve from the gauging tank has been closed.

When a gauging tank is refilled, it shall be refilled completely to its calibrated capacity. The finishing tank shall be completely filled each time, rather than filled to a point that is marked on the gauge board.

Repeat the filling and emptying of gauging tanks as needed until the car tank is nearly full.

When the car tank is nearly full, gauging shall be completed using the finishing tank. A straightedge shall be fastened across the manway opening in the shell of the car tank so that it is level with the inside of the shell at the shell-full point. When the water begins to trickle over the center of the straightedge, the tank is full.

The last 100 gallons shall not be permitted to run into the car tank faster than at the rate of 10 gpm.

Just before the car tank becomes full, any leakage from the outlet valve shall be poured back into the tank, since this water has already been measured. After the car tank has been filled, allow 15 min for settling to displace the air and fill to the top of straightedge if outage shows, care being taken to include any water that may have leaked from the outlet valve.

Measure the temperature of the water in the tank car using a calibrated thermometer according to the procedures in API MPMS Chapter 7.

The capacity of the tank shell shall be determined by using the total volume of water emptied from the gauging tanks into the car tank, plus the final reading of the gauge on the finishing tank.

7.3 Water gauge procedure for Incremental Capacity Table

7.3.1 Preparation

The location at which the car is placed within the gauge plant shall be such that the water from the finishing tank shall drain directly into the tank to be gauged.

Tank to be gauged must be placed in the shelter of the gauge plant after making sure that the track is level, both for length and width of car. The tank shall be leveled by means of wedges under the side bearings so that the bottom sheet on the inside of the tank is level longitudinally. The tank shall be leveled laterally by adjusting wedges at the side bearings so that the bob of a plumb line, when suspended from the center of the dome ring, rests on the longitudinal centerline of the bottom sheet at the center seam of the shell.

11 This document is not an API Standard; it is under consideration within an API technical committee but has not received all approvals required to become an API Standard. It shall not be reproduced or circulated or quoted, in whole or in part, outside of API committee activities except with the approval of the Chairman of the committee having jurisdiction and staff of the API Standards Dept. Copyright API. All rights reserved. Attach a gauge glass to the car or other nearby rigid surface such that the glass can be plumbed and remain fixed vertically throughout the gauging procedure. Attach the gauge glass to the bottom valve of the car tank using fittings of sufficient size and strength to be durable, not leak, and not deform in service. The exact dimensions of the gauge glass and fittings are not specified in this standard, but are described in general terms as a user aid. The gauge glass should have a valve that permits water to be drawn off to a container during the gauging to provide periodic circulation in the lines.

Apply a steel scale to bracket adjacent to gauge glass, locating the zero point on the scale at the level of the bottom of meniscus of the water in the glass at the top of the bottom sheet level. The steel scale shall be clamped securely in position to prevent any change in its position relative to the gauge glass during the gauging process.

Fill the outlet nozzle and piping until the water reaches the top of the bottom sheet on the inside of the tank. Fill the finishing tank in the gauge plant with water and allow it to settle 5 min to free the water from air and make up the outage, if any.

7.3.2 Incremental Gauging

When gauging operations have started, they shall be continued until the entire tank has been gauged. If gauging continues longer than one day, the water shall be emptied from the tank each night and refilled the next day to the level where gauging was discontinued the night before.

Allow enough water to pass from the finishing tank to the car tank to raise the water level in the tank car gauge glass close to but not exceeding the first one-half in. marking, and close the finishing tank valve. Allow the water to settle and become calm, after which add additional small quantities until the first one-half in. is reached. Allow the water to settle and become calm, then recheck to verify that the water in the gauge glass is exactly on the intended mark on the scale.

It is important to take each reading in gauge glass with the eye on the level of the bottom of the water curve on meniscus.

Read the gauge glass on the finishing gauge tank or the reading of the meter and record the volume of water conveyed to the car tank for the first one-half in.

Repeat the operations of this section for the second one-half in. mark and subsequent increment marks on the scale.

When nearing the top of the tank, apply a straightedge to the shell-full point on the inside of the tank shell.

The last reading is to be taken when the water is at the top of the straightedge and is about to trickle over.

Measure the water level inside the tank with the tank car gauge glass scale and record the reading on the finishing tank glass.

Draw off the water in the gauge glasses occasionally, and pour it back into the tank to which the glass is connected to equalize the temperature and density of the water in the tank and gauging system. Keep the outside gauge glass shaded from the sun to minimize temperature differences.

After the water is emptied from the car tank, the car tank must again be leveled; if it is found that the level of the tank has changed during the gauging operation, the tank shall be leveled again and regauged.


7.4 Metering Procedure Adaptation of the Water Gauge Procedure

For those gauging operations that are performed using water from gauging tanks, an acceptable alterna-tive procedure is to use a meter or combined with the use of gauging tanks to determine the volume of water delivered into the tank car. This is acceptable for the water gauge procedure, and the incremental capacity table procedure. If a mass meter is used with a volumetric readout, it is also acceptable.

For this procedure adaptation, all the following criteria shall be met:

1) The liquid meter shall be calibrated Per API MPMS Chapter 4.5. 2) The meter shall have a Minimum repeatability of 0.05%, or the statistical equivalent in delivered

volume. 3) The meter shall be traceable to an NIST volume measure or mass standard with agreement within

0.1% 4) The meter shall be operated within +/- 10% of its calibrated rate (See MPMS Chapter 4.5), except

for the final trimming of the level at an increment point.

8 Procedures for Calibrating Pressure Tank Cars

8.1 General

Determine the volume capacity of -pressure-type tank car tanks in either of the two following ways:

(1) By filling the tank with a quantity of water measured by discharge from calibrated tank or tanks (water gauge procedure).

(2) By computing the volume from external measurements of the tank and deducting for the thickness of walls, etc. ("strapping" procedure). The strapping procedure is used prior to any insulation being applied.

8.2 Preparation for Calibrating

Fill the sump (if tank is so equipped) and piping until the water reaches the top of the bottom sheet on the inside of the tank.

8.3 Modification to Water Gauge Procedure for Pressure Tanks

To provide an entire incremental capacity table, gauge the tank of an exemplar car to inside top of shell, record capacity, and note reading of inside diameter on gauge glass scale (see Figure 2). Fill or drain the tank to exactly one-half its capacity as gauged to inside top of shell and record the reading on scale as being at center of inside diameter of tank.

Allow water to flow from the finishing tank into the car tank until the level is nearly 3 cm (1 in.) higher than the midpoint of the car tank and close the gauge tank valve. Allow the water to settle and become calm, and resume flow from the finishing tank into the car tank at a reduced rate of flow until the car tank level is exactly 3 cm (1 in.) above the midpoint level in the gauge glass.

Allow the water level to come to rest and check to determine if the bottom of the meniscus in the gauge glass is exactly in the same horizontal plane as the specified scale mark.

Repeat operations for the second increment, third increment, etc., until the one-half meter (18-in.) outage level is reached, after which readings for each cm (half in.) shall be taken.

Use the incremental capacities thus determined in reverse order for the determination of incremental capacities for bottom half of tank. Determine capacities for fractional increments by interpolation.


Figure 2 Piping and Gauge Class Arrangement to Be Used for Incremental Gauging of Pressure Cars

9 Calibrating Nonpressure Tank Cars by External Strapping Procedure

9.1 General

The procedures for determining all measurements shall be those described in the applicable sections of API MPMS 2.2E, except as modified here. All readings except thicknesses shall be made to the nearest 1 mm (1/16 in.); thickness measurements shall be made to the nearest 0.5 mm (1/64 in.).

The tape used for calibrating tanks shall be traceable to the National Institute of Standards and Technol-ogy and comply with the requirements of API MPMS 2.2E.

Steel rulers used may be verified against the calibrated tape to read the same over their marked length by the operator with the comparison documented locally. The rulers used in making measurements, except for plate thicknesses, shall be of steel and of such thickness as to ensure that they will not bend in ordinary use.

Plate thicknesses shall be measured using ultrasonic thickness testing. The ultrasonic thickness equipment must be calibrated and capable of accurately measuring the thickness to within ± 0.05mm (.002 in.)

Straightedges used in making measurements at the heads of tanks or at manways shall be of wood, metal, or other suitable material of sufficient width and thickness to maintain a deflection of less than 1.5 mm


(1/16 in.) when held flat in a horizontal position and supported only at its ends. The length of the straight-edge should be at least 12 in. greater than the span of the tank or manway on which it is to be used.

All measurements shall be made and recorded to the marked resolution of the device being used. All rounding shall be done only during the calculation steps and according to the rounding procedures speci-fied elsewhere in this standard.

9.2 Measurement Steps

The external circumference and plate thickness shall be measured for each ring of the main cylinder ac-cording to the procedures in API MPMS 2.2E as modified by this standard. Each ring circumference shall be measured in two places approximately at the 20% and 80% of ring width, the measurements repeated and the results for each ring averaged. If successive measurements of the same circumference differ by more than ±3 mm (±1/8 in.) those measurements shall be ignored and the measurement repeated until two successive measurements agree within ±3 mm (±1/8 in.).

The plate thickness of each ring shall be measured approximately on the 20% line on one side of the tank and on the 80% line on the other side on each ring and the values averaged for each ring.

Establish reference points at ends of main cylinder as shown as “X” in Figure 3. Establish six (6) refer-ence points two (2) at each end of the car and two (2) at the center. These points will be in the middle of the weld seam of the head to first tank shell, at the Top Dead Center and Bottom Dead Center locations, and at the center of the tank at Top Dead Center and Bottom Dead Center locations. In addition, estab-lish two additional reference points at each end of the car in the middle of the weld seam on the tank lon-gitudinal centerlines (quarter points).

Figure 3 Reference Points and Named Dimensions of a Tank

Establish the length of the head straight flange length by measuring the head straight flange length on the head knuckle area in the four reference locations per head marked according to the section above. The measurement will be from the reference point until the head transitions from straight tangent to curved surface. The average of these measurements shall be the “head straight flange” length.

Determine average half tank straight length (dimension L) by measuring the distance from the top refer-ence point on the head-to-shell seam to the top reference point at the middle of the car. Repeat for the

15 This document is not an API Standard; it is under consideration within an API technical committee but has not received all approvals required to become an API Standard. It shall not be reproduced or circulated or quoted, in whole or in part, outside of API committee activities except with the approval of the Chairman of the committee having jurisdiction and staff of the API Standards Dept. Copyright API. All rights reserved. bottom of the tank and then calculate the average of the top and bottom measurements for one end. Add the head straight flange length to obtain the half tank straight length for one end. Repeat for the other end of the tank and average the two halves for the average half tank straight length measurement, L.

Determine the head depth (E) and straight flange length. Using a straightedge held against the center of the head, and two rulers perpendicular to the straight edge, and along the head straight flange at the ref-erence points, measure the depth of the head to the reference points.

Measure the straight flange length, the distance from the reference point(s) to the point at which the ellipse starts. Subtract the head straight flange measurement from the measured head depth including the flange to obtain the inside head depth.

Measure the thickness of the head in four (4) places on the curved portion and spaced equally around the axis to obtain an average.

The head depth may be measured prior to joining the head to the tank car tank provided that records show the traceability of the head being installed on the tank car tank. It may be measured by placing a straight edge across the head straight flange and measuring the inside head depth at the lowest point at the middle of the head.

Using a tape or steel ruler, measure the distance from the bottom of the tank shell at center to the shell-full height.

Determine the radius of each tank head. The theoretical head radius shall be taken from form AAR 4-2 (Certificate of Construction) or other comparable documents.

Determine the slope of the tank car tank, s using any device capable of accurately defining a datum level over a distance at least the length of the tank. The accuracy of any level measuring instrument used shall be 0.5 mm/m (0.5 in./100ft). For straight tanks, the slope is assumed to be zero (0). For sloped tanks, the tank shall be level to ground and the datum used shall also be level relative to ground. Measure the difference in vertical drop of the tank from the end of the main cylinder (at head bottom reference point) and at the center of the tank at Bottom Dead Center reference point to the datum. Record this difference as the slope for the respective half tank. Repeat the measurements for the other end and record the values obtained. The tank slope shall be the average of the slopes of the two half tanks.

9.3 Recording of Data

All measurements and derived dimensions shall be recorded on suitable record forms and retained. The measurements shall be recorded in written form immediately after the readings are made but may be transferred to permanent record forms subsequently. A suggested form is illustrated in Annex B.

10 Calculation of Tank Volume

10.1 General Considerations

Tank volume and capacity tables shall be generated by the procedures in this section. The specific method chosen depends to some extent on the measurements obtained in Sections 7, 8, or 9. If he ex-ternal strapping method used, then the calibration table is calculated as shown below using either geo-metric formulas or a finite element method. If capacity measurements were made using either the proce-dures in Section 7 or Section 8, then the method detailed in Section 10.4 shall be used.


If only the total contained volume and shell-full height was measured as in Section 7.2, then a suitable calibration table shall be chosen from existing tables using the criteria in Section 5 and a new table is not calculated.

If the tank is straight, either the geometric approach in Section 10.2 or the finite element method in Section 10.3 shall be used.

If the tank is sloped, only the finite element approach in Section 10.3 shall be used.

Multiple compartment tanks shall be calibrated as individual tanks.

10.2 Calculation of Tank Volume Using the Geometric Method

The measurements obtained in Section 9 shall be used in this procedure.

A straight tank can be broken into two sections for the volume calculations, the cylinder section, and the head section. The calculation inputs are all based on half tank measurements but are doubled within the equations to yield the full tank volume. Figure 3 provides an overview of the dimensions used and their relationships.

Figure 4 Variables and Nomenclature for Tank Calculations

Using the measured circumference and thickness for each ring, determine the theoretical inside radius for each ring, and then obtain an average inside radius for the tank. The theoretical inside radius can be cal-culated using equation 1.

.2

# 1

Where R is the radius of the main cylinder of the tank in cm (in.) Outside Circumference is the average of all the circumference measurement of the cylindrical rings in cm (in.) Thickness is average wall thickness of the cylindrical rings in cm (in.)


For every level (h) from zero (0) to the shell-full height by 0.5 cm (one-quarter inch) increments calculate the volume of the cylindrical and head portions of the tank. Each equation is presented individually for clarity, but the calculation shall be carried out using the full unrounded result of the previous equation.

For the cylinder section calculate the cross-sectional area of the tank that is filled with fluid to a height of h. Note that equation 5 calculates the volume of the full tank cylinder but uses the half tank length as an in-put.,

# 2

1 # 3

2# 4

2 # 5

Where

H is the relative height of the fluid to the radius h is the fluid height at specific level in cm (inches) α is is the segment included angle in radians A is the area of the flooded cross-section at the level h Vcylinder is the volume of the cylinder at level h in cubic cm (cubic in)

For the head section, each head of the tank is considered identical, and the volume of the combined two heads is calculated. The necessary dimensions and formula are shown in Figure 5.

33

# 6

Figure 5 Dimensions of Elliptical Head


# 7 Where L is the half tank length as measured Vhead is the volume of the cylinder at level h in cubic cm (cubic in) Vh is the total volume of the tank at level h in cubic cm (cubic in)

The total volume is obtained by adding the volumes of the cylinder section and the head section, and if applicable, the volume contained in nozzles, manways, etc.

Outage tables are calculated by first calculating the calibration table (innage) as detailed above and then restating each level as an outage. The outage shall be calculated as follows:

# 8

Where h is the innage liquid level for which the volume was calculated

The outage table is formatted such that an outage of 0” is the shell-full volume, with the outage increasing as the volume decreases.

Example:

A straight tank car tank is constructed with an inside diameter of 100”, an average half tank straight length of 200”, with 2:1 ellipsoidal heads having a depth of 25”. The tank is filled to a fluid height of 75”. Determine the volume in the tank. All calculations are carried though as a chain with no intermediate rounding.

Volume of cylinder section:

7550

1.5# 2

2 cos 1 2 cos 1 1.5 4.188790205 # 3

2sin

50 ∗ 4.188790205 sin〖4.188790205 〗2

6318.519510714 # 4

2 6318.519510714 2 200

2,527407.804285420 10,941.159325911 # 5

Volume of Tank Heads:

33

25 3 50 75 753 50

220,893.233455532 956.247763877 # 6

Total Volume at 75”:

10,941.159325911 956.24776387711,897.407089788 # 7

19 This document is not an API Standard; it is under consideration within an API technical committee but has not received all approvals required to become an API Standard. It shall not be reproduced or circulated or quoted, in whole or in part, outside of API committee activities except with the approval of the Chairman of the committee having jurisdiction and staff of the API Standards Dept. Copyright API. All rights reserved. By industry convention, railcar volumes are expressed in liters (1000 cu cm / 1 liter) or gallons (231 cubic inches / 1 gallon).

10.3 Calculation of Tank Volume Using the Finite Element Method

10.3.1 General Approach and Considerations

For a sloped tank, the surface of the fluid is not parallel with the bottom of the tank. However, for the purpose of measurement, the fluid height, h, is taken at the center of the tank. The liquid surface is truly horizontal and of equal elevation referenced to the earth, but to simplify the calculations, the half tank is assumed to be horizontal with the liquid level changing along its axis according to the slope of the tank. This is accomplished by considering the tank as made up of a series of small slices (finite elements) whose properties approximate a two-dimensional geometrical figure. Each slice is a cross-section of the tank and is normal to the tank, but not normal to the liquid level (in a sloped tank).

If enough slices are used (the length of a slice is small) the error in the volume is small.

For calculation purposes, tank is separated into three sections: the center section, the cylinder section, and the head section (see Figure 6).

Each section (center, cylinder, and head) is divided into slices that are perpendicular to the axis of the tank cylinder. Slices in each section shall be of equal thickness (Length of section / number of slices). Some reduction in the number of calculations can be achieved by using more slices in the center and head sec-tions where the geometry is more complicated and fewer slices in the cylinder section, but the reduction in computer computation time is almost unnoticeable at the precision levels suggested. The same slice size for the entire tank is suggested. Geometry is recommended to be calculated at the center of each slice to reduce total error. See Figure 6. For a straight tank, the method is the same but the center section is of zero length.

The number of slices in each section of the tank shall be sufficient to give a total error of less than 0.1%. As an example, using a personal computer and spreadsheet macros, the calculations for 1000 uniform slices produced a total volume result within 0.00008% of the result obtained with 10,000 slices and required about 0.3 seconds per incremental level.


Figure 6 Volume Calculation Methodology for Finite Element

Each slice has a circular cross-section of radius, Rs, that is partially filled with fluid to a height of hs, measured from the bottom of the circle. The fluid height for each slice will vary and must be calculated, and then the area can be found. The volume of each slice is calculated by multiplying the area by the thickness of the slice. The volume from each slice is added to produce the final tank volume.

Each section is characterized by constraints of its geometry. The center section height (hs) of a slice is constrained to the intersection of the center cross-sectional plane of the tank. The cylindrical section hs is set by the height of the liquid at the beginning of the cylinder, reduced by the angle of the tank slope. Within the head section, the apparent liquid level also is reduced by the slope and the radius of the slice also varies.

10.3.2 Tank Slope

The angle of the tank is calculated based on the tank slope, s, and the half tank straight length, L:

# 9

Where θ is the angle of the tank slope in radians s is the averaged rise of the tank as measured L is the averaged length of the half tank Note: s/L is calculated within the measurement procedure.

10.3.3 Section Lengths

The lengths of each section change for each incremental level and are calculated for each level.

21 This document is not an API Standard; it is under consideration within an API technical committee but has not received all approvals required to become an API Standard. It shall not be reproduced or circulated or quoted, in whole or in part, outside of API committee activities except with the approval of the Chairman of the committee having jurisdiction and staff of the API Standards Dept. Copyright API. All rights reserved. The boundary between the center section and the cylinder section depends on fluid height. The bound-ary is placed normal to the tank's axis, and positioned to pass through the point where the fluid level in-tersects the centerline of the tank. The center section has a total length of:

sin # 10

Where Lcenter is the length of the center section in cm (in.) h is the height of the liquid in the increment in cm (in.) θ is the angle of the tank slope in radians from equation 10

The cylinder section encompasses the remaining straight length before reaching the head section, given by:

tan # 11

Where Lcylinder is the length of the center section in cm (in.) L is the length of the half tank as measured in section 0 R is the radius of the cylindrical portion θ is the angle of the tank slope in radians from equation 10

The length of the head section is the head depth from the start of the tangent curve of the head to the inside surface of the head as measured in9.2. The head section slices are designated by how far they are into the elliptical portion of the head. Both the apparent liquid level and the radius change with the distance into the ellipse.

10.3.4 Slice Radius

In the center and cylinder sections of the tank, the radius of the slice is equal to the measured tank radius.

# 12

In the head section, Rs decreases elliptically as the slices approach the end. If “x” is the distance from the end of the cylinder section to the slice in the head section, then:

, 1 # 13

Where Rs,head is the radius of the slice within the elliptical head in cm (in.) x is the distance from the end of the cylinder section to the slice in cm (in.) E is the full depth of the head in cm (in.) as measured in 0

10.3.5 Apparent Fluid Level

Determining the apparent fluid level of a specific slice, hs, is also dependent on the section of the tank in which the slice is located.

For the center section, fluid height is a function of both the actual free liquid level and the slope of the tank. Because the orientation of the slices is normal to the sloped axis of the tank, the center slices of sloped


tanks are bounded by the distance from the bottom of the circular slice to the centerline of the car, given by:

, tan# 14

Where hs,center is the fluid height in cm (in.) xcenter is the distance from the center of the tank to the center of the slice θ is the angle of the tank slope in radians from equation 10

For a straight tank, the length of the center section is zero (see Equation 10) and the xcenter and hs are meaningless.

For the cylinder and head section, the fluid level is given by:

# 15

Where hs, is the fluid height in cm (in.) h is the fluid height as measured at the center of the tank in cm (in.) x is the distance from the end of the previous section to the center of the slice in cm (in.) θ is the angle of the tank slope in radians from equation 10 Lcylinder is the length of the center section in cm (in.) from equation 11

Note that the fluid height will decrease as the slices move towards the head of the tank.

For the head section, the apparent fluid level is complicated by the decreasing radii of the slice. For straight tanks the problem is simpler, but for sloped tanks the entire wetted segment is vertically displaced by different amounts for each slice. The simplest method to handle this complication is to calculate the area of the slice by defining the axial liquid height to be the distance of the liquid height from the center of the tank axis. Centering the slice concentric with the axis of the tank, the fluid level relative to the center of the tank can be then be calculated. The top and bottom of the head slice determine boundary conditions for 0 and 100% full.

Using the Rs for the slice calculated in equation 13 and the fluid height hs at the slice using equation 15, determine if the fluid level is above or below the level of the slice radius. If hs is not outside the boundaries identified in equations 16a and 16c the hs remains as calculated in equation 15 (equation 16b).

, 0# 16

, # 16

, 2 # 16

Where hs,head is the fluid height in cm (in.) R is the tank shell radius as measured Rs,head is the radius of the slice within the elliptical head in cm (in.)

10.3.6 Slice Area and Volume

Using the above calculated values, the cross-sectional area (A) of each slice can be calculated using equations 17 through 20.


The relationship among the liquid level, the wetted segment, and the included triangle and sector are shown in Figure 7. The area of the wetted circle segment is calculated by determining the difference between the areas of the angular sector of a circle and the triangle formed by the sides of the sector and the liquid level (hs) using theorems from plane geometry.

The height of the liquid is converted to a dimensionless fraction of the radius per equation 17.

# 17

Where H is the dimensionless ratio of the liquid height to the radius hs is the fluid height in cm (in.) Rs is the radius of the slice within the elliptical head in cm (in.)

Using the geometric properties of a unit circle, H defines the length of a chord that would be the top of the segment. It also therefore defines the angle α which is central angle of both the sector containing the wetted segment and the triangle that excludes it.

2 1 # 18

Where α is in radians.

The angle α and the radii Rs completely define both the areas of the sector and the triangle, whose dif-ference is calculated using equation 19 to provide the area of the specific slice.

2# 19

The area of each slice is multiplied by the thickness of each slice to give the volume. The volumes of all slices are added together to give the overall volume for the specific fluid height. If different thickness slices are used in the analysis, care must be taken to ensure that the correct thickness is used for each specific slice.

Figure 7 Area of Segment Within Circle


10.3.7 Completion of the Table

Increment the value h by the specified amount and repeat the procedure in Sections 10.3.4 through 10.3.6 for each calibration table level from the bottom of the tank (zero) to the shell-full level. The final increment that includes the shell-full level could be a lesser increment than the specified increment depending on actual tank dimensions.

Shell-full volume is calculated using the shell-full height from Section 6 as the fluid height.

10.4 Calculation of Volumes from Water Gauge Methods

The water gauging procedures in Sections 7 and 8, yield a table of measurements consisting of a height and water volume from the lowest point measured to the highest point measured. The point at which the tank is empty can be assumed to have zero volume. The designated shell-full volume of an exemplar car shall be as measured, for cars using a same-class calibration table the shell-full volume shall be within the specified limits.

If during calibration, the entire tank was not measured from bottom to top at the specified increments, the measured results shall be used to calculate the volume table using one of the following methods.

If either the bottom or top half of the tank was measured incrementally, the measured results shall be used to represent the corresponding levels in the unmeasured half. In these cases, the starting point for the calculation shall be 50% of shell-full height. This is generally expected to be the level represented by the maximum volume per incremental height. Using change in distance from the next lower (higher) level and the change in measured volume contained in the increment add (subtract) that volume to the starting level. Continue this process with each successively lower measured increment to estimate the missing levels.

#20

#20 Where k is the distance above the centerline and increasing towards the top of the tank n is the distance below the midline and increasing towards the bottom of the tank V50 is the volume of the tank with the liquid level at the midline Vk is the volume to be estimated bounded by the tank midline and the plane n in-crement away from the midline Vn is the volume bounded by the tank midline plane and the plane n increment below centerline

For an innage table, the volume calculated at the zero-height level shall equal zero and the volume at the shell-full point shall equal the volume measured at shell-full. If one of these values is not as specified, each of the increments shall be multiplied by the same coefficient to adjust the zero or shell-full value to the specified value.

If the entire vertical span of the tank was measured but the measurements or calculations made during calibration were at levels other than that required for the volume table or if a metric table must be converted to a customary units table or vis versa, the necessary values shall be obtained by interpolation of the available values. The interpolation may be by linear interpolation of the two adjacent points.

All calculations and intermediate recorded values shall be carried to at least 4 decimal places; fully chained calculations without any intermediate rounding are preferred.

25 This document is not an API Standard; it is under consideration within an API technical committee but has not received all approvals required to become an API Standard. It shall not be reproduced or circulated or quoted, in whole or in part, outside of API committee activities except with the approval of the Chairman of the committee having jurisdiction and staff of the API Standards Dept. Copyright API. All rights reserved. 10.5 Structure of the Calibration Table

The results of Sections 7, 8, or 9 shall be presented either as an innage table or as an outage table listing the distance from a specific datum in ascending order in cm (in.) with the corresponding volume at that level. The table shall be prepared with increments of one (1) cm (one-quarter in). The volume shall be expressed in whole liters (gallons) without decimals.

The innage table shall use the lowest point on the inside bottom of the tank underneath the gauging point as the zero innage. The zero innage point may have an associated volume if the lowest shell point is not underneath the gauging point.

An outage table shall present each increment as the distance from the shell-full point. The outage table is formatted such that an outage of 0” is the shell-full volume, with the outage increasing as the volume de-creases. Since calibration methods generally are performed from the bottom of the tank to the top of the tank, preparation of an outage table in specified increments may require interpolation of the calibration results to correspond to the specified increment.

A subsidiary table may be included that assists with interpolation of the increments but is not required.

Deadwood allowance shall be made for any fittings or appurtenances inside the tank. Such volume shall be deducted in its proper relation to the bottom of the tank.

10.6 Required Elements

The table as published shall include clearly all the elements identified in this section, though the form and design of the table may be developed for the best use of the owner.

The car for which the table is applicable shall be identified by tank number. If the table is for a class of cars, a unique number identifying the table rather than the car may be listed.

The table shall be identified as either an innage or outage table exclusively.

The point at which measurements of liquid level are referenced (i.e. the zero point of the capacity table) shall be identified in writing on the capacity table such that a gauger, with no knowledge of the internal structure of the tank or the procedure for designating shell-full, can correctly measure the contents. Simple references to “shell-full” or “reference point” should be avoided in preference to specific descriptions like, “from the bottom of the nozzle insertion opposite the hinge”.

The liquid height shall be listed with its corresponding accumulated volume in the designated units. The table shall not contain incremental or other volumes in the same table unless the units used render the numbers for incremental and accumulated volume different by at least 2 orders of magnitude in a half full tank. This can be achieved by only using one set of units for the entire table.

10.7 Rounding of Volumes

The only rounding that is permitted in this standard is in the preparation of the published calibration table.

Liquid heights shall be listed in the increments chosen. As independent variables, they are not rounded; they are as printed.

Volumes shall be listed in whole liters or in whole gallons. Incremental volumes, if included, shall be listed rounded to 4 decimal places.


27 This document is not an API Standard; it is under consideration within an API technical committee but has not received all approvals required to become an API Standard. It shall not be reproduced or circulated or quoted, in whole or in part, outside of API committee activities except with the approval of the Chairman of the committee having jurisdiction and staff of the API Standards Dept. Copyright API. All rights reserved. Annex A. Annex Design and Construction of Gauge Plants - Informative

A.1 Design and Construction of Gauge Plants for the Water gauge procedure

The gauge plant (see Figure A.1) shall consist of one or more elevated tanks of convenient size, and should be used for water gauging tank car tanks. The supporting structure should be designed to support the weight of the tanks, including water capacity. The gauge tanks shall be at such a height that water from them will drain directly into the car tank to be gauged. Suitable apparatus should be installed to raise the water into the gauge tanks. During gauging operations, the gauge tanks and the tank car tanks shall be housed to protect them from the sun and rain.

A section of level track—preferably laid on concrete—on which a car may remain undisturbed for any desired length of time should pass directly under or at the side of the gauge tanks.

Several gauging tanks are needed to reach the goal of being able to “dump” several tanks to fill a large tank car. These primary tanks are used to enter the large measures of water into the tank car, and the finishing tank is used to complete the filling of the tank car with smaller quantities. Typically, there are four larger tanks with capacities of 7800, 5800, 4000 and 2400 gallons, with a finishing tank that has a ca-pacity of 500 gallons.

The finishing tank shall be equipped with an external gauge glass throughout its length and so connected that the water level in the glass shall conform to the water level in the tank. This finishing tank should be of small diameter so that accurate readings are obtained when small quantities of water are withdrawn.

The gauge tanks shall conical bottoms and tops—preferably inclined at an angle of 45° or greater from the horizontal—and shall be provided with draw off valves at the bottom and suitable connections at the top for filling with water. The connections for filling the tank should be provided with swing joints so that they may be moved away from the opening at the top of the tank. The water in the tank will then be completely separated from its source of supply. All connections shall be so placed that the water on the tank side of the valve will drain completely.

The water drains by gravity from the gauge tanks to the car tank. The piping between the valve of the gauge tank and the manway opening of the car tank shall be as short and direct as possible, and shall be inclined at an angle that will promote rapid and complete drainage.

When the gauge tank is filled from the bottom, a downspout shall also be used which reaches to within a few inches of the bottom of the car tank to be gauged, so that the outlet is under the surface of the water after the first few seconds of filling. The piping between the valve of the gauge tank and the end of the downspout shall· be as short and direct as possible, and shall be inclined at an angle which will promote rapid and complete drainage.

The openings at the top of the gauge tanks (which should be large enough to permit entrance for in-spection of the tanks) should be circular or elliptical in shape, have true and level edges, or be equipped with V-notches, so that, when filled to overflowing, the tanks shall necessarily contain a definite volume.

When desired, gauge tanks may be equipped with suitable connections for filling from the bottom, in which case the valves in the supply line leading to the gauge tanks shall be doubled and the nipples between the valves shall be, equipped with a drain cock or bleeder. To ascertain that no water is leaking into or out of the supply line, the drain cock or bleeder shall be opened after the tank has been filled.

The water should be circulated in underground tanks and the temperature controlled by heating or cooling. The water supply and ambient conditions will influence how much heating or cooling is needed to maintain


the 60 Degree Fahrenheit temperature. The water used should have a temperature indicator but each gauging tank is not required to have a temperature sensor.

Treatment of the water should be in accordance with plant safety and health requirements.

A.2 Calibration of Water Gauge Plants

In all cases, the capacities of gauging and finishing measures used shall be certified by a process that is traceable to the U.S. National Institute of Science & Technology (NIST) with an uncertainty of 0.03%. The calibration certificates shall show the capacity based on the number of liters (gallons) the measure delivers at 15°C (60°F).

The calibration for gauging tanks shall be considered current for 5 years.

Acceptable methods for calibrating gauging and finishing tanks shall be API MPMS Chapter 4.9.2 (Wa-terdraw Method) and 4.9.4 (Gravimetric Method) exclusively.

Figure A- 1 Typical Layout of a Water Gauge Plant

The temperature of the water in a gauge glass may vary considerably with the temperature of the water in the main body of the finishing tank. To equalize the temperature and to prevent errors in marking, water from the gauge glass should be occasionally drained into a container and immediately poured back into the main body of the finishing tank

Finishing tanks are intended to be drained partially and are equipped with sight gauges. The calibration procedure shall ensure that the scale is attached in a manner that prevents movement and accurately reflects the volume delivered.

After the gauge plant has been calibrated as outlined it c a n be checked, if possible, by tank cars which have been gauged previously whose accuracy has been established.

31 This document is not an API Standard; it is under consideration within an API technical committee but has not received all approvals required to become an API Standard. It shall not be reproduced or circulated or quoted, in whole or in part, outside of API committee activities except with the approval of the Chairman of the committee having jurisdiction and staff of the API Standards Dept. Copyright API. All rights reserved. Annex B. Data Forms - Informative

A suggested form for recording tank measurements is illustrated below.

Straight Length

A-End B-End Aver-age Half Tank Straight Length

Head Straight Flange Length

Head to Mid Seam Length

A Half Tank Straight Length

Head Straight Flange Length

Head to Mid Seam Length

B Half Tank Straight Length

Top Dead Center

Bottom Dead Center

Quarter 90°

Quarter 270°

Average Half Tank Straight Length

Head Depth

A End Dimensions B End Dimensions Aver-age Head Depth

Head Depth

Head Thick-ness

Inside Head Depth

Head Depth

Head Thick-ness

Inside Head Depth

Top Dead Center

Bottom Dead Center

Thickness Point 1

Thickness Point 2

Thickness Point 3

Thickness Point 4

Average


Determine Radius of Each Tank Head

From AAR 4-2 A Head B Head

Aver-age

Radius

Determine slope of the tank car, s

Elevation from Datum A End B End Aver-age

Bottom Dead Center

Car Center Bottom

Slope

33 This document is not an API Standard; it is under consideration within an API technical committee but has not received all approvals required to become an API Standard. It shall not be reproduced or circulated or quoted, in whole or in part, outside of API committee activities except with the approval of the Chairman of the committee having jurisdiction and staff of the API Standards Dept. Copyright API. All rights reserved. Annex C. Calculated Examples – Informative

We will add 10 examples after the committee gives some feedback on the initial draft. We will provide a spreadsheet that calculates the examples so that they can be changed or updated going forward.

Please provide the specific type of examples Mechanical strapping, water gauge at a few specific levels, etc. The input values or ranges of input values would be helpful but not required. Does the Committee want the examples in the form of a table of inputs with outputs (space efficient allowing more examples) or as a single page per example(formats nicer but reduces number of cases dramatically).


Product No. XXXXXX

Documents

Standard Method for Calibration of Tank Cars - API Ballotsballots.api.org/copm/colm/ballots/docs/Std2554_e2_COLM_9_17.pdf · Standard Method for Calibration of Tank Cars 4 1 Introduction