deterioration by lading or in service, and must withstand without leakage a pressure equal to test pressure of tank. Provision must be made for closing service outlet of valves.*+ [Par. 7, as amended Jan. 13, 1932]

72.107A-8 Safety devices. (a) Tank must be equipped with one or more safety devices of approved type and discharged area, made of metal not subject to rapid deterioration by the lading or in service. Total discharge capacity must be such that, with tank filled with air at pressure equal to 70 percent of test pressure of tank, discharge capacity will be sufficient to reduce air pressure to 30 percent of test pressure within 3 minutes after safety devices open.

(b) Safety devices must open at pressure not exceeding test pressure. (For tolerance for safety valves, see § 72.107A-12 (a)).*† [Par. 8, as amended Jan. 13, 1932]

72.107A-9 Fixtures. Attachments, other than those mounted on tank cover, are prohibited.*+ [Par. 9, as amended Jan. 13, 1932]

72.107A-10 Tests of tanks. (a) After heat treatment, tanks must be subjected to hydrostatic tests in a water jacket, or by other accurate method, operated so as to obtain reliable data. No tank shall have been subjected previously to internal pressure greater than 90 percent of test pressure.

(b) Each tank must be tested to 10/7 of pressure developed at 130° F. by the gas which the tank is designed to transport.

(c) Pressure must be maintained for 30 seconds, and sufficiently longer to insure complete expansion of tank. Pressure gage must permit reading to accuracy of 1 percent. Expansion gage must permit reading of total expansion to accuracy of 1 percent. Expansion must be recorded in cubic centimeters.

(d) Permanent volumetric expansion must not exceed 10 percent of total volumetric expansion at test pressure.*+ [Par. 10, as amended Jan. 13, 1932]

72.107A-11 Handling of tanks failing in tests. Tanks rejected for failure in any of the tests prescribed may be reheat treated, and will be acceptable if subsequent to reheat treatment they are subjected to and pass all of the tests.*† [Par. 11, as amended Jan. 13, 1932]

72.107A-12 Tests of safety devices. (a) Safety devices of valve type must be tested by air or gas before being put into service and also at intervals as prescribed in § 72.107A-13 (b). Valve must open at pressure not exceeding test pressure of tank and be vapor tight at 80 percent of test pressure. These limiting pressures must not be affected by any auxiliary closure or other combination.

(b) For safety devices of frangible disk type, samples of disks used must burst at pressure not exceeding test pressure of tank. (See also § 72.107A-13 (b)).*+ [Par. 12, as amended Jan. 13, 1932]

72.107A-13 Retests, alterations, and upkeep of tanks and safety devices. (a) Each tank must be subjected at least once every 5 years to test prescribed in § 72.107A-10 (a)-(d). A tank must be condemned

**For statutory and source citations, see note to § 72.1A-1.

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1

when it leaks or when premanent expansion exceeds 10 percent of total expansion. Reports giving data showing results of these tests' must be rendered by party making tests to owner of tank and to the Bureau of Explosives, and each tank passing test must be marked with date (month and year), plainly and permanently stamped into metal of one head. For example, 1-29, for January 1929. Dates of previous tests must not be obliterated.

(b) Safety devices of valve type must be retested at least once every 2 years in manner prescribed in § 72.107A-12 (a). When safety devices of frangible disk type are used, one from each car must be tested every 2 years as prescribed in § 72.107A-12 (b).

(c) All prescribed markings on tanks must be kept legible. Use of copy of markings, in letters and figures of prescribed size, stamped on a brass plate secured to the tank, is authorized. Markings must not be added to or changed, except as follows:

(1) By application of additional marks not affecting test pressure or water capacity; these marks must not obliterate prescribed marks previously applied.

(2) By application of test pressure marks, or alteration of such marks, to indicate reduced test pressure; authorized only for tanks that have not failed in 5-year test.

(3) By change of serial numbers or ownership marks, or both, in which case report, in sufficient detail so that previous serial number and ownership mark can be determined for each tank, and arranged by lot numbers or by consecutive serial numbers, must be filed with the Bureau of Explosives.

(d) Tanks exposed to action of fire must not again be placed in service until they have been inspected inside and outside, to determine that no reduction in wall thickness has resulted, and properly heat treated and retested: Provided, That tanks made of plain carbon steel, of not exceeding 0.20 percent carbon content need not be heat treated and may be used after passing pressure test prescribed in § 72.107A-10 (a)-(d). These operations must be carried out, supervised, and reported, as prescribed by this specification for original heat treatment and test.* [Par. 13, as amended Jan. 13, 1932]

72.107A-14 Marking. (a) Each tank must be plainly and permanently marked, thus certifying that tank complies with all requirements of this specification. These marks must be stamped into metal of one head, in letters and figures at least 1/2-inch high, as follows: (b) ICC-107A to be replaced by figures indicating test pressure.

* * *

*, the

* * *

(c) Serial number (immediately below foregoing).

(d) Inspector's official mark (immediately below serial number). (e) Name, mark (other than a trade-mark), or initials of company or person for whose use tank is being made, which must be recorded with the Bureau of Explosives.

(f) Date (month and year) of tank test, such as 1-29, for January 1929, so placed that dates of subsequent tests may easily be added

thereto.

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**For statutory and source citations, see note to § 72.1A-1.

(g) Date (month and year) of safety-device or frangible-disk test, such as 1-29, for January 1929, so placed that dates of subsequent tests may easily be added thereto.

(h) Water capacity-0.000 pounds.

(i) Name of gas for which tank is designed, and maximum pressure at which tank may be operated, stenciled in letters and figures at least 2 inches high on each tank, and where they are clearly visible to person loading tank, for example:

HELIUM

Maximum pressure

at 130° F., ** * lbs. per sq. in.*†

[Par. 14, as amended Jan. 13, 1932]

NOTE 1: Charging pressure must be such that at 130° F. the stenciled pressure will not be exceeded.

NOTE 2: If desired to show only a single charging pressure for all tanks on any car, the minimum charging pressure for any tank on the car must be used and prominently displayed in an approved location.

72.107A-15 Inspection and reports. (a) Purchaser of tanks must provide for inspection by a competent and disinterested inspector.

(1) Inspector must carefully inspect all material and reject that not complying with § 72.107A-2.

(2) Inspector must stamp his official mark on each forging or seamless tube accepted by him for use in making tanks, and must verify proper application of heat numbers to such material by occasional inspections at steel manufacturer's plant.

(3) Inspector must obtain certified chemical analysis of each heat of material. He must also verify analysis by a check analysis of one sample from top of each ingot after cropping and boring, or after cropping, piercing, and forging. Sample must be taken at midwall thickness. For tanks made of seamless tubing, when the foregoing ingot check analysis is not practicable, inspector must verify analysis by check analysis of sample from one section of tubing from each heat of material. Check analysis must include quantitative determinations of all important elements present, in addition to those specified in § 72.107A-2 (b).

(4) Inspector must make inspection of inside surface of tanks before necking down, to insure that no seams, cracks, laminations, or other defects exist.

(5) Inspector must fully verify compliance with specification, verify heat treatment of tank as proper, obtain samples for all tests and check chemical analyses, witness all tests, and report tank capacity in pounds of water, tare weight, minimum thickness of tank wall noted, and maximum outside diameter of each tank.

(6) Inspector must stamp his official mark on each accepted tank immediately below serial number, and make certified report (see paragraph (b)), to maker, to company, or person for whose use

**For statutory and source citations, see note to § 72.1A-1.

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tanks are being made, to maker of car structure on which tanks are to be mounted, to the Bureau of Explosives, and to the secretary, mechanical division, American Railway Association.

(b) Inspector's report required herein must be clear and legible and in the following form:

Specification 107A

and test pressure as recorded on record of general data on tanks attached hereto. NOTE: In place of stars insert test pressure. Serial numbers

to

inclusive.

Steel used was verified as to chemical analysis and record thereof is attached hereto. Heat numbers were stamped into metal.

All material was inspected and each tank was inspected both before and after closing in ends; all material accepted was found free from seams, cracks, laminations, and other defects which might prove injurious to strength of tank. Processes of manufacture and heat treatment of tanks were witnessed and found to be efficient and satisfactory.

Wall of each tank was measured and minimum thickness in inches was recorded. Maximum outside diameter of each tank was measured and recorded. Maximum fiber stress in wall of each tank was calculated for internal pressure developed by contents of tank at 130° F., and recorded.

Hydrostatic tests, tensile tests of material, and other tests, as prescribed in this specification, were made in the presence of the inspector, and all material and tanks accepted were found to be in compliance with the requirements of this specification. Records thereof are attached hereto.

I hereby certify that all of these tanks proved satisfactory in every way and comply with the requirements of Interstate Commerce Commission specification No. 107A *

(Signed).

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Inspector.