Sec. 1276.6. Cargo tank construction

(a) Capacity.

Cargo tanks shall not exceed 6,000 gallons capacity. Fuel truck filling racks must be designed for static electricity control.

(b) Compartmentation.

Every cargo tank shall be divided into compartments and provided with baffles as follows:

(1) Every tank larger than 1,200 gallons shall be divided into compartments, none of which shall have a capacity exceeding 1,200 gallons.

(2) Every tank and every compartment of a tank over 90 inches in length shall be provided with baffles, the number of which shall be such that the linear distance between any two adjacent baffles, or between any tank head or bulkhead and the baffle nearest it, shall in no case exceed 60 inches.

(3) Each bulkhead required herein shall have adequate strength without undue stress or any permanent set to withstand a horizontal force equal to the weight of so much of the contents of the tank as may come between it and any adjacent bulkhead or tank head, applied as a uniformly distributed load on the surface of the bulkhead or tank head.

(4) Each baffle required herein shall have an area at least equal to 80 percent of the cross-sectional area of the tank.

(5) Each compartment of the completed tank shall be hydrostatically tested and proven tight at three pounds minimum pressure at top of tank, at initial inspection and at such times thereafter as may be designated by the Port Authority.

(c) Tolerance.

A tolerance of 10 percent shall be allowed for tank or compartment capacity.

(d)

(1) Dome covers and tank outlets.

Each compartment shall be fitted with an approved dome cover, securely fastened to the tank, constructed of steel, bronze or malleable cast iron. The dome cover shall be hinged toward the front of the vehicle, be designed to open not more than 91 degrees, drop shut upon forward movement of the truck and be fitted with a self-locking spring latch for secure closing, and a gasket to prevent leakage during overturn in transportation. Tank outlets shall be substantially made and attached to the tank in a manner to prevent breakage at outlet point. Sump drains shall be installed in a manner to permit complete drainage, fitted with an internal valve at the tank or sump and shall not contain any sight glasses or readily breakable parts.

(2) Bottom loading flow controls.

Cargo tanks arranged for bottom loading shall be fitted with approved hose connecting devices so as to open and permit product flow into the tanks when the companion nozzle is connected and locked in position. The device shall close automatically preventing product discharge when the companion nozzle is disconnected. Each compartment shall be fitted with an automatically operated vent and product level control device interlocked with the internal valve and designed to shut off the flow of product into the compartment and close the vent when the “full” level is reached. A single level control is acceptable if such manifold and valves are designed, tested and proven to permit uniform filing of all compartments. A manually operated level control testing by-pass valve and visual position indicating devices shall be provided for pre-checking the control and the operation of internal valves.

(e) Grounding, bonding and securing.

Cargo tanks shall be adequately supported and securely bolted or clamped to the frame of the vehicles. Such tank or tanks that are an integral part of such vehicles, tanks, chassis, axles and springs shall be electrically bonded to insure a complete grounding of all parts. Shell and head joint shall be welded.

(f) Vents.

Each cargo tank or each compartment shall be provided with normal breather vent a loading and unloading release vent, and emergency venting system as indicated herein.

(1) Normal breather vent.

The normal breather vent shall provide pressure and vacuum release through an area of 0.44 square inches. Pressure vents shall be set to open at no more than one psig or a vacuum not more than six ounces. Normal vents shall be designed to prevent loss of liquid in case of overturn, and flame propagation through the opening.

(2) Loading and unloading and emergency vents.

The loading and unloading venting protection shall be designed to limit the created vacuum to not exceed one psig or created pressure to not exceed three psig based on the maximum product transfer rate and be so certified by the tank vehicle manufacturer.

(i) The emergency venting system shall provide vent capacity in cubic feet of free air per hour (14.7 psia at 60 degrees Fahrenheit) as indicated in the table below:

20 square feet of exposed area requires

 

15,800 cu. ft./hr.

100 square feet of exposed area requires

 

79,100 cu. ft./hr.

500 square feet of exposed area requires

 

300,600 cu. ft./hr.

800 square feet of exposed area requires

 

392,200 cu. ft./hr.

1000 square feet of exposed area requires

 

445,000 cu. ft./hr.

(ii) Pressure actuated devices shall be designed to prevent leakage of liquids in case of surge, or vehicle upset.

(iii) When pressure actuated, the emergency venting system shall open at not less than three psig and close when the pressure drops to three psig or less.

(iv) The minimum vent capacity shall be 6000 cubic feet of air per hour at three psig.

(v) When fusibly actuated, the emergency venting system shall operate at not more than 250 degrees Fahrenheit and shall prevent any pressure build-up in excess of three psig at this temperature.

Breather vents, loading and unloading vents and emergency venting systems shall be fitted with proper backflash screens to control flame propagation. Backflash screens shall be securely attached, periodically checked and protected from mechanical damage, or snow and ice formation.

(g) Overturn protection.

All openings for filling, venting or other purposes shall be protected from damage in the event of overturning of the vehicle by being enclosed within the body of the tank or within a dome attached thereto, or by the use of metal guards securely attached to the tank or the frame of the vehicle. A minimum protecting clearance of one inch shall be provided by overturn protecting devices.

(h) Specifications.

Cargo tanks shall be constructed of either hot rolled tank steel or low alloy low carbon (high tensile) steels, and the minimum thickness of tank sheets shall be limited by the volume capacity of the tank expressed in terms of gallons per inch of length, and by the distance between bulkheads, baffles or other steel stiffeners, as well as by the radius of shell curvature in case of shell sheets, as shown on the following tables.

TABLE 1

HOT ROLLED TANK STEEL MINIMUM THICKNESS OF HEAD, BULKHEAD AND BAFFLE SHEETS^* (DISHED, CORRUGATED, REINFORCED OR ROLLED)

Volume capacity of tank in gallons per inch of length	10 or less	Over 10 to and including 14	Over 14 to and including 18	Over 18
U.S. standard gauge No.	14	13	12	11

*

Thickness of exterior head sheets shall never be less than the maximum requirements for shell sheets in any specific unit.

MINIMUM THICKNESS OF SHELL SHEETS

Distance between attachments of bulkheads, baffles, or other shell stiffeners
Volume capacity of tank in gallons per inch of length	36 in. or less	Over 36 to and including 54 in.	Over 54 to and including 60 in.
U.S. standard gauge for maximum shell radius of less than 70 in.:
10 gals. or less	14	14	14
Over 10 to and including 14 gals.	14	14	13
Over 14 to and including 18 gals.	14	13	12
Over 18 gals	13	12	11
U.S. standard gauge for maximum shell radius of 70 inches or more, but less than 90 inches:
10 gals. or less	14	14	13
Over 10 to and including 14 gals.	14	13	12
Over 14 to and including 18 gals.	13	12	11
Over 18 gals.	12	11	10
U.S. standard gauge for maximum shell radius of 90 inches or more, but not over 125 inches:
10 gals. or less	14	13	12
Over 10 to and including 14 gals.	13	12	11
Over 14 to and including 18 gals.	12	11	10
Over 18 gals	11	10	9
U.S. standard gauge for maximum shell radius over 125 inches:
10 gal. or less	13	12	11
Over 10 to and including 14 gals.	12	11	10
Over 14 to and including 18 gals.	11	10	9
Over 18 gals	10	9	8

TABLE 2

LOW ALLOY LOW CARBON (HIGH TENSILE) STEEL MINIMUM THICKNESS OF HEAD, BULKHEAD AND BAFFLE SHEETS^* (DISHED, CORRUGATED, REINFORCED OR ROLLED)

Volume capacity of tank in gallons per inch of length	10 or less	Over 10 to and including 14	Over 14 to and including 18	Over 18
U.S. standard gauge No.	15	14	13	12

*

Thickness of exterior head sheets shall never be less than the maximum requirements for the cargo tank shell sheets.

MINIMUM THICKNESS OF SHELL SHEETS

Distance between attachments of bulkheads, baffles, or other shell stiffeners
Volume capacity of tank in gallons per inch of length	36 in. or less	Over 36 to and including 54 in.	Over 54 to and including 60 in.
U.S. standard gauge for maximum shell radius of less than 70 in.:
10 gals. or less	16	16	15
Over 10 to and including 14 gals.	16	15	14
Over 14 to and including 18 gals.	15	14	13
Over 18 gals	14	13	12
U.S. standard gauge for maximum shell radius of 70 inches or more, but less than 90 inches:
10 gals. or less	16	15	14
Over 10 to and including 14 gals.	15	14	13
Over 14 to and including 18 gals.	14	13	12
Over 18 gals.	13	12	11
U.S. standard gauge for maximum shell radius of 90 inches or more, but not over 125 inches:
10 gals. or less	15	14	13
Over 10 to and including 14 gals.	14	13	12
Over 14 to and including 18 gals.	13	12	11
Over 18 gals	12	11	10
U.S. standard gauge for maximum shell radius over 125 inches:
10 gals. or less	14	13	12
Over 10 to and including 14 gals.	13	12	11
Over 14 to and including 18 gals.	12	11	10
Over 18 gals	11	10	9

Notation

*

Thickness of exterior head sheets shall never be less than the maximum requirements for shell sheets in any specific unit.