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363 

Pipeline and Haz. Matls. Safety Admin., DOT 

§ 172.102 

hour per square meter per degree Celsius 
(0.075 Btu per hour per square foot per de-
gree Fahrenheit) temperature differential. 
Insulating materials must not promote 
corrosion to steel when wet. 

B15

Packagings must be protected with 

non-metallic linings impervious to the lad-
ing or have a suitable corrosion allowance. 

B16

The lading must be completely covered 

with nitrogen, inert gas or other inert ma-
terials. 

B18

Open steel hoppers or bins are author-

ized. 

B23

Tanks must be made of steel that is 

rubber lined or unlined. Unlined tanks 
must be passivated before being placed in 
service. If unlined tanks are washed out 
with water, they must be repassivated 
prior to return to service. Lading in un-
lined tanks must be inhibited so that the 
corrosive effect on steel is not greater than 
that of hydrofluoric acid of 65 percent con-
centration. 

B25

Packagings must be made from monel 

or nickel or monel-lined or nickel-lined 
steel. 

B26

Tanks must be insulated. Insulation 

must be at least 100 mm (3.9 inches) except 
that the insulation thickness may be re-
duced to 51 mm (2 inches) over the exterior 
heater coils. Interior heating coils are not 
authorized. The packaging may not be 
loaded with a material outside of the pack-
aging’s design temperature range. In addi-
tion, the material also must be covered 
with an inert gas or the container must be 
filled with water to the tank’s capacity. 
After unloading, the residual material also 
must be covered with an inert gas or the 
container must be filled with water to the 
tank’s capacity. 

B27

Tanks must have a service pressure of 

1,034 kPa (150 psig). Tank car tanks must 
have a test pressure rating of 1,379 kPa (200 
psig). Lading must be blanketed at all 
times with a dry inert gas at a pressure not 
to exceed 103 kPa (15 psig). 

B28

Packagings must be made of stainless 

steel. 

B30

MC 312, MC 330, MC 331 and DOT 412 

cargo tanks and DOT 51 portable tanks 
must be made of stainless steel, except 
that steel other than stainless steel may 
be used in accordance with the provisions 
of § 173.24b(b) of this subchapter. Thickness 
of stainless steel for tank shell and heads 
for cargo tanks and portable tanks must be 
the greater of 7.62 mm (0.300 inch) or the 
thickness required for a tank with a design 
pressure at least equal to 1.5 times the 
vapor pressure of the lading at 46 

°

C (115 

°

F). In addition, MC 312 and DOT 412 cargo 

tank motor vehicles must: 
a. Be ASME Code (U) stamped for 100% ra-

diography of all pressure-retaining welds; 

b. Have accident damage protection which 

conforms with § 178.345–8 of this sub-
chapter; 

c. Have a MAWP or design pressure of at 

least 87 psig: and 

d. Have a bolted manway cover. 

B32

MC 312, MC 330, MC 331, DOT 412 cargo 

tanks and DOT 51 portable tanks must be 
made of stainless steel, except that steel 
other than stainless steel may be used in 
accordance with the provisions of 
§ 173.24b(b) of this subchapter. Thickness of 
stainless steel for tank shell and heads for 
cargo tanks and portable tanks must be 
the greater of 6.35 mm (0.250 inch) or the 
thickness required for a tank with a design 
pressure at least equal to 1.3 times the 
vapor pressure of the lading at 46 

°

C (115 

°

F). In addition, MC 312 and DOT 412 cargo 

tank motor vehicles must: 

a. Be ASME Code (U) stamped for 100% radi-

ography of all pressure-retaining welds; 

b. Have accident damage protection which 

conforms with § 178.345–8 of this sub-
chapter; 

c. Have a MAWP or design pressure of at 

least 87 psig; and 

d. Have a bolted manway cover. 
B33

MC 300, MC 301, MC 302, MC 303, MC 305, 

MC 306, and DOT 406 cargo tanks equipped 
with a 1 psig normal vent used to transport 
gasoline must conform to Table I of this 
Special Provision. Based on the volatility 
class determined by using ASTM D 439 and 
the Reid vapor pressure (RVP) of the par-
ticular gasoline, the maximum lading pres-
sure and maximum ambient temperature 
permitted during the loading of gasoline 
may not exceed that listed in Table I. 

T

ABLE

I—M

AXIMUM

A

MBIENT

T

EMPERATURE

— 

G

ASOLINE

 

ASTM D439 volatility class 

Maximum lading and 
ambient temperature 

(see note 1) 

A ........................................................

131 

°

(RVP 

≤ 

9.0 psia) 

B ........................................................

124 

°

(RVP 

≤ 

10.0 psia) 

C ........................................................

116 

°

(RVP 

≤ 

11.5 psia) 

D ........................................................

107 

°

(RVP 

≤ 

13.5 psia) 

E ........................................................

100 

°

(RVP 

≤ 

15.0 psia) 

N

OTE

1: Based on maximum lading pressure of 1 psig at 

top of cargo tank. 

B35

Tank cars containing hydrogen cyanide 

may be alternatively marked 
‘‘Hydrocyanic acid, liquefied’’ if otherwise 
conforming to marking requirements in 
subpart D of this part. Tank cars marked 
‘‘HYDROCYANIC ACID’’ prior to October 
1, 1991 do not need to be remarked. 

B42

Tank cars constructed before March 16, 

2009, must have a test pressure of 34.47 Bar 

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