UL 142: Steel Aboveground Tanks for Flammable and Combustible Liquids

Question 1

What is the minimum thickness allowed for the flanged section of a pressed steel fitting? (refer to No. 3 of Figure 7.1 for an illustration of this type of fitting) (UL 142, Table 7.4)

Answer 1

0.135 in.

Question 2

What is the minimum length of thread required for threaded pipe connections that are 2.5 to 3.5 inches in diameter? (UL 142, Table 7.4)

Answer 2

1 inch

Question 3

What is the minimum length of thread required for a threaded pipe connection that is one inch in diameter? (UL 142, Table 7.4)

Answer 3

5/8 inch

Question 4

Each primary containment tank and each compartment of a compartment tank shall have provision for what kinds of venting? (UL 142, Section 8.1)

Answer 4

Each primary containment tank including each compartment of a compartment tank shall have provisions for both normal venting and emergency venting.

Question 5

The interstitial space of a secondary containment tank shall have provisions for what type of venting? (UL 142, Section 8.1.2)

Answer 5

The interstitial space of a secondary containment tank shall have provisions for emergency venting.

Question 6

According to UL 142, if a horizontal steel aboveground tank has a diameter of six feet, what is the maximum length of the tank? (UL 142, Section 13.1.2)

Answer 6

The overall length of a horizontal tank shall not be greater than six times its diameter with a maximum of 72 feet, therefore 36 feet for a tank 6 feet in diameter.

Question 7

Under what condition would the flanged flat head of horizontal tank more than 72 inches in diameter need an additional brace welded to the tank head? (UL 142, Section 13.3.3)

Answer 7

If it is made of steel that is less than 5/16 in (7.9 mm) thick.

Question 8

According to UL 142, what is the minimum diameter allowed for a vertical cylindrical steel tank that is 20 feet tall? (UL 142, Section 15.1.1)

Answer 8

The minimum diameter of a vertical tank shall not be less than one-quarter of its height. Therefore, a 20 foot tall tank should be at a minimum 5 feet in diameter.

Question 9

What is the maximum allowable shell height for a vertical cylindrical steel tank constructed according to UL 142? (UL 142, Section 15.1.2)

Answer 9

The shell height of a vertical tank shall not be more than 50 feet (15.24 m) and not to exceed 60,000 gallons of capacity.