API 576

Question 1

Pressure/Vacuum-Relief Valves operate:

Answer 1

Very near atmospheric pressure

Question 2

The relieving pressure for Pressure/Vacuum-Relief Valves is “set” by:

Answer 2

adding or removing weights

Question 3

What causes air-space pressure to increase or decrease in a tank?

Answer 3

Product being pumped in or out

Thermal inbreathing or outbreathing

Question 4

A weight-loaded emergency vent:

Answer 4

Provides additional relieving capacity in an emergency

Is typically set at a pressure higher than the Pressure/Vacuum-Relief Valve

Question 5

Pressure/Vacuum-Relief Valves are very prone to:

Answer 5

Sticking

Question 6

Flame arrestors in the inlet of the Pressure/Vacuum-Relief Valves are very prone to:

Answer 6

Plugging

Question 7

Tanks equipped with heating coils can cause vapors that might:

Answer 7

Condense & freeze in the PVRV during cold temps

Question 8

A PVRV pallet has a weight of 4 pounds. The pallet area that is exposed to the pressure is 200 square inches. What pressure will lift this pallet allowing it relief.

Answer 8

Pressure = Force / Area = 4lbs / 200in = 0.020 PSIG