API 570 Piping Classes (Onsite vs. Offsite)

Question 0

H2, Fuel Gas, Natural Gas

Onsite - Offsite?

Answer 0

Class 2

Question 1

Class of piping with C2-4, H2S, HC (hydrocarbons auto refrigerate, or Boiling point < 50 *F

Onsite - Offsite?

Answer 1

Class 1

Question 2

Hydrocarbons - slowly vaporize (operate > flash point)

Onsite - Offsite?

Answer 2

Class 2 (Onsite) - Class 3 (Offsite)

Class 1(over road or water)

Question 3

Acids & Caustics

Onsite-Offsite?

Answer 3

Class 2 (Onsite) - Class 3 (Offsite) 
Class 1 (over road or water)

Question 4

Hydrocarbons - No significant vaporization, Operate below flashpoint

Onsite - Offsite?

Answer 4

Class 3 in both Onsite & Offsite!