National Fire Protection Association NFPA 30 Flammable and Combustible Liquids Code

Question 1

What is the definition of an “atmospheric tank”? (NFPA 30, Section 3.3.52.2)

Answer 1

According to NFPA 30, Section 3.3.52.2, an “atmospheric tank” is a storage tank designed to operate at pressures ranging from atmospheric pressure to a gauge pressure of 6.9 kPa (1.0 psi), measured at the top of the tank.

Question 2

2. What is the definition of “emergency relief venting”? (NFPA 30, Section 3.3.61.1)

Answer 2

in NFPA 30, Section 3.3.61.1 defines “emergency relief venting” as the venting of a container or tank to prevent a buildup of pressure that could cause the container to rupture or explode due to fire exposure or other abnormal conditions.

Question 3

3. What is meant by the term “fugitive emissions”? (NFPA 30, Section 3.3.22)

Answer 3

in the context of NFPA 30, Section 3.3.22 defines “fugitive emissions” as the releases of flammable vapor that continuously or intermittently occur from process equipment during normal operations.

Question 4

What is the definition of a “low-pressure tank”? (NFPA 30, Section 3.3.52.3)

Answer 4

According to NFPA 30, Section 3.3.52.3, a “low-pressure tank” is defined as a tank designed to operate at a pressure not exceeding 15 psig (103.4 kPa).

Question 5

What is the definition of a “pressure vessel”? (NFPA 30, Section 3.3.44)

Answer 5

According to NFPA 30, Section 3.3.44, a “pressure vessel” is defined as a container designed to hold gases or liquids at a pressure substantially different from the ambient pressure.

Question 6

What is meant by the term “protection for exposures”? (NFPA 30, Section 3.3.46)

Answer 6

In the context of NFPA 30, “protection for exposures” (Section 3.3.46) refers to measures taken to safeguard other structures, equipment, or personnel from the potential hazards of a fire involving flammable or combustible liquids.

Question 7

What is the definition of a “secondary containment tank”? (NFPA 30, Section 3.3.52.5)

Answer 7

According to NFPA 30, Section 3.3.52.5, a “secondary containment tank” is a tank designed to contain a spill or leak from a primary tank, preventing the release of flammable or combustible liquids into the environment.

Question 8

What is the definition of a “cryogenic fluid”? (NFPA 30, Section 3.3.14)

Answer 8

a “cryogenic fluid” is defined as a fluid with a boiling point lower than -130°F (-90°C) at an absolute pressure of 14.7 psi (101.3 kPa).

Question 9

9. What is the definition of a “stable liquid”? (NFPA 30, Section 3.3.33.3

Answer 9

a “stable liquid” as a liquid that does not undergo rapid or violent decomposition, polymerization, or other reactions under normal storage and handling conditions.

Question 10

10. What is the definition of an “unstable liquid”? (NFPA 30, Section 3.3.33.4)

Answer 10

an “unstable liquid” is defined as a liquid that is capable of undergoing a violent reaction, even without the presence of an ignition source.

Question 11

11. What is the NFPA definition of “ventilation”? (NFPA 30, Section 3.3.62)

Answer 11

For the purpose of this code, movement
of air that is provided for the prevention of !re and explosion.

Question 12

12. What is the definition of “boiling point”? (NFPA 30, Section 3.3.5)

Answer 12

The temperature at which the vapor pres‐
sure of a liquid equals the surrounding atmospheric pressure.

Question 13

13. What is the definition of “flash point”? (NFPA 30, Section 3.3.21)

Answer 13

The minimum temperature of a liquid at
which suf!cient vapor is given off to form an ignitible mixture
with the air, near the surface of the liquid or within the vessel
used, as determined by the appropriate test procedure and
apparatus specifed in Section 4.4.

Question 14

14. What is the definition of “vapor pressure”? (NFPA 30, Section 3.3.55)

Answer 14

The pressure, measured in pounds
per square inch, absolute (psia), exerted by a liquid, as deter‐
mined by ASTM D323, Standard Test Method for Vapor Pressure of
Petroleum Products (Reid Method).

Question 15

15. What is the definition of a “class I flammable liquid”? (NFPA 30, Section 4.3.1)

Answer 15

Any liquid that has a closed-cup
“ash point below 100°F (37.8°C), as determined by the test
procedures and apparatus set forth in Section 4.4 and a Reid
vapor pressure that does not exceed an absolute pressure of
40 psi (276 kPa) at 100°F (37.8°C), as determined by ASTM
D323, Standard Test Method for Vapor Pressure of Petroleum Products
(Reid Method). Flammable liquids are classi!ed according to
Section 4.3. (See A.3.3.33.2.)

Question 16

16. What is the definition of a “combustible liquid”? (NFPA 30, Section 3.3.33.1)

Answer 16

Any liquid that has a closed-cup
“ash point at or above 100°F (37.8°C), as determined by the
test procedures and apparatus set forth in Section 4.4. Combustible liquids are classified according to Section 4.3.

Question 17

Vapor detectors in vaults shall be located no higher than above the lowest point of the vault. (NFPA 30, Section 25.15.3)

Answer 17

Vapor detectors shall be located no higher than 12 in.
(300 mm) above the lowest point in the vault.

Question 18

Table 22.4.1.1(a) & (b) in NFPA 30 is used to determine the minimum spacing between an aboveground tank shell and the nearest important building. In order to correctly determine the spacing, what four items must be known? (NFPA 30, Table 22.4.1.1(a) & (b))
a)

b)

c)

d)

Answer 18

Type of tank
Protections
Tank size
distances to property lines, or public way

Question 19

When remote impounding is used for control of spillage from aboveground tanks, what is the minimum slope required away from the tank? Over what distance must this slope be maintained? (NFPA 30, Section 22.11.1.1)

Answer 19

The drainage route shall have a slope of not less than 1 percent away from the tank for at least 50 ft (15 m)toward the impounding area.

The impounding area shall have a capacity not less than that of the largest tank that drains into it.

The impounding area shall be located so that, when filled to capacity, the liquid will not be closer than 50 ft (15 m)
from any property line that is or can be built upon or from any

Question 20

When remote impounding is used for control of spillage from aboveground tanks, and the impoundment area is filled to capacity, what is the minimum distance allowed between the liquid and any property line that can be built upon or any tank? (NFPA 30, Section 22.11.1.4)

Answer 20

The impounding area shall be located so that, when filled to capacity, the liquid will not be closer than 50 ft (15 m)
from any property line that is or can be built upon or from any

Question 21

When calculating the required capacity of a diked area that contains several tanks, how do you take into account the volume of the smaller tanks? (NFPA 30, Section 22.11.2.2.1)

Answer 21

To allow for volume occupied by tanks, the
capacity of the diked area enclosing more than one tank shall
be calculated after deducting the volume of the tanks, other
than the largest tank, below the height of the dike.

Question 22

What is the minimum distance allowed between the shell of aboveground tanks and the toe of the interior dike wall? (NFPA 30, Section 22.11.2.5(3))

Question 23

What is the minimum distance allowed between the outside base of a dike surrounding an aboveground tank and any property line that is or can be built upon? (NFPA 30,
Section 22.11.2.3)

Answer 23

Where the average interior height of the walls of the diked area exceeds 6 ft (1.8 m), provisions shall be made for
normal access; necessary emergency access to tanks, valves, and
other equipment; and egress from the diked enclosure. The following requirements shall apply:
(1) Where the average height of a dike containing Class I liquids is over 12 ft (3.6 m) high, measured from interior
grade, or where the distance between any tank and the top inside edge of the dike wall is less than the height of
the dike wall, provisions shall be made for operation of valves and for access to tank roof(s) without entering below the top of the dike. These provisions shall be
permitted to be met through the use of remote-operated valves, elevated walkways, or other arrangements.
(2) Piping passing through dike walls shall be designed to withstand imposed stresses as a result of settlement or !re exposure.
(3) The distance between the shell of any tank and the toe of the interior of the dike wall shall be not less than

Question 24

What information must be stamped on each commercially made tank venting device? (NFPA 30, Section 22.7.3.10)

Answer 24

(1) Start-to-open pressure
(2) Pressure at which the valve reaches the full open position
(3) Flow capacity at the pressure indicated by 22.7.3.10(2)

Question 25

How shall vent pipe outlets for tanks storing class I liquids adjacent to buildings or public ways be located? (NFPA 30, Section 27.8.1.1)

Answer 25

Where the outlets of vent pipes for tanks storing Class I liquids are adjacent to buildings or public ways, they shall be located so that vapors are released at a safe point outside of buildings and not less than 12 ft (3.6 m) above the adjacent ground level.

Question 26

As a general rule, manifolding of vent piping should be avoided. What are three special purposes that may require vent piping to be manifolded? (NFPA 30, Section 27.8.1.4.1) a) b) c)

Answer 26

Manifolding of vent piping shall be prohibited except where required for special purposes such as vapor recovery, vapor conservation, or air pollution control.

Question 27

31. In order to be able to separate a tank from its piping in an emergency, what must be provided at each opening in an aboveground tank through which liquid can normally flow? (NFPA 30, Section 22.13.1)

Answer 27

Each connection to an aboveground tank through which liquid can normally "ow shall be provided with an inter‐ nal or an external valve located as close as practical to the shell of the tank.

Question 28

32. Each opening below liquid level in an aboveground tank through which liquid does NOT normally flow must be equipped with a liquid tight closure. What are some examples of the type of hardware that can be used to meet this requirement? (NFPA 30, Section 22.13.2)

Answer 28

Each connection below the liquid level through which liquid does not normally "ow shall be provided with a liquid‐ tight closure such as a valve, plug, or blind, or a combination of these.

Question 29

33. In order to control static electricity, what must be done with metallic equipment? What must be done with non-metallic equipment? (NFPA 30, Section 6.5.4)

Answer 29

All equipment such as tanks, machinery, and piping shall be designed and operated to prevent electrostatic igni‐ tions. 6.5.4.2 All metallic equipment such as tanks, machinery, and piping where the potential exists for an ignitible mixture to be present shall be bonded and grounded.

Question 30

What are three acceptable methods of overfill prevention for aboveground tanks at terminals receiving Class I liquids from mainline pipelines or marine vessels? (NFPA 30, Section 27.7.1.1) a) b) c)

Answer 30

27.6.6.3 Each connection to a piping system by which equipment such as tank cars, tank vehicles, or marine vessels discharges liquids into storage tanks shall be provided with a check valve for automatic protection against backflow if the piping arrangement is such that backflow from the system is possible. (See also 22.13.1.) 27.6.7 Common Loading and Unloading Piping. If loading and unloading is done through a common pipe system, a check valve shall not be required. However, an isolation valve shall be provided. This valve shall be located so that it is accessible or shall be remotely operable.

Question 31

35. What are three things that must be included in the written procedures to prevent overfilling of aboveground tanks? (NFPA 30, Section 21.7.1.4) a) b) c)

Answer 31

Formal written procedures required by 21.7.1.1 shall include the following: (1) Instructions covering methods to check for lineup and receipt of initial delivery to tank designated to receive shipment. (2) Provision for training and monitoring the performance of operating personnel by supervisors. (3) Schedules and procedures for inspection and testing of gauging equipment and high-level instrumentation and related systems. Inspection and testing intervals shall be approved but shall not exceed 1 year.

Question 32

36. If loading and unloading is done through a common pipe system, a check valve is not required. However, what type of valve is required? Where should this valve be located? (NFPA 30, Section 27.6.7)

Answer 32

Isolation valve

Question 33

38. How long must a hydrostatic or pneumatic test of piping that has not yet been covered or enclosed last? (NFPA 30, Section 27.7.1.1)

Answer 33

Testing shall be done hydrostatically to 150 percent of the maximum anticipated pressure of the system or pneumatically to 110 percent of the maximum anticipated pressure of the system, and the test pressure shall be maintained while a complete visual inspection of all joints and connections is conducted. In no case shall the test pressure be less than a gauge pressure of 5 psi (35 kPa) measured at the highest point of the system, and in no case shall the test pressure be maintained for less than 10 minutes.

Question 34

What is the “flash point” of a liquid? (NFPA 30, Section 3.3.21)

Question 35

What is the definition of “flammable liquid”? (NFPA 30, Section 3.3.33.2)

Question 36

What is the minimum distance required between an underground tank containing Class I liquids and any property line that can be built upon? (NFPA 30, Section 23.4.2)

Question 37

What is the minimum distance required between an underground tank containing Class II or Class III liquids and the nearest wall of any basement, pit or property line that can be built upon? (NFPA 30, Section 23.4.3)

Question 38

What are three options for the minimum acceptable depth of cover for underground tanks located in a traffic area? (NFPA 30, Section 23.5.2.2

Question 39

How high above adjacent ground level must vent pipes for Class I liquids be located? (NFPA 30, Section 27.8.2.1)

Question 40

What is the minimum inside nominal diameter for a vent pipe for an underground tank? (NFPA 30, Section 23.6.2)

Question 41

What are the three factors that determine venting capacity for an underground tank? (NFPA 30, Section 23.6)

Question 42

Openings for manual gauging on tanks shall be provided with _____________ . (NFPA 30, Section 21.8.7)

Question 43

What is the only acceptable type of joint when piping systems handling Class I liquids are located in concealed spaces within buildings? (NFPA 30, Section 27.5.1.4

Question 44

What type of material should be used to fill an underground tank that is abandoned in place? (NFPA 30, Appendix C.4.11)

Question 45

After removal and cleaning, how should an underground tank be disposed? (NFPA 30, Appendix C.6.3, C.6.4)