NFPA 30: Flammable and Combustible Liquids Code

Question 1

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

Answer 1

An opening, construction method, or device that will automatically relieve excessive internal pressure due to an exposure fire.

Question 2

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

Answer 2

Releases of flammable vapor that continuously or intermittently occur from process equipment during normal operations.

Question 3

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

Answer 3

Any liquid not defined as unstable.

Question 4

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

Answer 4

A liquid that, in the pure state or as commercially produced or transported, will vigorously polymerize, decompose, undergo condensation reaction, or become self-reactive under conditions of shock, pressure, or temperature.

Question 5

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

Answer 5

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

Question 6

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

Answer 6

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

Question 7

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

Answer 7

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

Question 8

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

Answer 8

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 9

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

Answer 9

Any liquid that has a closed-cup flash 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).

Question 10

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

Answer 10

Any liquid that has a closedcup flash point at or above 100°F (37.8°C), as determined by the test procedures and apparatus set forth in Section 4.4.

Question 11

What does adequate venting of an atmospheric storage tank prevent? (NFPA 30, Section 21.4.3.1)

Answer 11

Storage tanks shall be vented to prevent the development of vacuum or pressure that can distort the tank or exceed the rated design pressure of the tank when the tank is filled or emptied or because of atmospheric temperature changes.

Question 12

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 12

Each connection to an aboveground tank through which liquid can normally flow shall be provided with an internal or an external valve located as close as practical to the shell of the tank.

Question 13

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 13

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

Question 14

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

Answer 14

All metallic equipment such as tanks, machinery, and piping where the potential exists for an ignitable mixture to be present shall be bonded and grounded.

Question 15

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)

Answer 15

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 16

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 16

An isolation valve shall be provided. This valve shall be located so that it is accessible or shall be remotely operable.

Question 17

If the piping test procedures in ASME B31 are not followed, what procedures should be used to test piping before it is covered, enclosed or placed in use? (NFPA 30, Section 27.7)

Answer 17

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.

Question 18

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 18

In no case shall the test pressure be maintained for less than 10 minutes.

Question 19

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

Answer 19

All nonmetallic equipment and piping where the potential exists for an ignitable mixture to be present shall be designed and operated to prevent electrostatic ignition.

Question 20

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

Answer 20

A storage tank that has been designed to operate at pressures from atmospheric through a gauge pressure of 1.0 psi (6.9 kPa) (i.e., 760 mm Hg through 812 mm Hg) measured at the top of the tank.

Question 21

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

Answer 21

For the purposes of this code, a storage tank designed to withstand an internal pressure above a gauge pressure of 1.0 psi (6.9 kPa) but not more than a gauge pressure of 15 psi (103 kPa) measured at the top of the tank.

Question 22

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

Answer 22

A container or other component designed in accordance with the ASME Boiler and Pressure Vessel Code or CSA B51, Boiler, Pressure Vessel and Pressure Piping Code. [52, 2016]

Question 23

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

Answer 23

Fire protection for structures on property adjacent to liquid storage that is provided by (1) a public fire department or (2) a private fire brigade maintained on the property adjacent to the liquid storage, either of which is capable of providing cooling water streams to protect the property adjacent to the liquid storage.

Question 24

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

Answer 24

A tank that has an inner and outer wall with an interstitial space (annulus) between the walls and that has a means for monitoring the interstitial space for a leak.

Question 25

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

Answer 25

A fluid with a boiling point lower than −130°F (−90°C) at an absolute pressure of 14.7 psi (101.325 kPa). [55, 2016]

Question 26

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

Answer 26

12 in.

Question 27

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))

Answer 27

a) Type of Tank,
b) Diameter
c) Capacity
d) Type of Protection supplied

Question 28

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 28

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.

Question 29

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 29

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 tank.

Question 30

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 30

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 31

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))

Answer 31

The distance between the shell of any tank and the toe of the interior of the dike wall shall be not less than 5 ft (1.5 m).

Question 32

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 32

To permit access, the outside base of the dike at ground level shall be no closer than 10 ft (3 m) to any property line that is or can be built upon.

Question 33

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

Answer 33

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

Question 34

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 34

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 35

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)

Answer 35

1) vapor recovery
2) vapor conservation
3) air pollution control

Question 36

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)

Answer 36

Tanks shall be gauged at intervals in accordance with established procedures by personnel continuously on the premises during product receipt. Acknowledged communication shall be maintained with the supplier so flow can be shut down or diverted in accordance with established procedures.
Tanks shall be equipped with a high-level detection device that is either independent of any gauging equipment or incorporates a gauging and alarm system that provides electronic self-checking to indicate when the gauging and alarm system has failed. Alarms shall be located where personnel who are on duty throughout product transfer can arrange for flow stoppage or diversion in accordance with established procedures.
Tanks shall be equipped with an independent high-level detection system that will automatically shut down or divert flow in accordance with established procedures.

Question 37

Except where special provisions have been made, what is the maximum interior height of a dike wall above the interior grade of the diked area? (NFPA 30, Section 22.11.2.5(1))

Answer 37

6 feet