CHAPTER 7 - CONCEPTS TO PREVENT FIRES AND EXPLOSIONS

Question 1

Capacitance is defined as

Answer 1

The ability to store electrical charge

Question 2

What is the recommended residence time in an enlarged section of pipe to reduce charge buildup during liquid transfer?

Answer 2

Half the relaxation time.

Question 3

To reduce charge buildup during the transfer of a liquid into a vessel, it is recommended to

Answer 3

Install a dip pipe

Question 4

The primary purpose of bonding and grounding in electrostatic hazard prevention is to

Answer 4

Reduce the potential difference between objects

Question 5

When handling flammable powders, what is the most effective way to prevent electrostatic ignitions?

Answer 5

Inerting the atmosphere.

Question 6

To prevent lightning-like discharges in a vessel, it is recommended to

Answer 6

Reduce the vessel volume

Question 7

An effective way to increase the conductivity of a nonconducting organic liquid is to

Answer 7

Introduce a polar solvent

Question 8

The “twice the relaxation time” rule provides a safety factor of

Answer 8

Four

Question 9

What is the purpose of a dip pipe in a liquid transfer system?

Answer 9

To prevent siphoning

Question 10

Which of the following is NOT a special design feature to prevent electrostatic ignitions?

Answer 10

D. Relaxation

Question 11

What is the primary purpose of an inert atmosphere when handling solids with flammable vapors?

Answer 11

To prevent the ignition of flammable vapors

Question 12

Which type of containers are recommended for solids containing flammable solvents?

Answer 12

Conductive and grounded containers

Question 13

What is the primary function of explosion-proof housings for electrical equipment in XP areas?

Answer 13

To withstand an internal explosion and prevent the spread of combustion

Question 14

Which of the following is not a class designation for flammable materials in the National Electrical Code (NEC)?

Answer 14

Class IV

Question 15

What is the purpose of ventilation in preventing fires and explosions in chemical plants?

Answer 15

To dilute explosive vapors with air to prevent ignition

Question 16

Which type of ventilation system is recommended for open-air plants?

Answer 16

Natural ventilation

Question 17

What is the primary function of sprinkler systems in fire prevention?

Answer 17

To suppress fires by applying water

Question 18

What is the primary purpose of deluge systems in vessel protection?

Answer 18

To keep the vessel walls cool and prevent metal failure

Question 19

What is the main purpose of monitors in chemical plants?

Answer 19

To provide a water source for firefighting

Question 20

Which of the following is not a design technique for preventing fires and explosions in chemical plants?

Answer 20

Increase in process temperature

Question 21

In Spark Discharge, the electrons migrate to leave the charged object at a single point and enter the second object at a single point because both are

Answer 21

Conductive

Question 22

What charge is created when electrons flow over a material interface

Answer 22

Positive or Negative

Question 23

The number of charge accumulation processes exist in a chemical facility that are relevant to hazardous electrostatic discharges?

Answer 23

Four

Question 24

The maximum charge density that the surface can reach is

Answer 24

2.7 × 10^(-5) C/m^2

Question 25

What is formed between two conductors when their distance is small compared to their diameter and the electric field intensity is around 3 MV/m.

Answer 25

Spark

Question 26

The most elusive of ignition sources.

Answer 26

Static Electricity

Question 27

A discharge that does not occur in vessels with capacity less than 60 m^3 or silos with diameters less than 3 m.

Answer 27

Lightning-like discharge

Question 28

What quantity of fines are necessary for coarse particles to create an explosive atmosphere in conical pile discharge so that the dust can ignite?

Answer 28

Small

Question 29

The flow of electricity produced by transmitting electrons from one surface to another through a flowing fluid or solid

Answer 29

Streaming Current

Question 30

What occurs when the distance between two conductors exceeds their radius of curvature

Answer 30

Brush Discharge

Question 31

What is the primary purpose of inerting a vessel?

Answer 31

To reduce the concentration of oxygen in the vessel.

Question 32

Which purging method is most suitable for large storage tanks?

Answer 32

Sweep-through purging

Question 33

During vacuum purging, what remains constant throughout the process?

Answer 33

The initial oxidant concentration within the vessel.

Question 34

What is the primary advantage of pressure purging over vacuum purging?

Answer 34

Shorter cycle times

Question 35

What is the primary disadvantage of sweep-through purging?

Answer 35

High consumption of inert gas.

Question 36

What is the role of the flammability diagram in inerting processes?

Answer 36

To identify potential flammable mixtures.

Question 37

Which of the following is NOT a common inert gas used in inerting processes?

Answer 37

Oxygen

Question 38

What is the typical limiting oxygen concentration (LOC) for gases?

Answer 38

10%

Question 39

During pressure purging, what happens to the number of moles of oxygen as the vessel is pressurized?

Answer 39

It remains constant.

Question 40

What is the primary goal of siphon purging?

Answer 40

To reduce the consumption of inert gas.