Line B Exam guide Flashcards
Why is wearing eye protection important during oxy-fuel welding and cutting processes?
a) To protect from flying molten oxides
b) To reduce the intensity of visible light
c) Both a and b
d) Neither a nor b
c) Both a and b
What is the purpose of wearing a full-face shield during oxy-fuel welding and cutting?
a) To protect the eyes from visible light
b) To shield the entire face from flying debris
c) To reduce the intensity of electromagnetic waves
d) All of the above
d) All of the above
Which of the following is NOT recommended as eye protection during oxy-fuel processes?
a) Clear face shield
b) Safety glasses with side shields
c) Auto-darkening helmets
d) Full-face shield with correct shade
a) Clear face shield
What additional protection does a full-face shield provide compared to safety glasses?
a) Protection from flying debris
b) Reduction in visible light intensity
c) Shielding of the entire face
d) Protection from electromagnetic waves
c) Shielding of the entire face
What specific materials pose a risk of causing burns when striking exposed skin during cutting?
a) Nitrogen gas
b) Tungsten particles
c) Slag and sparks
d) Liquid nitrogen
c) Slag and sparks
What should be considered regarding body position when using oxy-fuel processes?
a) It doesn’t matter where body parts are positioned
b) Body parts should be directly exposed to heat
c) Body parts, cylinders, and hoses should be away from direct heat, molten metal, sparks, and slag
d) Body parts should be positioned above gas hoses for better control
c) Body parts, cylinders, and hoses should be away from direct heat, molten metal, sparks, and slag
Where have a significant number of accidents occurred during metal cutting operations?
a) At high altitudes
b) Near volcanic regions
c) In close proximity to gas hoses or flammable materials
d) In controlled laboratory environments
c) In close proximity to gas hoses or flammable materials
Light and energy are transferred from one location to another when using oxy-fuel, which is why we wear PPE. In what form is the process done?
A) Ionizing wave lengths
B) Compound air-bound UV Rays
C) Electromagnetic Waves
D) Infrared Light
C) Electromagnetic Waves (Radiation)
When oxy-fuel-cutting a plate with a thickness of 0.9”, what is the SUGGESTED lens shade number?
A) 3
B) 4
C) 5
B) 4
When oxy-fuel-cutting a plate with a thickness of under an inch, the SUGGESTED lens shade number should be 4.
When oxy-fuel-cutting a plate with a thickness of 0.9”, what is the MINIMUM lens shade number?
A) 3
B) 4
C) 5
A) 3
When oxy-fuel-cutting a plate with a thickness of under an inch, the MINIMUM lens shade number would be 3, but 4 is highly recommended.
When oxy-fuel-cutting a plate with a thickness of 4.3”, what is the SUGGESTED lens shade number?
A) 3
B) 4
C) 5
C) 5
When oxy-fuel-cutting a plate one to six inches thick (1-6”), the SUGGESTED lens shade number should be 5.
When oxy-fuel-cutting a plate with a thickness of 5.2”, what is the MINUMUM lens shade number?
A) 3
B) 4
C) 5
B) 4
When oxy-fuel-cutting a plate one to six inches thick (1-6”), the MINUMUM lens shade number would be 4, but 5 is highly suggested.
When oxy-fuel-cutting a plate with a thickness of 8.3”, what is the SUGGESTED lens shade number?
A) 3
B) 4
C) 5
B) 5
When oxy-fuel-cutting a plate OVER 6” thick the SUGGESTED lens shade number should be 5.
When oxy-fuel-cutting a plate with a thickness of 6.3”, what is the MINIMUM lens shade number?
A) 3
B) 4
C) 5
B) 4
When oxy-fuel-cutting a plate OVER 6” thick, the MINIMUM lens shade number would be 4, but 5 is highly suggested.
What is slag?
a. Burned oxides
b. Metal
c. Sparks
d. Trapped air bubbles
a. Burned oxides
Slag is a by-product formed during certain processes, such as welding, when impurities in the materials being processed combine with fluxes or substances to form a molten compound. This compound solidifies as it cools and forms a layer on the surface of the molten metal, which is known as slag. It often consists of burned oxides, among other compounds, depending on the specific process and materials involved.
A fire triangle is made up of:
A) Oxygen, Heat, and Combustible Material
B) Fuel, Oxygen, and Heat
C) Ignition, Flame, and Smoke
D) Carbon, Hydrogen, and Oxygen
B) Fuel, Oxygen, and Heat
A Fire triangle is made up of three parts; removing any one of the three will prevent or extinguish a fire in the workplace.
What typically must be done during and after welding or cutting?
a. Fire watch
b. Hot work permit
c. Monitoring temperature
d. Spraying the area with water
a. Fire watch
During and after welding or cutting, it’s important to have someone keep an eye out for fires. This person, called a fire watch, is ready to put out any sparks or flames that might start a fire.
A backfire occurs where?
a. The cylinders
b. The hoses
c. The torch body
d. The torch tip
d) The torch tip
A backfire happens when the flame at the end of the torch tip moves back into the torch instead of staying at the tip where it should be. This can cause a sudden popping sound or even a flame coming out of the torch handle, which can be dangerous.
What is a possible cause of flashback?
a. Having oxygen and acetylene mixed in the acetylene hose
b. Not purging the lines properly
c. Overheating the torch tip
d. All of the above
d. All of the above
All the mentioned factors can contribute to a flashback in welding. Having oxygen and acetylene mixed in the acetylene hose, not purging the lines properly, and overheating the torch tip are common causes of flashback incidents during welding operations.
What device prevents flashbacks from travelling further?
a. Flashback arrestor
b. Mixing chamber
c. Pressure regulator
d. Reverse flow check valve
a. Flashback arrestor
A flashback arrestor is a safety device designed to prevent flashbacks from travelling further back into the hoses and gas supply systems. It works by extinguishing the flashback and preventing it from reaching the gas cylinders or other parts of the equipment where it could cause a more significant incident.
What is a backfire in oxy-acetylene equipment?
a. A momentary recession of the flame into the torch tip or mixer.
b. A steady flame burning from the torch tip.
c. A complete extinguishment of the flame without any sound.
d. A continuous flame that does not recede or make any noise.
a. A momentary recession of the flame into the torch tip or mixer,
followed by a loud popping sound.
What sound may indicate that the flame has reignited after a backfire?
a. A loud popping sound.
b. A squealing sound.
c. A hissing sound.
d. A crackling sound.
b. A squealing sound.
What should you shut down first in the event of a flashback?
a) Acetylene cylinder valve
b) Acetylene valve (torch)
c) Oxygen cylinder valve
d) Oxygen valve (torch)
d) Oxygen valve (torch)
What should you shut down first in the event of a backfire?
a. Acetylene cylinder valve.
b. Acetylene valve (torch).
c. Oxygen cylinder valve.
d. Oxygen valve (torch).
b. Acetylene valve (torch).
When is a backfire most commonly likely to occur in oxy-acetylene equipment?
a. When working with cold metal.
b. When adjusting the gas flow.
c. When the torch tip touches hot metal.
d. When the equipment is not properly cleaned.
c. When the torch tip touches hot metal.
What should be done if backfires continue to occur despite cleaning and purging the equipment?
a. Increase the gas flow.
b. Replace the torch tip.
c. Remove the torch from service for cleaning and possible repair.
d. Ignore it and continue working.
c. Remove the torch from service for cleaning and possible repair.
What can cause a flashback when using oxy-fuel torch lines?
a. Insufficient gas pressure
b. Excessive gas flow rate
c. Presence of contaminants in the gas lines
d. All of the above
d. All of the above
What are the potential aftereffects of a flashback?
a. Damage to the torch tip
b. Damage to the hoses
c. Both a and b
d. None of the above
c. Both a and b
At what temperature does the burning speed of the gas mixture increase dramatically during a flashback?
a. 150°C
b. 190°C
c. 220°C
d. 250°C
c. 220°C
At approximately what temperature can spontaneous ignition and burning of the gas mixture within the tip occur?
a. 220°C
b. 250°C
c. 280°C
d. 315°C
d. 315°C
What temperature must the torch tip be kept below to prevent spontaneous ignition of the gas mixture within the tip?
a. 150°C
b. 190°C
c. 220°C
d. 250°C
b. 190°C
In addition to extinguishing flames, what other function do flashback arrestors serve?
a. They increase the pressure of the gas
b. They regulate the oxygen-to-fuel ratio
c. They prevent the backflow of gas
d. They cool down the torch line
c. They prevent the backflow of gas
What happens if certain temperatures and/or pressures are exceeded in a flashback arrestor?
a. The gas flow is increased
b. The flashback arrestor shuts off the gas flow
c. The flashback arrestor ignites
d. The flashback arrestor expands
b. The flashback arrestor shuts off the gas flow
How are flashback arrestors typically marked to indicate the direction of gas flow?
a. With a circle
b. With a square
c. With an arrow
d. With a triangle
c. With an arrow
Where can flashback arrestors be installed in oxy-fuel torch lines?
a. Only at the torch
b. Only at the regulators
c. Both at the torch and regulators
d. None of the above
c. Both at the torch and regulators
What is the primary function of a torch-mounted flashback arrestor?
a. To protect the regulator
b. To prevent flashback from entering the hose
c. To stop the flow of gas
d. To extinguish flames on the torch tip
b. To prevent flashback from entering the hose
What is the purpose of a regulator-mounted flashback arrestor?
a. To protect the torch
b. To prevent flashback from going further back to the acetylene bottle
c. To stop the flow of oxygen
d. To extinguish flames on the regulator
b. To prevent flashback from going further back to the acetylene bottle
Why won’t a reverse-flow check valve stop a flashback?
a. Because it is not designed for gas flow direction
b. Because it is ineffective in high-pressure systems
c. Because it does not extinguish flames
d. Because it cannot prevent gas from flowing backwards
d. Because it cannot prevent gas from flowing backwards
What is the primary function of a reverse flow valve in oxy-fuel torch lines?
a. To increase the flow rate of gases
b. To regulate the temperature of the torch flame
c. To prevent the backflow of gases into the hoses
d. To adjust the pressure of the gases
c. To prevent the backflow of gases into the hoses
How does a reverse flow valve function in oxy-fuel torch lines?
a. By allowing the gases to flow in one direction only
b. By mixing oxygen and fuel gases to create a combustible mixture
c. By controlling the speed of the gas flow
d. By shutting off the gas supply in case of an emergency
a. By allowing the gases to flow in one direction only
What is he typical life expectancy of a reverse flow check valve?
a. 4 months
b. 8 months
c. 16 months
d. 18 months
- months
Cylinder pressure regulators have how many gauges?
a. 1
b. 2
c. 3
d. 4
c. 2
What position should the pressure regulator adjusting knob be set at prior to opening the cylinder valve?
a. Backed out all the way.
b. Threaded in all the way.
c. Threaded in 1-1.5 turns.
d. Threaded halfway.
a. Backed out all the way.
Which of the fuel gases has the widest range of mixtures with which it could explode?
a. Acetylene
b. Natural gas
c. Propane
d. Propylene
a. Acetylene (C2H2)
Acetylene has the widest range of mixtures with oxygen in which it can potentially explode. This wide range of explosive limits makes acetylene particularly hazardous if not handled properly, as it can ignite and cause explosions even at relatively low concentrations in the air.
True or false? Acetylene leaks are easy to detect because it has a strong pungent smell.
a. True
b. False
a. True
Acetylene has a distinctive, strong, and pungent odour that is often described as garlic-like or similar to that of rotten cabbage. This odour is intentionally added to acetylene gas to aid in the detection of leaks, making them easier to identify for safety purposes. Therefore, acetylene leaks are generally easy to detect due to this characteristic odour.
At what temperature does acetylene (C2H2) become unstable when oxy-fuel cutting?
a. Above 780 °C
b. Just below 810 °C
c. Just Above 870 °C
d. Approximately 930 °C
a. Above 780 °C
Acetylene becomes unstable at temperatures above approximately 780°C (1436°F) when used in oxy-fuel cutting. At this temperature, acetylene can decompose and become highly reactive. It’s crucial to monitor and control the temperature during oxy-fuel cutting to prevent acetylene from reaching its stability limit.
Which fuel gas produces the hottest flame temperature?
a. Acetylene.
b. Natural gas.
c. Propane.
d. Propylene.
a. Acetylene
Acetylene produces the hottest flame temperature among the options provided. When combined with oxygen in the oxy-fuel welding or cutting process, acetylene can reach flame temperatures of around 3,200°C (5,792 °F), making it ideal for applications requiring high heat intensity, such as metal cutting or welding thick materials.
What unstable compound is formed when acetylene comes into contact with copper or brass fittings?
a. Acetylide.
b. Carbon hydroxide.
c. Carbon monoxide.
d. Phosgene gas.
a. Acetylide
When acetylene comes into contact with copper or brass, it can form an unstable compound called copper acetylide. This compound is highly sensitive to shock, friction, or heat and can lead to explosive decomposition. So it’s crucial to avoid using copper and brass fittings with acetylene systems to prevent the formation of copper acetylide.
What is the molecular composition of acetylene?
a) Two carbon atoms and one hydrogen atom
b) Two carbon atoms and two hydrogen atoms
c) One carbon atom and two hydrogen atoms
d) One carbon atom and three hydrogen atoms
a) Two carbon atoms and one hydrogen atom
C2H2 (Acetylene)
What is the maximum temperature that an oxy-acetylene flame can reach?
a) 2500 °C (4532 °F)
b) 3000 °C (5432 °F)
c) 3200 °C (5792 °F)
d) 3500 °C (6332 °F)
c) 3200 °C (5792 °F)
Which type of fittings are recommended for acetylene gas systems?
a) Copper
b) Red brass
c) Yellow brass, iron, or steel
d) Aluminium
c) Yellow brass, iron, or steel
At what temperature and pressure does acetylene become unstable?
A) Above 500°C (932°F) and 100 kPa (15 psi)
B) Above 600°C (1112°F) and 150 kPa (22 psi)
C) Above 700°C (1292°F) and 180 kPa (26 psi)
D) Above 780°C (1436°F) and 200 kPa (30 psi)
D) Above 780°C (1436°F) and 200 kPa (30 psi)
What are the flammability limits of acetylene in oxygen by volume?
A) 0.5 to 10%
B) 2.3 to 82%
C) 10 to 50%
D) 90 to 100%
B) 2.3 to 82%
What is the ignition temperature of acetylene in oxygen?
A) 100 °C (212 °F)
B) 200 °C (392 °F)
C) 300 °C (572 °F)
D) 400 °C (752 °F)
C) 300 °C (572 °F)
What is the ignition temperature of acetylene in air?
A) 100 °C (212 °F)
B) 200 °C (392 °F)
C) 300 °C (572 °F)
D) 335 °C (635 °F)
D) 335 °C (635 °F)
What makes oxygen a hazardous gas?
a) It emits toxic fumes
b) It is highly corrosive
c) It enhances combustion intensity
d) It causes respiratory irritation
c) It enhances combustion intensity
In what form is oxygen available for use?
a) Liquid only
b) Gas only
c) Both gas and liquid
d) Solid only
c) Both gas and liquid
Oxygen is available either as a gas in a high-pressure cylinder or as a liquid in relatively low-pressure cryogenic cylinders.
Why is oxygen necessary for combustion to occur?
a) It provides fuel
b) It generates heat
c) It serves as a catalyst
d) It supports combustion
d) It supports combustion
Which statement is true regarding oxygen and flammability?
a) Pure oxygen is highly flammable
b) Oxygen inhibits combustion
c) Oxygen is non-reactive with most materials
d) Oxygen enhances the flammability of materials
d) Oxygen enhances the flammability of materials
Which gas is often preferred in areas where it can be piped to eliminate risks related to handling fuel cylinders?
a) Propane
b) Natural gas
c) Acetylene
d) Hydrogen
b) Natural gas
What is a characteristic of natural gas compared to propane?
a) Higher flame temperature
b) Lower cost
c) Requires a specific torch and tip
d) More dense than air
b) Lower cost
Which gas is produced by rearranging the molecules in acetylene and propane to form a new compound?
a) Hydrogen
b) Natural gas
c) MPS gas
d) Propylene
c) MPS gas (Methylacetylene-propadiene, stabilized)
How is MPS (methylacetylene-propadiene, stabilized) gas stored?
a) In a gaseous form
b) Under low pressure
c) In a liquefied form under high pressure
d) In small, portable containers
c) In a liquefied form under high pressure
What is a characteristic of MPS gas?
a) Low working pressures
b) Odorless
c) Lower flame temperature than acetylene
d) Less stable than acetylene
c) Lower flame temperature than acetylene
Which gas is used for underwater cutting and can be generated with an electrolysis plant?
a) Propylene
b) MPS gas
c) Hydrogen
d) Natural gas
c) Hydrogen
What is a safety consideration when using hydrogen?
a) Transparent flame
b) Dense flame
c) Low explosive potential
d) Well-defined inner cone
a) Transparent flame
Which gas is more effective than propane for cutting rusted material?
a) Acetylene
b) MPS gas
c) Hydrogen
d) Propylene
d) Propylene
With RENTED cylinders, who is responsible for cylinder maintenance?
a. Employee
b. Employer
c. Supervisor
d. Supplier
d. Supplier
Where do oxygen and fuel gases typically come from?
a. Gas stations
b. Gas cylinders
c. Gas pipelines
d. Gas generators
b. Gas cylinders
What should be done if any noticeable damages or faults are observed in a RENTED gas cylinder?
a. Ignore them
b. Report them to the manufacturer
c. Report them to the user’s employer
d. Report them to the supplier
d. Report them to the supplier
What is the typical pressure at which oxygen is supplied in compressed gas cylinders?
a. 10,000 kPa (1,450 psi)
b. 15,000 kPa (2,175 psi)
c. 18,000 kPa (2,600 psi)
d. 20,000 kPa (2,900 psi)
c. 18,000 kPa (2,600 psi)
What is the range of capacities for oxygen cylinders in compressed form?
a. 0.1 m³ - 1.0 m³ (5 ft³ - 50 ft³)
b. 1.0 m³ - 5.0 m³ (50 ft³ - 250 ft³)
c. 0.5 m³ - 9.35 m³ (20 ft³ - 335 ft³)
d. 10 m³ - 20 m³ (500 ft³ - 1000 ft³)
c. 0.5 m³ - 9.35 m³ (20 ft³ - 335 ft³)
Which two types of large-size oxygen cylinders are commonly used in industry?
a. A-type and B-type
b. T-type and K-type
c. X-type and Y-type
d. M-type and N-type
b. T-type and K-type
What is the capacity of a T-type oxygen cylinder in compressed form?
a. 7 m³ (244 ft³)
b. 9.35 m³ (335 ft³)
c. 5 m³ (177 ft³)
d. 10 m³ (354 ft³)
b. 9.35 m³ (335 ft³)
What is the capacity of a K-type oxygen cylinder in compressed form?
a. 7 m³ (244 ft³)
b. 9.35 m³ (335 ft³)
c. 5 m³ (177 ft³)
d. 10 m³ (354 ft³)
a. 7 m³ (244 ft³)
At what pressure is oxygen compressed in a K-type cylinder?
a. 10 MPa (1450 psi)
b. 15 MPa (2200 psi)
c. 20 MPa (2900 psi)
d. 25 MPa (3625 psi)
b. 15 MPa (2200 psi)
What is the temperature at which the T-type oxygen cylinder is compressed?
a. 10°C
b. 15°C
c. 21°C
d. 25°C
c. 21°C
Same as K-type
What is the temperature at which the K-type oxygen cylinder is compressed?
a. 10°C
b. 15°C
c. 21°C
d. 25°C
c. 21°C
Same as T-type
What material are high-pressure oxygen cylinders typically made of?
a. Aluminum
b. Copper
c. High-carbon steel
d. Plastic
c. High-carbon steel
What is the minimum thickness of the walls of high-pressure oxygen cylinders?
a. 3 mm (1/8 in)
b. 4 mm (3/16 in)
c. 5 mm (1/5 in)
d. 6 mm (1/4 in)
d. 6 mm (1/4 in)
How are threaded collars fitted for high-pressure oxygen cylinders?
a. Weld-fitted
b. Thread-fitted
c. Compression-fitted
d. Bolt-fitted
c. Compression-fitted collar
What type of collars do high-pressure oxygen cylinders have?
a. Welded collar
b. Screwed collar
c. Compressed collar
d. Threaded collar
d. Threaded collar
How does temperature affect the gas pressure within the oxygen cylinder?
a. It has no effect
b. Gas pressure increases when heated and decreases when cooled
c. Gas pressure decreases when heated and increases when cooled
d. Gas pressure remains constant regardless of temperature changes
b. Gas pressure increases when heated and decreases when cooled
What material is typically used to fabricate the high-pressure oxygen cylinder valve?
a. Steel
b. Aluminum
c. Forged brass
d. Copper
c. Forged brass
What covers the high-pressure oxygen cylinder valve when the cylinder is not in use?
a. Rubber seal
b. Protective cap
c. Metal latch
d. Plastic sleeve
b. Protective cap
What type of construction does the oxygen cylinder valve have to prevent oxygen leaking around the stem?
a. Single-seal
b. Double-seal
c. Triple-seal
d. No seal
b. Double-seal
What stops oxygen from coming out of the cylinder when the oxygen cylinder valve is CLOSED?
a. Oxygen flow seal
b. Stem seal
c. Back seating seal
d. Valve handle
a. Oxygen flow seal
What stops oxygen from going up the valve stem when the oxygen cylinder valve is fully OPEN?
a. Oxygen flow seal
b. Stem seal
c. Back seating seal
d. Valve handle
c. Back seating seal
In which direction should the valve wheel be turned to open the oxygen cylinder valve?
a. Clockwise
b. Counterclockwise
c. Upwards
d. Downwards
b. Counterclockwise
What could happen if the oxygen cylinder valve is suddenly opened?
a. The cylinder may explode
b. The valve may jam
c. The regulator may burst
d. The valve may leak
c. The regulator may burst
What safety device is equipped on high-pressure oxygen cylinder valves?
a. Hexagonal nut
b. Safety disk
c. Capped nut
d. Vent holes
b. [a burstable] safety disk
What is the purpose of the burstable safety disk inside the safety nut?
a. To release the oxygen
b. To evenly distribute pressure
c. To seal the cylinder valve
d. To prevent leaks
a. To release the oxygen
At what pressure does the specially designed safety disk rupture?
a. 27,000 kPa (4,000 psi)
b. 4,000 kPa (580 psi)
c. 27 MPa (3,900 psi)
d. 4 bar (58 psi)
a. 27,000 kPa (4,000 psi)
What happens if the safety disk ruptures?
a. Oxygen is released through the hexagonal nut
b. The cylinder valve is sealed shut
c. The cylinder becomes pressurized
d. The hexagonal nut expands
a. Oxygen is released through the hexagonal nut
What first action should be taken if a faulty cylinder valve or ruptured safety disk is found?
a. Replace the safety disk.
b. Move the cylinder to a closed area.
c. Move the cylinder to an open area and tag it.
d. Notify the supplier for immediate pickup.
c. Move the cylinder to an open area and tag it.
What precaution should be taken regarding lubricants and oxy-fuel gas equipment?
a. Too little lubricant won’t enhance the performance of oxy-fuel gas equipment.
b. Lubricants must be applied sparingly to ensure sealing.
c. Lubricants can catch fire or explode in the presence of compressed oxygen.
d. Lubricants are necessary for proper maintenance of oxy-fuel gas equipment.
c. Lubricants can catch fire or explode in the presence of compressed oxygen.
What is the critical pressure of acetylene?
a) 104 kPa (15 psi)
b) 193 kPa (28 psi)
c) 28 psi (193 kPa)
d) 15 psi (104 kPa)
c) 28 psi (193 kPa) [at 21°C]
What is the maximum working pressure for free acetylene?
A) 104 kPa (15 psi)
B) 193 kPa (28 psi)
C) 28 psi (193 kPa)
D) 15 psi (104 kPa)
D) 15 psi (104 kPa)
According to the revised CGA guidelines, what is the maximum draw limit for CONTINUOUS use?
A) 1/5 of the cylinder’s capacity per hour
B) 1/7 of the cylinder’s capacity per hour
C) 1/10 of the cylinder’s capacity per hour
D) 1/15 of the cylinder’s capacity per hour
D) 1/15 of the cylinder’s capacity per hour
Why should acetylene cylinders always be kept upright?
A) To prevent explosions
B) To avoid liquid acetone flow
C) To maintain pressure
D) To prevent leakage
B) To avoid liquid acetone flow
True or false, acetylene cylinders operate at a lower pressure than oxygen cylinders.
a. True
b. False
a. True
What is the purpose of acetone in acetylene cylinders?
A) To increase pressure
B) To absorb acetylene
C) To prevent explosions
D) To reduce temperature
B) To absorb acetylene
How many times its weight of acetylene can acetone absorb?
A) 10 times
B) 15 times
C) 20 times
D) 23 times
D) 23 times
What happens if acetone flows into the system?
A) It enhances cutting quality
B) It reduces pressure
C) It damages equipment
D) It increases acetylene storage
C) It damages equipment
What risk is associated with a drop in pressure caused by acetone entering the system?
A) Decreased gas consumption
B) Increased flame temperature
C) Risk of flashback
D) Improved welding performance
C) Risk of flashback
What factor can contribute to a high withdrawal rate of acetylene from the cylinder?
A) Increased cylinder temperature
B) Decreased cylinder pressure
C) Reduced cutting tip size
D) Decreased gas flow rate
B) Decreased cylinder pressure
What has the Compressed Gas Association (CGA) established regarding draw limits for acetylene cylinders?
A) Draw limits based on remaining volume
B) Draw limits based on cylinder weight
C) Draw limits based on cylinder capacity
D) Draw limits based on temperature
C) Draw limits based on cylinder capacity
According to the revised CGA guidelines, what is the maximum draw limit for INTERMITTED use?
A) 1/5 of the cylinder’s capacity per hour
B) 1/7 of the cylinder’s capacity per hour
C) 1/10 of the cylinder’s capacity per hour
D) 1/15 of the cylinder’s capacity per hour
C) 1/10 of the cylinder’s capacity per hour
Which scenario increases the likelihood of acetone entering the system when drawing acetylene?
a) Drawing acetylene at a slower rate
b) Drawing acetylene at a higher rate
c) Using a smaller acetylene cylinder
d) Using an approved manifold system
b) Drawing acetylene at a higher rate
What is recommended when large amounts of acetylene are needed for heating and cutting operations?
a) Using a smaller acetylene cylinder
b) Drawing acetylene at a slower rate
c) Using a larger acetylene cylinder or an approved manifold system
d) Increasing the pressure in the acetylene cylinder
c) Using a larger acetylene cylinder or an approved manifold system
Where should compressed gas cylinders be stored to minimize the risk of fire, explosion, and other hazards?
a) Near doorways, aisles, elevators, and stairs
b) In a designated area separate from the shop environment
c) In a non-ventilated area
d) Near heat sources like radiators and stoves
b) In a designated area separate from the shop environment
What is the recommended separation distance between oxygen and fuel gas cylinders?
a) 3 meters (10 feet)
b) 6 meters (20 feet)
c) 1 meter (3 feet)
d) 9 meters (30 feet)
b) 6 meters (20 feet)
What precaution should be taken when storing cylinders with regulators removed?
a) Store them upside down for better stability
b) Keep them near sources of heat to prevent freezing
c) Ensure protective valve caps are in place
d) Store them near grease or oil for lubrication
c) Ensure protective valve caps are in place
How should empty cylinders be marked for identification?
a) Remove all labels to indicate emptiness
b) Place rings around the valve caps
c) Paint them a different colour from full cylinders
d) Keep them in a separate storage area
b) Place rings around the valve caps
What should be done if the valve head of a compressed gas cylinder is fractured?
a) Store it in a separate area for repairs
b) Secure it with a chain to prevent movement
c) Replace the cylinder immediately
d) Use it cautiously until it is completely empty
c) Replace the cylinder immediately
According to NFPA 51, what is the standard for the separation distance between oxygen manifold systems and combustible material?
A) 1 meter (3 feet)
B) 3 meters (10 feet)
C) 6 meters (20 feet)
D) 9 meters (30 feet)
C) 6 meters (20 feet)
How is liquified oxygen converted into gas for distribution in pipelines or manifold systems?
A) Through condensation
B) Through vaporization
C) Through combustion
D) Through compression
B) Through vaporization
What is the purpose of the automation system mentioned in the passage?
A) To regulate the temperature of the oxygen containers
B) To monitor oxygen levels in the manifold
C) To switch between oxygen containers if pressure drops below a pre-set level
D) To control the flow of oxygen gas into pipelines
C) To switch between oxygen containers if pressure drops below a pre-set level
What is the minimum bursting pressure that manifolds must be constructed to withstand?
A) 1.7 MPa (250 psi)
B) 3.4 MPa (500 psi)
C) 6.9 MPa (1,000 psi)
D) 10.3 MPa (1,500 psi)
C) 6.9 MPa (1,000 psi)
What type of regulator is used to set the working pressures for welding or cutting operations?
A) High-pressure regulator
B) Two-stage regulator
C) Low-pressure regulator
D) Main pressure regulator
C) Low-pressure regulator
What is the maximum service pressure allowed for welding or cutting operations?
A) 1.7 MPa (250 psi)
B) 3.4 MPa (500 psi)
C) 6.9 MPa (1,000 psi)
D) 10.3 MPa (1,500 psi)
A) 1.7 MPa (250 psi)
What additional safety features does the acetylene manifold system have compared to the oxygen manifold system?
a) Flash arrestors
b) Pressure relief valve
c) Hydraulic seals
d) All of the above
d) All of the above
What is drawn from the acetylene cylinder when the maximum rate of withdrawal is exceeded?
a) Liquid oxygen
b) Liquid nitrogen
c) Liquid acetone
d) Liquid hydrogen
c) Liquid acetone
What must be installed between each acetylene cylinder and the coupler block?
a) Pressure relief valve
b) Flash arrestor
c) Backflow check valve
d) Hydraulic seal
b) Flash arrestor
How often should hydraulic flashback arrestors be serviced?
a) Bi-annually
b) Quarterly
c) Annually
d) Monthly
c) Annually (once a year)
Who should install manifold systems according to safety regulations?
a) Anyone with basic plumbing skills
b) Qualified persons only
c) Trainees under supervision
d) Homeowners
b) Qualified persons only
Where should signs be posted in relation to low-pressure manifolds?
a) Inside a cabinet
b) In plain view on all low-pressure manifolds
c) Inside a locked room
d) Near the ceiling
b) In plain view on all low-pressure manifolds
What is the main job of a gas pressure regulator?
a. To make the gas pressure higher
b. To control the torch’s temperature
c. To slow down the gas flow
d. To lower the strong cylinder pressure to the right pressure for the torch
d. To lower the strong cylinder pressure to the right pressure for the torch
A gas pressure regulator is like a control valve for gas. Its main job is to take the high pressure from a gas cylinder and reduce it to a safe and usable pressure for whatever one’s using the gas for, like a torch or a burner. It makes sure that the pressure of the gas coming out is just right for the equipment being used.
Oxygen has _______ pressure setting compared to acetylene.
a. The same
b. A higher
c. A lower
d. About the same
b. A higher
Oxygen has a higher pressure setting compared to acetylene.
A recommended operating pressure for the cutting torch falls within the range of:
a. 140 kPa (20 psi) for oxygen and 100 kPa (15 psi) for acetylene
b. 240 kPa (35 psi) for oxygen and 200 kPa (30 psi) for acetylene
c. 275 kPa (40 psi) for oxygen and 69 kPa (10 psi) for acetylene
d. 400 kPa (60 psi) for oxygen and 138 kPa (20 psi) for acetylene
c. 275 kPa (40 psi) for oxygen and 69 kPa (10 psi) for acetylene
The oxygen CYLINDER pressure is typically in the range of 15 MPa (2,200 psi)
Which device is installed at the cylinder valves for oxygen, acetylene, or other gases to decrease the cylinder pressure to a suitable working pressure at the torch tip?
a. Flow meters
b. Safety valves
c. Pressure regulators
d. Hose connectors
c. Pressure regulators
A pressure regulator is a device that controls the pressure of a gas coming from a high-pressure source, like a cylinder, and lowers it to a safe and consistent level for use. It’s like a valve that adjusts the flow of gas to ensure it’s just right for whatever you’re using it for, like welding or cooking.
Which of the following is typically used to identify pressure regulators?
a. The colour of the casing
b. The manufacturer’s logo
c. The type of gas for which they are used
d. The size of the pressure gauge
c. The type of gas for which they are used
For example, an oxygen pressure regulator body will have “oxygen” printed on it and will usually be green in colour.
An acetylene pressure regulator body will have “acetylene” printed on it and will usually be red in colour.
Although exact identification and other features vary with different manufacturers,
Which components make up a pressure regulator?
a. A nozzle, rigid diaphragm, and gears.
b. A cylinder, piston, and levers.
c. A seat, flexible diaphragm, and springs.
d. A valve, gearbox, and bearings
c. A seat, flexible diaphragm, and springs.
The “seat” is like a tight seal or a stopper where the gas flow is controlled. It’s a fixed part against which the flexible diaphragm presses to regulate the gas pressure.
A “diaphragm” is like a thin, stretchy membrane that moves to control the flow of gas. It acts like a barrier between high-pressure and low-pressure areas, flexing to adjust the gas flow and keep it at the right level.
The “springs” are like little coils that help control the pressure. They push against the diaphragm to keep the pressure steady and just right for what you’re using the gas for.
What is the range of pressure typically displayed on oxygen cylinder pressure regulator gauges?
a. 0-20,000 kPa (0-2,900 psi)
b. 0-30,000 kPa (0-4,350 psi)
c. 0-25,000 kPa (0-3,625 psi)
d. 0-27,500 kPa (0-4,000 psi)
d. 0-27,500 kPa (0-4000 psi)
This gauge tells you how much gas is left in the cylinder before you start using it.
Which of the following best describes the range of a working pressure gauge for oxygen?
a. 0-100 kPa (0-15 psi)
b. 0-300 kPa (0-45 psi)
c. 0-200 kPa (0-30 psi)
d. 0-400 kPa (0-60 psi)
c. 0-200 kPa (0-30 psi)
This gauge shows you the pressure of the gas coming out of the cylinder and going into your equipment.
What is the typical pressure range shown on acetylene cylinder pressure regulator gauges?
a. 0-5 MPa (0-725 psi)
b. 0-3.5 MPa (0-500 psi)
c. 0-2.7 MPa (0-400 psi)
d. 0-1.5 MPa (0-225 psi)
c. 0-2.7 MPa (0-400 psi)
AKA 0-2700 kPa (0-400 psi)
This gauge tells you how much gas is left in the cylinder before you start using it.
Which of the following best describes the range of a working pressure gauge for acetylene?
a. 0-100 kPa (0-15 psi)
b. 0-150 kPa (0-22 psi)
c. 0-200 kPa (0-30 psi)
d. 0-250 kPa (0-36 psi)
c. 0-200 kPa (0-30 psi)
Although acetylene working pressure must be kept below 103 kPa (15 psi)
This gauge shows you the pressure of the gas coming out of the cylinder and going into your equipment.
Which of the following statements accurately describes the recommended working pressure for acetylene?
a. The acetylene working pressure should exceed 100 kPa (14.5 psi).
b. The acetylene working pressure should be precisely 130 kPa (19 psi).
c. The acetylene working pressure must be kept below 103 kPa (15 psi).
d. The acetylene working pressure is irrelevant for safe usage.
c. The acetylene working pressure must be kept below 103 kPa (15 psi).
This is to prevent the unstable acetylene gas from exploding.
Which feature distinguishes the hex nut on an acetylene pressure regulator from that on an oxygen pressure regulator?
a. The acetylene hex nut is larger in size.
b. The acetylene hex nut is smooth.
c. The acetylene hex nut is grooved.
d. The acetylene hex nut is painted red.
c. The acetylene hex nut is grooved.
Which feature distinguishes the hex nut on an oxygen pressure regulator from that on an acetylene pressure regulator?
a. The oxygen hex nut is larger in size.
b. The oxygen hex nut is grooved.
c. The oxygen hex nut is painted blue.
d. The oxygen hex nut is smooth.
d. The oxygen hex nut is smooth.
Which statement accurately describes the threading of connections for gas pressure regulators?
a. Both oxygen and fuel gas pressure regulators have right-hand threads.
b. Both oxygen and fuel gas pressure regulators have left-hand threads.
c. The connections of oxygen pressure regulators have right-hand threads, while fuel gas pressure regulators have left-hand threads.
d. The connections of oxygen pressure regulators have left-hand threads, while fuel gas pressure regulators have right-hand threads.
c. The connections of oxygen pressure regulators have right-hand threads, while fuel gas pressure regulators have left-hand threads.
This makes it impossible to connect a pressure regulator or hoses to the wrong cylinder.
Which classification system is used to categorize gas cylinder pressure regulators based on the number of pressure regulation steps?
a. Primary and Secondary regulators
b. Low and High-pressure regulators
c. Single-stage and Two-stage regulators
d. Initial and Final regulators
c. Single-stage and Two-stage regulators
Gas cylinder pressure regulators are categorized based on how many steps they use to control the pressure of the gas.
Which type of regulator typically provides a more stable and smooth working pressure for high pressure cylinders?
a. Single-stage regulator
b. Two-stage regulator
c. Both types provide equally stable working pressure
d. None of the above
b. Two-stage regulator
a two-stage regulator provides a more stable and smooth working pressure because it reduces the pressure in two steps instead of just one. This means it can handle variations in pressure from the cylinder better, giving you a steadier flow of gas for your work.
What distinguishes a single-stage pressure regulator from a two-stage regulator?
a. Single-stage regulators are more commonly used in industrial applications.
b. Two-stage regulators are typically used with individual cylinders.
c. Single-stage regulators provide more precise control over pressure.
d. Two-stage regulators maintain a more constant working pressure as cylinder pressure decreases.
d. Two-stage regulators maintain a more constant working pressure as cylinder pressure decreases.
Which type of system is a single-stage pressure regulator typically used with?
a. Bulk system or manifold system
b. Individual cylinder
c. High-pressure system
d. Low-pressure system
a. Bulk system or manifold system
What are the characteristics of a single-stage pressure regulator?
a. It provides finer control over pressure compared to two-stage regulators.
b. It is typically used with individual cylinders.
c. It is less expensive and simpler in construction than two-stage regulators.
d. It maintains constant working pressure regardless of cylinder pressure.
c. It is less expensive and simpler in construction than two-stage regulators.
How does the control over pressure of a single-stage regulator compare to that of a two-stage regulator?
a. It provides more precise control.
b. It provides less precise control.
c. It provides equal control.
d. It provides no control over pressure.
b. It provides less precise control
Which type of regulator provides more precise regulation over a wide range of varying inlet pressures?
a. Single-stage pressure regulator
b. Double-stage pressure regulator
c. Three-stage pressure regulator
d. Variable-stage pressure regulator
b. Double-stage pressure regulator
Which type of pressure regulator is utilized when the cylinder pressure is reduced to working pressure in two steps?
a. Single-stage pressure regulator
b. Multi-stage pressure regulator
c. Dual-action pressure regulator
d. Two-stage pressure regulator
d. Two-stage pressure regulator
What is the primary function of the first stage in a two-stage pressure regulator?
a. To maintain the cylinder pressure at its maximum level
b. To reduce the gas pressure to a safe level for immediate use
c. To decrease the gas pressure to intermediate levels
d. To regulate the gas flow to the desired rate
c. To decrease the gas pressure to intermediate levels
What pressure range does the first stage of a two-stage pressure regulator typically drop the cylinder pressure to?
a. Less than 100 kPa (15 psi)
b. Between 500 and 800 kPa (75 and 115 psi)
c. Between 1,200 and 2,800 kPa (180 and 400 psi)
d. More than 5,000 kPa (725 psi)
c. Between 1,200 and 2,800 kPa (180 and 400 psi)
Which function does the second stage perform in a two-stage pressure regulator?
a. It increases the intermediate pressure.
b. It maintains the intermediate pressure constant.
c. It reduces the intermediate pressure to the desired working pressure.
d. It switches between different working pressures.
c. It reduces the intermediate pressure to the desired working pressure.
Why are two-stage cylinder pressure regulators preferred over single-stage regulators?
a. They are cheaper.
b. They have a simpler design.
c. They deliver a more constant pressure with finer control.
d. They require less maintenance.
c. They deliver a more constant pressure with finer control.
What happens to the gas flow rate in single-stage cylinder pressure regulators as the cylinder pressure drops?
a. It increases.
b. It decreases.
c. It remains constant.
d. It fluctuates unpredictably.
d. It fluctuates unpredictably.
Why are two-stage cylinder pressure regulators recommended for precise cutting jobs?
a. They are cheaper than single-stage regulators.
b. They require frequent readjustment.
c. They offer more stable gas flow.
d. They are easier to install.
c. They offer more stable gas flow.
In which types of cutting operations are two-stage pressure regulators commonly used?
a. Only in manual cutting operations.
b. Only in automatic cutting operations.
c. Only in machine cutting operations.
d. In both automatic and machine cutting operations
d. In both automatic and machine cutting operations
Why are two-stage pressure regulators more common in automatic and machine cutting applications?
a. They are less precise compared to single-stage regulators.
b. They are easier to operate manually.
c. They can handle higher gas pressures.
d. They provide finer control, which is crucial for automated processes.
d. They provide finer control, which is crucial for automated processes.
Which type of pressure regulator is recommended for accurate cutting and welding operations?
a. Single-stage pressure regulators
b. Two-stage pressure regulators
c. Variable pressure regulators
d. Fixed pressure regulators
b. Two-stage pressure regulators
What precaution should be taken with the pressure-adjusting screw in cylinder pressure regulators?
a. Tighten it firmly before opening the cylinder valve.
b. Keep it at the maximum setting to ensure proper gas flow.
c. Back it out until it moves freely before opening the cylinder valve.
d. Leave it untouched, as it does not affect the gas flow.
c. Back it out until it moves freely before opening the cylinder valve.
Why is it important to back out the pressure-adjusting screw in cylinder pressure regulators?
a. To increase the gas flow rate.
b. To prevent damage to the regulator mechanism.
c. To decrease the gas pressure in the cylinder.
d. To make it easier to open the cylinder valve.
b. To prevent damage to the regulator mechanism.
What risk is associated with allowing a sudden surge of cylinder gas into the pressure regulator?
a. Decreased gas pressure at the torch tip.
b. Damage to the cylinder valve.
c. Potential damage to the regulator mechanism.
d. Improved performance of the pressure regulator.
c. Potential damage to the regulator mechanism.
What is the potential consequence of a damaged pressure regulator due to a sudden surge of cylinder gas?
a. Reduced gas consumption.
b. Increased safety during operation.
c. Risk of personal injury.
d. Enhanced gas flow control.
c. Risk of personal injury.
What should you check for after attaching hoses and a torch to cylinder pressure regulators?
a. The colour of the hoses
b. The length of the hoses
c. An increase or “creep” in the working-pressure gauge
d. The temperature of the regulator
c. An increase or “creep” in the working-pressure gauge
What is the possible cause of an increase or “creep” in the working-pressure gauge after attaching hoses and a torch to cylinder pressure regulators?
a. Faulty torch valves
b. Loose hose connections
c. Faulty seat valve in the regulator
d. Insufficient gas pressure
c. Faulty seat valve in the regulator
What action should be taken if there is an increase or “creep” in the working-pressure gauge after attaching hoses and a torch to cylinder pressure regulators?
a. Continue using the equipment as usual
b. Tighten the hose connections
c. Adjust the torch valves
d. Repair the faulty seat valve in the regulator before further use
d. Repair the faulty seat valve in the regulator before further use
What is the recommended precaution when connecting a pressure regulator to a gas cylinder?
a. Use pliers or a pipe wrench to tighten connections.
b. Always check for the correct pressure regulator before connecting.
c. Force connections if they don’t fit properly.
d. Connect the regulator without using a cylinder wrench.
b. Always check for the correct pressure regulator before connecting.
Why is it important to verify the correct pressure regulator before connecting it to a gas cylinder?
a. To save time during the connection process.
b. To ensure proper functionality and safety.
c. To increase gas pressure.
d. To avoid using a cylinder wrench.
b. To ensure proper functionality and safety.
What tool should be used to tighten connections when attaching a pressure regulator to a gas cylinder?
a. Pliers
b. Pipe wrench
c. Cylinder wrench
d. Screwdriver
c. Cylinder wrench
What should you avoid using on the connections of cylinder pressure regulators?
a. Grease
b. Oil-based pipe compound
c. Teflon tape
d. All of the above
d. All of the above
Who should repair pressure regulators according to safety guidelines?
a. Any experienced individual
b. Any individual with basic mechanical skills
c. A trained technician
d. The user themselves
c. A trained technician
What should you never attempt to do with a faulty pressure regulator?
a. Label it as faulty
b. Place it in an area where it will not be used
c. Repair it
d. Order a replacement
c. Repair it
What precaution should be taken when handling cylinder pressure regulators?
a. Drop them gently to ensure they are securely in place.
b. Misuse them to test their durability.
c. Handle them with care and never drop or misuse them.
d. Handle them loosely to avoid crushing them.
c. Handle them with care and never drop or misuse them.
Why is it important to handle cylinder pressure regulators with care?
a. To test their durability.
b. To ensure they are securely in place.
c. They have precise internal mechanisms.
d. None of the above.
c. They have precise internal mechanisms.
What action should be taken when transporting or removing pressure regulators from service?
a. Turn the working pre-adjusting screw as much as possible.
b. Leave the pressure regulators as they are.
c. Turn the working pre-adjusting screw just enough to take the pressure off the inlet seat valves.
d. Completely disassemble the pressure regulators for transportation.
c. Turn the working pre-adjusting screw just enough to take the pressure off the inlet seat valves.
What is the purpose of turning the working pre-adjusting screw when transporting or removing pressure regulators from service?
a. To increase pressure on the inlet seat valves.
b. To ensure the pressure regulators are tightly secured.
c. To prevent sticking and corrosion of the seat.
d. None of the above.
c. To prevent sticking and corrosion of the seat.
Which statement accurately describes the threading of Compressed Gas Association (CGA) fittings on cylinder pressure regulators?
a. CGA fittings always have right-hand threads.
b. CGA fittings always have left-hand threads.
c. CGA fittings can have either right-hand or left-hand threads.
d. CGA fittings have reverse threads compared to standard fittings.
c. CGA fittings can have either right-hand or left-hand threads.
What precaution should be taken when replacing fittings on a cylinder pressure regulator?
a. Use any available fitting for replacement.
b. Tighten the fitting as much as possible.
c. Always use an exact replacement fitting.
d. Only use fittings with left-hand threads.
c. Always use an exact replacement fitting.
What is the consequence of replacing a CGA 580 fitting with a CGA 680 fitting on a regulator?
a. It will not affect the regulator’s performance.
b. It will decrease the pressure in the regulator.
c. It will over-pressurize the regulator.
d. It will cause the regulator to leak gas.
c. It will over-pressurize the regulator.
This can cause serious injury and damage.
What is a crucial requirement for hoses used in cylinder pressure regulators?
a. Rigidity for stability
b. Stiffness for less risk of mobility
c. Flexibility for mobility and manipulation
c. Flexibility for mobility and manipulation
Why must hoses used in cylinder pressure regulators be able to withstand high line pressures?
a. To minimize gas leakage
b. To increase gas flow rate
c. To reduce equipment weight
d. To enhance portability
a. To minimize gas leakage
What utility and safety requirements must hoses for cylinder pressure regulators meet?
a. They must be resistant to extreme temperatures
b. They must be able to conduct electricity
c. They must be flexible and durable
d. They must be transparent for visual inspection
c. They must be flexible and durable
What is the structure of the hoses used in cylinder pressure regulators for fuel gases and oxygen?
a. Single-layer rubber with fabric reinforcement
b. Two or three rubber layers, each separated by a layer of strong fabric
c. Three rubber layers without any fabric reinforcement
d. A single rubber layer without any fabric reinforcement
b. Two or three rubber layers, each separated by a layer of strong fabric
What colour is typically used for the oxygen hose in cylinder pressure regulators?
a. Red or Yellow
b. Green or Black
c. Black or Blue
d. Blue or Red
b. Green or Black
Which colour is commonly assigned to the fuel gas (acetylene) hose in cylinder pressure regulators?
a. Yellow
b. Black
c. Green
d. Red
d. Red
Why are hoses for cylinder pressure regulators reinforced with two layers?
a. To increase flexibility
b. To decrease durability
c. To avoid kinking and wear
d. To simplify maintenance
c. To avoid kinking and wear
What is the purpose of the outside layer of rubber in most oxy-fuel gas hoses?
a. To reduce flexibility
b. To increase tangling
c. To prevent tangling
d. To decrease durability
c. To prevent tangling
What factor determines the sizing of oxy-fuel hoses in cylinder pressure regulators?
a. The length of the hose
b. The outside diameter of the hose
c. The inside diameter of the inner tube
d. The material of the hose
c. The inside diameter of the inner tube
Which of the following is the most common size for oxy-fuel hoses used in light-duty cutting and welding?
a. 4.0 mm
b. 5mm
c. 6.4 mm
d. 8mm
b. 5mm (3/16 in)
Why is a large-diameter hose recommended for cutting thick material?
a. To decrease gas flow
b. To increase gas pressure
c. To deliver the required oxygen and fuel-gas
d. To improve manoeuvrability
c. To deliver the required oxygen and fuel-gas
What is the recommended solution for overcoming greater pressure drops in long lengths of hose connected to cylinder pressure regulators?
a. Increasing the gas flow rate
b. Using a higher regulator pressure
c. Decreasing the diameter of the hose
d. Using a longer hose
b. Using a higher regulator pressure
Why is a larger diameter hose recommended for delivering gas from cylinder pressure regulators to the torch?
a. To reduce the gas flow rate
b. To increase pressure drops
c. To decrease the volume of gas delivered
d. To overcome greater pressure drops and deliver more volume
d. To overcome greater pressure drops and deliver more volume
What should be checked regarding hose size when using cylinder pressure regulators?
a. Shops supervisors’ recommended torch size
b. The gas flow rate through the hose
c. The manufacturer’s oxy-fuel gas hose size
d. The pressure rating of the hose material
c. The manufacturer’s oxy-fuel gas hose size
Why are shorter hose lengths recommended for safety reasons when using cylinder pressure regulators?
a. To reduce the risk of gas leaks
b. To increase the pressure drop
c. To decrease gas flow rate
d. To improve the efficiency of the torch operation
a. To reduce the risk of gas leaks
Which grade of oxy-fuel gas hose is suitable for use with liquid fuel gases?
a. Grade T
b. Grade R
c. Grade G
d. Grade L
a. Grade T
Which grade of oxy-fuel gas hose is specifically designed for use with acetylene?
a. Grade T
b. Grade R
c. Grade A
d. Grade G
b. Grade R
True or False. Grade R oxy-fuel gas hoses are suitable for acetylene.
a. True
b. False
a. True
Which grade of oxy-fuel gas hose is versatile and can be used with all fuel gases, including acetylene?
a. Grade T
b. Grade R
c. Grade F
d. Grade G
a. Grade T
What precautions should be taken to prevent fires or explosions related to oxy-fuel gas hoses?
a. Ensuring hoses are coiled and supported
b. Cleaning hoses with oil and grease
c. Storing hoses in dry, direct sunlight
d. Securing puncture holes with grade A tape
a. Ensuring hoses are coiled and supported
What should be done with damaged oxy-fuel gas hoses?
a. Keep using them if the damage is minor.
b. Replace or repair them.
c. Wrap them with tape for temporary fixes.
d. Ignore the damage if it’s on the exterior.
b. Replace or repair them.
Why should oxy-fuel gas hoses be purged before use and after every cylinder change?
a. To increase the flexibility of the hoses.
b. To decrease the risk of kinking.
c. To prevent dirt or debris from clogging the torch passages.
d. To remove excess smell from gas.
c. To prevent dirt or debris from clogging the torch passages.
What type of air should be used when blowing out hoses?
a. Air with oil content.
b. Oil-less compressed air.
c. Air mixed with gasoline.
d. Air from a regular compressor
b. Oil-less compressed air.
What should never be used for repairs on oxy-fuel gas hoses?
a. Tape.
b. Welding tacks.
c. Glue.
d. All of the above
d. All of the above
Which material is used to make fittings and connectors for oxy-fuel hoses, regulators, and torch bodies?
a. Steel
b. Aluminum
c. Brass alloys
d. Copper
c. Brass alloys
True or False. Brass alloys are preferred for making fittings and connectors because they do not corrode or create dangerous by-products when exposed to oxy-fuel gases and do not generate sparks if they contact other metals or materials.
a. True
b. False
a. True
What is the purpose of using yellow brass fittings for oxy-fuel gas hoses?
a. To increase flexibility
b. To reduce weight
c. To avoid generating sparks
d. To enhance gas flow
c. To avoid generating sparks
How can you identify the threading on acetylene hose fittings?
a. By the colour of the hose
b. By the presence of a groove cut into the fitting
c. By the material used for the fitting
d. By the size of the fitting
b. By the presence of a groove cut into the fitting
Why are acetylene fittings distinctly different from oxygen fittings?
a. To prevent gas leaks
b. To enhance compatibility
c. To facilitate interchangeability
d. To prevent accidental interchange
d. To prevent accidental interchange
Which materials are recommended for use in acetylene gas systems?
a. Copper or red brass
b. Aluminium or plastic
c. Yellow brass, iron, or steel
d. Titanium or ceramic
c. Yellow brass, iron, or steel
Why are copper or red brass fittings not recommended for acetylene hose fittings?
a. They are too expensive.
b. They are prone to corrosion.
c. They can react with acetylene to form a dangerous residue.
d. They do not provide a secure connection.
c. They can react with acetylene to form a dangerous residue (Acetylide).
What precaution should be taken before using fittings on oxy-fuel gas hoses?
a. They should be cleaned with water.
b. They should be lubricated with oil.
c. They should be firmly secured.
d. They should be heated to a certain temperature.
c. They should be firmly secured.
What is a backfire in oxy-acetylene equipment?
a. A momentary recession of the flame into the torch tip or mixer.
b. A steady flame burning from the torch tip.
c. A complete extinguishment of the flame without any sound.
d. A continuous flame that does not recede or make any noise.
a. A momentary recession of the flame into the torch tip or mixer,
followed by a loud popping sound.
What sound may indicate that the flame has reignited after a backfire?
a. A loud popping sound.
b. A squealing sound.
c. A hissing sound.
d. A crackling sound.
b. A squealing sound.
What action should be taken if a backfire occurs in oxy-acetylene equipment?
a. Immediately relight the torch.
b. Close the oxygen and fuel gas valves immediately to check the equipment.
c. Ignore it and continue working.
d. Increase the gas flow to prevent further backfires.
b. Close the oxygen and fuel gas valves immediately to check the equipment.
When is a backfire most commonly likely to occur in oxy-acetylene equipment?
a. When working with cold metal.
b. When adjusting the gas flow.
c. When the torch tip touches hot metal.
d. When the equipment is not properly cleaned.
c. When the torch tip touches hot metal.
What should be done if backfires continue to occur despite cleaning and purging the equipment?
a. Increase the gas flow.
b. Replace the torch tip.
c. Remove the torch from service for cleaning and possible repair.
d. Ignore it and continue working
c. Remove the torch from service for cleaning and possible repair.
What is a flashback in oxy-fuel torch lines?
a. An unexpected increase in gas pressure
b. A sudden ignition of the gas mixture within the torch or hoses
c. A decrease in flame temperature
d. A decrease in gas flow rate
b. A sudden ignition of the gas mixture within the torch or hoses
What can cause a flashback when using oxy-fuel torch lines?
a. Insufficient gas pressure
b. Excessive gas flow rate
c. Presence of contaminants in the gas lines
d. All of the above
d. All of the above
What are the potential aftereffects of a flashback?
a. Damage to the torch tip
b. Damage to the hoses
c. Both a and b
d. None of the above
c. Both a and b
At what temperature does the burning speed of the gas mixture increase dramatically during a flashback?
a. 150°C
b. 190°C
c. 220°C
d. 250°C
c. 220°C
At approximately what temperature can spontaneous ignition and burning of the gas mixture within the tip occur?
a. 220°C
b. 250°C
c. 280°C
d. 315°C
d. 315°C
What temperature must the torch tip be kept below to prevent spontaneous ignition of the gas mixture within the tip?
a. 150°C
b. 190°C
c. 220°C
d. 250°C
b. 190°C
What is the primary function of flashback arrestors in oxy-fuel torch lines?
a. To increase the flow rate of gas
b. To regulate the temperature of the flame
c. To extinguish flames
d. To create a spark in the torch line
c. To extinguish flames
In addition to extinguishing flames, what other function do flashback arrestors serve?
a. They increase the pressure of the gas
b. They regulate the oxygen-to-fuel ratio
c. They prevent the backflow of gas
d. They cool down the torch line
c. They prevent the backflow of gas
What happens if certain temperatures and/or pressures are exceeded in a flashback arrestor?
a. The gas flow is increased
b. The flashback arrestor shuts off the gas flow
c. The flashback arrestor ignites
d. The flashback arrestor expands
b. The flashback arrestor shuts off the gas flow
How are flashback arrestors typically marked to indicate the direction of gas flow?
a. With a circle
b. With a square
c. With an arrow
d. With a triangle
c. With an arrow
Where can flashback arrestors be installed in oxy-fuel torch lines?
a. Only at the torch
b. Only at the regulators
c. Both at the torch and regulators
d. None of the above
c. Both at the torch and regulators
What is the primary function of a torch-mounted flashback arrestor?
a. To protect the regulator
b. To prevent flashback from entering the hose
c. To stop the flow of gas
d. To extinguish flames on the torch tip
b. To prevent flashback from entering the hose
What is the purpose of a regulator-mounted flashback arrestor?
a. To protect the torch
b. To prevent flashback from going further back to the acetylene bottle
c. To stop the flow of oxygen
d. To extinguish flames on the regulator
b. To prevent flashback from going further back to the acetylene bottle
Why won’t a reverse-flow check valve stop a flashback?
a. Because it is not designed for gas flow direction
b. Because it is ineffective in high-pressure systems
c. Because it does not extinguish flames
d. Because it cannot prevent gas from flowing backwards
d. Because it cannot prevent gas from flowing backwards
What is the primary function of a reverse flow valve in oxy-fuel torch lines?
a. To increase the flow rate of gases
b. To regulate the temperature of the torch flame
c. To prevent the backflow of gases into the hoses
d. To adjust the pressure of the gases
c. To prevent the backflow of gases into the hoses
How does a reverse flow valve function in oxy-fuel torch lines?
a. By allowing the gases to flow in one direction only
b. By mixing oxygen and fuel gases to create a combustible mixture
c. By controlling the speed of the gas flow
d. By shutting off the gas supply in case of an emergency
a. By allowing the gases to flow in one direction only
What is he typical life expectancy of a reverse flow check valve?
a. 4 months
b. 8 months
c. 16 months
d. 18 months
d. 18 months
Cylinder pressure regulators have how many gauges?
a. 1
b. 2
c. 3
d. 4
c. 2
What position should the pressure regulator adjusting knob be set at prior to opening the cylinder valve?
a. Backed out all the way.
b. Threaded in all the way.
c. Threaded in 1-1.5 turns.
d. Threaded halfway.
a. Backed out all the way.
Which component of a cutting torch controls the flow of cutting oxygen?
a) Fuel gas needle valves
b) Cutting oxygen control lever
c) Mixing chambers
d) Cutting tips
b) Cutting oxygen control lever
Where are the mixing chambers located in a cutting torch?
a) In the tip
b) In the torch body
c) Both a and b
d) None of the above
c) Both a and b
What is the purpose of cutting tips in a cutting torch?
a) To control the flow of cutting oxygen
b) To concentrate and direct the preheat flame and cutting oxygen
c) To regulate the temperature range
d) None of the above
b) To concentrate and direct the preheat flame and cutting oxygen
Which temperatures are generally used for preheating steel before cutting?
a) 200-315 °C (400-600 °F)
b) 500-870 °C (932-1600 °F)
c) 1000-1500 °C (1832-2732 °F)
d) 0-100 °C (32-212 °F)
b) 500-870 °C (932-1600 °F)
At what heated temperature can most of the carbon and alloy steels be cut?
a) 200-315 °C (400-600 °F)
b) 500-870 °C (932-1600 °F)
c) 1000-1500 °C (1832-2732 °F)
d) 0-100 °C (32-212 °F)
a) 200-315 °C (400-600 °F)
What happens when high purity oxygen is directed onto hot steel during cutting?
a) The steel becomes harder
b) The steel becomes more brittle
c) The metal oxidizes and becomes fluid
d) None of the above
c) The metal oxidizes and becomes fluid
What is the function of fuel gas needle valves in a cutting torch?
a) To control the flow of cutting oxygen
b) To control the flow of preheating flame oxygen and fuel gas
c) To concentrate and direct the preheat flame and cut oxygen
d) To mix oxygen and fuel gas for the preheat flame
b) To control the flow of preheating flame oxygen and fuel gas
Which of the following is NOT a type of oxy-fuel gas cutting torch?
A) High-pressure type
B) Equal pressure-type
C) Injector-type
D) Low-pressure type
D) Low-pressure type
What determines the selection between the two types of oxy-fuel gas cutting torches?
A) The size of the tip being used
B) The type of metal being cut
C) The fuel gas supply pressure
D) The oxygen pressure
C) The fuel gas supply pressure
At what minimum pressure is the equal pressure-type oxy-fuel gas cutting torch designed to operate?
A) 2 psi (13.8 kPa)
B) 10 psi (68.9 kPa)
C) 14 kPa (2 psi)
D) 70 kPa (10 psi)
C) 14 kPa (2 psi)
What is the typical range of oxygen pressure required for the equal pressure-type oxy-fuel gas cutting torch?
a) Greater than 175 kPa (25 psi)
b) Less than 175 kPa (25 psi)
c) Equal range to acetylene
d) 14-100 kPa (2-15 psi)
b) Less than 175 kPa (25 psi)
What is the typical range of acetylene pressure required for the equal pressure-type oxy-fuel gas cutting torch?
a) 14-100 kPa (2-15 psi)
b) 2-15 kPa (0.3–2 psi)
c) 20-80 kPa (3–12 psi)
d) 70-275 kPa (10-40 psi)
a) 14-100 kPa (2-15 psi)
What is the typical range of acetylene pressure required for the injector-type oxy-fuel gas cutting torch?
a) 14-100 kPa (2-15 psi)
b) 2-15 kPa (0.3–2 psi)
c) 20-80 kPa (3–12 psi)
d) 70-275 kPa (10-40 psi)
d) 70-275 kPa (10-40 psi)
What is the primary function of oxy-fuel gas cutting tips?
a) Providing cooling during cutting
b) Initiating the cutting process
c) Emitting preheating flames and cutting oxygen
c) Emitting preheating flames and cutting oxygen
How are the preheat flame orifices typically arranged in oxy-fuel gas cutting tips?
a) Randomly dispersed
b) In a straight line
c) In an outer circle
d) In a square pattern
c) In an outer circle
What should be done with cutting tips when not in use?
a) Dispose of them immediately
b) Leave them on the workbench
c) Return them to their original container or a storage rack
d) Use them as makeshift tools
c) Return them to their original container or a storage rack
How should the nut of the cutting tip be tightened during installation?
a) Finger-tightened
b) With a hammer
c) With a wrench to a snug fit
d) Left loose for easy removal
c) With a wrench to a snug fit
What is the consequence of the accumulation of slag in the preheat and cutting oxygen passages?
a) Increase in gas flow
b) Disturbance in preheat flame and oxygen stream flow
c) Enhancement of performance and cut quality
d) Reduction in tip life expectancy
b) Disturbance in preheat flame and oxygen stream flow
What is recommended to be done when the holes of the tip are clogged?
a) Increase the gas flow
b) Replace the tip immediately
c) Restore the tip to a good working condition
d) Ignore it until performance is severely affected
c) Restore the tip to a good working condition
What is the recommended size of the cleaning needle in comparison to the tip opening?
a) Same size as the tip opening
b) Two sizes smaller than the tip opening
c) One size smaller than the tip opening
d) Double the size of the tip opening
c) One size smaller than the tip opening
What motion should be used when cleaning the tip with a needle?
a) Circular motion
b) Back and forth motion
c) Straight up-and-down motion
d) Twisting motion
c) Straight up-and-down motion
What should be done to remove the scrapings during tip cleaning?
a) Leave them inside the tip
b) Blow them out by opening the oxygen valve
c) Wash them out with water
d) None of the above
b) Blow them out by opening the oxygen valve
What consequence can occur if the cleaning needle is bent or twisted during use?
a) Enhanced performance
b) Reduced tip life expectancy
c) Decreased gas flow
d) Flame distortion due to flare in the tip opening
d) Flame distortion due to flare in the tip opening
How can worn and damaged areas of the tip be reconditioned?
a) By replacing the tip entirely
b) By using a tip file or dresser
c) By applying oil to the tip
d) By soaking the tip in water overnight
b) By using a tip file or dresser
What is an alternate method of cleaning cutting tips mentioned in the statement?
a) Using a chemical solution
b) Using a brush to scrub the tip
c) Removing the tip from the torch head and cleaning from the backside
d) Ignoring cleaning altogether
c) Removing the tip from the torch head and cleaning from the backside
Where should cutting tips be stored when not in use?
a) In a bucket of water
b) In their original packaging or a dry area
c) Encased in oil and grease for better preservation
d) Wrapped in a cloth and left in humid enclosed area
b) In their original packaging or a dry area
What aspect of cutting do manual cutting guides control?
a) Cutting speed
b) Cutting torch position
c) Preheat flame height
d) None of the above
b) Cutting torch position
What type of guide is recommended for cutting straight edges?
a) Circular cutting guide
b) Template
c) Straight-line cutting guide
d) Irregular cutting guide
c) Straight-line cutting guide
How are circle cutting guides utilized?
a) To cut straight edges
b) To measure preheat flame height
c) To cut circles and arcs
d) To control cutting speed
c) To cut circles and arcs
Which of the following statements accurately describes the function of manual cutting guides?
a) They control cutting speed and preheat flame height.
b) They control cutting torch position but not cutting speed or preheat flame height.
c) They control preheat flame height but not cutting torch position or cutting speed.
d) They control cutting speed but not cutting
b) They control cutting torch position but not cutting speed or preheat flame height.
What is the purpose of straight-line cutting guides?
a) To control cutting torch position.
b) To control cutting speed.
c) To produce a reasonably true straight edge.
d) To control preheat flame height.
c) To produce a reasonably true straight edge.
What material can be used to create straight-line cutting guides?
a) Round bars.
b) Aluminum sheets.
c) Flat bar or angle iron.
d) Plastic tubing.
c) Flat bar or angle iron.
What component of a typical circle-cutter adjusts the preheat flame-to-work distance?
a) Adjustable rod
b) Rotating mechanism
c) Drive system
d) Adjustable wheel
a) Adjustable rod
Which part of the circle-cutter is responsible for attaching to the cutting tip?
a) Adjustable wheel
b) Rotating mechanism
c) Drive system
d) Adjustable rod
b) Rotating mechanism
What feature do some torch bodies incorporate in their circle-cutting mechanism?
a) Adjustable rod
b) Centre pivoting point
c) Drive system
d) Rotating mechanism
c) Drive system
What is the purpose of the centre pivoting point in a circle cutting guide?
a) To set the preheat flame-to-work distance
b) To adjust the size of the circle to be cut
c) To attach to the cutting tip
d) To provide a pivot for rotation
d) To provide a pivot for rotation
How are templates utilized in cutting irregular shapes?
a) They are used as a guide for measuring and cutting each shape individually.
b) They serve as a master pattern for cutting irregular shapes.
c) They are discarded after one-time use.
d) They are used solely for decorative purposes.
b) They serve as a master pattern for cutting irregular shapes.
What is the benefit of using a single accurate pattern piece for cutting multiple identical pieces?
a) It reduces the need for measuring.
b) It ensures greater accuracy and consistency.
c) It increases the likelihood of errors.
d) It doesn’t affect the outcome significantly.
b) It ensures greater accuracy and consistency.
Why is including the kerf allowance important when cutting with templates?
a) It ensures the shapes are cut with precision.
b) It reduces the size of the pattern piece.
c) It simplifies the cutting process.
d) It is unnecessary for accurate cuts.
a) It ensures the shapes are cut with precision.
What is the purpose of measuring and cutting one accurate pattern piece?
a) To increase the workload.
b) To save time and effort.
c) To create a guide for future cuts.
d) To complicate the process unnecessarily.
c) To create a guide for future cuts.
Which of the following is NOT a characteristic of oxy-fuel gas cutting machines?
a) Portable or stationary use
b) Electrically driven
c) Slow and expensive cutting process
d) Can cut precise dimensions at set speeds
c) Slow and expensive cutting process
How do gas cutting machines achieve accurate cuts?
a) By randomly moving the torch
b) By propelling the part at varying speeds
c) By moving the torch or propelling the part at a uniform speed
d) By using high-pressure water jets
c) By moving the torch or propelling the part at a uniform speed
What is needed to ensure smooth and accurate cuts with gas cutting machines?
a) A dirty and irregular track
b) An oily track
c) A clean and irregular track
d) A clean and regular track
d) A clean and regular track
Which type of machine is most generally used for straight edge preparation or plate trimming?
a) Simple type
b) Elaborate fixed type
c) Magnetic holding type
d) Grooved track type
a) Simple type
What components are typically found in the oxy-fuel gas cutting machine torch body?
a) Two control valves
b) Four control valves
c) Three control valves
d) Five control valves
c) Three control valves
Why is the first type of machine generally preferred for cutting large plates?
a) Because it requires less maintenance
b) Because it is more accurate
c) Because it is easier to move the machine than the plate
d) Because it is faster
c) Because it is easier to move the machine than the plate
What feature allows tracks to be bent to suit the application?
a) Magnetic holding plates
b) Grooved tracks
c) Special carriages
d) Tracks that can be bent
d) Tracks that can be bent
Oxy-fuel gas shape-cutting machines can have up to _____ oxy-fuel gas cutting torches.
a) 8
b) 12
c) 4
d) 10
b) 12
What is a characteristic of portable single-torch shape-cutting machines?
a) They are not available in North America
b) They can only cut metal of a certain thickness
c) They cannot be moved
d) They have only one cutting torch
d) They have only one cutting torch
Which type of tracer uses a magnetized roller to follow the edge of a metal template?
a) Electronic-eye tracer
b) Computer-controlled tracer
c) Magnetic tracer
d) None of the above
c) Magnetic tracer
How does an electronic-eye tracer follow the template?
a) It uses a magnetized roller pre-set program
b) It uses a photoelectric cell program
c) It uses a computer numerical control program
d) It does not follow a template
c) It uses a computer numerical control program [CNC]
What type of tracer uses special tracer ink as a template?
a) Magnetic tracer
b) Electronic-eye tracer
c) Computer-controlled tracer
d) None of the above
b) Electronic-eye tracer
What energy does the photoelectric cell convert light into in an electronic-eye tracer?
a) Mechanical energy
b) Electrical energy
c) Heat energy
d) Chemical energy
b) Electrical energy
What is the purpose of oxy-fuel gas pipe-bevelling machines?
a) To cut shapes out of metal
b) To weld metal together
c) To bevel or cut pipe to size
d) To engrave patterns on metal
c) To bevel or cut pipe to size
What drives oxy-fuel gas pipe-bevelling machines?
a) Motor only
b) Hand only
c) Either hand or motor
d) They are stationary and don’t need driving
c) Either hand or motor
How is a computer-controlled oxy-fuel gas cutting torch ignited and extinguished?
a) Manually
b) By a magnetized roller
c) By the computer
d) By a photoelectric cell
c) By the computer
Why is manual cutting usually undesirable for the preparation of long joint edges?
a) It is too time-consuming
b) It results in excessively smooth edges
c) It tends to be inaccurate and irregular
d) It is difficult to handle the torch
c) It tends to be inaccurate and irregular
What should be done if excessive roughness or adhering oxide is present on joint edges before welding?
a) Ignore it and proceed with welding
b) Clean it off before setting up for welding
c) Cover it with filler material
d) Increase the heat of the torch
b) Clean it off before setting up for welding
In what situations is manual cutting often used for the preparation of structural sections and plate edges?
a) Only for long joint edges
b) Only for short joint edges
c) For modest length joints
d) For joints of any length
c) For modest length joints
How can the quality, precision, and speed of oxy-fuel cutting be improved?
a) By using a nozzle guide
b) By increasing the cutting speed
c) By using a larger cutting tip
d) By reducing the oxygen flow
a) By using a nozzle guide
What function does a nozzle guide serve in machine oxy-fuel cutting?
a) It adjusts the angle of the torch
b) It keeps the torch at a uniform distance from the metal surface
c) It controls the flow of oxygen
d) It removes adhering oxide from the metal surface.
b) It keeps the torch at a uniform distance from the metal surface
How can operators achieve smooth freehand cuts during manual cutting?
a) By holding the torch with both hands
b) By adopting a comfortable position with one hand supporting the nozzle end of the torch
c) By using cutting accessories and machines
d) By using a nozzle guide
b) By adopting a comfortable position with one hand supporting the nozzle end of the torch
What should operators do to ensure smooth, high-quality cuts during manual cutting?
a) Keep the oxy-fuel gas hoses in the way
b) Place the oxy-fuel gas hoses in the range of falling slag and sparks
c) Position themselves so they can clearly see the cut
d) Twist the oxy-fuel gas hoses
c) Position themselves so they can clearly see the cut
What is recommended for operators to develop an effortless, even torch movement during manual cutting?
a) Increasing the cutting speed
b) Decreasing the oxygen flow
c) Positioning themselves for clear visibility of the cut
d) Using cutting accessories and machines
c) Positioning themselves for clear visibility of the cut
What should be done with the oxy-fuel gas hoses during manual cutting to prevent interference?
a) Keep them well out of the way
b) Place them directly under the torch
c) Twirl them around the operator’s hand
d) Remove them entirely
a) Keep them well out of the way
How can unevenness of movement be minimized during manual cutting?
a) By adopting an uncomfortable position
b) By using excessive force on the torch
c) By minimizing effort
d) By increasing the speed of movement
c) By minimizing effort
How far above the base metal surface should the ends of the preheat flame cones be when starting a cut?
a) 3 mm (1/8 in)
b) 5 mm (1/4 in)
c) 2 mm (1/16 in)
d) 8 mm (1/3 in)
a) 3 mm (1/8 in)
What is one method mentioned for starting a cut?
a) Placing the tip halfway over the edge of the plate
b) Placing the tip fully over the edge of the plate
c) Holding the torch perpendicular to the plate
d) Heating the entire surface of the plate evenly
b) Placing the tip fully over the edge of the plate
True or false. Molten hot metal may be propelled outward if the edge is not heated enough
a) True
b) False
a) True [Molten hot metal may be propelled outward if the edge is not heated enough]
What color should the edge of the material be before starting the cut?
a) Blue
b) Yellow
c) Cherry red
d) White
c) Cherry red
What advantage does the preferred method of starting a cut have?
a) Produces smoother cuts
b) Reduces the need for repositioning during longer cuts
c) Produces sharper corners and reduces slag
d) Requires less oxygen consumption
c) Produces sharper corners and reduces slag
What should be done once the cut is started?
a) Increase the speed of torch movement
b) Reposition the torch for better visibility
c) Maintain a consistent distance between the torch and workpiece
d) Decrease the distance between preheat flame cones and workpiece
c) Maintain a consistent distance between the torch and workpiece
What sound indicates the appropriate speed of torch movement during cutting?
a) Sizzling
b) Popping
c) Ripping
d) Hissing
c) Ripping
In which direction should the torch/cut ideally be moved during cutting?
a) Toward the body
b) Away from the body
c) Sideways
d) Upward
b) Away from the body
What should be the speed of torch movement during cutting?
a) Fast, to finish quickly
b) Slow, to ensure precision
c) Smooth and steady
d) Erratic, to prevent overheating
c) Smooth and steady [producing a ripping sound.]
True or false. A neutral flame is not used for cutting.
a) True
b) False
b) False
What should be done to direct slag away from the body during cutting?
a) Move the torch in a circular motion
b) Tilt the torch upwards
c) Move the torch towards the body
d) Move the torch away from the body
d) Move the torch away from the body
What is one of the most important factors affecting a cut?
a) Torch temperature
b) Material thickness
c) Speed of torch movement
d) Type of gas used
c) Speed of torch movement
How does excessive slag buildup impact the cost of a cut?
a) It decreases the cost
b) It increases the cost
c) It has no effect on the cost
d) It improves the quality of the cut
b) It increases the cost
What happens if the travel speed during cutting is too fast?
a) Slag buildup increases
b) Metal penetration decreases
c) Kerf becomes cleaner
d) Draglines curve towards the direction of travel
b) Metal penetration decreases
What is a result of using travel speeds that are too slow during cutting?
a) Even bottom edge
b) Square top edge
c) Noticeable draglines
d) Clean opening kerf
c) Noticeable draglines
What does low oxygen pressure during cutting result in?
a) Rounded top edge of the cut
b) Excessive expansion below the cutting jet
c) Clean and square kerf
d) Increased cutting efficiency
a) Rounded top edge of the cut
What should be ensured before starting a cut to maintain cutting speed and kerf quality?
a) Presence of rust
b) Clean work surfaces
c) Excessive slag buildup
d) Slow torch movement
b) Clean work surfaces
Why is it common for operators to use excessive oxygen pressure during cutting?
a) To reduce slag buildup
b) To improve cut quality
c) To increase cutting speed
d) Due to lack of knowledge or training
d) Due to lack of knowledge or training
What role does consistent oxygen pressure play in producing a quality cut?
a) It reduces slag buildup
b) It increases travel speed
c) It affects the cutting jet
d) It has no impact on the cut quality
c) It affects the cutting jet
What impact does high oxygen pressure have on the kerf during cutting?
a) It narrows the kerf
b) It widens the kerf at the bottom
c) It reduces draglines
d) It produces a clean opening
b) It widens the kerf at the bottom
What is the primary component responsible for performing the cutting during oxy-fuel cutting?
a) Nitrogen
b) Hydrogen
c) Oxygen
d) Acetylene
c) Oxygen
What is “kerf”?
a) The speed at which the torch moves
b) The amount of slag buildup
c) The quality of the cut
d) The width of the cut produced by the torch
d) The width of the cut produced by the torch
When cutting a base plate, normally the cutting tip is help _______ to the base metal.
a) 45°
b) 90°
c) 110°
d) 160°
b) 90° [perpendicular]
When cutting a base plate 13 mm (1/2”) or thinner, it is better to use a(n) _______ angle.
a) Extreme push
b) Extreme pull
c) Slight push
d) Slight pull
c) Slight push [angle 70°-90° off the base metal]
When cutting a base plate 13 mm (1/2”) or thinner, it is better to use a slight push angle ( ______off the base metal)
a) 70°-90°
b) 10°-20°
c) 90°-135°
d) 100°-180°
a) 70°-90°
Steel sheet metal requires a(n) ______ angle.
a) Extreme push
b) Extreme pull
c) Slight push
d) Slight pull
a) Extreme push [angle (10°-20° off the base metal).]
This low angle makes for faster, straighter, and cleaner cuts with less slag attaching itself to the base metal.
Steel sheet metal requires an extreme push angle (________ from the base metal).
a) 70°-90°
b) 10°-20°
c) 90°-135°
d) 100°-180°
b) 10°-20°
This low angle makes for faster, straighter, and cleaner cuts with less slag attaching itself to the base metal.
Where should the inner cone of the preheat flame be held in relation to the surface of the base metal?
a) 1-1.5 mm (1/16-1/8 in)
b) 3-5 mm (1/4-3/16 in)
c) 1.5-3 mm (1/8-1/16 in)
d) 2-4 mm (3/16-1/4 in)
c) 1.5-3 mm (1/8-1/16 in)
Why is it important to remove scale or slag from the surface of the base metal before cutting?
a) To increase tip temperature
b) To improve cut quality
c) To reduce preheat time
d) To decrease visibility of layout lines
b) To improve cut quality
What happens to layout lines if mill scale is not removed prior to cutting?
a) They become more visible
b) They disappear
c) They move with the scale as it heats up
d) They remain unaffected
c) They move with the scale as it heats up
What is recommended to remove loose mill scale from the surface prior to layout?
a) Abrasive wheel or wire wheel
b) Sandpaper
c) Chemical cleaner
d) Hammer and chisel
a) Abrasive wheel or wire wheel
When cutting a bevel, what is recommended regarding the positioning of preheat holes?
a) No change is necessary
b) Move them closer together
c) Change their position for better preheating
d) Remove preheat holes entirely
c) Change their position for better preheating
How should preheat holes be positioned for a straight, square cut?
a) Randomly
b) So that two preheat holes follow each other along the line of cut
c) In a circular pattern
d) At the corners of the base metal
b) So that two preheat holes follow each other along the line of cut
What is the result of improper positioning of preheat holes for a straight, square cut?
a) Improved preheating
b) Irregular kerf
c) Faster preheating
d) Smooth top edge
b) Irregular kerf
Why is careful positioning of preheat holes important for cutting tips with two or four preheat holes?
a) To increase tip lifespan
b) To reduce preheat time
c) To improve preheating efficiency
d) To enhance cut quality
c) To improve preheating efficiency
For cutting tips with more than four preheat holes, what is the significance of exact positioning?
a) It’s crucial for safety reasons
b) It’s irrelevant
c) It’s important for maintaining tip temperature
d) It’s less of a factor compared to tips with fewer holes
d) It’s less of a factor compared to tips with fewer holes
When cutting a straight, square cut, how should the preheat holes be positioned?
a) Randomly dispersed along the cutting line
b) Two preheat holes following each other along the line of cut
c) Clustered at one end of the cutting line
d) Alternating between preheat and cutting holes
b) Two preheat holes following each other along the line of cut
What is the recommended action when cutting a bevel?
a) Keep preheat holes in the same position as for a straight cut
b) Ignore preheat hole positioning altogether
c) Change the position of the preheat holes in the cutting tip
d) Add more preheat holes for better cutting precision
c) Change the position of the preheat holes in the cutting tip
Why is it important to carefully position preheat holes for cutting tips with two or four holes?
a) It speeds up preheating process
b) It prevents overheating of the cutting tip
c) It ensures better preheat to the metal
d) It makes the cut display a rounded top edge
c) It ensures better preheat to the metal
What happens if preheat holes are not properly positioned when cutting a straight, square cut?
a) Preheating process speeds up
b) Cut displays irregular kerf
c) Metal doesn’t get preheated
d) Cut becomes too precise
b) Cut displays irregular kerf
During oxy-fuel gas cutting of light gauge sheet metals, what can be a potential problem?
a) Rust formation
b) Distortion
c) Surface smoothness
d) Material discoloration
b) Distortion
What happens to the metal when it’s heated during oxy-fuel gas cutting?
a) It contracts
b) It expands
c) It remains unchanged
d) It becomes brittle
b) It expands
What can occur near the cut surfaces during oxy-fuel gas cutting?
a) Rust formation
b) Residual stress distribution
c) Surface hardening
d) Material softening
b) Residual stress distribution
How can warping be limited when trimming opposite edges of a plate?
a) By cutting only one edge
b) By preheating the workpiece
c) By cutting both edges simultaneously
d) By cooling the workpiece after cutting
c) By cutting both edges simultaneously
Which technique helps distribute expansion evenly throughout the workpiece?
a) Intermittent cutting
b) Stack cutting
c) Preheating
d) Submerging in water
c) Preheating
What technique involves making a series of unconnected cuts to minimize distortion?
a) Preheating
b) Stack cutting
c) Intermittent cutting
d) Submerging in water
c) Intermittent cutting
What is a serious problem during oxy-fuel cutting of cast irons, higher carbon steels, and some alloy steels?
a) Rust formation
b) Material softening
c) Surface hardening
d) Buckling
c) Surface hardening
How does the rapid cooling during oxy-fuel cutting affect high carbon steels?
a) It causes surface softening
b) It induces surface hardening
c) It leads to material expansion
d) It prevents distortion
b) It induces surface hardening
What should be done before welding to avoid weld defects later?
a) Increase the cutting speed
b) Remove any hardened surfaces
c) Apply additional heat
d) Use a different cutting technique
b) Remove any hardened surfaces
Which material may not experience significant hardening during oxy-fuel cutting?
a) Cast iron
b) Low-carbon steel
c) Alloy steel
d) Stainless steel
b) Low-carbon steel
How can the surface hardening effect be decreased for high carbon steels?
a) Increase the cutting speed
b) Apply post-heating
c) Reduce the preheating temperature
d) Increase the carbon content
b) Apply post-heating
What should be done if cracks develop after oxy-fuel cutting?
a) Leave them as is
b) Remove them by grinding or gouging
c) Fill them with filler material
d) Ignore them until welding
b) Remove them by grinding or gouging
Which of the following materials present specific cutting issues for oxy-fuel gas cutting due to the formation of a protective oxide layer?
a) Aluminum
b) Cast iron
c) Copper
d) Brass
b) Cast iron
Cast iron and other ferrous alloys with a high carbon/alloy content such as, high-speed steel, stainless steels, chromium steels and manganese steels, present specific cutting issues for oxy-fuel gas cutting.
What is the main reason behind the cutting issues faced when cutting high-carbon and alloy steels using oxy-fuel gas cutting?
a) Formation of a protective oxide layer with a low melting point
b) Formation of a protective oxide layer with a higher melting temperature
c) Rapid cooling of the metal
d) Excessive heat generation
b) Formation of a protective oxide layer with a higher melting temperature
At what temperature does the oxy-fuel process preheat carbon steel to, which is referred to as the kindling point?
a) 500 °C (932 °F)
b) 650 °C (1202 °F)
c) 870 °C (1600 °F)
d) 1000 °C (1832 °F)
c) 870 °C (1600 °F)
When cutting stainless or high-carbon steels, which of the following methods can produce the same effect as using a waster plate?
a) Using a high-carbon steel rod
b) Using a low-carbon steel rod
c) Using a high cutability flux
d) Using a high-carbon steel wire
c) Using a high cutability flux
What role does the flux play when using a high cutability flux or low-carbon steel rod for cutting stainless or high-carbon steels?
a) It increases the melting point of the alloying elements.
b) It reacts with oxides of alloying elements to produce compounds with higher melting points.
c) It lowers the melting point with alloying elements to produce low melting points
d) It enhances the cutting speed of the steel rod.
b) It reacts with oxides of alloying elements to produce compounds with higher melting points.
Why is feeding a low-carbon steel rod into the cut usually the preferred method when cutting stainless or high-carbon steels?
a) It is cheaper than using high cutability flux.
b) It produces a smoother cut surface.
c) It reacts faster with alloying elements.
d) It requires less manual effort.
a) It is cheaper than using high cutability flux.
How can low-carbon steel wire be fed into the preheat flames for a faster start when cutting cast iron?
a) Manually feeding it into the flames
b) Using a torch attachment that feeds the wire continuously
c) Preheating the wire before feeding it into the flames
d) Using a waster plate for preheating purposes
b) Using a torch attachment that feeds the wire continuously
