OAW/OAC/SAFETY

Question 1

Combustibles

Answer 1

Easily ignited materials that stay ignited easily.
-wood, paper, etc

Question 2

Non-combustibles

Answer 2

Not easily ignited
- metal, asbestos
Materials that are not usually combustible can be with excess oxygen

Question 3

Fire extinguishers- Class A

Answer 3

Class a fired are ordinary combustion- wood, paper- and there’s just water inside

Question 4

Fire extinguishers- Class B

Answer 4

Caused by flammable liquids - filled with carbon dioxide to get rid of oxygen.

Question 5

Fire extinguishers- Class C

Answer 5

Caused by electrical equipment - filled with foam

Question 6

Fire extinguishers- Class D

Answer 6

By combustible metals like lithium - filled with fire retardant powders or dry chemicals

Question 7

Welding in confined spaces - must haves

Answer 7

Ventilation and a fire watcher

Ventilation keep harmful vapours out of your lungs

Fire watcher keep watch for fires while you’re welding.

Question 8

Deep burns

Answer 8

Third degree burns
Damage nerves, blood, muscles, etc, and cause permanent damage.
Skin is black and charred or a ring around the wound.

Question 9

Superficial burns

Answer 9

First and second degree burns
Less damage and surface burns
First degree are sunburns, slight burns, etc
Second degree it starts to blister

Question 10

Fire triangle

Answer 10

Fire needs the triangle to survive - oxygen, fuel, and heat

Question 11

Respirator

Answer 11

Block out tiny little particles and vapours, the stuff you can’t see.

There are two kinds, negative pressure and positive pressure.

Question 12

Dust mask

Answer 12

Same job as respirator but larger particles.

Question 13

Metal fumes fever

Answer 13

Caused by inhaling metal vapours, zinc oxide, a condition characterized by flu symptoms

Question 14

Types of light

Answer 14

Three types of light associated with welding:
Ultraviolet - can’t experience but get sunburnt
Infrared - experienced through heat
And viable light
Exposure can cause serious damage

Question 15

Safety glasses: why?

Answer 15

Protect you from sparks flying or metal particles that hike grinding or cutting. Also protect you from uv rays - clear glass

Question 16

Welding helmet/lenses

Answer 16

Protect you from bright light rays. Your helmet protects your periphery vision. There are three lenses in your helmet, two clear to protect you from uv and one dark that can change. That one protects from visible and infrared.

Question 17

Acetylene

Answer 17

C2H2
Acetone is saturated into cement and then acetylene is pumped into the porous holes as carbonized material.
Draw limit - 1/7 of tanks volume per hour
Calcium carbide and water.
Working pressure - 10psi
Slightly unstable - 15psi
Explosive - 25psi
Stored - 250psi

Question 18

Oxygen

Answer 18

O2
Added to fire and makes it burn harder
Stored at 2200psi
Pumped into tank that is made with one seamless forged metal tank - extrusion. Air is pumped in and out at freezing levels and oxygen bubbles out, then it’s collected.

Question 19

OAC

Answer 19

Oxy-acetylene cutting

Question 20

OAW

Answer 20

Oxy-acetylene welding

Question 21

Gas leak

Answer 21

Spray soap and leak will bubble

Question 22

Cylinder pressure

Answer 22

oxygen - 2200 psi (stored), 10 psi (working)
acetylene - 250 psi (stored), 10 psi (working)
pressure is always the same no matter the size of the tank, the volume would just be different.

Question 23

Cylinder safety features

Answer 23

How it’s made - one seam
Acetylene & acetone - made this way so it won’t explode
Safety plug - melts at 100 degrees C when it heats up (pressure gets higher too) so it can slowly release the gas so it doesn’t explode

Question 24

Which way do you turn oxygen valve?

Answer 24

righty tighty lefty loosey

Question 25

Which way do you turn fuel gas valve?

Answer 25

lefty tighty righty loosey

Question 26

Bursting disc fracture pressure

Answer 26

Safety valve prevents explosions. Disc bursts when temperature gets higher than 3000-3500 degrees C.

Question 27

Backfire

Answer 27

not as dangerous as flashback.
a small explosion that produces a popping sound, making the flame recede back into the torch.
Caused by gas burning faster than it’s coming out.

Question 28

Flashback

Answer 28

Occurs when the flame recedes into or further than the mixing chamber, hose, or regulator. This is very dangerous and may cause explosion. Happens when the flame is able to go back and cross the valves.
Caused by reverse flow of gas or loose connections.

Question 29

Check valve

Answer 29

a valve that allows the flow of gas in only one direction. Gas pressure one way opens the valve but from the other direction it closes. Not as good as a flashback arrestor because sometimes it may not close fast enough and traps fire inside the hose.

Question 30

Flashback arrestor

Answer 30

prevents reverse flow of fuel gas back into the hose, regulator, or cylinder. Similar to a check valve but this one has a special chamber inside that allows the fire to burn inside to allow a split second longer for the valve to close.

Question 31

Neutral flame

Answer 31

correct balance of oxygen to acetylene (or other fuel gas). correct ratio is 2.5 (O2) : 1 (C2H2), but set oxygen to 1 because the rest will come from the air.

Flame has to flame areas, the envelope (even and smooth and round) and the cone (shaped like a bullet).

wont be dirty with excess carbon.

Question 32

Carburizing/Carbonizing flame

Answer 32

produced when excess acetylene (carbon) is present or when too little oxygen is present.

Three flame areas are visible:
cone, rougher envelope, and feather inside.

Results in large carbon pockets in the weld and make the weld brittle.

Question 33

Oxidizing flame

Answer 33

produced when too much oxygen is present.

Two flame areas are present:
very bright, tiny, pointed corner, and more turbulent and shorter envelope.

instead of melting and welding metal, it just burns away.

Question 34

Oxygen : acetylene ratio

Answer 34

2.5 : 1

1.5 of oxygen comes from air so set it to one.

Question 35

Arc/welding flash

Answer 35

a bright flash of uv light usually from the flame or torch that can severely damage eyes. similar to a sunburn but for your eyes.

Question 36

Bourdon tubes

Answer 36

part of the pressure gauge. One side is connected to the pressure and the other is out to the atmosphere. Hollow inside and fills with gas to detect pressure.

There are two: one on the working hose and the other on the cylinder.

Question 37

Regulator

Answer 37

regulators detect the pressure in a cylinder or hose and help it to lessen.

Question 38

Gauges

Answer 38

pressure regulators usually have two gauges - one shows cylinder pressure and the other shows pressure through the tube. Shows when psi gets to unsafe levels.

Question 39

Lighting welding torch

Answer 39

1) open acetylene and oxygen valves slightly
2) open valves completely
3) set to working pressure
4) open acetylene to torch slowly until turbulent and no more smoke
5)open oxygen to torch slowly until a neutral flame is achieved.

slowly open acetylene, then strike it with flint, the open torch valve

Question 40

Shutting down

Answer 40

1) turn off acetylene to torch valve
2) turn off oxygen to torch valve
3) close acetylene valve
4) close oxygen valve
5) close acetylene pressure
6) close oxygen pressure
7) slightly open torch valves to clear hose

Question 41

attaching regulator to hose

Answer 41

start by screwing hose into the regulator with your hand, and once you can’t move it anymore, take a proper sized wrench and slightly tighten it only a little bit.

Question 42

attaching regulator to cylinder

Answer 42

line up the regulation in the correct position and start screwing it in by hand until you cant then tighten with wrench.