Modlue 1 Flashcards
3 methods of jointing steel
Threaded ,voltaic , welded
What is purpose of regulator
To reduce the high pressure to working pressure
What is mild steel coated to make it galvanised
Zinc
What presure is oxygen bottle pressurised to
230 bars
Acetylene bottles pressurised to?
17 bar
What reacts with oxygen
Oil grease
List two safety precautions
Visual check, don’t use faulty tools, Ppe
Where would a chain wrench be used in plumbing
Working on big sizes
Mild steel pipe
What 2 compoenents make up mild steel
0.2% carbon 99.8% iron
4 gaskets material
Taylor rings, insertion rubber , tuxerine, halite
What’s an alloy
Is a metal substance made by mixing two or more elements
What’s maximum denisty
It is a temperature that will no longer shrink , it occupies least space
Explain conduction
When heat travels in straight lines or along a solid
What’s convection
Convection is the transfer of heat through the air caused when the molecules rise upwards after heating because they come lighter
What’s radiation
When heat travels in straight lines
List 3 characters of water
Odourless Tasteless Transparent Boils at 100 degree Celsius Freezes at 0 degree Celsius
What’s h2o stand for
The chemical has two parts of hydrogen and one part of oxygen
What’s water weigh in
Kg’s
What’s the unit for time
Seconds
What’s the unit for force
Newton
What’s unit for heat
Joule
What’s unit for power
Watt
What does 48 litres weigh
48 kg’s
What’s purification
Is the filtration of water to remove unwanted chemicals
What does water boil at
100•c
What does what freeze at
0•c
What’s Linear expansion
When plumber deals with lengthways movement
Explain thermal insulation
Prevention of heat energy loss
Good properties of thermal insulation
Low thermal conductivity Porosity Easy to apply Good surface finish Moisture resistance Light weight
Explain fusibily
A metal will melt with another metal
What’s malleability
A metal to be worked into a new shape without breaking
What’s elasticity
A material to return to it’s original shape after being pulled or pushed out of shape
What is Durability ?
Is the ability of a material to resist wear and tear
How long is a length of pipe
6.4 meters
2 reasons why galvanised pipes shouldn be welded
Remove zinc and injurious to health
3 ways of joints mild steel pipe
Threaded voltaic welded
What is the purpose of the zinc coating on galvanised pipe
To protect from corrsion
What diameter does mild steel pipe come in
8mm -200mm and above
How is mild steel pipe ordered in to relation to ends of the pipe
Plain threaded
How would you identify medium grade
Mark with a blue band
What type of instalments would medium grade be used for
Suitable for gas installations
How would you identify heavy grade
Marked with a red band
What the of installations would heavy grade be used for
Steam installations
How would you identify for schedule 40:80
Number stamped on pipe
What type of installations would schedule 40,80 be used for
Used in process industries
What is the main difference between the 3 grades of pipe
The wall thickness
How would you order a t fitting
From left to right to centre
Why are fittings tapered ?
To tighten the pipes and fittings together
What does b.s.p.t stand for
British standard pipe thread
What type of jointing compounds would be used for steam
Ptfe tape , black foliac
What type of jointing compounds would be used for oil
Ptfe flax , with red foliacstag
What type of jointing compounds would be used for Air
Ptfe tape
What type of jointing compounds would be used for natural gas?
Gas grade ptfe tape white foliac
How much of a gap should be left between pipes
3mm
State 3 pure metals in plumbing
Copper Iron Lead Zinc aluminium Tin
Thermal expansion ?
When a material will expand when heated and contract when cooling
Linear expansion?
When a plumber deals with lengthways movement
What’s Thermal insulation used for?
Use of heat lost
Three type of insulation
Glass fibre Polystyrene Rigid Lose fill Plastic
Good properties of insulation
Easy to apply Lightweight Moisture resistance Fungal attack resistance A good surface finish
Where’s most heat lost?
Through the walls
Where’s least heat loss
Through windows
Explain ductility
A metal that can be streched without breaking
Tenacity
Resist to be pulled apart
Tensile strength
To test various materials
State 3 alloys
Brass Bronze Mild steel Soft solder Hard solder
