Review packages

Question 1

State the chemical abbreviations for propane and natural gas?

Answer 1

C3H8

CH4

Question 2

What are the ignition temperatures for propane and natural gas?

Answer 2

1300F for natural gas

920F for propane

Question 3

List the specific gravity for natural gas vapour and propane vapour?

Answer 3

natural gas - 0.6

propane vapour - 1.5

Question 4

What is the specific weight of liquid propane?

Answer 4

0.51

Question 5

What are the upper and lower limits of flammability for natural and propane gas?

Answer 5

2.4-9.5% propane

4-14% natural gas

Question 6

What are the maximum flame temperatures for natural and propane gas?

Answer 6

3600F both

Question 7

List the atmospheric boiling temperatures for natural and propane gas?

Answer 7

• 44F propane

- 260F natural gas

Question 8

What are the expansion ratios for natural and propane liquid when they change to gas?

Answer 8

1: 600 natural gas
1: 270 propane

Question 9

What are the flame speeds of natural and propane gas?

Answer 9

25 in/sec - natural

32 in/sec - propane

Question 10

what is the calorific value (heat content) of natural and propane gas?

btu/cubic foot:

btu/cubic meter:

Answer 10

btu/cubic foot: 1000btu/2520btu

btu/cubic meter: 33,100/88275

Question 11

What number would be used to convert BTU’s to kW?

Answer 11

0.000293

Question 12

How many btus equal one kilowatt?

Answer 12

3412

Question 13

How many times larger is a cubic meter than a cubic foot?

Answer 13

35.31

Question 14

How many times larger is the calorific value of a cubic meter than a cubic foot using the same gas?

Answer 14

35.31

Question 15

What is the maximum pressure for low pressure gas? IN (psi. and inches water column)?

Answer 15

14’’ wc

Question 16

An appliance is considered high input when it exceeds what input?

Answer 16

400,000btu/h

Question 17

How many cubic feet of combustion air are required by a hydrocarbon fuel for each 1000 Btu’s of input?

Excess air:

Dilution air:

Total air:

Answer 17

excess = 5

dilution = 15

total = 30

Question 18

List the products of combustion of natural gas?

Answer 18

CO2, H2O, N2, Heat, Light

Question 19

Is a 2psig system considered high pressure?

Answer 19

no

Question 20

An appliance has a rating of 283,000 btus, and runs on propane. How long would it take to burn 1,865 ft3 of fuel?

Answer 20

2520 x 1865 = 4,699,800 / 283,000 = 16.6

Question 21

Define BTU

Answer 21

British thermal unit - amount of energy to raise 1lb of water 1 degree Fahrenheit

Question 22

What are the percentages of nitrogen and oxygen found in air?

Answer 22

20% oxygen

80% nitrogen

Question 23

What is the air/gas ratio required to achieve complete combustion of natural gas and propane?

Answer 23

10: 1 - for CH4
25: 1 for C3H8

Question 24

Explain the term primary air, with reference to an atmospheric burner?

Answer 24

air supplied with mixed fuel before ignition

Question 25

What is the term used to describe the additional air supplied to the combustion chamber of a gas appliance to ensure complete combustion?

Answer 25

excess air

Question 26

What is the purpose of dilution air?

Answer 26

reduce velocity of flue gases

Question 27

A gas appliance is considered to be high input when it exceeds what input?

Answer 27

400,000btu

Question 28

What are the pressure limitations of a class "b" license?

Answer 28

no pressure limit

Question 29

What is the name of the odorant used in natural gas to give it a distinct smell?

Answer 29

mercaptin

Question 30

1kw = _______btu's

Answer 30

3412

Question 31

1m3 = ____ft3

Answer 31

35.31

Question 32

1psi = _____ inches water column

Answer 32

28"

Question 33

1 psi = ____ feet of head

Answer 33

2.31

Question 34

1 psi = ___ ounces per square inch

Answer 34

16

Question 35

An appliance burns 400 cubic meters of natural gas. How many cubic feet is this?

Answer 35

400 x 35.31 = 14,124 cu ft

Question 36

1000btu's = ____kw

Answer 36

0.293kw

Question 37

Define calorific value

Answer 37

amount of heat released during combustion

Question 38

State the calorific value of natural gas in the four different ways we may need to refer to it?

Answer 38

1. btu/ft3 2. btu/m3 3. kw/ft3 4. kw/m3

Question 39

What is standard pressure in psi?

Answer 39

101.235psi

Question 40

What is standard temperature?

Answer 40

60F

Question 41

What is the manifold pressure for propane and natural gas?

Answer 41

propane = 11" w.c natural gas = 3.5" w.c

Question 42

When converting propane to natural gas what must you do to the orifice and pressure?

Answer 42

increase orifice size and reduce pressure

Question 43

doubling the diameter _______

Answer 43

increased by 4 times

Question 44

Name the four parts of the regulator

Answer 44

1. measuring element 2. restricting element 3. loading element 4. vent opening

Question 45

How does a direct operating regulator close?

Answer 45

on downstream pressure

Question 46

What is the main difference between category 1 and 4 appliances?

Answer 46

category 1 is negative pressure category 4 is positive pressure

Question 47

Which part of a cathode corrodes?

Answer 47

anode

Question 48

What is the main function of the pilot?

Answer 48

light the main burner

Question 49

When tubing enters or exits a concrete slab what must we do?

Answer 49

put a protective sleeve around it

Question 50

Can a homeowner always do his own work?

Answer 50

Not if there is a dwelling unit being rented out