HOW TO PREPARE A COST ANALYSIS FOR CHEM-O-LENE FUEL GAS
To properly evaluate the cost per foot of cutting steel with different fuel gases it is necessary
to prepare a cost analysis chart. Flowmeters and a stopwatch are needed to arrive at flows for oxygen
and fuel gas and to measure the inches-per-minute cut. These calculations will give you a
true picture of your cost per 100 feet of cut and allow you to evaluate different fuels as to their total savings.
The following steps will aid in completing the cost analysis chart. Generally, it will be necessary
to analyze each job since prices vary with locale.
- Calculate the cost of each fuel. For fuels sold by the pound use the formula
Fuel cost per poundcu/ft per lb. x 100 = Cost per 100 cu/ft.
For example,
.80 per lb.8.76 x 100 = $9.13 per 100 cu. ft.
- Obtain the cost of oxygen per 100 cu/ft.
- Calculate the labor or labor/overhead costs for your company
- Arrive at a fuel gas cost figure. The following chart will aid in arriving at
a gas cost figure; however, costs vary with locale and volume used.
| Chem-O-Lene | $9.13 per 100 cu/ft | 80¢ per lb. |
| Acetylene | $11.00 per 100 cu/ft | |
| Propane | $2.96 per 100 cu/ft | 25¢ per lb. |
| Natural Gas | .30 per 100 cu/ft | |
| Propylene | $8.70 per 100 cu/ft | 80¢ per lb. |
| Oxygen | $1.50 per 100 cu/ft | |
- Setting up to make the actual cost analysis requires connecting the oxygen and fuel gas
flow meters to one torch. Normally only two flow meters are used. One for the preheat oxygen
and one for the fuel gas. The cutting oxygen flow can be determined from a cutting chart
and remains constant for a given pressure and for a given tip size regardless of what fuel is being used.
- Use a stopwatch to determine the speed of travel in inches per minute. This can be obtained
while the cut is in progress or on a dry run after the cut is competed.
With flow meters installed it is generally best to have the operator set the torches and speeds on
the fuels that he is currently using. He should get the best quality cut at the best speed.
These figures should then be entered on the cost analysis chart. You may want to try several different
thickness cuts. If so complete all cuts on this fuel.
- Now switch the fuel gas hose to Chem-O-Lene gas and properly adjust the flame to correctly burn
Chem-O-Lene gas. You will find that less fuel and consequently less oxygen will be required from the preheat flame.
- The proper tips for Chem-O-Lene gas will also be installed at this time. Chem-O-Lene gas operates
best on tips made for natural gas or propane. You will find the MAPP and Propylene gases require
special tips that have virtually no recess. These fuels require special tips because they flashback
when used with a recessed tip even though a recessed tip improves the efficiency of any fuel.
Chem-O-Lene gas is blended to virtually eliminate flashback into the tip, mixer, or torch.
- As the demonstration progresses fill the cost analysis chart up to line “D”. Have
the machine operator sign the chart after he has verified the speeds, flows, etc. Copies should
be made and retained for future reference.
|
Cost
Analysis
|
Company
Name Date
|
|
|
Gas Flows-scfh
|
Cost- $/hr
|
D
Total
Cost-$/hr
A+B+C
|
E
Hrs per 100 ft = 20/ipm
|
Total Cost
$/100 ft cut
D X E
|
|
Fuel/Tip
|
Plate Thk.
|
Cut Speed ipm
|
Fuel
|
Pre O2
|
Cut O2
|
A
Labor
$/hr
|
B
Fuel
cfh x $/ft3
|
C
Oxygen
Cfh x $/ft3
|
|
cfh
|
cfh
|
Cfh
|
|
Acetylene
2490-1S
|
1 ¼
|
14
|
15
|
23
|
145
|
$25.00
|
1.65
15 x 11
|
2.10
168 x 1.25
|
28.75
|
1.43
|
41.11
|
|
Propylene
VVCM #1
|
1 ¼
|
15
|
15
|
53
|
145
|
$25.00
|
1.31
15 x 8.70
|
2.47
198 x 1.25
|
28.78
|
1.33
|
38.28
|
|
Propane
VVC #1
|
1 ¼
|
16
|
14
|
62
|
145
|
$25.00
|
.41
14 x 2.96
|
2.59
207 x 1.25
|
28.00
|
1.25
|
35
|
|
Natural Gas
VVC #1
|
1 ¼
|
13
|
26
|
52
|
145
|
$25.00
|
.16
|
2.46
197 x 1.25
|
27.62
|
1.54
|
42.53
|
|
Chem-O-Lene
VVC #1
|
1 ¼
|
19
|
10
|
26
|
145
|
$25.00
|
.91
10 x 9.13
|
2.13
171 x 1.25
|
28.04
|
1.05
|
29.44
|
|
