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| Installation (Continued) |
Table |
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Sizing Natural Gas Pipe Mains & Branches |
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Sizing Natural Gas Pipe Mains & Branches |
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| Gas Input (Cubic Feet/Hour)* |
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| Notes: | ||||
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| 1. If more than one unit is served by |
Gas Supply | 2" | 3" | 4" |
| the same main gas supply, consider | |||
Pipe Run (ft) | Pipe | Pipe | Pipe | Pipe | Pipe | Pipe | the total gas input (cubic feet/hr.) | |
10 | 1050 | 1600 | 3050 | 4800 | 8500 | 17500 |
| and the total length when determining |
20 | 730 | 1100 | 2100 | 3300 | 5900 | 12000 |
| the appropriate gas pipe size. |
30 | 590 | 890 | 1650 | 2700 | 4700 | 9700 |
| 2. Obtain the Specific Gravity and |
40 | 500 | 760 | 1450 | 2300 | 4100 | 8300 |
| BTU/Cu.Ft. from the gas company. |
50 | 440 | 670 | 1270 | 2000 | 3600 | 7400 |
| 3. The following example demonstrates |
60 | 400 | 610 | 1150 | 1850 | 3250 | 6800 |
| the considerations necessary when |
70 | 370 | 560 | 1050 | 1700 | 3000 | 6200 |
| determining the actual pipe size. |
80 | 350 | 530 | 990 | 1600 | 2800 | 5800 |
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90 | 320 | 490 | 930 | 1500 | 2600 | 5400 |
| Example: A 40' pipe run is needed to |
100 | 305 | 460 | 870 | 1400 | 2500 | 5100 |
| connect a unit with a 500 MBH furnace to a |
125 | 275 | 410 | 780 | 1250 | 2200 | 4500 |
| natural gas supply having a rating of 1,000 |
150 | 250 | 380 | 710 | 1130 | 2000 | 4100 |
| BTU/Cu.Ft. and a specific gravity of 0.60 |
175 | 225 | 350 | 650 | 1050 | 1850 | 3800 |
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200 | 210 | 320 | 610 | 980 | 1700 | 3500 |
| Cu.Ft/Hour = Furnace MBH Input |
* Table is based on a specific gravity of 0.60. Use Table | Gas BTU/Cu.Ft. X Multiplier (Table |
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specific gravity of the local gas supply. |
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| Table 3 indicates that a | is required. | |||||||
Specific Gravity Multipliers |
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Specific |
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| Gas Heating Capacity Altitude Correction Factors |
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Gravity | Multiplier |
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| Altitude (Ft.) |
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0.50 | 1.10 |
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| Sea Level | 2001 | 2501 | 3501 | 4501 | 5501 | 6501 | |||
0.55 | 1.04 |
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| To 2000 | To 2500 |
| To 3500 | To 4500 | To 5500 | To 6500 | To 7500 | ||
0.60 | 1.00 |
| Capacity |
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0.65 | 0.96 |
| Multiplier | 1.00 | .92 | .88 | .84 | .80 | .76 | .72 |
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| Note: Correction factors are per AGA Std. 221.30 - 1964, Part VI, 6.12. |
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| Local codes may supersede. |
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Figure
Unit Gas Trains (Natural Gas)
235 and 350 MBH |
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| 500 and 850 MBH |
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33