Page 205 - Pipeline Rules of Thumb Handbook

192 Pipeline Rules of Thumb Handbook

How much coal-tar enamel for a mile of pipe?

For an average cover of 3 /32 in., multiply outside diameter 8.625 ¥ 0.6 = 5.2 tons per mile
of pipe by 0.6. The answer is in tons of enamel per mile. (Add 5.2 ¥ 15% = 0.8
15% to take care of gate valves, drips, bends, etc.) = 6 tons per mile

Examples. How many tons of coal-tar enamel will be These factors strongly affect the amount of coating
3
/
required to apply a 32 -in. coat to a 26-in. pipeline? used per mile on pipelines: 1. Temperature of the pipe,
and ambient temperatures. (It is assumed that the tempera-
26 ¥ 0.6 = 15.6 tons per mile ture of the enamel can be controlled.) 2. The kind of dope
machine. 3. Humidity. 4. The number of bends per mile. 5.
Add 15% to take care of gate valves, bends etc. The number of valves, crossovers, etc. 6. Condition of the
pipe.
15.6 + 2.3 = 17.9 or 18 tons per mile This latter point has a great effect on the amount of enamel
required for a mile of pipeline. In fact, where reconditioned
How many tons of coal-tar enamel will be required to apply pipe is being coated, it is recommended that the amount of
3
a /32-in. coat to a 8.625-in. pipeline? enamel be increased by about 20%.

How much wrapping for a mile of pipe?

For 14-in. to 48-in. pipe multiply diameter in in. by 15 to ( 4 1) ¥ 15 75 squares of felt
=
+
2
3
get number of squares (100ft ). For pipe sizes of 12 4 in. and
/
smaller add 1 (one) to nominal size of pipe and multiply by
15. These figures are conservative and do not allow for wrap-
ping drips, for patching holidays, and for short ends which are
Examples. How many squares of asbestos felt would be usually discarded. They allow for machine wrapping using
3
required to wrap one mile of 30-in. pipeline? 3 /4 -in. lap on diameters up to 10 4 -in. and using 1-in. lap on
/
larger diameters.
30 ¥ 15 = 450 squares of felt
For smaller diameters of pipe this figure should be
How many squares of felt would be required to wrap one increased about 5% to take care of additional wastage and
mile of 4-in. pipe? patching.
Estimating coating and wrapping materials required per mile of pipe

Primer and coal-tar enamel
Nominal 3 /32≤ Coal-tar Glass Kraft 15-Pound
Pipe Primer Enamel Wrap Paper Felt
Gallons of primer and tons of coal-tar enamel are based on
Size Gallons Tons Squares Squares Squares
covering new pipe in good condition. For rough pipe, increase
primer quantities by 25% and the coal-tar quantities by 20%. 4 11 3 75 75 75
No allowance is included for spillage or waste. 6 17 4 105 105 105
8 22 6 135 135 135
10 28 7 165 165 165
12 33 8 195 195 195
Wrappings 14 39 10 210 210 210
16 44 11 240 240 240
18 50 13 270 270 270
Squares are based on machine wrapping, allowing 3 /4-in. 20 55 14 300 300 300
laps on pipe sizes through 10-in., and 1-in. laps on pipe sizes 24 66 17 360 360 360
greater than 10in. No allowance is included for wrapping 30 83 21 450 450 450
drips, patching holidays or short ends which are usually 36 99 25 540 540 540
42 116 29 630 630 630
discarded.