Diam.

of Col.

In.

Thickness. In.

Length of Column in Feet.

8 ft.

10 ft.

12 ft.

14 ft.

16 ft.

18 ft.

20 ft.

6

1/2

418

6

5/8

505

412

6

3/4

570

465

374

6

7/8

651

525

423

347

7

1/2

560

474

393

332

270

7

5/8

655

566

476

402

332

287

7

3/4

820

658

544

456

384

324

280

7

7/8

880

732

610

510

425

360

313

7

1

971

810

670

559

470

896

839

8

5/8

850

735

631

542

462

400

352

8

3/4

1,000

910

743

640

545

468

405

8

7/8

1,120

960

810

710

620

529

455

8

1

1,260

1,082

930

785

675

578

502

8

1 1/8

1,360

1,185

1,005

865

732

625

545

9

5/8

1,040

928

810

710

620

535

480

9

3/4

1,220

1,073

950

820

720

628

560

9

7/8

1,360

1,200

1,050

918

805

595

614

9

1

1,550

1,362

1,192

1.039

900

758

682

9

1 1/8

1,710

1,500

1,300

1,130

958

851

751

10

3/4

1,420

1,280

1.141

1,020

900

398

706

10

7/8

1,640

l,495

1,318

1,170

1,036

910

820

10

1

1.830

1,580

1.460

1,292

1,143

1,010

896

10

1 1/8

2,030

1,810

1,470

1,310

1,160

1.110

980

11

3/4

1,640

1,510

1,363

1,260

1,120

1,000

895

11

7/8

1,840

1,680

1,540

1,385

1,250

1,113

990

11

1

2,100

1,923

1,740

1,570

1,420

1,258

1,119

11

1 1/8

2,300

2,110

1,920

1,720

1,550

1,370

1,217

12

3/4

1,869

1,740

1,600

1,440

1,310

1,200

1,080

12

7/8

2,130

1,960

1,800

1,630

1,490

1,360

1,223

12

1

2,380

2,180

2,020

1,840

1,670

1,500

1,360

12

I 1/8

2,580

2,350

2,180

1,990

1,800

1,620

1.470

13

3/4

2,020

1.900

1,740

1,620

1,480

1,363

1,265

13

7/8

2,400

2,250

2,100

1,920

1,760

1,590

1.465

13

1

2,660

2,480

2.320

2,120

1,940

1.745.

1,610

13

1 1/8

2,920

2,720

2,540

2,310

2,120

1.900

1,750

14

7/8

2,600

2,450

2,310

2,160

1,970

1,820

1,670

14

1

2,930

2,700

2,580

2.390

2,140

2.090

1,880

14

1 1/8

3,250

3,090

2,850

2,670

2,440

2,300

2.070

14

1 1/4

3,560

3,360

3,140

2,910

2,660

2,440

2,250