C O I R   R O P 

 

 

 

The general requirements of three types of coir ropes for which standards have been specified are as follows:

      a)      Two grades of Hawser-laid (3 strand) coir ropes of diameter 8 to 176 mm  and with a liner density from 47 to            15720 ktex (g/m) for dry coir rope and from 60 to 21112 ktex (g/m) for oiled coir rope.

      b)      Two grades of Shroud-laid (4 strand) coir ropes of diameter 24 to 176 mm  and with liner density from 321 to            27170 ktex(g/m) for dry coir rope and from 437 to 23257 ktex (g/m) for oiled coir rope.

      c)      To grades Cable –laid (9 strand) coir ropes of diameter 48 to 176 mm  and with a liner density from 1010 to              13335 ktex (g/m) for dry coir rope and from 1371 to 17184 ktex (g/m) for oiled coir rope.

The standard does not cover ropes intended for use for lifting purpose

For the purpose of this standard, the definitions given in IS: 3871-1966 shall apply.

Coir rope shall be graded as Grade I or Grade II on the basis of the breaking load values.

The tolerance permitted for liner density in respect of the three types of coir ropes shall be plus or minus 5% of the specified nominal value.

  Manufacture

The fibre iused in the manufacture of ropes shall be coir, true to its type and shall be unadulterated and free from siliceous matter and shorts.  The fibre shall be of good quality, fineness and colour necessary to produce ropes having the  characteristics required and specified in tables 1 to 3.

  The yarn shall be well and evenly spun.  All coir yarns are two-fold being formed by twisting together two single loosely twisted thread.  They are all hand-made.

  Strand of rope shall be well formed, free from grooves, kinks and sunken yarns and each strand shall contain an equal number of yarns.  The strand shall have S-lay.

  The rope shall be well laid and free from defects and each coir shall be continuous throughout its length and shall not contain loose ends,. Splices or joints in the strands or in the rope.  The number of strands in the rope and the lay of rope, unless otherwise specified, ahall be as under.

Construction

Number of Strand

Lay of Rope

Hawser-laid

3

Z-lay

Shroud-laid

4

Z-lay

Cable - laid

9(with 3 primary ropes

twisted together)

Z-lay for primary rope and

S-lay for final rope

For the purpose of dressing the fibre or for preservation of the rope, a lubricant may be added.  The quantity of dressing material applied to the fibre when determined by extracion with peetrolium ether or other suitable solvent, shall be not less than 10 or more than 15 percent calculated on the mass of the finished rope.

  Unless specifically required by the buyer, no colouring agent shall be used. Weighing or loading material shall not be used.  All ends shall be securely shipped or marked.

  Rope shall be maked for the purpose of identification as agreed to between the buyer and the seller. Unless otherwise specified, ropes shall be packed conforming to the requirements laid down in IS:3256-1965.

  Each coil shall have at both ends lables securely attached on which the following shall be marked.

  a)Manufacturer’s name and trade mark.

b)Length of rope in the coil

c)Diameter of the rope

d)Any other marking required by the buyer.

  Requirements:

  1.Mass:- The net mass of the coil of ropes in a lot shall not differ by more than +  5% from the mass of the coils as calculated from the liner density.

  2 Pitch :-The pitch of rope when determined by the method given in IS:7071 (Part III)-1974 shall conform to the following requirements.

Construction

Pitch X Diameter of rope

Hawser-laid

Between 2.5 and 3.3

Shroud-laid

Between 2.7 and 3.5

Cable-laid

Between 2.2. and 3.2

  3.Length of coils :-The length of each coil shall be 220 m. or as agreed to between the buyer and the seller.

  4.Other requirements :-The Hawser laid coir ropes shall conform to the requirements of tables 1,Shroud-laid coir ropes to the requirements of table 2 and Cable-laid ropes to the requirements of table –3.

  TABLE –I  REQUIREMENTS FOR HAWSER-LAID COIR ROPE

Diameter

No.of yarns /

Strands,Min.

Linear Density

Breaking Load Min.

 

 

 

 

mm.

 

Dry

 

 

Ktex

(g/m)

Oiled

 

 

Ktex

(g/m)

Grade I

(Dry or

Oiled)

 

kN

Grade 2

(Dry or

Oiled)

 

kN

8

2

47

60

0.784

0.637

10

3

55

75

1.225

1.157

12

2

67

95

1.911

1.764

16

2

130

178

3.431

3.088

20

4

200

273

5.343

4.657

24

5

295

405

7.451

6.618

28

7

390

528

9.951

8.873

32

9

520

705

12.941

12.255

36

10

645

875

16.912

13.333

40

11

815

1098

20.931

19.310

48

12

1180

1600

29.657

26.569

56

16

1550

2110

45.735

35.441

64

21

2 070

2 811

51,716

49,706

72

27

2 570

3 488

66,225

65,196

80

33

3 790

4 169

80,735

76,982

88

40

3 930

5 276

97,324

86,569

96

48

4 715

6 396

111,078

106,330

104

56

5 465

7 417

130,490

110,784

112

65

6 215

8 934

150,882

141,814

120

75

7 255

9 845

173,333

160,294

128

85

8 290

11 244

205,196

198,334

136

96

9 290

12 601

231,078

205,392

144

108

9 830

13 353

259,314

241,176

152

120

11 280

15 317

288,824

256,912

160

133

12 230

16 675

320,198

313,824

168

147

14,010

18 955

353,039

313,824

176

161

15 720

21 112

388,745

346,176

 

Note:- 1 kN= 102 kgf approximately.

TABLE –2  REQUIREMENTS FOR SHROUD-LAID COIR ROPE

Diameter

No.of yarns /

Strands,Min.

Linear Density