ABOUT HUBS AND CLAMPS

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Revised: 12/12/2008

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Test Pressures and Applied Loads
For Clamps Designed to Fit
API Spec 16A Specified Hubs

API Spec 16A clamps differ from all other API equipment in regard to design and hydrotest. Clamps serve as fasteners similar to bolts, they do not come in contact with well fluid, and they may connect several API specified connectors having different nominal sizes and working pressures.

API Spec 16A permits clamps to have marking as to clamp number, e.g. No. 6, or a specific connection, e.g. 3-1/16” 15M.

API Spec 16A, 3rd Edition, states that: “Each clamp shall be designed for the highest loading that may be induced by any hub it is intended to fit.” WOODCO USA interprets this to mean any API 16A specified hub a clamp will fit. We also understand this to mean that any and all clamps shall experience a test to this highest loading regardless of the manufacturers or users choice in marking.

The table below identifies the API Spec 16A clamps by number designation and identifies the hub(s) each numbered clamp will fit. The table further provides the maximum load applied to the clamp at test pressure related to each specified hub, with the hub which applies the greatest load to the clamp at test pressure highlighted and indicated in bold type.

CLAMP NO.

HUB

NOMINAL BORE

HUB

WORKING PRESSURE (PSI)

HUB

RING GASKET

MAXIMUM LOAD (LBS.) APPLIED TO CLAMP AT TEST PRESSURE
(1.5 X WP)
RX

BX

  1 *

1 13/16

10,000

 

151

 131,086

 

2 1/16

5,000

  

152

 86,999

  2 *

1 13/16

15,000

  

151

 190,086

 

2 1/16

10,000

  

152

 159,195

 

2 9/16

5,000

  

153

 120,230

  3 *

1 13/16

20,000

  

151

 249,084

 

2 1/16

15,000

  

152

 231,390

 

2 1/16

20,000

  

152

 303,586

 

2 9/16

15,000

  

153

 324,090

  4 *

2 9/16

10,000

  

153

 222,160

 

3 1/8

5,000

  

154

 157,577

  5 *

3 1/16

10,000

  

154

 293,446

 

4 1/16

5,000

  

155

 244,770

  6 *

2 9/16

20,000

  

153

 426,020

 

3 1/16

15,000

  

154

 429,315

 

4 1/16

10,000

  

155

 460,951

 7

5-1/8 **

10,000

 

169

 621,164

 8

3 1/16

20,000

 

154

 565,183

 

4 1/16

15,000

 

155

 677,133

 

5-1/8 **

15,000

 

169

 917,346

 

7 1/16

5,000

 

156

 600,140

 

9

5,000

 

157

 901,744

   9 *

11

3,000

53

-

 690,839

   10 *

4 1/16

20,000

 

155

 893,314

 

7 1/16

10,000

 

156

 1,151,311

 

9

10,000

 

157

 1,714,299

 

11

5,000

 

158

 1,270,351

   11 *

13 5/8

3,000

57

-

 924,974

   12 *

16 3/4

2,000

65

-

 919,579

    13 * 

13 5/8

5,000

  

160

 1,599,602

   14 *

16 3/4

3,000

65

-

 1,360,313

   15 *

7 1/16

20,000

 

156

 2,253,657

 

11

15,000

 

158

 3,659,760

 

13 5/8

10,000

  

159

 3,588,470

   16 *

21 1/4

2,000

73

   1,409,609

   17 *

20 3/4

3,000

73

 

 2,087,840

    18 * 

21 1/4

2,000

73

 

 1,409,609

   19 *

16 3/4

5,000

 

162

 2,145,269

20

30**

1,000

SPCL

 

 1,327,524

22

7 1/16

15,000

 

156

 1,702,490

 

11

10,000

 

158

 2,465,061

25

7 1/16

2,000

45

 

 235,318

26

18 3/4

15,000

 

164

 9,406,187
 

21 1/4

10,000

 

166

 7,893,053

27

18 3/4

10,000

 

164

 6,300,799
 

21 1/4

5,000

 

165

 3,800,556

28

11

20,000

 

158

 4,854,467
 

13 5/8

15,000

 

159

 5,336,027
 

16 3/4

10,000

 

162

 4,261,948

*   Clamps marked with an asterisk also fit existing hubs not specified in API Spec 16A. In some cases the currently required test pressures may not verify the clamp safety when installed on hubs other than those identified in API Spec 16A.

**  We have also included a WOODCO USA proprietary  5-1/8 10M hub utilizing a No. 7 clamp, a 5-1/8 15M hub utilizing a No. 8 clamp, as well as a 30" 1000 special hub and No. 20 clamp for diverters.
 

Caution: For Older Cast Steel Clamps For Clamp Hub Connections Click Here.

For an example Q & A on this subject Click Here.
 
 

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Information above, and in other parts of this Web Site, may help persons who really seek to know. If you have a question, and you think WOODCO USA may have the capacity to answer it, please use our Contact Us link and give us a chance to help.

WOODCO USA provides Web Site Tools for identification, estimating, and reference only. Do not use this information for manufacturing or inspection. Users of these tools should not use them as a substitute for professional engineering advice.  Anyone making use of the information presented does so at his own risk and assumes any and all liability resulting from such use.

FOR FURTHER INFORMATION, OR TO LEARN MORE ABOUT WOODCO USA PRODUCTS AND SERVICES,

CONTACT:

WOODCO USA
P.O. Box 1261
Houston, Texas 77251-1261
Phone: 713-672-9491
USA and Canada: 1-800-496-6326
Fax:  713-672-8768
www.woodcousa.com
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