Riser Clamp Installation (Air Diving Range)

Posted on 10 February by OffshoreMan

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This is an excellent high quality video showing Air Diver performing underwater clamp installation.  The waterdepth is about 14 m ( 46 ft).  I believe the video was taken usingROV.  (ROV umbilical – 03:08).  It is possible to perform double operation Diving & ROV as long as in accordance with all the safety requirement.  I’ll share these requirement in future post.

From the video we can observe the following:

  • Newly installed riser clamp ( WD ~ 14m)
  • Subsea Riser Clamp No. 1 from MSL (Refer to the mark no. 1 on the riser clamp door)
  • Seen no anode on the clamp.  Assumed there is a metal contact between horizontal jacket brace & riser clamp.
  • The bolt & nuts are impact tighten.
  • Messenger line to supply divers with all required tools & equipment.
  • Diving in tropical water.  Diver wears denim diving suit.
  • The that i’m not sure is the yellow structure shown in 03:39

What is Riser Clamp?

It is a Structure which is intended to keep the riser in place.  There are various type, size and design of riser clamp.

  • Hanger Clamp (Load Bearing Clamp) : a clamp design to handle the vertical loading which capable to takes the weight of the entire riser + horizontal restraint.  The clamp allowed the riser to slide axially.
  • Sliding or Guide Clamp :  The clamp installed below after the load bearing clamp towards seabed.  It provide horizontal restraint but again allow the riser to move/slide axially (typically 5mm anulus gap between riser & neoprene pad installed on internal surface of riser clamp shell.
The following document will be required during installation of riser clamps.
  • Client specifications / Contractual requirement.
  • Riser Clamps design & drawings – To ensure the right clamps installed at the right position.
  • Approved Riser Clamps installation procedure.  Typically its a subsection of Riser Installation Procedure.  The riser clamp installation procedure will become standalone if the installation is performed by different vessel which install the riser.  Normally a small DPDSV or small barge.  This approach is more economic if there is a lot of riser clamps need to be installed in a year programme/contract.  In this case most of the time, the final tightening will also performed by this small DSV.  The main work barge will only tighten the load bearing clamp.
  • Riser clamp installation Action List.  This is a small field document but a very important piece of info.  its a suit to site type of document but in line with all the above document.  I’ll share sample of riser clamp action list in future post.
  • As built report (document/visual) signed/withness by client.

Ok Offshoreman, need to stop here.  been a long time i’m not writing.  Please come back or comment this post.  I might miss an important notes.  Or maybe someone expert from subsea division may add notes to this post … Spasiva!

Offshore Riser Installation

Offshore Riser Installation (Source Flickr)

3 Comments For This Post

  1. Bimal Bosmia Says:

    MOST IMPORTANT FOR RISER CLAMP INSTALLATION IS MOCK RUN AT ONSHORE ! and well coated Neoprene rubber plus matching of bolt holes ! cheers

  2. Irwan Hamid Says:

    And it a clear water. Im sure everybody happen on this task

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