Lock / locking wire (also known as indicator wire) should only be applied by competent persons specifically trained in its correct use.
The lock-wiring of bolts is a locking method adopted from the aviation industry. in brief, the method involves threading a special stainless wire through a hole in the bolt head, which is twisted and locked to the next bolt or structure, thus preventing the bolt from rotating and loosening. The wire can be used to lock a maximum of three bolts in a row, as shown in the illustration.
Areas of use:
used extensively for locking external bolted connections on drilling and pipe-handling equipment. Often used where there are no through-bolts and/or it is necessary to be able to easily check the locking visually.
The locking wires may stretch, break or corrode if not properly fitted, allowing fastener rotation and loosening when exposed to dynamic loading.
Examples of locking wires in practice
A split pin is a metal fastener with two 'tines' that are bent during installation. Also known as a ccotter pin or cotter key (USA), These are used to secure other fasteners such as bolts, nuts and clevis pins
Some best practice recommendations:
Securing pins of the type shown in the images should not be used in lifting equipment Securing pins shall provide secondary retention
Securing pins shall be of the proper size and quality.
Securing pins shall be secured by wire (where this is appropriate) to prevent dropping during removal.
It is a requirement that securing pins are inspected regularly and replaced when necessary.
Areas of use:
Scaffolding bolts, security bolts on removable railings, claw couplings and securing brackets on gas cylinder racks, etc.
The pin in the top image is usually used in the diving and subsea industry
Best practice recommendations
Always check design ratings of equipment before installing securing devices as integrity may be compromised.Never re-use securing wires, connectors or chains that have sustained shock loading.
All securing devices and all attachments to tools and equipment shall be documented and have traceability information. As a minimum this shall include batch marking, the name of the manufacturer/importer, production year, and information about the maximum load/WLL.
Incorrect installation of wire clamps is a challange in de thindustry
Best practice reommendations:
Correct installation of iron grip wire clamps
Wire rope diameter
3-9 1/8 - 3/8
10-16 3/8 - 5/8
17-20 5/8 - 3/4
21-26 3/4 - 1
27-37 1 - 1 1/2
This displays the number of wire clamps needed to secure a wire rope with a specific diameter.
Minimum number of wire clamps