Flying Multi-Wire Battens With A Limited Budget

Flying Multi-Wire Battens With A Limited Budget

Flying Multi-Wire Battens

Single wire-rope load-brake winches are sometimes used to fly multiwire battens where budgets are tight and options are severely limited. This type of installation is far from best-practice, but if the budget will only stretch so far, then sometimes they can appear to be the only viable option.

If there really is no way at all that the budget can be stretched to use, at the very least, a multi-wire hand operated hoist, then we need to ensure that the installation is as safe as it can be.

Is it legal? Is there a specific piece of legislation or a standard that prohibits the use of a single wire load brake winch in this manner? No there isn’t, but your local WorkCover inspector is going to be interested in reading the Risk Assessment you produce to demonstrate that the installation is safe.

What are the risks inherent specifically in the use of single wire rope load-brake winches, and how do we minimise these risks to ensure that the installation as safe as is reasonably possible?

Failure of the winch or winch brake (the last thing we want is for the winch to “let go”).

  • Purchase a winch from a reputable manufacturer and verify that it complieswith AS1418.
  • Make sure you consider the friction losses within the system – this can add as much as 100kg to the rated capacity requirement of the winch.
  • Follow the manufacturer's instructions regarding load brake servicing to the letter.
  • DO NOT under any circumstances use a boat winch from your local auto parts shop.

Failure of the (single) winching wire rope attachment to the clew plate.

  • Ask the supplier to supply the winch pre-fitted with the lifting rope, thimble and swage.
  • Ask the supplier to make at least 2 sample swages, using the same rope, swaging machine and operator, before AND after swaging the lifting rope, and have the supplier produce destruction test certificates for these samples.

Structural failure of the (single) winching wire rope.

  • Use the manufacturer's recommended lifting rope as an absolute minimum.
  • Use a rope with a factor of safety of 10:1 if at all possible.
  • Inspect this rope regularly and replace it if it shows signs of wear or damage.

Twisting of the clew plate.

  • The clew MUST be guided over its entire length of travel – apart from a failure of the connection of the lifting rope to the clew plate, this is the most serious hazard to deal with.
  • The clew guide must be designed either as a rigid guide (bushes and channels) or with the ability to tension the guides (wire rope guides).

Collision of the clew plate with the head pulley sheave and winch.

  • Place markers on the lifting rope and on the wall adjacent to the hoist to give an indication of where to stop raising or lowering – driving the clew plate or
    rigging gear into either the head pulley or the hoist can cause serious damage to the ropes and fittings.
  • Keep your eyes open and WATCH the clew plate through its travel.

Untrained and unobservant operators. The continued safety of this type of winching arrangement depends on operators:

  • paying close alltention to the travel of the winch rope and clew plate;
  • regularly inspecting ropes, winch and fittings for any sign of wear or damage.

This article forms general opinion only and must not be relied on without a detailed, professional risk assessment undertaken specific to your situation. Consult a professional staging company every time you consider anything that may involve risk with flown objects or people.

 

Jands Staging provide articles to the "Staging What If" section in CX Magazine. If you have any questions regarding this article then please comment below or email info@jands.com.au.

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