Difference between Scaffold and Aluminium Towers

Aluminium Scaffold

The difference between scaffold and aluminium towers are not so obvious and to the untrained eye these structures look very much alike but they are very different in use, legal compliance and training requirements.

Note: Verify training training providers with the IWH

Steel scaffolding must conform to SANS 10085-1

This standard is stipulated in the Government Gazette of 2 June 2017 entitled “Occupational Health and Safety Act 1993 Construction Regulations 2014, Guidelines. Refer notes after Regulation 12 as well as after Regulation 16.

If steel scaffolding is to be erected on any premises for the purpose of carrying out “alterations, renovations, repairs, demolition or dismantling of or addition to a building or any similar structure” {see full definition of construction work in Construction Regulations 2014}, then such scaffolding must comply with both Regulations 12 and 16.  

In a nutshell: –

  • Regulation 12 covers “Temporary works” which includes, scaffolding and requires, inter alia, that a temporary works designer be appointed in writing. All persons that erect, move or dismantle must be properly trained. (Put I full stop to shortem sentence and make reading easy)
  • Regulation 16 covers scaffolding per se and here again is the requirement for the appointment of a competent person to supervise all work operations.

Broadly speaking, scaffolding is considered as a structure whereas mobile access towers is  deemed to be equipment used by trained individuals for the purpose of gaining access to elevated work positions to carry out light-duty and short duration maintenance type of activities.  

Mobile access towers must conform to SANS 51004 (EN1004)

In South Africa this European safety standard was adopted by the SABS and named SANS  51004.

It covers mobile access towers and working towers made from prefabricated elements with a height from 2,5m to 12,0m (indoors) and from 2,5m to 8,0m (outdoors).

The standard covers the design and testing of towers. On all of these towers, outriggers are compulsory even for towers as low as 3,0m in height.

Each manufacturer of SANS 51004 compliant towers will specify the outrigger requirement. The old 3:1 rule for the ratio of tower height to base width no longer works for determining stability of a mobile tower. The base dimensions are determined by complex calculations in SANS 51004.

See the photo below which distinguishes between code compliant mobile access towers and the non-compliant steel interlocking frame contraption. 

Building site in Gauteng

These self-lock frames are illegal and unsafe because:

  • They do not have full width working decks/floors,
  • They lack plan bracing or other structures to prevent the rectangular shape of the tower from going out of shape (twisting into a parallelogram shape). If this happens the reduced width/ length ratio of the tower will make it severely unstable. This will almost always lead to the tower falling over.
  • There are no outrigger stabilisers attached to the bottom portion of the tower.
  • There are no kickboards around the floor to prevent equipment and materials from being pushed off. These should be all around the floor and at least 150mm high.
  • There are no intermediate safety rails a.k.a. “Knee Rails” and on some towers not even handrails. The handrails should be 1,0m above the working deck / floor.
  • Ladder access is not provided. Rungs should be spaced between 230mm and 300mm apart.

The above photo illustrates the problems clearly.

  • The access ladder does not provide safe access- It should be installed through the trap door in the decking and must extend at least 900mm above the decking floor and reach down to the base of the tower. {See SANS 51004}
  • No full width platform / working deck
  • No kickboards
  • No knee rail along two sides
  • No stabilisers
  • No cross bracing / plan bracing

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