SMART Compliance

Free-standing tower scaffolding module

Summary of the Module

The Free-standing tower scaffolding module checks tube and fitting stationary free-standing tower scaffolding for compliance with TG20:21. The tower may be located internally within a structure, shielded from the wind, or may be used externally or within an open frame structure under a wind management system in accordance with section 15.2 of the TG20:21 Operational Guide.

The software checks whether the scaffold is TG20:21 compliant, checks whether it meets the criteria to resist overturning, and calculates the maximum leg loads for foundation design.

The following sections provide details of the user inputs required, and also explain the outputs provided by the software.

Display Panel Options

The display panel options are similar to that of the Tied independent scaffolding module, with the following options available:

Options Available to you:

  • Map

    • A map is provided to search for the site address. Note that, for free-standing tower scaffolding, a wind calculation is not performed from the site location as is the case for independent scaffolding because, if the tower is used externally, it must be in accordance with a wind management system.

  • 3D model

    • A 3D preview of the tower is displayed, which updates as the input options are selected. Holding down the left mouse button will allow you to rotate the view, the mouse scroll wheel can be used to zoom in or out and holding the right mouse button will allow you to pan the view.

  • 2D view

    • 2D illustrations of the tower are provided in first-angle projection, displaying the front elevation, side elevation and plan view.

  • Calculation report

    • A summary report is provided when the calculations are performed, including the 2D elevations, the tower loading and dimensions, the calculated leg load and the results of the TG20:21 check.

Input Panel Options

Site

The following options are available for selecting the site location:

Input Description
Site details The site address can be selected by searching for an address from the Search bar above the map, or by moving the site marker. This address can be manually overwritten if required, which does not alter the location of the site on the map.
Location

Specifies whether the tower will be used within an enclosed building shielded from the wind, or outdoors in an environment exposed to the wind.

An external tower does not require a site wind calculation. Instead, it is subject to a wind management system, which is stated in the calculation report. An internal tower permits a higher height-to-base ratio and may be clad.

Scaffolding

You can enter the scaffolding dimensions by selecting the Scaffolding tab, this will automatically switch the display from the map to the 3D model. The 3D model updates whenever the inputs are modified.

Input Description
Load class

The maximum loading on the scaffold tower platforms, assuming one lift is fully loaded.

Load classes 1 to 3 are permitted for a TG20 compliant tower. The maximum tower length and width reduce as the load class increases.
Scaffold length

The length of the scaffold tower in the direction of the ledgers.

The maximum tower length and width are limited by the load class. The TG20 check will report the permitted maximum if it is exceeded:

Load class Maximum length and width (m)
1: Very light duty 2.7
2: Light duty 2.1
3: General purpose 1.8
Scaffold width

The width of the scaffold tower in the direction of the transoms.

The maximum tower length and width are limited by the load class, as shown above.
Lift height The maximum height of the scaffold tower lifts, including the first, limited to the 2.0 m maximum permitted by TG20.
Number of lifts

The total number of scaffold tower lifts, whether boarded or unboarded.

The permitted height is limited by a maximum height-to-base ratio, which depends on the tower location: 4 times the minimum base dimension for an internal free-standing tower, 3.5 times for an internal mobile tower and 3 times for an external tower. The TG20 check will report the maximum height if it is exceeded.
Lift boarding

Specifies which of the tower lifts are boarded: the top lift only, the top two lifts, the top lift and the alternate lifts below it, or every lift.

An external tower of two or more lifts must have at least two boarded lifts.
Tube material

The tube material from which the scaffold will be constructed, in accordance with TG20:21 Operational Guide section 4.1:

  • Type 4 galvanised steel tubes to BS EN 39.
  • Cold formed galvanised steel tubes to BS EN 10219-1, grade S 355.
  • Hot formed galvanised steel tubes to BS EN 10210-1, grade S 355.

The tube material can be identified on delivery with a stamped marking or attached tag stating the steel designation, for example ‘EN 10219 – S 355 JOH’.
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