SMART Compliance

Lift shaft tower scaffolding module

Summary of the Module

The Lift shaft tower scaffolding module checks tube and fitting lift shaft tower scaffolding for compliance with TG20:21, in accordance with section 15.3 of the TG20:21 Operational Guide. The scaffolding should be completely enclosed by a lift shaft, shielded from the wind and prevented from lateral movement by securely butting at every lift.

The software checks whether the scaffold is TG20:21 compliant, checks whether it is within the maximum permitted safe height for its loading and dimensions, 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 lift shaft tower scaffolding, a wind calculation is not performed from the site location as is the case for independent scaffolding.

  • 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. A cutline is introduced if the tower exceeds 10 lifts in height, to ensure the diagram remains at a reasonable scale.

  • 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.

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 tower platforms, assuming up to two lifts are fully loaded.

Only load class 1 (very light duty) is permitted for a TG20 compliant lift shaft tower.
Scaffold length

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

The maximum tower length and width are interrelated, with the maximum of one reducing as the other increases. The TG20 check will report the permitted maximum if it is exceeded:

Tower width (m) Maximum length (m)
2.2 or less 3.0
2.3 2.9
2.4 – 2.5 2.8
2.6 – 2.7 2.7
2.8 – 2.9 2.6
3.0 2.5
Scaffold width

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

The maximum tower length and width are interrelated, with the maximum of one reducing as the other increases. The TG20 check will report the permitted maximum if it is exceeded:

Tower length (m) Maximum width (m)
2.5 or less 3.0
2.6 2.9
2.7 2.7
2.8 2.5
2.9 2.3
3.0 2.2
Lift height

The maximum height of the scaffold tower lifts, including the first, limited to the 2.0 m maximum permitted by TG20.

The TG20 results have only been prepared for the 2.0 m maximum lift height, so a tower with a shorter lift height is conservatively limited to the number of lifts permitted at the maximum lift height.
Number of lifts

The total number of tower lifts, whether boarded or unboarded, which is limited to the 25 lifts of the 50 m maximum tower height at the 2.0 m maximum lift height. A shorter lift height does not permit more lifts.

The number of lifts is also limited by the maximum safe height of the tower, which reduces as the tower plan area increases and depends on the tube material. The TG20 check will report the permitted number of lifts, and the height it gives, 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.

The options available depend on the number of 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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