TBN: Alternative Stabilisation Tying-In: An Introduction
INTRODUCTION
These guidance notes outline general tying-in methods for use with Alto mobile access towers. They are not a substitute for a detailed Risk Assessment and Method Statement (RAMS), nor do they replace a formal design plan for the relevant temporary works. This document also does not replace proper industry training.
Only competent and trained personnel should undertake the erection, alteration, dismantling, supervision, or planning of mobile access towers—including tying-in procedures. Where there is any uncertainty, further relevant training must be provided to ensure safe use.
For additional guidance, consult PASMA (www.pasma.co.uk | +44 (0)845 230 4041).
PRE-WORK REQUIREMENTS
A Risk Assessment and Method Statement must be completed prior to installation. This should include:
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The proposed tying-in method(s)
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Specific tie locations
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Consideration of the structure’s characteristics and environmental factors
WHEN TYING-IN IS REQUIRED
Properly constructed towers in accordance with BS EN 1004 and the manufacturer’s instructions are inherently safe and stable. However, additional stabilisation may be required in the following scenarios:
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Tower height exceeds 8m outdoors or 12m indoors
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Tower is used to access another structure
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Exposure to significant side or wind loads
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Restricted space preventing the use of standard stabilisers
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Use of cantilevered platforms
Where any of these apply, supplementary stabilisation methods must be considered. These include:
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Larger stabilisers or raker beams
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Butt transom stabilisation
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Buttress stabilisation
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Tying-in
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Kentledge or ballast
WHAT IS TYING-IN?
Tying-in refers to securing a tower to a fixed structure using rigid components, ensuring stability against external forces such as wind or side loads. This prevents the tower from tipping, distorting, or collapsing.
Effective tying-in must:
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Resist both tension and compression
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Use rigid structural components (not flexible items like ropes or straps)
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Avoid introducing distortion to the tower
Tying-in is typically achieved by connecting rigid tubes from the tower to an adjacent structure using appropriate couplers. The system is only as strong as its weakest component; failure of one element compromises the entire tie.
TECHNICAL CONSIDERATIONS
Alto towers are manufactured using 48mm extruded aluminium tube, compatible with standard scaffolding couplers. In contrast, some towers use 50mm tubing, which requires specialised couplers—often at additional cost and with reduced grip performance.
APPLICATION GUIDELINES
As a general rule:
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Ties should be installed at 4m intervals vertically and horizontally
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For single towers: ties should be placed at every other lift
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For linked, façade, or bridge towers: use the pattern “every other lift, every other bay”
Ties should be applied alternately at opposite ends of each bay to evenly distribute loads and stabilising forces.
Common tying-in types include:
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Anchor ties
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Through ties
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Reveal ties
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Box ties