Types of Scaffold Ties
Types of scaffold ties It is essential that all scaffolds are properly tied into the building or structure at intervals to ensure the safety and stability of the scaffold.
Types of tie include:
A tie fixed through an opening in a wall or a window.
A reveal tube with wedges or screwed fittings and pads, fixed between opposing faces of an opening in a wall together with the tie tube. Relies solely on friction, therefore safe working capacity is reduced. Ideally, they should not be more than 50% of the total number of ties.
The assembly of tubes and couplers, usually around columns or other elements of the building. The above types of the tie are all of the moveable variety, this means they can be removed, one at a time systematically then replaced after the task necessitating the removal is complete. No tie may be removed without the agreement of the competent person. The following are non-removable
Cast-in and Drilled Anchorages
Provided by casting in, or fixing a threaded anchor sleeve into the structure itself. The attachment of the scaffold to the anchor sleeve is either by a ring bolt or tied and secured by wire lashing. These types should be used in accordance with the manufacturer’s recommendations. The capacity of the anchorage into the structure must be established by test, 50% need to be pull tested. See also Scaffolding parts name
Tie Frequency Table
The spacing of lines of ties should not exceed 8.5m horizontally or vertically. Ties should be reasonably evenly distributed over the scaffold at the following minimum frequency based on ties of 6.25kn capacity. See also Scaffolding safety checklist
Names of ties Unsheeted Scaffold Sheeted Scaffold
Movable Ties 32m2 12.5m2
Non-Movable Ties 40m2 16m2
When dealing with sheeted scaffold above 5m high and on all other scaffolds greater than 10m high, the scaffolding should comply with Reveal ties are not to be used on sheeted scaffolds. Ties should be secured to both inside and outside standards and ledgers to be fixed within 300mm of a braced standard. See also Working at heights procedure
Returns, Buttresses, and Rakers
May be used as an alternative to a tie and are generally considered to provide attachment for a 3m length either side of the buttress or raker. A return is considered adequate for a 3m length measured from the outside corner. Rakers should be set at an angle not more than 2 verticals to 1 horizontal and fixed at its base to prevent sinking or slipping. Tubes more than 2.7m in length should be fitted with a brace, tied back to the scaffold to prevent distorting under load. See also Working at height safety & How to calculate scaffolding load & What are fall protection systems for scaffolders & How safety officers can save themselves from the court in case of an accident