Tubular ledger

A round steel tube with a wedge head at each end that links two standards; it serves as guard rail, bracing and deck support in one.

Also called: O-ledger, ledger, horizontal, transom, guard rail ledger

Few parts are fitted as often in a modular scaffold as the tubular ledger. It connects two standards horizontally and takes on different jobs depending on where it sits. Along the facade it acts as guard rail and intermediate rail, or as a lower ledger holding the bay together. Across the scaffold it carries the decks, whose claws rest over the round tube. And at the base collar it forms the base rectangle on which the whole structure is aligned.

Design and lengths

The tubular ledger is a steel tube of 48.3 mm diameter with a wedge head welded to each end, its wedge captive so it cannot get lost. Because of the round cross-section it is often called an O-ledger, as opposed to the U-ledger with its open profile.

• Lengths: matched to the grid – 0.73 m and 1.09 m across the scaffold, bay lengths of 1.57 m up to 3.07 m along it, plus intermediate sizes in some systems.
• Material: galvanised steel; lightweight versions sometimes use thinner walls of higher-strength steel.
• Reinforced versions: for longer spans or higher loads there are ledgers with a bottom chord or truss, known as double or lattice ledgers.

Fitting sequence

1. At the base collar, hook ledgers into the small holes of the rosettes and level the rectangle.
2. Fit the standards and install the transverse ledgers at deck level.
3. Lay the decks and lock them against uplift where the system requires it.
4. Add side protection: main rail about 1.00 m and intermediate rail about 0.50 m above the deck, which fits the 0.50 m disc spacing. Then the toe board.
5. Strike every wedge home with the 500 g hammer until it bounces back, then check the bay for squareness once more.

When dismantling, remove a level's side protection only once nothing stands above it and you are secured against falling yourself.

Used ledgers and common errors

• A ledger must not sag. A bent one is useless both as guard rail and as deck bearer.
• Check the wedge heads for cracked welds and the wedges for deformation. A wedge that no longer drives straight is replaced.
• Deck claws must match the ledger profile. Decks for round tube on a U-profile, or the reverse, are a typical assembly fault.
• Do not climb ledgers like a ladder or use them as an anchor point for fall arrest unless the instructions expressly allow it.
• Used: clean galvanising, wedges seated firmly, undamaged tube ends.

O-ledger or U-ledger?

Many modular systems come in two deck variants: decks hooked onto round ledgers or into open U-profiles. The tubular ledger fits everywhere, as rail and as support, and decks on it are usually locked against lifting without an extra part. The U-ledger gives a very stable bearing. Along the facade, as guard rail, the tubular ledger is used almost without exception. Used ledgers in all common lengths are listed under ledgers.