Mobile Access Towers — Safe Erection, PASMA and Daily Checks (2026)

Why It Matters — and the Law Behind It

Mobile towers are work at height equipment, and they sit squarely within the Work at Height Regulations 2005. Those regulations require that work at height is properly planned, supervised and carried out by competent people using suitable equipment. On top of that, a tower is "work equipment" under the Provision and Use of Work Equipment Regulations 1998 (PUWER), which means it must be suitable for the job, maintained in good order, and used only by people who have been trained.

The third document that governs how you use a tower is the manufacturer's instruction manual. This is not optional reading. The manual tells you the correct configuration for the height you need, where stabilisers and outriggers go, the safe working load, and the build sequence. If you deviate from it, you are no longer using the equipment as designed and you carry the liability for whatever happens next.

Most serious tower incidents trace back to a handful of causes: the tower was built without stabilisers, guard rails were missing, someone climbed the outside of the frame, the safe working load was exceeded, or the tower was moved with people or materials still on the platform. Every one of those is avoidable.

Erecting a Tower Safely

Only competent, trained people should build, alter or dismantle a tower. In the UK the recognised industry standard for that competence is PASMA (the Prefabricated Access Suppliers' and Manufacturers' Association) training. A valid PASMA card demonstrates that the holder has been trained to assemble, use, move and dismantle a mobile tower safely. Insurers, principal contractors and clients increasingly ask to see PASMA cards before letting anyone put a tower up on their site.

Always build to the manufacturer's instruction manual for the specific tower you have — components from different systems must not be mixed. The critical principle is that no one should ever stand on an unprotected platform. To achieve that you use one of two recognised build methods, both designed so guard rails are in place before you put your weight on a platform:

• 3T (Through The Trapdoor): the assembler works from a position in the trapdoor of the platform below, fitting the guard rails to the next level before climbing up onto it. You are never standing on a platform that doesn't already have its guard rails.
• AGR (Advance Guard Rail): temporary guard rail frames are fixed from the level below and locked into place so that the platform above is already protected before anyone steps onto it. The advance guard rails are moved up as the build progresses.

Both methods are valid; which one you use depends on the tower system and how it's specified. What is never acceptable is building "traditionally" by climbing onto an unguarded platform to fit the rails — that is the exact moment most fall-from-tower injuries happen.

Key Requirements for a Safe Tower

Whatever the job, a correctly set-up tower meets the same basic conditions. Run through these every time before anyone goes up:

• Firm, level ground: the tower must stand on ground that can take the load without sinking or shifting. On soft or uneven surfaces use suitable base plates or boards, and never pack castors up on bricks or offcuts.
• Locked castors: all castor wheel brakes must be locked on before the tower is used or climbed. Castors should be turned outward for maximum stability.
• Stabilisers and outriggers: fit them exactly as the manufacturer's manual specifies for the height you're building to. They are not an optional extra — the tower's stability rating assumes they are fitted, and the higher the tower the more they matter.
• Guard rails and toe boards: every working platform must have double guard rails and toe boards fitted to stop both people and materials falling.
• Safe internal access: climb up the inside of the tower using the built-in ladder frames or integral ladders. Never climb the outside of the tower or the rungs of the end frames — that loads the tower sideways and risks tipping it.
• Safe working load: do not exceed the safe working load stated in the manual. That figure includes the people, their tools and any materials on the platform — it's easy to overshoot when two people and a stack of plasterboard go up together.

Moving a Tower Safely

The mobility that makes a tower useful is also where a lot of accidents happen. The rules for moving one are simple and non-negotiable:

• Reduce the height if the manual requires it. Tall towers can become unstable when moved — the manufacturer's instructions will tell you the maximum height at which a tower may be moved, and you may need to lower it first.
• Check the route. Look for overhead obstructions and, critically, overhead power lines before you move. Contact with a live line can be fatal through an aluminium frame. Check the floor or ground for holes, slopes, kerbs and soft spots.
• Never move a tower with people, tools or materials on the platform. Everyone comes down first and anything loose comes off. This is the single most common cause of serious tower incidents during a move.
• Push at the base, not the top. Apply the force manually at or near the base by hand, and move it slowly. Never push from the top, and never use a vehicle or powered equipment to move a tower.
• Re-lock the castors and re-check level ground and stabilisers once the tower is in its new position, before anyone climbs back up.

Inspection and Records

A tower has to be inspected, and the inspections have to be recorded. Under the Work at Height Regulations you must inspect a tower:

• After it has been assembled, and before it is used for the first time
• After any event likely to have affected its stability or safety — for example after it has been moved, struck, or left exposed to severe weather
• At regular intervals not exceeding 7 days while it remains in position

Record those inspections. A tower inspection tag system — commonly a Scafftag-type holder fitted to the tower — is the standard way to show at a glance whether a tower is safe to use and when it was last checked. A green tag means it has been inspected and is fit for use; if there is no current tag, treat the tower as not for use until it has been inspected and signed off.

If you find damage — bent tubes, cracked welds, missing locking clips, worn castors — quarantine the tower and tag it out so nobody uses it. Don't bodge a repair or substitute parts from another system. Damaged components should be replaced with the correct manufacturer parts before the tower goes back into service.

Weather and Wind

A tall, lightweight aluminium tower acts like a sail. Don't use a tower in high winds. Typical guidance is to stop work or reduce the tower height as wind strength increases — many manufacturers quote a maximum safe wind speed for a tower in use, and a lower threshold above which the tower should be dismantled or further reduced.

If you are leaving a tower up overnight or during a break in the work, either tie it in to a solid structure as the manual allows, reduce its height, or dismantle it. An unattended, untied tower in rising wind is a hazard to your crew and to the public. Rain and ice are factors too: wet platforms and rungs are slippery, and frost on the ground can affect both footing and the stability of the base.

Quick Reference: Safe-Use Checklist

Building It Into Your Systems

Tower safety isn't just a one-off check on the day — it's a record-keeping habit. Keep copies of your operatives' PASMA cards, the manufacturer's manual for each tower you own, your tower inspection records and the COSHH and risk assessments that sit alongside them. On a site inspection or after an incident, being able to produce a current, signed inspection record is the difference between a quick conversation and a serious problem.

A tower used correctly is one of the safest ways to work at height on a small site. Build it to the manual, fit the stabilisers, use 3T or AGR, climb the inside, move it empty and inspect it every seven days — and it will do its job for years without incident.