The advice given in this procedure is general.
It does not override either the manufacturers instructions for the tower system being used, or the safety regulations currently in force. These should be followed at all times.

1. Introduction

Mobile towers are light and easy to erect. They are incredibly versatile. They are ideal for jobs which are going to take a few hours. Used properly they are safe and usually a lot safer than trying to work from a ladder. However, people do take them for granted. This procedure has been produced to assist Group companies in ensuring that mobile scaffolds are assembled safely.

This procedure is based on aluminium towers. Although the advice given is relevant to towers constructed from other materials, many of the points may well apply to other systems but not all.

2. Assembly erection and dismantling requirements for mobile scaffolds at Group factories.

There are several key points to consider before permitting mobile scaffolds, these include;

2.1 Ignorance

Scaffolds must not be erected by untrained personnel. You must satisfy yourself that contractors have received adequate training to safely assemble the scaffold. These include; The Construction Industry Training Board (C.I.T.B) scheme, and National Plant Operators Registration scheme.

2.2 Instability

a) What is the ground like?

b) Is it level?

c) Is it clear of drains, trenches or holes?

d) Is the ground firm enough to take the weight of the workmen, their tools and materials?

e) Is there enough room? You should be aware that the base of the tower will often be larger than the platform, particularly if you need to fit outriggers.

f) Never support a tower on bricks, blocks or anything else to try and make it taller. You should alter the height by either adding or taking away a section. Towers will move slightly as people climb and work on them. This will be enough to loosen any packing. This will result in the tower becoming unstable and dangerous.

g) If you're using wheels and casters make sure they have brakes that work. If they don't send them back and ask for ones that do.

h) Check every part of the tower before you assemble it. If anything is damaged, does not fit properly or perhaps comes from another manufacturer's system, reject it.

Report it to your Manager and ask for a replacement.
He/she can not refuse, it is your safety that counts.

i) You may need to move the tower, so why not fit the wheels first rather than struggle when the tower is assembled?

j) When you have fitted wheels, that does not mean it is safe to move the tower. If the ground is bad, and the use of the tower is unavoidable, you will have to use sole plates to spread the load.

k) There may well be some situations where you have got no choice than to take it down and rebuild it in a new position.

l) Never move a tower with people or materials on it.

m) There are no short cuts. Every piece, every brace, every fixing must be in the correct place and secure. The only way to be sure is to have properly trained personnel who follow the manufacturer's assembly guide.

n) Once the towers are in the correct position, level it if you need to by using jacks. The jacks are only for levelling, never use them to try and add height to the tower.

2.3 Exceeding the Safe Working Height

a) Every tower system has its own safe working height.

b) The systems are designed as safe free standing structures.

c) These can reach between 12 and 16 metres.

There used to be a simple rule;
The safe working height being 3 times the size of the base. This no longer applies.

d) The safety standards for stability are much more strict then they used to be, check the manufacturer's assembly guide to see exactly how high you can safely go.

e) If you need to go higher than the limits for the basic tower, use either outriggers or stabilisers. You will require different sizes for different heights. So once again refer to the manufacturer's guidance notes.

f) By fitting outriggers or stabilisers, you will be giving the tower a larger base. This may permit you to go up another level or two.

g) If you don't have the space for outriggers, you may well be able to tie the tower to a rigid structure. You should use the couplers designed for this purpose or some other technique that is recommended by the manufacturer.

h) Counter weights can be used, however, these are a specialist technique and outside the brief of this procedure.

i) The manufacturer of the tower system will probably give lower heights outdoors than when working undercover. This is because you are less likely to be affected by high winds.

2.3.1 Ladder or access systems

Never climb up the end frame of a scaffold unless they are specifically designed as ladders. You should only climb inside the tower on a properly designed ladder. The ladder must be long enough to reach either the working platform or an intermediate access platform safely.

Never use loose ladders.

2.3.2 Unsafe Working Platforms

a) Guard rails must always be fitted.

b) Two guard rails, the top being one metre high, the other half way between that and the toe board are required.

c) Toe boards prevent tools, materials and equipment falling of the scaffold.

d) Toe boards should be at least 150 mm high. There should be no gap greater than 470mm.

e) Keep mobile tower scaffolds boards free from clutter.

f) Never use general scaffold boards with a mobile structure. Only use the correct size pre-formed platform that comes with the aluminium tower.

2.3.3 Weather Conditions

a) You should not be working on a free standing mobile scaffold tower in a wind of 17mph or above. This may be indicated by the winds ability to blow dust and paper about.

b) At 25mph the scaffold tower must be tied in to a rigid structure.

c) At 40mph or above, the tower should be dismantled as quickly as possible.

d) Manufacturers Design Criteria

For specific information, relating to stability refer to the manufacturers guidance which will be supplied with the equipment.

2.3.4 Sheeted Mobile Towers

a) If you need to cover a mobile tower for containment of substances or product, the wind will affect it a lot more so tie the tower to a rigid structure.

b) All towers should be tied in if they are to be left overnight. If you can not tie it in safely, take it down.

2.4 Safe Working Load

a) The scaffold tower will have a safe working load capacity. This will be marked on the tower itself and will certainly be in the manufacturer's recommendations.

b) The safe working load is not just that of the tools and materials, but also the weight of the people who will be working up there and the weight of the platform itself.

c) You should consider using double platforms not only for safety, but it will increase the amount of materials that you can have up there with you.

Example
A double platform can have a safe working load of up to 450 kilos. Two workmen can weigh up to 200 kilo's (about 16 stone). This leaves 250 kilos of capacity for tools and materials. The safe working load for many single platforms is much less. Check the manufacturer's guidance before starting.

d) If you have to haul tools or materials up the tower, keep the load inside the tower. If this is not possible, keep it within the area bounded by the outrigger. Remember every time you pull on a load outside the tower you are trying to pull the tower over.