Acrow props are an extremely versatile product that can be found on many construction sites. They are commonly used on construction sites to provide a quick and easy method of providing temporary support for reinforced concrete floor and beam formwork. Acrow props are equally useful as raking props to support column, wall and stair formwork. They are invaluable in repair work, demolition or to replace a permanent support, to support canopies, lintels and the like while bricks or concrete are being laid.

Acrow struts consist of two circular steel tubes, an inner tube with a top plate that slides up and down freely within an outer tube that is attached to the base plate. The inner tube has holes throughout its length so you can quickly extend it just below the desired height and insert a steel pin to lock that length. To extend the strut to the correct height, the top of the outer tube is threaded on and a collar, which is similar to a nut on a bolt, picks up and holds the steel pin. So turning the collar and moving it up extends the inner strut. This allows you to achieve the exact height required.

The ‘Acrow Prop Safe Installation Guide’ gives you a checklist of what to check before you even start and then shows you what to check to ensure the safe installation of your Acrow props. Once installed, there is a list of items that should be checked regularly to ensure the continued safe performance of your acrow prop installation and then ends with a checklist for safe disposal.

Pre-Installation Checklist

• Start by planning the work. Make sure you have the correct number and size of accessories. Survey the site and, if necessary, mark the locations of the struts.
• Have you correctly selected the correct size props for the job? Do you have enough to support the weight? Never exceed the safe working load (SWL) for your specific size props. Consult the manufacturer’s load charts. If you are unsure, consult your engineer or other responsible person who will consider the weight of the upper structure to be supported and determine the correct size and quantity.
• It is the user’s responsibility to check the props each time before they start working. When inspecting accessories, items to check include:-
  • Check that the inner and outer tubes are straight and slide easily.
  • Check that the collar turns freely around the thread and that the tread is not damaged or blocked.
  • Check for pin damage. If the pin is secured with a chain, make sure it is still attached. If equipped with a wraparound pin, it is not necessary to secure it with a chain. Only use the original pin, do not use any other pin.
• Do not try to repair any defective accessory. If an accessory is defective, it must be immediately tagged and isolated and must not be used.

Installation checklist

• Warning fittings that are designed to be used in compression CANNOT be used in tension.
• Always wear proper safety equipment when using this equipment.
• Make sure the work area is cordoned off to prevent public access, only essential people should work in the area.
• Make sure the props are installed by qualified individuals who have the necessary knowledge and experience to perform the job safely.
• It is important that the prop is installed vertically to ensure that it can support the specified load. Props should never be used more than 1.5 degrees from vertical as this can substantially decrease their capacity. This is approximately 2 inches (50 mm) off true vertical for every 6 feet (1.8 m) of length.
• Make sure the base plate and top plate of your strut sit squarely on the surface. Also make sure that the floor surface and ceiling surface are strong enough to support the weight that will be placed on them.
• When stanchions are supported on a flexible surface, such as a gravel surface, each stanchion must be supported on a wooden base or equivalent. A wooden sole should be at least 9 inches (225 mm) wide by 1.5 inches (38 mm) thick. It should be long enough to protrude at least 300mm (1ft) on each side of the strut base plate. A soleplate can also be used on top of the main plate to help spread the load if needed. If you are unsure or in any doubt, consult your engineer or other competent person.
• Acrow props come in 5 different sizes, so don’t use props that are too short to fill the space with wood. Always use the correct length Acrow prop.

Post Installation Checklist

• Props left to support a curing slab can loosen over time. As the slab cures it naturally shrinks which can cause the strut to loosen so it is recommended that they be inspected and retightened regularly by a competent person.
• At a minimum, all fixtures should be inspected at least once a week.
• Make sure the area is safe from the general public if fixtures are to be left in place unattended.
• Do not string or tie anything to the struts.

Accessory Disposal Checklist

• Start by planning the work.
• Always wear proper safety equipment when using this equipment.
• Make sure the work area is cordoned off to prevent public access, only essential people should work in the area.
• Make sure the struts are removed by qualified people who have the knowledge and experience to do the job safely.
• Do not remove or adjust any accessory until you are sure it is safe to do so.
• Always return the equipment to the rental company clean.

Always seek professional advice before undertaking any shoring/shoring project. A shoring job gone wrong can be disastrous, life-threatening and an extremely expensive exercise to repair.