Choosing the right material for safe restricted space access

Safe access to areas such as lift machinery/pits, HVAC, roof cavities and many other industrial plant areas is normally obtained by stairs, platforms, crossovers and walkways, usually manufactured in either steel or aluminium.

These areas are most often small spaces that are difficult to manoeuvre in, out and around and require access equipment that is highly flexible in their design.

When choosing the most appropriate construction materials for these applications, there are many factors that must be considered. While they are two of the most commonly used metals in the world, both aluminium and steel have their advantages and disadvantages. So, which is better?

Below are some considerations to take into account when choosing between steel or aluminium installations.

Cost

Raw materials

The price of both aluminium and steel continue to fluctuate, and unfortunately COVID-19 has added even more volatility. The pandemic has resulted in major global supply issues, significant increases in fuel and shipping costs, and labour shortages, which all impact on the raw material cost and which ultimately have a bearing on the overall price of components.

At the base level, the production of aluminium is always accepted as more expensive, purely because of higher raw material pricing and the manufacturing process. However, the difference is slight and is ultimately a very minor factor to be taken into account when selecting products.

Labour/installation time

Depending on application, there can be quite significant differences in the cost of labour and install times between aluminium and steel.

Due to their increased weight, steel components often require the use of heavy lifting machinery to place them onsite and in location. This can be quite problematic if space is limited. A larger workforce may be necessary as the heavier weight will not allow easy handling. In addition to this, hot works/welding is predominantly a normal part of installation.

With regards to aluminium, the lighter weight construction can enable workers to manhandle components, often without machinery assistance. Not all aluminium must be welded onsite and systems, such as modular stairs, walkways, crossovers and platforms, can often be completely or partially assembled elsewhere and then installed, some without requiring any hot works at all. This can dramatically reduce install times and costs, and also prevent long spells of production downtime.

Installation

The placement of access stairs, platforms, walkways or crossovers in small or tight spaces can be extremely difficult. This can be made even more troublesome if the location cannot be accessed easily, and if the area where the installation is to be carried out is restrictive.

In such cases it may be necessary for workers to carry systems onto site part by part. This makes the selection of lightweight aluminium an extremely viable option, and one that is fast growing in popularity.

Using hot works in these areas may be dangerous and impractical so the selection of modular systems that simply bolt together is another great choice.

Corrosion

Aluminium is by far the less corrosive material. It contains a natural property that forms a thin oxide layer, protecting the metal and preventing rust. In addition, it requires little to no upkeep to maintain, and even with exposure to the elements it will last for many, many years. A testament to this is the fact that many artillery parts made from aluminium can still be found intact in war zones around the world, some of which date back as far as the early 1900s.

The same cannot be said for steel — unless of course discussing stainless steel, which is highly corrosive-resistant. However, stainless steel is simply not practical for large-scale applications as it would be far too cost-prohibitive.

Steel, on the other hand, is highly corrosive — with ongoing maintenance such as painting or similar treatments required to ensure longevity and function.

Flexibility

Aluminium is definitely the best choice if the material is required to be bent and formed. Steel will crack or rip during fabrication if processed too far, whereas aluminium is malleable and has quite a flexible nature.

Strength

Steel is approximately 2.5 times denser than aluminium in its composition, and provides a higher degree of strength. It is less prone to bending or warping if exposed to excessive forces such as weight or heat.

Having said that, aluminium still has a very good strength to weight ratio and for many applications offers far above what is required. Aluminium can also be engineered to further increase its strength.

Weight

With the higher density qualities of steel comes additional weight. Steel is approximately 2.5 times heavier than aluminium, and is consequently most often a core component in the structural skeleton for stadiums, airports and skyscrapers, because it will not buckle under excessive weight.

Conversely, due to its lightweight construction, aluminium is used predominantly in the aerospace sector and recently has seen its use in motor vehicle production increased. It is also much easier to handle, and depending on application, can cut down labour costs significantly.

Lifetime costs

Often overlooked — but definitely something that needs to be factored in — is the lifetime cost of any product that is chosen for installation. All businesses want value for money and products that will last.

In many cases the cost of maintenance is not regarded as a vital part of the decision-making process. However, products that require ongoing maintenance add costs that, over time, can mount up to major expenses.

The verdict

The lightweight nature of aluminium can work extremely well in the production of stairways and platforms for example, where they can be easily assembled at less cost and time. However, the strength of steel is particularly effective when used for building construction frames.

Although aluminium costs more than steel on a $/kg basis, far less of this material is required in order to achieve a similar result to steel in many applications. That, combined with its ease of use and savings in labour time, makes it a very attractive option for many construction systems.

At the end of the day, both aluminium and steel are strong, durable and cost-effective materials. However, the most important thing when it comes to the selection of systems to enable safe access to tight or restricted areas is to ensure that the selected product is suitable for the application at hand.