Comparing Anchoring Solutions for Lift Installations

Understanding Elevator Anchoring Fundamentals

Anchoring systems play a crucial role in the structural integrity, long term performance and occupant safety elevators and lifts. But when it comes to elevator anchoring, which factors do you need to consider to arrive at the most appropriate anchor design?

With an estimated 8,033 new elevators and escalators installed in the UK alone in 2023, and a forecast for the UK elevator and escalator installation market to increase to 9,183 units by 2029, the sector is significant. Lift modernisation and maintenance is a key driver for this growth in the sector, but there are a number of other trends affecting the sector in the UK.

In particular, there is an increase in the number of older buildings being converted or refurbished. This is driving demand for elevators as many do not currently have one installed, or they have small elevators that may not suit the needs of a modern building. In addition to building renovation projects, major infrastructure schemes such as the construction or refurbishment of railway stations and airport terminals also mean there is a need for more elevators.

Another factor is demographic. As our population ages, elevators become more important given how they maximise accessibility in buildings. Regardless of building type, however, every elevator must meet a variety of safety and performance standards that apply to the whole industry, and key to that is the choice of anchor bolts used for installation.

In this article we explore the role that anchor bolts play in elevator anchoring and the key considerations for selecting products, whether these are concrete anchors or anchors for other hard substrates. We look at anchor testing, anchor placement and anchor design and how all these provide solutions with the required material strength, load capacity and long term durability.

Anchor Design and Material Strength

Key factors to consider when assessing the suitability of anchoring systems for elevators include corrosion resistance and material strength.

Steel anchors are widely used in all kinds of construction projects because of the suitability of their material characteristics. This makes them effective in many different construction materials including concrete, of course. Providing the hole is drilled and prepared according to the anchor manufacturer’s recommendations, a well-designed anchor bolt will be suitable for many elevator anchoring purposes. This is subject to the size and metal composition being appropriate, and that the stated performance meets the design brief.

Choosing the correct anchor design is crucially important because the performance of different types of anchors varies widely. This means there is no one-size-fits all approach when it comes to traction elevator anchorage or hydraulic elevator anchorage, but there are some important factors that apply to every elevator anchoring project.

Which anchor approaches are best for hyrdaulic elevators? And, how do anchors for traction elevators differ? Whilst chemical anchoring is quite correctly regarded as the most reliable option for safety critical applications, mechanical anchoring solutions from LIEBIG could provide lift installers with an effective time-saving alternative, especially in elevator shaft modernisation projects.

In projects where the substrate allows, mechanical anchoring options including the LIEBIG Superplus BLS may the required load capacity. This could make them a viable first choice whilst keeping chemical (or resin) anchors in reserve as a back-up option. In particular, mechanical anchors can prove to be an excellent choice for installing guide rail brackets in many different elevator types, in all kinds of base materials, including lightweight blocks, where a secure anchor must be achieved without compromising fixing strength.

Load Capacity and Distribution

A common question which arises in the early stages of selecting anchoring systems is ‘how does load capacity affect anchor choice?’

Most elevators have standard a weight limit, typically between 250–500kg for standard residential and commercial elevators, although some elevators can accommodate as much as 5000kg. The anchors used to secure the component parts into the elevator shaft, therefore, particularly the guide rails, will need to have sufficient load capacity to cope with these loads.

How the anchors are distributed is also important. For example, when installing the guide rails, if anchors with a relatively high load capacity are used, fewer anchors in total will be required. This could reduce cost and installation time significantly.

Remember, it is vitally important to understand the implications of anchor distribution to ensure this does not compromise the smooth operation and safety of the elevator. Hence why load distribution, both in terms of the anchor placement and how the elevator is used on a daily basis are equally important!

Specific Anchoring Needs

Partnering with an anchor manufacturer who understands the challenges of elevator installation and elevator safety can deliver significant benefits. LIEBIG has worked closely with elevator industry partners for many years to ensure mechanical anchors can be deployed for the numerous fixing points along the full height of the elevator shaft.

Through extensive dialogue, testing and verification, the team can provide a full and thorough recommendation for different base materials that elevator installers can use with confidence to meet the required safety standards.

Anchoring for Lifts and Elevators

The anchoring approach will differ according to the building substrate – i.e. concrete, brick and block masonry, CLT (cross laminated timber), steel, etc. – and different elevator types. The load capacity of anchors used in a passenger elevator shaft, particularly in smaller buildings, may be much lower than what we would expect to see in a service elevator or freight elevator. And where the elevator is situated in an external environment and subject to weather conditions, additional loads such as wind loads may also come into play.

The building’s design could impact on the type and size of elevator, and these will determine the installation process. This is consideration at the anchoring systems specification stage. For example, whilst a chemical anchoring approach may be preferred at the outset due to the high load capacity offered, the practicalities of being able to install them could make mechanical anchors more attractive and cost-effective.

Common Anchoring Systems for Hydraulic Elevators

Hydraulic lifts are one of the two most common types of elevator, along with traction-driven. So what are common anchoring solutions for hydraulic elevators?

Hydraulic elevators are mainly used in low-rise buildings, typically up to six stories high, or to transport extremely heavy loads and they operate at low speeds. They are lifted by pistons from below, powered by an electric motor, and require more energy to operate than other types of elevator. The electric motor pumps hydraulic fluid into the piston as it ascends and this fluid is releases as the lift descends. This elevator tends to be used in low-rise buildings, as it has limited reach and can only operate at low speeds.

When it comes to hydraulic lift anchors, mechanical anchoring systems may offer time and cost saving advantages. The LIEBIG Superplus BLS, for example, works by creating an undercut as torque is applied – thus making it a ‘self-undercutting’ anchor.

No special tool is needed to create the undercut before installing, making it quick and easy to use. But this also means it has the capacity for exceptionally high loads, as well as shock and seismic loads. Its expansion segments are driven down to the undercut in the drilled hole, with spring pressure automatically expanding the segments into the undercut with an audible click.

Hydraulic Lift Anchors and Building Renovation

Elevator installation is common in building renovation projects where a lift was not previously in place, but equally significant is the need for elevator upgrade projects in older buildings.

But when it comes to retrofitting elevators, what are the anchoring challenges that apply specifically to hydraulic elevators? With hydraulic elevators being one of the two most common types used, it is important to understand that the anchor challenges associated with this type are largely the same as they are all other types.

Elevator Anchoring and Safety Considerations

The elevator anchoring approach for elevators must be compliant with all the relevant safety standards that apply, whether that is in relation to steel anchors, concrete anchors or any other types.

Elevator safety is reliant on compliance with the building codes. so it is important to familiarise yourself with the ones that apply to your elevator types. Some standards take the form of the Building Regulations which exist to ensure elevators are safe and accessible, including Approved Document B (fire safety) and Approved Document M (accessibility in line with the Equality Act).

Others are standards applying to buildings more generally, such as BREEAM which considers environmental factors and BS 8300:2018 – Parts 1 and 2 which relate to creating an accessible and inclusive external built environment.

But there are host of more specific technical standards for lifts and elevators which could have a bearing on the anchoring design. These include:

• BS EN 81-3:2000 – this covers the safety rules for the construction and installation of electric and hydraulic service lifts.
• BS EN 81-20:2020 – this applies to the design of the lift shaft.
• BS EN 81-21:2018 – this is concerned with the safety rules for the construction and installation of new passenger lifts, goods passenger lifts and complete lift modernisations in existing buildings.

Hence why answering the question “What safety standards apply to elevator anchoring?” is not straightforward.

Cost Considerations in Elevator Anchoring

With budgetary pressures always a major challenge in lift installation, retrofitting elevators and maintenance projects, one of the most important questions that arises when considering anchor design is “what are cost considerations for elevator anchoring systems?”

Chemical anchors play an important role in lift shafts, especially those constructed using lightweight blocks, largely because mechanical anchors will not usually be able to overcome the key challenges posed by such materials. Lightweight blocks have less capacity to resist the expansion, compressive and tensile forces generated when installing mechanical anchors, and they are less able to accommodate vibration loads.

Any mechanical anchoring approach in lightweight materials must also be able to cope with the variability in the strength and density of different blocks. Hence why resin anchors have traditionally been recommended by fixing manufacturers for anchoring safety-critical elements, as they will almost certainly be able to provide the required performance when the conditions of the material are likely to be variable.

Cost Comparison of Different Anchoring Systems

There is always a trade-off which could result in costs being prohibitively high, principally resulting from additional time.

Chemical anchors may offer a valuable way to handle the variability associated with blocks, but they do not enable the workflow to be particularly efficient.

Ultimately, this means the process for using chemical anchors to install brackets is slower than it is for mechanical anchors because of the number of stages involved. For example, the resin must fully cure before the anchors are able to resist the applied load and every hole must be cleaned thoroughly after drilling. This all adds time to the job, stifling productivity, adding risk and potentially increasing costs.

In addition, the correct installation of chemical anchors requires a specific skillset that is not so widely available as the skills required to install mechanical anchors. Hence, finding a team with the relatively specialist skills needed to accurately install chemical anchors can prove difficult and, because their skills are in high demand, project delays could result if there is a lengthy wait for their availability on-site.

So in terms of a direct cost comparison, mechanical anchors, i.e. anchor bolts, could offer a more attractive proposition.

Maintenance and Long-Term Cost Implications

One of the most obvious signs that an elevator requires maintenance is corrosion of the anchor bolts. This could be one of the reasons why an elevator shakes during operation or feels unsteady as it moves. This motion could alarm users and present a risk in terms of occupant safety.

However, if the anchor bolts are corroded and need replacement, mechanical anchors could offer advantages in the replacement project versus chemical or resin anchors. This is because mechanical anchors which offer high load capacity, such as the LIEBIG Superplus BLS, may meet the required performance without the cost associated with chemical anchors and in a much shorter timeframe.

This could even apply in locations subject to seismic activity, where a seismic retrofit may enable higher levels of elevator safety to be achieved without the need to use more costly seismic anchors.

Lifetime costs are also reduced because it may be easier for installers to get things right first time when using mechanical anchors, and that minimises the potential for costly reworks and corrections. This can result in higher levels of client satisfaction due to the reduction in lift service outages and disruption to building occupiers.