Key Takeaways
Designing an accessible platform lift for level changes of around 1.5 metres often comes down to one critical constraint: pit depth. This article explains how different bespoke Sesame Access platform lift configurations respond to varying pit limitations, how enclosure and barrier choices affect usability, and how projects can balance independence, aesthetics, and safety in public environments. It also outlines how these systems can be adapted for international projects, harsh climates, and complex structural conditions.
Introduction
In public, cultural, and civic environments, level changes of around 1.5 metres are common. These height differences frequently appear at main entrances, within tiered public spaces, and across multi-level circulation routes where ramps are not feasible due to space, gradient, or heritage constraints.
The challenge is delivering a wheelchair-accessible solution that feels intuitive, safe, and visually integrated, while also working within strict structural limits such as restricted pit depth. This article explores how bespoke platform lift engineering addresses these challenges, with a focus on shallow-pit solutions, enclosure strategies, and independent versus assisted operation, supported by real engineering coordination discussions.
The problem: 1.5 metre level changes with limited pit depth
A vertical rise of approximately 1500 mm immediately places a platform lift into the category of fully enclosed systems. At this height, safety standards typically require barrier protection of around 1100 mm in height around the user, which directly affects how much space is needed below finished floor level.
In many projects, achieving a pit depth of around 1600 mm may be possible in some locations but not others. Architects and engineers are therefore faced with a recurring question: can one lift concept be adapted across multiple locations with different pit depths, or are multiple lift types required across a single site?
How pit depth affects platform lift selection
Pit depth is one of the most influential parameters in platform lift design. It governs the type of lifting mechanism that can be used, the form of enclosure, and whether additional elements such as retracting stairs can be integrated.
For a detailed technical overview of how pit depth constraints are resolved across different projects, see the related guidance on bespoke pit design here: https://www.sesameaccess.com/knowledge-hub/bespoke-lift-pit-depth-solutions
Fully enclosed platform lifts and why enclosure matters
For rises above one metre, a fully enclosed platform becomes essential. Enclosure can be achieved through several engineering strategies:
- Permanent glass, stainless steel, or aluminium barrier panels surrounding the platform
- Automatic rising barriers that deploy from beneath the platform during travel
- Manual barrier systems that are installed and removed by staff
Each approach has implications for pit depth, visual appearance, independence of use, and day-to-day operational management.
Deep pit solutions with retracting stairs
Where a pit depth of approximately 1600 mm to 1650 mm is achievable, a retracting stair platform lift provides a high level of independence and architectural integration. In this configuration, the stair flight retracts into the pit, automatic barriers rise to a height of around 1100 mm, and the platform travels independently without staff assistance.
This approach is commonly associated with solutions such as the Westminster Equality Act Lift. Typical platform dimensions for this type of lift are in the region of 1250 mm x 1650 mm, providing comfortable space for wheelchair users and attendants.
The benefit of this configuration is a clean, uninterrupted stair when the lift is not in use, alongside fully independent operation for wheelchair users and standing users with mobility impairments. The primary constraint is the requirement for a deeper pit to accommodate both the lifting mechanism and the retracting stair assembly.
Shallower pit options: reducing depth without losing safety
When pit depth is constrained, alternative configurations allow accessibility to be delivered without compromising safety.
One metre pit solutions using collapsible systems
Recent platform lift developments allow total rises of around 1500 mm to be achieved with pit depths closer to 1000 mm. This is achieved by using collapsible bellows or telescopic barrier systems that compress within the pit during travel.
In these configurations, the platform remains fully enclosed with barrier heights of approximately 1100 mm, but flexible bellows replace rigid underfloor structures. This allows the mechanism to compress safely into a shallower pit while maintaining compliance.
A deeper explanation of how bellows systems are engineered for limited pit depth environments can be found here: https://www.sesameaccess.com/knowledge-hub/bellows-design-accessibility-lifts-limited-pit-depth
Ultra-shallow pits and assisted operation
In scenarios where pit depths are extremely limited, typically between 350 mm and 650 mm, assisted-operation solutions may be considered. These systems often use lightweight manual barrier panels that are positioned behind the user before travel and removed afterwards.
While this approach allows accessibility to be delivered in highly constrained environments, it is not fully independent. It requires trained staff, barrier storage locations, and clear operational procedures.
Platform-only solutions without retracting stairs
In some layouts, the stair is located to one side of the lift, allowing the platform to operate independently without retracting steps. Removing the stair mechanism significantly reduces pit depth requirements and mechanical complexity.
An example of this approach is the Richmond Rising Platform Lift. In this configuration, permanent glass or metal barriers surround the platform, typically to a height of 1100 mm, making the lift suitable for wheelchair users and standing users alike.
Shallow pit platform lifts versus traditional lift solutions
Traditional passenger lifts typically require full shafts, overhead clearances, and pit depths well in excess of 1000 mm, often exceeding 1400–1500 mm. In contrast, bespoke shallow pit platform lifts are designed specifically for constrained environments.
| Feature | Shallow pit platform lift | Traditional passenger lift |
|---|---|---|
| Typical pit depth | 350–1600 mm | 1400–2000+ mm |
| Shaft required | No | Yes |
| Platform size | ~1100 mm x 1400 mm | Variable |
| Independent use | Yes (configuration dependent) | Yes |
| Heritage suitability | High | Limited |
This comparison highlights why shallow pit platform lifts are often recommended for heritage, retrofit, and architecturally sensitive projects.
Installation time and operational considerations
Installation times vary depending on pit formation, structural readiness, and configuration. For most shallow pit platform lifts, on-site installation typically takes several days once the pit and power supplies are prepared. Commissioning follows installation and includes safety testing, barrier calibration, and user controls verification.
Platform lifts in open environments typically operate at controlled speeds of around 100 mm per second. For a 1500 mm rise, this equates to a travel time of approximately 15 seconds, excluding barrier deployment and retraction.
Designing for external and harsh environments
Platform lifts can be engineered for challenging external conditions, including sand, salt air, freezing temperatures, and heavy rainfall. Drainage channels, corrosion-resistant materials, heated surfaces, and sealed components are selected based on environmental exposure.
In sandy environments, controlled drainage paths allow debris to pass through the pit without interfering with the lifting mechanism. In colder climates, integrated heating paths prevent ice build-up around moving components.
International projects and long-term support
Bespoke platform lifts are frequently supplied internationally and designed to align with local codes and standards. Systems are commissioned by specialist engineers, supported by remote diagnostics, and maintained through trained local partners.
Remote monitoring allows lift status and fault data to be reviewed off-site, supporting faster diagnosis and more efficient maintenance coordination.
Frequently Asked Questions
What is the minimum pit depth for a 1.5 metre platform lift?
Depending on configuration, pit depths can range from approximately 350 mm for assisted-operation lifts to around 1600 mm for fully automated retracting stair systems.
How long does it take to install a shallow pit platform lift?
Once the pit, power supply, and surrounding structure are ready, installation typically takes several days, followed by commissioning and safety testing.
What building regulations apply to 1.5 metre platform lifts in the UK?
Platform lifts must comply with applicable British Standards and safety requirements, including enclosure and barrier height rules for rises above one metre. Requirements vary depending on whether the lift is enclosed, assisted, or independently operated.
Can one platform lift design work across multiple pit depths?
A single core platform concept can often be adapted using different barrier and enclosure strategies to suit varying pit constraints across a project.
Are shallow pit platform lifts suitable for standing users?
Fully enclosed shallow pit platform lifts with barrier heights of around 1100 mm are suitable for both wheelchair users and standing users with mobility impairments.
Can these lifts be used outdoors or in harsh climates?
Yes. Materials, drainage, heating, and protective detailing can be tailored for sand, salt, snow, and temperature extremes.
Next steps
Every project has unique constraints around structure, appearance, and use. Early-stage discussion is the most effective way to identify the right platform lift configuration for your site.
To explore which solution best suits your project, book a Teams meeting with one of our Project Managers here: