## Context & challenge
An architect asked whether a **Sesame Wellington** hidden stairlift could serve a shallow level difference at a bank entrance while maintaining safety in continuous public footfall. The total rise is around **350 mm** across two shallow risers. The proposed solution is a **Wellington** (a vertical‑retracting first step) integrated into the existing staircase so that the top tread drops down to become part of the lift platform. Because this is an **always‑busy public environment**, questions centred on seated‑user operation, supervision and the temporary void when the step lowers.
## Key insights
- **Platform length & step logic.** The Wellington uses **one retracting step**: when it lowers, the **first tread becomes part of the platform**, giving about **1.4 m of usable length** without needing the bolt‑on section the architect initially sketched.
- **User category.** With perimeter toe‑guarding rather than 1100 mm full‑height barriers, the Wellington is for **seated use only**. It should be **switched off when not in use** to avoid misuse and to keep the step flush.
- **Public‑area risk control.** BS 6440:2011 allows the omission of a top barrier where the **rise is under 500 mm**. Even so, staff should attend the upper landing whenever the step lowers to act as a human barrier and ensure pedestrians don’t walk into the temporary void.
- **Control placements.**
- *Upper call*: install on a post or wall roughly **400 mm back from the nosing** to keep users away from the drop.
- *Lower‑level controls*: use an **on‑lift control station** with the top row of buttons about **1100 mm above the lower finished floor level (FFL)**. When the platform rises 350 mm, those buttons sit at **~750 mm above the upper landing**, within the **400‑100 mm seated‑user reach range**.
- If the lift is sometimes left raised, install additional **lower‑landing call buttons** so a user can bring it down.
- **Width strategy.** The concept drawings showed **~925 mm usable width** between a removable handhold post and a wheel stop. Space can be tightened to **about 800 mm usable width** by reducing overall width to **~956 mm** and storing the handhold post out of sight when not needed.
- **Pit depth & finishes.** An available pit depth of **~1130 mm** is more than sufficient; finish the stair fascia with a **stainless‑steel skirt**.
- **Services & maintenance.** Because the lift is external, the base must be **drained**. Provide a **machine‑room cabinet** — ideally in the adjacent **basement plant room** — and, if permitted by fire/waterproofing, an **access hatch** from the basement to aid maintenance.
- **Alternative model for standing use.** If the client insists on **standing passengers** and the lift remaining **powered on at all times**, a **Sesame Westminster** (with full‑height barriers and different controls) is required.
## Recommended solution
For this enquiry, specify a **Wellington** with one retracting tread for **seated‑user‑only** operation and staff supervision in public hours:
1. **Platform**: ~1.4 m long, using the upper step as part of the platform.
2. **Controls**: place the **upper call button** about **400 mm from the nosing**; mount **on‑lift controls** at **~1100 mm above the lower FFL**, which translates to **~750 mm** above the upper landing when the platform is raised; install **additional lower‑landing call buttons** if needed.
3. **Width**: target **~800 mm usable width** (overall width ~956 mm) with the removable handhold post stowed when not required.
4. **Pit & finishes**: accept the **~1130 mm pit**, finish the stair reveal with a **stainless‑steel skirt**.
5. **Drainage & services**: ensure the base is drained; locate the **machine‑room cabinet** in the basement plant room; provide an **access hatch** from the basement where possible.
6. **Operational policy**: the lift should be **switched off when not in use**, and a **staff member** should attend the upper landing when the step retracts, to act as a barrier.
7. **Contingency**: if **standing use** or continuous operation becomes a requirement, switch to a **Westminster model** with full‑height barriers.
## Why this matters
Hidden platform lifts are common in heritage and public buildings where preserving aesthetics is important. This case illustrates how carefully managing platform length, user category, control positions, pit depth, drainage and staff oversight ensures a safe installation that blends into its surroundings. A thorough understanding of **BS 6440:2011** and the practical implications of a small rise helps select the right product and define an operational policy that minimises risk in busy public spaces.
## Q&A
**Q1. Why seated‑only here?**
A. The Wellington has a perimeter toe‑guard rather than 1.1 m barriers, so in a public setting it is suitable only for **seated use**. It should be **switched off** when idle to avoid misuse.
**Q2. Can we omit a top barrier for a 350 mm rise?**
A. BS 6440:2011 permits no fixed barrier for rises under **500 mm**, but the risk assessment for this busy bank entrance recommends a **staff member** attend the upper landing whenever the step lowers.
**Q3. How do we lay out the controls?**
A. Position the **upper call** about **400 mm back** from the nosing. Mount **on‑lift buttons** about **1100 mm above the lower FFL** (≈750 mm above the upper landing when raised), within the 400‑100 mm reach range for seated users. Install **lower‑landing call buttons** if the lift may be left raised.
**Q4. What if the client later wants standing use and always‑on operation?**
A. Switch to a **Westminster** lift. This model includes **full‑height barriers** and a different control regime suitable for standing passengers.