# Elevator and Escalator Design Vertical transportation (VT) is the circulatory system of multi-storey buildings — its design determines the building's capacity to move people efficiently, its core planning and structural requirements, and the occupant experience of arrival, circulation, and egress. For the practicing architect, VT design is one of the most constrained and consequential aspects of tall building planning: elevator shafts consume 15-25% of the core area in high-rise buildings, and errors in VT calculation are irrecoverable without fundamental redesign. Early engagement with a VT consultant is essential for any building above 4-5 storeys. --- ## Table of Contents - [Elevator Types](#elevator-types) - [Traffic Analysis and Sizing](#traffic-analysis-and-sizing) - [Elevator Dimensions and Planning](#elevator-dimensions-and-planning) - [Elevator Shaft Requirements](#elevator-shaft-requirements) - [Machine Room and Machine-Room-Less](#machine-room-and-machine-room-less) - [Escalators and Moving Walks](#escalators-and-moving-walks) - [Firefighting and Evacuation Lifts](#firefighting-and-evacuation-lifts) - [Accessible Lifts](#accessible-lifts) - [Energy Efficiency](#energy-efficiency) - [Planning Rules of Thumb](#planning-rules-of-thumb) - [See Also](#see-also) --- ## Elevator Types | Type | Drive System | Speed (m/s) | Travel (storeys) | Application | |------|-------------|-------------|------------------|------------| | **Traction — geared** | Electric motor with gearbox; steel ropes | 0.5-2.5 | Up to 20 | Low-to-mid-rise; residential; budget commercial | | **Traction — gearless** | Direct-drive permanent magnet motor | 1.0-10.0+ | Up to 100+ | Mid-to-high-rise offices; premium residential | | **Machine-room-less (MRL)** | Gearless motor in shaft (hoistway) | 1.0-4.0 | Up to 30 | Standard for most new low/mid-rise buildings | | **Hydraulic** | Oil-filled ram/cylinder | 0.3-1.0 | Up to 5-6 | Low-rise; goods lifts; where shaft headroom limited | | **TWIN** | Two independent cars in one shaft | 2.0-4.0 | High-rise | Space-efficient; complex control | | **Double-deck** | Two-storey car; serves odd/even floors | 2.5-7.0 | Supertall | Maximum capacity from minimum shaft count | | **Ropeless (MULTI)** | Linear motor; multi-directional | Variable | Concept/prototype | ThyssenKrupp MULTI; future technology | --- ## Traffic Analysis and Sizing Elevator sizing is determined by traffic analysis — calculating the number, size, and speed of elevators required to serve the building population within acceptable waiting times. ### Key Parameters | Parameter | Definition | Typical Target | |-----------|-----------|---------------| | **Building population** | Total number of occupants above ground floor | Based on occupancy density (see below) | | **Handling capacity** | % of building population served in 5 minutes (up-peak) | 12-17% (offices); 8-12% (residential) | | **Average waiting time (AWT)** | Mean time from call to car arrival | <25 seconds (Grade A office); <40s (residential) | | **Average travel time (ATT)** | Mean time from boarding to destination | <60-90 seconds | | **Interval** | Average time between successive car departures from lobby | <25 seconds (premium); <35s (standard) | | **Round trip time (RTT)** | Time for one car to complete a full circuit | Calculated from speed, stops, loading/unloading | ### Occupancy Densities for VT Calculation | Building Type | Density (m² NIA per person) | 5-min Handling Capacity Target | |--------------|---------------------------|-------------------------------| | Office — standard | 10-12 | 12-15% | | Office — premium (Grade A) | 8-10 | 14-17% | | Residential — apartment | Per unit (1.5-2.5 persons) | 5-8% | | Hotel | Per room (1.5 guests + 0.5 staff) | 12-15% | | Hospital | Variable by department | 12-15% (public lifts) | | Retail | Not population-based | Escalators primary; lifts for access | ### Elevator Group Sizing (Rules of Thumb) | Building Height | Number of Lifts (typical office) | Configuration | |----------------|--------------------------------|---------------| | 4-8 storeys | 2-4 | Single group | | 8-15 storeys | 4-6 | Single group | | 15-25 storeys | 6-8 | Single group or low/high split | | 25-40 storeys | 8-12 | Sky lobby or zone system | | 40-60 storeys | 12-20 | Sky lobby with shuttle + local groups | | 60+ storeys | 20-30+ | Double-deck shuttles + local groups | **Sky lobby system**: Express (shuttle) elevators serve a transfer floor (sky lobby) at mid-height, where passengers transfer to local elevators. This allows local elevator groups to be stacked vertically, significantly reducing the core area consumed by shafts. --- ## Elevator Dimensions and Planning ### Standard Car Sizes (EN 81-20) | Capacity (kg) | Persons | Internal Dimensions (W × D mm) | Shaft Size (W × D mm approx) | Application | |--------------|---------|-------------------------------|------------------------------|------------| | 630 | 8 | 1,100 × 1,400 | 1,600 × 1,800 | Small residential; low-rise | | 1,000 | 13 | 1,600 × 1,400 | 2,100 × 1,900 | Standard office passenger | | 1,275 | 17 | 1,600 × 1,750 | 2,100 × 2,300 | Standard office passenger (deep car) | | 1,600 | 21 | 2,000 × 1,600 | 2,500 × 2,100 | Large office; hospital bed lift | | 2,000 | 26 | 2,000 × 2,100 | 2,500 × 2,600 | Hospital bed lift; goods-passenger | | 2,500 | 33 | 2,000 × 2,700 | 2,500 × 3,200 | Goods; service; vehicle (small) | **Door widths**: 800mm (8-person); 900mm (13-person); 1,100mm (17-21 person); 1,300mm (bed lifts, through-car). Centre-opening doors are faster than side-opening. ### Lobby Planning | Parameter | Recommendation | |-----------|---------------| | **Lobby depth** (from shaft wall to opposite wall) | Minimum 1.5× deepest car depth; typically 2.4-4.0m | | **Maximum lifts per group** | 8 (4 per side facing each other); beyond 8, split into zones | | **Facing groups** | Maximum 4 lifts per side; lobby 3.5-4.5m wide | | **Indicator visibility** | All indicator lanterns visible from waiting area | | **Wheelchair turning space** | 1,500 × 1,500mm clear in front of each lift door | --- ## Elevator Shaft Requirements | Parameter | Typical Requirement | |-----------|-------------------| | **Shaft walls** | Reinforced concrete or masonry; fire-rated (typically 2 hours) | | **Pit depth** | 1,200-2,000mm below lowest landing (depends on speed and buffer type) | | **Headroom above top landing** | 3,600-5,000mm (depends on speed; check with manufacturer) | | **Machine room (if required)** | Above shaft; minimum 2.0m clear height; access for maintenance | | **Ventilation** | Shaft ventilation to building exterior; 1% of shaft cross-section (minimum) | | **Structural loads** | Guide rail reactions; car weight; emergency buffer impact; machine room equipment | | **Smoke control** | Pressurisation or lobby ventilation per fire strategy | **Fire compartmentation**: Elevator shafts must be fire-separated from the building. Lift lobby doors are typically fire-rated (30 or 60 minutes). Landing doors inherently provide 30-60 minutes fire resistance. --- ## Machine Room and Machine-Room-Less **Machine-room-less (MRL)** elevators have become the standard for buildings up to ~30 storeys: - Motor and controller located within the shaft (hoistway top) - Eliminates the machine room above the shaft — saves one storey of structural and spatial overhead - Reduces energy consumption (permanent magnet motors) - Access for maintenance via the top landing or shaft access door **Machine room (MR)** installations are still preferred for: - High-speed lifts (>4 m/s) - Very high-rise applications - Heavy-duty goods lifts - Where shaft-top access is impractical --- ## Escalators and Moving Walks Escalators are the primary vertical transportation for high-volume, low-rise movement (retail, transit, airports, convention centres). ### Escalator Dimensions | Parameter | Standard (1,000mm) | Wide (800mm) | Notes | |-----------|-------------------|-------------|-------| | Step width | 1,000mm | 800mm | 1,000mm is standard for commercial | | Overall width | 1,400-1,600mm | 1,200-1,400mm | Including balustrades | | Speed | 0.50 m/s (standard) | 0.50-0.65 m/s | 0.75 m/s for transit | | Inclination | 30° (standard) | 35° (up to 6m rise) | 30° is standard for public buildings | | Capacity | 6,000-9,000 persons/hour | 4,000-6,000 p/h | At 0.50 m/s | | Structural zone below truss | 800-1,200mm | — | Coordinate with floor structure | | Upper machine room | 2,500-3,500mm (horizontal) | — | Beyond top landing | | Lower machine room | 2,500-3,500mm (horizontal) | — | Below bottom landing | **Planning rules**: - Escalators are always provided in pairs (up and down) - Adjacent parallel arrangement is most space-efficient - Criss-cross (stacked) arrangement minimises floor opening but increases travel distance - Structural opening: typically 5.0-6.5m long × 1.4-1.6m wide per escalator for one-storey rise (3.5-4.5m) - Floor-to-floor height of 3.5-4.5m is ideal; rises above 6m become very long ### Moving Walks Horizontal or inclined (up to 12°) moving walkways for long horizontal distances: - Speed: 0.50-0.75 m/s - Width: 800-1,400mm - Typical application: airports, large transit stations, exhibition halls - Inclined moving walks replace escalators in retail (shopping trolley compatible) --- ## Firefighting and Evacuation Lifts ### Firefighting Lift (BS EN 81-72) A dedicated lift for fire service use during firefighting operations. Required in buildings where the topmost storey is more than 18m above fire service access level (UK Building Regulations Approved Document B). | Requirement | Specification | |------------|---------------| | Car size | Minimum 1,100 × 2,100mm (EN 81-72); typically 2,000 kg capacity | | Power supply | Primary + secondary (generator-backed) | | Water protection | Shaft drainage; waterproof car; protected controls | | Lobby | Protected firefighting lobby at every floor; ventilated or pressurised | | Communication | Intercom between car and fire control point | | Speed | Sufficient for 60-second travel top to bottom | ### Evacuation Lift (BS EN 81-76) Used for evacuating mobility-impaired persons. Increasingly specified in lieu of or in addition to refuge areas: - Protected lobby at every floor - Two-way communication - Secondary power supply - Trained attendant or automatic recall to exit level See [[Universal Design Principles]] and [[Fire Safety in Building Design]] for integration with inclusive fire strategy. --- ## Accessible Lifts All passenger lifts in public buildings must be accessible. Minimum requirements: | Standard | Minimum Car Size | Door Width | Controls | |----------|-----------------|-----------|----------| | EN 81-70 (Type 1) | 1,000 × 1,250mm | 800mm | Accessible; braille; audible | | EN 81-70 (Type 2) | 1,100 × 1,400mm | 900mm | Accessible; braille; audible | | ADA (US) | 1,727 × 1,372mm (68" × 54") | 914mm (36") | Accessible; braille; audible | | BS 8300 / Part M (UK recommended) | 1,100 × 1,400mm | 900mm | Accessible; mirror on back wall | **Key accessible features**: Low-level controls (900-1,200mm AFL); braille and tactile floor indicators; audible floor announcements; handrail inside car; mirror on back wall (wheelchair users can see to reverse); contrasting door frames; adequate dwell time. --- ## Energy Efficiency | Feature | Energy Saving | |---------|--------------| | Regenerative drives | 20-40% (energy recovered to building or grid during braking) | | LED car lighting | 60-80% vs halogen | | Standby mode (sleep) | Significant for low-traffic periods | | Destination dispatch control | 20-30% (reduces unnecessary stops; groups passengers) | | Variable speed doors | Reduced cycle time | | Efficient motor technology (PM gearless) | 30-50% vs geared | **VDI 4707 / ISO 25745**: Energy classification for lifts (A to G). Class A lifts with regenerative drives can reduce energy consumption to <1,000 kWh per year in low-rise applications. --- ## Planning Rules of Thumb | Parameter | Rule of Thumb | |-----------|---------------| | **Core area** (lifts, stairs, services) | 20-25% of gross floor area (offices) | | **Lift shaft area** | 6-10% of GFA for high-rise; 3-5% for low-rise | | **Number of lifts (office)** | 1 lift per 2,000-3,000 m² NIA (preliminary) | | **Goods/service lift** | At least 1 per building; 2,000-2,500 kg; separate from passenger core | | **Car park lift** | Separate from main passenger group; located at car park entry | | **Structural coordination** | Shaft walls are typically part of the building's lateral stability system | | **Programme** | VT consultant appointment at RIBA Stage 1; traffic analysis at Stage 2 | --- ## See Also - [[Office Building Design]] - [[Hospital Design Principles]] - [[Fire Safety in Building Design]] - [[Universal Design Principles]] - [[High Rise Building Design]] - [[RIBA Plan of Work]] --- #services #elevators #escalators #verticaltransport #accessibility #fire