1. Introduction

For many years the construction industry has been trending towards inclusivity and higher standards of accessible design, resulting in clear guidelines to accommodate occupants with disabilities, in particular wheelchair users. However, limited guidance is given on how these occupants may evacuate a building in the event of fire. 

Historically, evacuation of occupants is premised exclusively around the use of staircases, irrespective of building use or height, whereas the use of lifts/elevators during a fire event is prohibited or discouraged. This approach is not suitable for occupants with mobility impairments. 

In UK, the New London Plan was released in March 2021 addressing these issues and advocating for all occupants to be able to evacuate independently and with dignity. This prompted AESG to undertake a comprehensive review of international requirements related to the evacuation of mobility impaired occupants in order to assess the different approaches and ultimately try to develop an overarching best practice approach.

2. Review of International Accessibility Requirements

Section 2 explores the current practices through a review of the following international design codes:

• BS 9991:2015 Fire safety in the design, management and use of residential buildings – code of practice
• NFPA 101 Life Safety Code – 2021
• UAE Fire & Life Safety code – 2018
• Saudi Building Code 201 – 2018
• Singapore Code of Practice for Fire Precautions in Buildings – 2018

This paper focuses on residential apartment building, since other occupancies (such as retail, business, entertainment) are more likely to have a management team tasked with preparing personal emergency evacuation plans (PEEPs) for staff and visitors, which may compensate for a lack of built-in provisions. Moreover, while it is understood that there are a number of different disabilities that need to be considered and addressed, such as vision or hearing impairments, this paper focuses primarily on provisions for occupants with mobility impairments.

2.1. British Standard BS 9991

BS 9991 addresses the evacuation of disabled occupants in Chapter 54. While guidance is given on the use of horizontal evacuation and lifts and the need for ramps and handrails, Chapter 54 puts the emphasis on the operator to assess the needs of disabled occupants and develop evacuation plans, stating that ‘providing an accessible means of escape should be an integral part of fire safety management’. The lack of built-in provisions such as areas of refuge puts wheelchair occupants at a disadvantage and exposes them to a higher level of risk, due to their inability to use stairs. 

Residential buildings in the UK are typically designed without a stair lobby or lift lobby, meaning that in the event of a fire scenario, wheelchair occupants need to find refuge in the common corridor or within the staircase until help arrives. The concern with this approach is that in the event of a severe fire scenario, visibility in the corridor can be very low, whereas temperatures and toxicity levels may be high. As for the staircases, these are rarely sized to accommodate a wheelchair refuge point, because this is not mandated by the code. Moreover, staircases in the UK tend to not be pressurised, meaning that smoke from the corridor could enter the staircase. It is noted that a new version of BS 9991 is currently under development and is expected to introduce staircase pressurisation requirements in high-rise apartment buildings with single stairs, or the need for at least two exit stairs.

Some of the concerns described above were addressed with the publication of the New London Plan in March 2021.

2.1.1. New London Plan 2021

Policy D5 of the New London Plan states that evacuation lifts, at least one per core, shall be provided in order to obtain planning approval. The intent is to allow all building users to be able to evacuate with dignity and as independently as possible. Emergency carry down devices are no longer considered to be appropriate. Lastly, where once the use of firefighting lifts for evacuation purposes was deemed acceptable, Policy D5 states that ‘evacuation lifts should not be misinterpreted as firefighting lifts’ and that ‘applicants must not make the provision for the installation of a firefighting lift where an evacuation lift is required by London Plan Policy D5(B5)’. 

Below are the key design considerations for evacuation lifts:

• The lift should be used routinely as a passenger lift.
• The lift should be situated in a protected enclosure.
• The final exit to outside should be via a level access protected route.
• The evacuation lift should be associated with a refuge point.
• Emergency voice communication system should be provided to enable the rapid and unambiguous identification of those locations (e.g. refuges) where people requiring assistance with evacuation might be waiting, from a control point, and the relaying of this information to the person operating the evacuation or firefighters lift car.
• An evacuation lift should be provided with a switch clearly marked “Evacuation Lift” and situated adjacent to the lift landing door at the final exit level.
• “On the operation of the “Evacuation Lift” switch, or on a signal from a fire detection system, the evacuation lift should isolate all car and landing call controls and return to the final exit level and park with its doors open. Once at the final exit level and once the “Evacuation Lift” switch has been operated, the car controls should be enabled; the evacuation lift should then operate only in response to the car controls and the communication system provided should be in operation. The lift car should be taken only to those levels where a person is in need of assistance.”

In summary, the New London Plan has introduced measures that facilitate the safe evacuation of all occupants, thanks to the requirement for evacuation lifts and refuge points. 

2.2. NFPA 101

In comparison to BS 9991, NFPA 101 is a more prescriptive document which leaves little room for interpretation. Requirements for areas of refuge are addressed in Section 7.2.12. Here it is stated that an area of refuge used as part of a required accessible means of egress shall be provided at each elevator landing and shall be fitted with a two-way communication system for communication between the elevator landing and the fire command center or a central control point approved by the authority having jurisdiction. Moreover, it states that each area of refuge shall be sized to accommodate one wheelchair space of 30 in. × 48 in. (760 mm × 1220 mm) for every 200 occupants. However, not all building types have to comply with these requirements. For example, in residential apartment buildings (Chapter 30) the provision of areas of refuge is ‘permitted’, but not required. 

Additionally, Section 7.2.13 states that elevators shall be permitted to be used as a second means of egress from a tower, provided all of the following criteria are met:

• The tower and any attached structure shall be protected throughout by an approved, supervised automatic sprinkler system.
• The tower shall be subject to occupancy not to exceed 90 persons.
• Primary egress discharges shall be directly to the outside.
• No high-hazard content areas shall exist in the tower or attached structure.
• One hundred percent of the egress capacity shall be provided independent of the elevators.
• An evacuation plan that specifically includes the elevator shall be implemented, and staff personnel shall be trained in operations and procedures for elevator emergency use in normal operating mode prior to fire fighter recall.
• The tower shall not be used by the general public.

These prerequisites restrict the use of the elevators for evacuation to a limited number of scenarios. In fact, the use of elevators for evacuation has generally been discouraged as a result of incidents involving the use of elevators during fire scenarios. The issue consisted in elevators stopping at fire floors and the elevator doors not being able to close, due to too many people trying to evacuate, resulting in occupants becoming trapped. The rejection of evacuation elevators was universal for a long time, but attitudes started to change following the 9/11 investigation. The benefits of elevator evacuation are now outlined in the 20th Edition of the NFPA Fire Protection Handbook, which is referenced in NFPA 101.

In summary, NFPA 101 does not require refuge areas in residential apartments, nor the use of evacuation elevators, meaning that the evacuation of mobility impaired occupants relies on the building’s facility management team. To this point, NFPA has published a document titled Emergency Evacuation Planning Guide for People with Disabilities, which outlines how to develop suitable evacuation plans for occupants depending on the type of impairment.

2.3. UAE Fire & Life Safety Code

Chapter 3 of the UAE Fire & Life Safety Code covers the general requirements for means of egress, whereas Chapter 13 talks specifically about accessibility requirements, with the intent of ensuring that people with determination can ‘manoeuvre, evacuate and find refuge as naturally as everyone’. This chapter sets out the requirements for ensuring that access and egress routes, such as doors, corridors, elevators, stairs, etc., are suitable for people with physical disability or mobility impairments. Additionally, it outlines the minimum allowable number of accessible parking bays and accessible units within buildings.

On the other hand, the evacuation procedures for mobility impaired occupants are not presented in a prescriptive manner, leaving it up to the interpretation of the designer to determine where features such as refuge areas and evacuation elevators should be provided. For example, Chapter 3 Section 3.9 talks about the use of elevators for evacuation purposes, but it is not clear when and where they should be provided, if ever. Below are some of the prerequisites for elevator evacuation:

• Building shall be fully sprinklered. 
• Elevator shall be provided with a lobby.
• Elevator shafts shall be pressurized.
• Elevator shall have two-way communication system. 

The UAE Fire & Life Safety Code does not emphasize the need for independent evacuation and instead relies on able-bodied people to assist the evacuation of less able occupants through the use of stair descent devices and even elevator evacuation. In fact, Chapter 13 Section 5.2 states that ‘where mobility impaired people cannot use the accessible routes and elevators are not available for evacuation’, they can receive ‘assistance from first responders, Civil Defence personnel, fellow people, neighbours, colleagues, depending on the type of occupancy’. 

2.4. Saudi Building Code, SBC 201

The Saudi Building Code (SBC 201), which is largely based on the International Building Code (IBC), has two chapters that outline accessibility requirements. Chapter 11, which is dedicated entirely to the subject of accessibility, covers the general aspects of access and day-to-day livability of a building, whereas Chapter 10 focuses on addressing the needs of occupants during a fire scenario or other events requiring evacuation of the building. 

SBC is supplemented by the ‘Universal Accessibility Built Environment Guidelines for the Kingdom of Saudi Arabia’. This document is primarily intended to ensure that new buildings are inclusive towards occupants with disabilities by setting out accessibility requirements for common circulation areas and by defining minimum quotas for accessible rooms and parking.

SBC presents accessibility requirements in a prescriptive manner, setting out clear requirements for areas of refuge, two-way communication systems and evacuation elevators, among other requirements. However, numerous exceptions are made for buildings fitted throughout with an automatic sprinkler system and residential buildings. For example, Section 1009.2.1 states that ‘in buildings where an accessible floor is four or more stories above a level of exit discharge, not less than one required accessible means of egress shall be an elevator’. However, it also states that the evacuation elevator is not required in buildings equipped with an automatic sprinkler system. Another example is Section 1009.3, which states that ‘areas of refuge are not required in buildings equipped throughout with an automatic sprinkler system’. It is the opinion of the writer that the provision of active suppression systems such as sprinklers, while usually reliable and effective, should not replace built-in provisions. 

In the context of residential apartments specifically, Section 1009.3 states that ‘areas of refuge are not required at stairways in Group R-2 occupancies’.

2.5. Singapore Code of Practice for Fire Precautions in Buildings

Requirements for persons with disabilities (PWDs) are covered in Chapter 2.4 of the Singapore Fire Code. The Singapore Fire Code is accompanied by the Code on Accessibility in the Built Environment (2018), which is a comprehensive guide to ensuring that all aspects of a building are accessible for people with disabilities, as well as older persons.

The requirements of the Singapore Fire Code are prescriptive, but residential buildings (Purpose Group I and Purpose Group II buildings) are exempt from these requirements. In fact, residential buildings are exempt from needing PWD holding points (refuge points), as well as evacuation lifts. 

Super high-rise residential buildings are required to have refuge floors at intervals of no more than 20 storeys. However, this requirement is not specific to PWDs, and while it certainly benefits young children or older persons who may not be able to evacuate the building in its entirety, it does not benefit occupants with severe mobility impairments such as wheelchair occupants.

2.6. Summary

Among the codes reviewed, it is evident that the evacuation of mobility-impaired occupants relies heavily on external assistance from the building management team or firefighters. Only in UK with the introduction of the New London Plan, we are seeing compulsory measures being introduced in residential buildings intended to support the independent evacuation of mobility-impaired occupants. Findings from the review are presented and summarised inTable 1.

The next chapter looks at the challenges that wheelchair occupants may face in the event of a fire scenario and presents some ideas on how to mitigate these challenges.

3. Assessment of Conditions within Refuge Areas

Section 2 of this paper provides an overview of the accessibility requirements in residential apartment buildings, revealing that there is a lack of prescriptive guidance in terms of evacuating occupants with disabilities. One of the main concerns is the lack of stricter requirements in relation to areas of refuge. This raises the question of where wheelchair occupants should find refuge during an evacuation. Section 3 aims to answer this question and provide recommendations on how to mitigate the challenges they face. These recommendations are based on an in-house computational fluid dynamics (CFD) study which evaluates three areas of refuge to determine which are more favourable. The three scenarios considered are:

• Refuge within a common corridor.
• Refuge within a lift lobby.
• Refuge within a staircase.

The findings of the CFD analysis are summarised below:

• Where corridors are indented to be used as a refuge area, a mechanical ventilation system should be provided. The required flow rate is subject to the corridor geometry, but 6m3/s is likely to yield acceptable results. The geometry of the corridor has a big impact on tenability conditions. The best results were obtained where the corridor has a large reservoir for smoke above the door openings. A 1m reservoir produced acceptable results, but this should be assessed on a case-by-case basis. 
• A corridor ventilation system achieving 6 ACH does not remove smoke quickly enough to support the evacuation of occupants or to support firefighting operations. These systems are only suitable to remove smoke after a fire scenario.
• A mechanical ventilation system in the corridor does not guarantee that smoke will not enter the stair or lift lobby, as most of the escape phase occurs prior to the activation of the system and prior to the fans reaching 100% capacity.
• Unventilated lift lobbies do not guarantee a smoke-free refuge area. Lift lobby pressurisation is recommended where the lobby is intended to be used as a refuge area, especially where there is limited floor to ceiling height and/or where there is a limited reservoir for smoke.
• Non-pressurised staircases do not guarantee a smoke-free refuge area. Staircase pressurisation is recommended where the stair is intended to be used as a refuge area. 
• Apartment doors should not be located directly in front of stair and lobby doors in order to limit the risk of smoke ingress.
• Staircases and lobbies are recommended to be located between the supply and extract vents, preferably closer to the supply vent.

It is noted that the results presented herein are not absolute and are only relevant to this comparative case study. In fact, the study has demonstrated that the results vary greatly depending on the building’s geometry (ceiling height, corridor width/length, opening dimensions, etc) or the modeller’s assumptions, in particular regarding door opening times and fan ramp up times. While the study does provide some indication of which corridor arrangements and ventilation systems are more likely to perform best at maintaining tenable conditions, the results highlight that there is not a single overarching approach for all scenarios and that undertaking modelling is highly important.

4. Conclusion

This paper has been written with the intent of understanding typical egress provisions for mobility-impaired occupants in residential buildings and ultimately make recommendations on best practices. The international codes reviewed for this paper are:

• BS 9991:2015 Fire safety in the design, management and use of residential buildings – code of practice
• NFPA 101 Life Safety Code – 2021
• UAE Fire & Life Safety code – 2018
• Saudi Building Code 201 – 2018
• Singapore Code of Practice for Fire Precautions in Buildings – 2018

Given current building codes and regulations, the following is the authors opinion on general good practice for multi-storey residential apartments to ensure that all occupants are given the capability of escaping independently without outside support:

• The building should be fully sprinklered.
• Areas of refuge should be provided. 
• Areas of refuge can be located within a staircase if it is pressurised and if the landing is sized appropriately to ensure the egress width is not affected.
• Areas of refuge can be located within an elevator lobby. The lobby and the elevator hoistway should be pressurised. 
• Where neither of the above is possible, the corridor should be provided with a mechanical ventilation system which can rapidly remove the smoke and maintain tenable conditions for escaping occupants. This should be demonstrated by CFD analysis.
• A two-way communication system should be provided in areas of refuge and in elevator cabs used for evacuation. 
• Evacuation elevators should be provided, independent of the firefighting elevator.
• Evacuation elevators should be pressurised, water-resistant and have dedicated emergency power. 
• Elevator lobbies should have direct access to a pressurized stairway.
• Elevator response during fire emergencies should be pre-planned.
• The final exit to outside should be via a level access protected route.

How can AESG help?

AESG is a specialist consultancy, engineering and advisory firm with offices in London, Dubai. Riyadh and Singapore working on projects throughout Europe, Asia and Middle East. We pride ourselves as industry leaders in each of the services that we offer. We have one of the largest dedicated teams with decades of cumulative experience in sustainable design, fire and life safety, façade engineering, building commissioning and digital asset management, waste management, environmental consultancy, strategy and advisory, acoustics, cost management and carbon management.

James Kelland

Fire and Life Safety Technical Manager, AESG

James is an ambitious consultant engineer who is passionate about integrated design and specializes in fire safety and fire protection engineering. His experience demonstrates an ability to integrate and collaborate with people in a multidisciplinary team environment, as well as work independently as project lead on both small-scale and largescale international projects.

He has worked as project lead on a broad range of international projects, including low- and medium-rise flats, high-rise mixed-use developments, entertainment venues including retail stores, high-rise towers, airports and masterplan developments in Asia, Europe, North America and Middle East. James takes great responsibility in delivering high quality work on time, that is tailored to meet client needs.

For further information relating to specialist consultancy engineering services, feel free to contact us directly via info@aesg.com