BS9991:2024: New evacuation lift requirements for fire safety in residential buildings

December 2024 saw the publication of the biggest change in lift assisted building evacuation guidance for many years. Previously, evacuation lifts had been considered under a limited definition in BS9999:2008 code of practice for the design management and use of buildings. A standard for the design of evacuation lifts (EN81-76) has been under development now for many years, but is yet to be published, hopefully due soon.

The latest British Standard BS9991:2024, building on the previous BS9999:2008, outlines fire safety requirements for residential buildings. This article provides an overview of the key changes and updates, with a focus on evacuation lifts and what I feel are the most relevant and significant points. I urge anyone working in the field of fire safety, firefighters or evacuation lifts to obtain a copy of the standard and digest it for themselves. This article provides a flavour of evacuation lift requirements, but does not replace a thorough and in depth understanding of the standard.

Prior to the publication of BS9991:2024 evacuation lifts were never mandated by guidance for compliance with Building Regulations in any building in the UK, it was always a design choice. So, this new document is a major shift in that evacuation lifts are now seen as essential for life safety in certain circumstances.

Key aspects include:

• Covers fire safety design, management, and use of various residential buildings, including houses, flats, student accommodation, and care homes.
• Applies to buildings up to 100m tall with specific fire-resistant materials or up to 11m tall with less stringent requirements.
• Excludes Houses in Multiple Occupation (HMOs), hotels, and certain other building types.

The significant updates and changes detailed in BS9991:2024 are only a part of the story, with a new standard (EN81-76) due for publication in 2025 detailing the design requirements for evacuation lifts even further. BS9991 references that the new standard for evacuation lifts (EN81-76) is under development, and it expects that its more detailed requirements will be adopted by users of BS9991 when it is published.

When is an evacuation lift required in a residential building?

The key criteria evaluating when evacuation lifts are required in residential buildings as per BS9991:2024 are:

• Buildings provided with passenger lifts should also be provided with a means to use lifts for escape (aka evacuation lifts).
• At least one evacuation lift should be provided for each escape stairway, and more if required (e.g. if there is a high number of persons on a floor that may rely on a lift to evacuate).
• For buildings with floors above 50m high and with a stay put strategy, every lift should be designed as a firefighters lift and have the ability to function as an evacuation lift.
• Buildings provided with lifts for access should also be provided with a means of using lifts for escape, and that lifts may be used for both access and escape or else be separate/different lifts with separate or individual functions.
• Any lift provided for use in building escape should be an evacuation lift.
• One evacuation lift is needed for each escape stair as a minimum, and where escape stairs are in separate locations, an evacuation lift should be provided at the location of each stair instead of in a single location.

Note that the standard clarifies that lift is a device compliant to EN 81–20 with a speed greater than 0.15 m/s and therefore removes the potential for a platform lift or similar (which is limited to a speed of 0.15 m/s) to be used as an evacuation lift.

What is a stay put policy/strategy?

A stay put strategy is a fire safety measure used in high-rise buildings where residents are advised to stay in their apartments in the event of a fire unless it directly affects their unit. This strategy assumes that the building's fire safety features, such as fire-resistant walls and doors, will contain the fire to its origin.

Introducing different evacuation lift classifications:

Whilst not fully covered in BS9991:2024, mention is made that when EN81-76 is published, it will contain 2 classifications of evacuation lift:

Class B = full specification with all features and provisions
Class A = where secondary power is not available

Mention is also made of a Class B evacuation lift being physically larger / have a larger capacity than a class A evacuation lift, although this is not further expanded upon in the standard.

From a personal perspective, I suspect that class A will be relevant for existing buildings where full compliance cannot be achieved due to the constructed nature and inherent limitations of the existing building; and that class B would be the requirement for all new buildings. We will need to wait for the publication of EN81-76 to find out!

Evacuation lifts requirements:

• The minimum dimensions of an evacuation lift should be 1400mm deep by 1100mm wide with a 900mm door opening width.
• Lift landing doors need to be fire doors (and it is noted that is generally not feasible to provide smoke sealed lift landing doors).
• Lift landing doors do not need to be physically marked or labelled as fire doors, unlike all other fire doors.
• Means to prevent water penetration into the lift shaft (as firefighters lifts) where the lift is located close to a firefighting main outlet.
• Clear signage at the evacuation exit floor.

Evacuation lift secondary power supply requirements.

The evacuation lift, emergency communications system, and both lift and lobby lighting require primary and secondary power supplies:

• Buildings less than 18m tall can use a fire protected diverse routed secondary supply from the main incoming electrical supply.
• Buildings over 18m require a generator, independent supply from a different substation to the primary, or ups system.

Building design requirements related to evacuation lifts.

There are many requirements of the general building design and construction where it contains the evacuation lift, which would sit outside of the lift suppliers' provisions and require a coordinated approach by all involved in building design.

The key building design requirements related to evacuation lifts are:

• The evacuation lift shaft and lift lobbies should be constructed as a protected shaft, meaning they have minimum levels of fire resistance and ventilation.
• Lift wells should be enclosed with fire resisting materials throughout their height unless they are within a protected stair.
• Lift machinery spaces need to be protected in the same way as the lift shaft
  A visually contrasting floor surface of at least 1500x1500mm should be provided outside of the evacuation lift.
• Evacuation lift lobbies should be provided with an emergency voice communication system according to BS5839-9 as well as a separate evacuation lift communication system which supports the lift evacuation process.
• Access to the evacuation lift should be step free and include an evacuation temporary waiting area of minimum size 1500 x 2100mm which is within or connected to an evacuation stair. The standard provides several potential layouts for such a configuration, including where the corridor in front of a lift is formed into the waiting area.
• The evacuation waiting area should be provided with some means of ventilation to minimise exposure of waiting evacuees to smoke and heat and prevent further ingress of smoke into the area (example if mechanical extract only is being used then this means adjoining corridors will also need smoke ventilation, or as an alternative a pressurisation system could be used that protects the staircase, lift shaft and lobby. Either way this means more smoke ventilation shafts needed in residential buildings.).
• In buildings designed with a stay put policy, any firefighters lift can also be an evacuation lift. However, where a building’s evacuation strategy is not stay put, then firefighters and evacuation lifts must be separate from one another.

Regular maintenance and inspection of evacuation and firefighters lifts

Evacuation and firefighters lifts should be maintained and undergo periodic testing of correct function:

• Weekly tests of firefighters, evacuation lift recall switches, and any fire alarm recall features connected to lifts.
• Notification to the fire service if a fault to the lift cannot be rectified within 24 hours.
• Failure of the primary power supply should be simulated once a month, and where a generator provides the standby power, it must energise the lift for at least 60 minutes.
• Firefighting and evacuation lifts should be inspected and tested every 6 months by a competent person.
• Annual performance tests should be carried out (which we understand to be a coordinated test of the interconnected and interrelated systems).

If you would like to know more about how Cundall can help design your building in accordance with the new standard get in touch. As a multi-disciplinary engineering consultancy we offer a one stop shop of the engineering disciplines needed including vertical transportation, fire engineering, mechanical and electrical engineering, as well as many other disciplines to support your project.