Fire safety: Approved Document B, Volume 2 for Architectural Glazing
UK Building Regulations on Fire Safety in Buildings Other Than Dwellings
Approved Document B is an extensive part of the building regulations that outlines standards and requirements for fire safety in all UK buildings.
Volume 1 of the regulations focuses on fire safety for dwellings, and Volume 2 gives requirements for buildings other than dwellings.
This article will be focusing on Volume 2. Volume two is split into:
- Requirement B1: Means of warning and escape
- Requirement B2: Internal fire spread (linings)
- Requirement B3: Internal fire spread (structure)
- Requirement B4: External fire spread Requirement
- Requirement B5: Access and facilities for the fire service
- Regulations: 6(3), 7(2) and 38
For those of you who only want information regarding regulations on the fire safety of architectural glazing in buildings other than dwellings, IQ have read the 200-page long document and extracted the information relevant to specifying glazing.
IQ cannot recommend placement of the fire rated glazing, as this will depend on several other factors. This means the placement and the required level of fire rating for the glazing must be calculated by the architect.
Once the necessary glass specification has been calculated, the team at IQ will then be able to design and manufactured glazing to meet this standard.
We must also install the fire rated glazing, as this complex glazing solution needs to be transported, carried, and installed in a specific way to maintain the fire rating.
If a fire rate glass door were carried onto site horizontally, this could void the fire rating on the glazing due to it negatively affecting the intumescent gel interlayer’s ability to provide fire protection.
This is only a guide to highlight some of the key considerations for fire safety in non-dwellings in relation to architectural glazing, for the full information and regulations, please refer to the Approved Document B which can be found on the UK government website.
Requirement B1: Means of warning and escape
The regulations in this section ensure that the building has satisfactory means of sounding an alarm and means of escape for the building’s occupants.
Here fire rated glass doors and partitions can play a significant part. Internal fire rated glazing can be utilised to protect escape routes such as stairwells or corridors, and external fire rated doors with fire safety release can provide an exit from the building during the event of a fire.
Section 5: General provisions
Fire resistance of doors
5.3 Fire resistance test criteria are set out in Appendix C. Standards of performance are summarised in Table C1.
Fire resistance of glazed elements
5.4 If glazed elements in fire resisting enclosures and doors can only meet the required integrity performance, their use is limited. These limitations depend on whether the enclosure forms part of a protected shaft (see Section 8) and the provisions set out in Appendix B, Table B5. If both integrity and insulation performance can be met, there is no restriction in this document on the use or amount of glass.
5.5 Glazed elements should also comply with the following, where necessary.
- If the enclosure forms part of a protected shaft: Section 8.
- Appendix B, Table B5.
- Guidance on the safety of glazing: Approved Document K.
Doors on escape routes
5.6 Doors should be readily openable to avoid undue delay to people escaping. Doors on escape routes (both within and from the building) should comply with paragraphs 5.7 to 5.15. Guidance on door closing and ‘hold open’ devices for fire doorsets is set out in Appendix C.
5.7 In general, doors on escape routes (whether or not the doors are fire doorsets) should be either of the following:
- Not fitted with a lock, latch or bolt fastenings.
- Fitted only with simple fastenings that are all of the following:
- Easy to operate; it should be apparent how to undo the fastening.
- Operable from the side approached by people escaping.
- Operable without a key.
- Operable without requiring people to manipulate more than one mechanism.
Doors may be fitted with hardware to allow them to be locked when rooms are empty.
Other requirements in this section include the direction the doors should be opened and regulations for revolving and automatic doors.
IQ worked with Níall McLaughlin Architects to design a bespoke glazing package for Jesus College at Cambridge University. The glass doors in the student bar had to meet these building regulations in terms of fire escape and safety.
Our team worked closely with the architect and found the best solution to achieve this was with Schuco door systems that have electronic locking and a fire safety release.
Requirement B2: Internal fire spread (linings)
B2 sets out to inhibit the spread of fire within the building. This means the internal linings (materials or products used in lining any partition, wall, ceiling or other internal structure) shall:
- adequately resist the spread of flame over their surfaces
- have, if ignited, either a rate of heat release or a rate of fire growth, which is reasonable in the circumstances.
This section does not include windows or doors but does include non-opening glazing elements such as glass partitions that, in the requirement, are considered to be a part of the wall.
For roof glazing, non-plastic rooflights should meet the relevant classification in Table 6.1.
Requirement B3: Internal fire spread (structure)
This section focuses on the integral structure of the building, meaning glazing plays a pivotal role. Here architects must ensure adequate structure and supports are in place to prevent the building from collapsing in the event of a fire.
Requirement B3 also outlines that as well as this, the building must be built such that all the following are achieved in the event of a fire; sufficient fire separation is provided within buildings and between adjoining buildings, automatic fire suppression is provided where necessary, and the unseen spread of fire and smoke in cavities is restricted.
Section 8 of Requirement B3 in Approved Document B, Volume 2, states the requirements for compartmentation and sprinklers. Specifying fire resisting construction elements such as internal fire rated glazing is vital part of Requirement B3, as these building materials are used for the compartmentation of buildings.
Openings in compartment walls separating buildings or occupancies
8.30 Openings in a compartment wall common to two or more buildings, or between different occupancies in the same building, should be limited to those for either of the following.
- A fire doorset providing a means of escape, which has the same fire resistance as the wall and is fitted in accordance with the provisions in Appendix C
- The passage of a pipe that complies with the provisions in Section 10.
8.32 Any stair or other shaft passing directly from one compartment to another should be enclosed in a protected shaft. Protected shafts should be used for the following and may also include sanitary accommodations and washrooms.
- Additional provisions apply for both of the following.
- Protected shafts that are protected stairways: Sections 2 to 5.
- Stairs that are also firefighting stairs: Section 17.
Our bespoke fire rated glazing can be utilised for fire rated lift lobby glazing, fire rated doors and partitions around stairs, fire rated glass atria and more.
This included a mixture of EI30 and EI60 rated systems and steelwork between the faceted junctions between screens and doors in the lift lobbies.
The internal fire rated glazing around the stairwell in this modern London office also has manifestations on the glazing to comply with Approved Document K of the UK building regulations.
Uninsulated glazed screens to protected shafts
8.34 An uninsulated glazed screen may be incorporated in the enclosure to a protected shaft between a stair and a lobby or corridor entered from the stair. The enclosure must conform to Diagram 8.4 and meet all of the following conditions.
- The standard of fire resistance required for the protected stairway is not more than REI 60.
- The glazed screen complies with the following. i. It achieves a minimum rating of E 30. ii. It complies with the guidance on limits on areas of uninsulated glazing in Appendix B, Table B5.
- The lobby or corridor is enclosed with fire resisting construction achieving a minimum rating of REI 30.
Fire doorsets that provide a means of escape must have the same fire resistance as the wall and be fitted in accordance with the provisions in Appendix C.
Requirement B4: External fire spread Requirement
Restrict both the potential for fire to spread over external walls and roofs (including compliance with regulations 6(4) and 7(2)) and the spread of fire from one building to another.
The intention of Requirement B4 is to prevent undue fire spread from one part of a building to another or to other buildings by ensuring the external envelope of the building works to reduce the risk and rate of the fire spread.
If a building contains one or more atria, the recommendations in clause B8 of BS 9999 should be followed.
Requirement B5: Access and facilities for the fire service
In Requirement B5 of Approved Document B, Volume 2, the regulations outlined help to ensure that buildings are designed to allow for ease of access for emergency services in the event of a fire. This includes adequate vehicle access.
Relegations also stipulate that there are facilities in the building to help firefighters save people’s lives in and around the building, such as sprinklers and fire extinguishers.
Regulation 38 deals with providing fire safety information to building owners.
The aim of this regulation is to ensure that the person responsible for the building has sufficient information relating to fire safety to enable them to manage the building effectively. The aim of regulation 38 will be achieved when the person responsible for the building has all the information to enable them to:
- Understand and implement the fire safety strategy of the building.
- Maintain any fire safety system provided in the building.
- Carry out an effective fire risk assessment of the building
Appendix A outlines some key terms for Approved Document B, Volume 2, along with their definitions, for example, a fire doorset.
This section of the approved document states that a fire doorset may have one or more leaves. The term includes a cover or other form of protection to an opening in a fire resisting wall or floor, or in a structure that surrounds a protected shaft.
A fire doorset is a complete door assembly, assembled on site or delivered as a completed assembly, consisting of the door frame, leaf or leaves, essential hardware, edge seals and glazing, and any integral side panels or fanlight panels in an associated door screen
Appendix B: Performance of materials, products and structures
B24 The fire resistance necessary for different circumstances is set out in the following tables.
- Table B3 gives the specific requirements for each element of structure.
- Table B4 sets out the minimum periods of fire resistance for elements of a structure.
- Table B5 sets out limitations on the use of uninsulated fire resisting glazed element
Fire safety regulations, such as the number of required escape routes or limits, can differ depending on the type of non-dwelling and which purpose group it comes under. For more information on purpose groups please refer to ‘Table 0.1 Classification of purpose groups’ in Approved Document B, Volume 2.
As with all Approved Documents in the UK Building Regulations, IQ are not experts, but it is vital that our employees understand the building regulations, especially for sections relating to architectural glazing.
This article outlines some of the many considerations for fire rated glazing in non-dwellings outlined in Approved Document B of the building regulations. Understanding Approved Document B, Volume 2 allows us to work closely with the architects on the job to recommend the best solutions that will be able to meet the specific requirements of each project.