Concrete may be inherently non-combustible, but when it comes to a structural fire rating, combustibility is only part of the wider picture. 

Standard concrete lintels can undergo explosive spalling when subjected to high temperatures, so understanding the required fire performance and selecting an appropriately rated lintel is an important part of the specification process. 

A lintel is, first and foremost, a structural component. Where it forms part of a fire-resisting construction, it needs to provide the appropriate structural performance for the required period in a fire situation, while fulfilling its structural function within the building. 

This means lintel fire resistance cannot be considered in isolation. So, before looking at individual products or ranges, what should designers and specifiers establish when specifying a fire-rated concrete lintel? 

1. What Fire Resistance Does the Concrete Lintel Require? 

The first step is to establish the fire resistance required for the application. 

This will depend on the requirements of the building, the lintel's location within the building, the wider fire strategy and the applicable Building Regulations and fire safety guidance. 

The location of the lintel matters because fire performance requirements are determined as part of the wider building design. A particular fire resistance period should not therefore be assumed simply because the same type of lintel has been used elsewhere on the project. 

It's also important to distinguish between the combustibility of the material and the structural fire performance of the finished component. 

Concrete being non-combustible does not, by itself, establish how a particular lintel will perform structurally when exposed to fire. 

The relevant fire performance of the specific lintel section being considered should therefore be checked against current manufacturer technical information and supporting performance evidence. 

2. What Structural Load Does the Lintel Need to Support? 

Fire resistance doesn't replace the lintel's primary structural function. 

A lintel transfers loads from above an opening into the supporting wall. The anticipated loading therefore needs to be established before an appropriate lintel can be selected. 

Depending on the construction, the loads acting on a lintel can vary considerably. This is why selecting a lintel based solely on the width of an opening isn't sufficient. 

Once the relevant loading has been established as part of the structural design, the manufacturer's published lintel load tables can be used alongside the clear span and other specification requirements to identify an appropriate lintel section. 

For fire-rated applications, both structural and fire performance requirements need to be satisfied. 

A lintel shouldn't be selected simply because it provides the required fire resistance if it doesn't also provide the necessary structural performance for the application. 

Likewise, selecting a lintel based purely on its load-bearing capacity doesn't establish that it provides the fire resistance required by the project. 

3. What Clear Span and Lintel Bearing Are Required? 

The width of the opening is another fundamental consideration, but clear span and overall lintel length aren't the same thing. 

The clear span relates to the unsupported distance across the opening. The lintel itself extends beyond the opening to provide the required end bearing onto the supporting masonry. 

This bearing enables the reactions from the lintel to be transferred into the supporting structure. 

Selecting an appropriate lintel therefore requires consideration of the relationship between: 

• Clear span  

• Overall lintel length  

• Required end bearing  

• Structural loading  

• Lintel section and load-bearing capacity  

Manufacturer load tables and technical information should be consulted rather than selecting a lintel solely by matching an overall length to an opening. 

Correct product selection also needs to be supported by appropriate installation. The surrounding construction, bearing conditions and installation of the lintel should comply with the relevant project requirements and manufacturer's guidance. 

4. How Do You Choose the Correct Concrete Lintel Section? 

Fire resistance, structural loading and span shouldn't be treated as separate specification exercises. The selected lintel section needs to satisfy the combination of requirements for the application at hand. 

Different lintel sections can have different dimensions, load-bearing capacities and fire resistance ratings. The section also needs to be appropriate for the wall construction in which it will be installed. 

For example, two openings might have the same clear span but require different lintels because of their structural loading or fire performance requirements. 

Alternatively, two lintels requiring the same fire resistance period may need different sections because of the span, loading or wall construction. 

This is why identifying a required concrete lintel fire rating is only the beginning of the specification process. 

Why Is Fire Testing Important for Concrete Lintels? 

When specifying a structural component for use in a fire-resisting construction, its performance shouldn't be assumed solely from the material from which it is manufactured. 

Relevant technical evidence provides designers and specifiers with information about how a particular product or range performs under defined conditions. 

This is especially important with lintels because performance can vary between sections. A fire rating associated with one lintel should not automatically be assumed to apply to another section or product simply because both are manufactured from concrete. 

The manufacturer's current technical documentation should therefore be used to confirm the fire resistance and structural performance applicable to the specific lintel being specified. 

Bringing Structural and Fire Performance Together 

The key principle is straightforward: 

A fire-rated lintel still needs to be specified as a structural lintel. 

Selecting an appropriate solution isn't simply a case of choosing a non-combustible material or specifying a required number of minutes. 

Instead, fire resistance + structural loading + clear span and bearing + lintel section need to be considered together. 

Bringing these requirements together provides a more appropriate basis for lintel selection and helps ensure the specified product meets both the structural and fire performance requirements identified for the project. 

Fire-Rated Concrete Lintels from Naylor 

Naylor Concrete manufactures a range of concrete lintels offering different structural capabilities and levels of fire resistance, providing options for a variety of building and project requirements. 

This means fire-rated specification isn't limited to a single product range. 

Depending on the lintel selected and the level of fire resistance required, options are available across Naylor Concrete’s lintel portfolio. 

For applications requiring enhanced fire resistance, the XtraFire™ range extends these options further, with lintels available with load-bearing fire resistance ratings of R60, R90, R120 and R240 minutes, depending on the section selected. 

For a closer look at the XtraFire™ range, including available sections, fire resistance ratings, applications and product features, read our guide to Naylor XtraFire™ Lintels. 

Whichever Naylor lintel is being considered, the performance of the specific product and section should be checked against the requirements of the project using the latest published load tables, fire performance information and technical documentation. 

This allows the required fire rating to be considered alongside structural performance rather than treating either requirement in isolation. 

Getting your Fire-Rated Lintel Specification Right 

Fire-rated lintel specification is about more than selecting a non-combustible material. 

The lintel remains a structural component, so its required performance during a fire needs to be considered alongside the loads it needs to support, the opening it needs to span, its bearing requirements and the construction in which it will be installed. 

For project-specific selection, always refer to the latest manufacturer's technical data alongside the relevant project design, fire strategy and applicable Building Regulations and fire safety guidance to ensure the specified lintel meets the required structural and fire performance. 

Need Support Selecting a Fire-Rated Concrete Lintel? 

With different sections, load capacities and fire resistance ratings available, identifying an appropriate lintel means bringing together several project requirements. 

Naylor Concrete's technical team can help you navigate our lintel range and identify an appropriate product based on your project requirements and the latest technical information. 

Whether your project can be accommodated by one of our Fire-Spec Lintels or requires the enhanced fire resistance available from our XtraFire™ range, our team can help you understand the options available. 

Planning a project with fire-rated lintel requirements? Contact our technical team for specification support or explore our latest lintel technical literature. Alternatively, use our helpful Lintel Selector to narrow down your selection.