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Design considerations

It’s fair to say that specifying fire resistant glass can be a bit of a minefield. How do you meet the aesthetic requirements of your brief without compromising on fire safety? How can you be confident that you’ve selected the right product? Here, we look at some key design issues, considering when to specify fire resistant glass partitions and doors.

We all like to work in an environment that has natural daylight flooding in. Glazed partitions and doors are an excellent way of creating the ideal workplace for employee wellbeing. Since the concept of ‘frameless’ glazing was first embraced, we have been at the vanguard of cutting edge design in glass partitioning systems. We believe they should look good and deliver exceptional performance in terms of stability and acoustic privacy. Our highly skilled design teams constantly strive for improvements to our renowned product range with market-leading acoustic capability.

Using glass partitions for high quality fit-outs is a well-established practice. However, it’s not as straightforward where the specification requires fire resistant glass.

The compartmentation and protection of safe routes has typically been a job for solid walls and timber doors. However, recent advancements in glass technology have changed this. Consequently, specifiers increasingly look to incorporate the openness of glass into their fire resistant requirements.

Our Technishield range of doors and glass partitioning systems offers complete coverage. From glass doors providing 30 minutes integrity only fire resistance to glass partitions offering up to 2 hours integrity and insulation, we’ve got it covered.

fire resistant glass at SLCT
Considerations for full height fire rated glass partitions

But of course, it’s not that simple. Recent tragic events have brought the use of fire resistant construction products sharply into focus. Their use needs to be carefully and responsibly managed. It is not just a case of replacing an area of solid wall construction with fire resistant glass. A solid wall will typically span between structural floors, providing a complete fire barrier.

Glazing, however, typically spans between the false ceiling and the finished floor; often a raised access floor. It will also not necessarily form the entirety of the length of the compartmentation. A typical fire resistant glass partition spans between two areas of solid wall.

This is where the use of fire rated glass needs to be carefully managed. The zones above and below the glazing must be independently fire rated to at least an equivalent standard. The interfaces between the zones of protection must satisfy the requirements of the respective system fire certifications.

Also consider the weight of the glazing. A glass screen 3 metres high offering 60 minutes integrity and insulation could weigh more than 200kg per linear metre. The floor construction must be capable of supporting that kind of load under fire conditions. The same is true with vertical abutments. The wall construction must be compatible with the tested nature of the fire rated glazing system.

We work closely with glass manufacturers to ensure we use the correct glass product in every instance. Architects and designers can specify our Technishield range with confidence, complying with the requirements of Approved Document B (AD B).

Incorporating fire resistant glass doors

So much for AD B. But what about Approved Document M (AD M)? Yes, it is possible to incorporate fire rated glass doors into large areas of fire resistant glazing. However, their primary function is to act as a fire barrier when required to do so. That means that they must be capable of being closed, without manual intervention, when there is a fire.

They are still required to satisfy AD M wherever they are intended to offer freedom of movement around the building. This is particularly important for fire rated glass doors on heavy circulation routes within compartment walls, or partitions providing compartmentation.

Self-closing devices

We install glazed fire doors with a self-closing device like an overhead closer because they are heavy. They can, therefore, require an operating force to open them in excess of the acceptable level stipulated in AD M. Many sprung door closing devices will rightly claim that they can comply with AD M. However, this is only possible under certain conditions. Their use on heavy glazed fire doors will fall outside of those conditions.

Ambient conditions sometimes hinder the needs of a fire door to self-close. For example, there may be a significant disparity in air flow on opposite sides of the door. This can often require a closing device to increase its closing force to ensure the door shuts securely. This further hampers the operability of the door in normal use.

AD M is very clear on the subject. In stating its preference for there to be no doors at all, it recognises the necessity of doors in many cases. With an emphasis on fire doors, it recommends that they are held open and released only in the event of a fire. Alternatively, it suggests providing an automated means of assisted opening. Consider this as early as possible in the design process. It’s easier to budget for AD M compliance at the start of the process, rather than at the end.

Fire rated doors on circulation routes often require some form of access control. Again, this needs careful consideration, as not all systems are compatible with fire rated glass doors.

Specify with confidence

There’s no denying that this is a very complex subject, but specifying fire resistant glass needn’t fill you with dread. At Optima, we go to great lengths to ensure we understand the issues and can offer solutions to them. So let us help you to specify and deliver with confidence. Contact our technical team and feel assured that your chosen products not only look impressive but also comply with all necessary fire safety performance criteria.

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