Why dampers need an I Rating (Part 2)

By Sam Gocher
Wednesday 9th August, 20232 minute to read

We recently uploaded a blog on why Sertus feel I Rated dampers are so important in the smoke ventilation industry. This blog raised some positive discussions within the industry, and so we thought we’d make a second part, just to cover off a few extra things…

We want to draw your attention to BS EN 13501-4: 2016, and moving down to section 5.2.2, which states:

Insulation I is the ability of a component of a service installation to withstand fire exposure without the transmission of fire as a result of significant transfer of heat.

Heat transfer shall be limited so that non-exposed surfaces or any material in close proximity to that surface is not ignited. The product shall also provide a barrier to heat sufficient to protect people near to it.

Conformity to the requirements for criterion, I, is required for:

– multi-compartment smoke control ducts;
– multi-compartment smoke control dampers.

Conformity to the requirements for criterion, I is also required for powered smoke and heat ventilators outside the burning room inside the building.

As an industry, what we need to consider at all times, is that we’re creating tenable escape route conditions in a fire scenario for escapees.

So, focusing now on wall construction - 120 minute fire rated wall constructions in smoke shafts will typically be insulated, forming part of the compartmentation between the two areas. The reason this is the case is to stop heat transfer. To make sure we don’t break down compartmentation between two areas, such as the shaft or duct, along with the lobby or escape route, we therefore need to put a product into the construction which will maintain compartmentation, such as an I rated smoke control damper.

Focusing now on tenability, the reason that walls are fire rated and insulated from 30-120 minutes is to create the safest possible conditions for escapees. Therefore, the smoke control damper, or equivalent product, will need to meet the compartmentation of the wall build-up, to ensure tenable conditions can be maintained.

So to conclude, the reason why Sertus believe an I rated damper would be the best choice for your project, is purely because it meets the compartmentation values which are within a typical corridor, lobby or shaft wall construction. Basically, if you have an insulated wall, Sertus believes it’s crucial to maintain this compartmentation by installing a product of the same compartmentation performance as the wall.

Obviously this will depend on a lot of different factors within a building - as stated earlier, you may also find 30, 60, 90 or 120 minute walls depending on the building’s layout and complexity. Therefore, if you’re struggling to understand exactly what is needed in your own project, please do feel free to reach out to us, where a technical expert will be able to offer you the support you need.

Thank you for reading and if there's anything we can do to help, please do Contact Us.

Why dampers need an I Rating *PART 2*

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