Why it's important for dampers to have an I Rating

In this blog, Sertus are going to tell you why dampers NEED to have an I Rating!

Since launching our industry defining EIS 120 rated Shaft Natural Damper earlier this year, we’ve been receiving a lot of questions about the‘I’ in ‘EIS’. You’ll see most dampers on the market have an ‘ES’ rating, but the I is missing. So what does it stand for, and why’s it so important? Read on to find out.

Let’s start with what EIS actually stands for. E stands for Integrity, the S stands for Smoke Leakage, but that special I rating in the middle stands for Insulation. The ‘120’ which comes after EIS tells us that it’s efficient for up to 120 minutes during a fire scenario. So there will be a full 120 minutes where the damper functions fully and keeps escaping building occupants safe, which is obviously a very long time for occupants to evacuate.

More standard ES rated dampers on the market have their integrity & smoke ratings for 120 minutes, but what’s the point of having an insulation rating of 120 minutes? Well, there are a whole host of reasons. To put it plainly, this means that both sides of the damper are reinforced, so in a fire scenario, heat won’t be radiating through the damper from the smoke shaft and causing the people escaping burns and hazards. Without the I rating, the face of dampers can heat up very quickly and become a huge issue in what’s already an emergency situation.

Not just that, but if heat’s travelling through a smoke shaft as part of a smoke ventilation system, the ES rated dampers connected to that shaft can reach temperatures of 1000 degrees celsius. So if the front face of the damper is getting extremely hot, it can cause other parts of the building to combust, making the fire scenario much less tenable. For example, if someone could see how hot a damper is, they might retreat instead of continuing with the evacuation process.

With an EIS rated damper however, heat levels in the same 120 minute time frame are much more likely to reach temperatures of around 200 degrees, a fifth of the level of a damper without the I rating.

Of course people will make arguments against this I rating. They might suggest you don’t need an EIS rated damper to pass legislation. Currently, ES rated dampers meet compliance with BS EN 12101-8, so do you absolutely need your damper to be EIS rated? No, but the question here is why would you take the risk of not having them in your building? The added protection and safety the I rating offers occupants is paramount in a fire scenario.

The I rating isn’t only crucial for human life either. As mentioned previously, without the integrity rating, fires can be started on non-fire floors from the front face of the damper heating up. This makes it much less likely that the building will be occupiable again any time soon. If fires break out on each floor during a fire, the safety of your building will be compromised, whereas if the majority of damage is kept on just the fire floor and within the shaft, the building is much more likely to be recovered quicker.

One final point - fire and smoke is full of toxic gases, as explained in the video I’ve linked below. If these are able to leak out of the smoke shaft onto other floors, the threat to human life would be inevitable.

Hopefully you’re now more aware of the importance of having an I rating. If you're interested in seeing our EIS rated dampers, visit our product page here.