FT-CW

Fire rated curtain wall

Mullion and transom curtain wall in cold-rolled galvanised steel, on a slim 45 to 60 mm face — so a fire rated bay sits in the same elevation as an unrated one, and the fire strategy does not draw itself across the facade.

E120EI30EW120

Request the catalogue Compare the three systems

Fig. 1 · FT-CW sectionSection through a glass-to-glass joint, outside at the top. The component list below finds each part on the drawing.

120min

Integrity

120min

Radiation

42min

Insulation

Steel systems made by Firetec. The frame is specified together with the glass it holds, rather than assembled from whatever is available.

A slim face is what decides whether a fire rated bay can sit in the same elevation as an unrated one. Match the sight line and the fire strategy stops drawing itself on the facade — the rated bays are not wider, not heavier-looking, and not somewhere the eye stops. That is what makes a rated screen specifiable in a building somebody has designed, rather than only in a back-of-house corridor.

Depth is where the engineering happens. The shallow end carries a modest span and the deep end a serious one, and the range in between lets a single system follow a facade from a low-rise podium to a tall atrium without changing platform. Mullion and transom construction in cold-rolled galvanised steel, with a high-performance powder coat or a stainless finish.

NABL accredited laboratory, covered by ILAC

Tested in a furnace at a NABL accredited laboratory, to IS and BS standards. A fully glazed curtain wall held a two-hour fire rating — 120 minutes of integrity, radiation below 15 kW/m² throughout, and insulation of 42 minutes — and is classified E120 / EI30 / EW120.

The plainest thing is also the strongest: at the end of the test the curtain wall was intact on both faces.

Render of an FT-CW mullion and transom junction: two glazed panes meeting at a cruciform steel intersection, with the cover caps in place on the outside face.

Exploded render of an FT-CW assembly: two rows of glazed bays with the cover caps and pressure plates lifted clear of the mullions behind them.

Nine components

What the system is made of

Select a component from the list to find it on the drawing. This is Firetec’s own section through the joint, outside at the top.

Fig. 1 · FT-CW sectionSection through a glass-to-glass joint, outside at the top. Select a component to find it on the drawing.

After the test

What a fire test looks like

Photography from the fire test.

A glazed specimen in a masonry surround after a fire test, the glass darkened and discoloured across its full area, the frame still square.

Specification

What the reports record

Every row names its source. Where the reports, the catalogue and the previous website disagree, this table prints every candidate value and flags the row rather than picking one.

Specification for Fire rated curtain wall
Classification	E120orEI30orEW120	NABL accredited laboratory
Integrity achieved	120 min	NABL accredited laboratory
Insulation achieved	42 min	NABL accredited laboratory
Radiation	Below 15 kW/m² to 120 minutes	NABL accredited laboratory
Test standards	BS 476-20:1987orBS 476-22:1987	NABL accredited laboratory
Profile face width	45–60 mm	Firetec
Profile depth	60–200 mm	Firetec
Construction	Standard mullion and transom	Firetec
Material	Cold-rolled galvanised steel	Firetec
Finish	High-performance powder coat, or a stainless finish	Firetec
Specimen at end of test	Intact on both faces	NABL accredited laboratory

E · EI · EW

Integrity, insulation and radiation are three different things

They are measured in the same test and they fail at different times. Most fire rated glazing material in this market treats them as one number with a bigger version, and reading a specification that way is how a building ends up with the wrong product in it.

Integrity

It holds the fire back.

The element stops flames and hot gases getting through to the protected side. No sustained flaming, no gap a gauge can pass through, no ignition of a cotton pad held against the unexposed face. This is the base performance: an element with no integrity has failed, whatever else it does.

Insulation

The protected side does not get hot enough to set things alight.

The unexposed face is limited to an average of 140 °C above where it started, and 180 °C at any single point. This is the one that governs whether somebody can stand next to it, and whether what is stacked against it will ignite on its own. It is also the hardest of the three to achieve on a glazed element, which is why insulation figures are so much shorter than integrity figures — and why quoting only the integrity number is misleading.

Radiation

It does not cook what is standing in front of it.

Radiated heat measured one metre from the unexposed face stays below 15 kW/m². It sits between integrity and insulation: the element gets hot, but not hot enough to ignite an escape route somebody is moving along. On a long glazed corridor this is often the performance that actually matters.

The number The number is minutes, and it is the duration for which that performance was maintained in the furnace — not a guess at how long the element lasts in a real fire. EI includes E EI includes E. An element classified EI30 has also achieved E30. The reverse is not true, and it is where most of the confusion lives: E120 says nothing at all about insulation. They fail apart The three are separate measurements from the same test, and they fail at different times. An element can hold integrity for three hours and lose insulation in twenty minutes. Both numbers are true and only quoting the first one is not.

Which is why this range is stated as E120 / EI30 / EW120. Insulation measured 42 minutes, which reaches EI30 and no further — so the EI60, EI90 and EI120 classes that appear in older catalogue material are not printed anywhere on this site. Two hours of integrity with radiation held below 15 kW/m² throughout is the result, and it is a good one.

Where it goes