Intumescent Grilles – by Envirograf

These intumescent air transfer grilles have two plates which should be used either side of a ventilation opening in fire rated doors or walls.

They are available in two variations to suit situations where only one or both sides of the wall, or door, are at risk. The inner and outer plate houses the intumescent material which, in a fire, would seal up slots and louvres giving up to 73 minutes fire protection. This reaction occurs at 70 degrees Celcius.

Key Product Features:

Envirograf’s intumescent vent covers come in a wide range of sizes. Their external size should be 50mm bigger than the hole size they are being inserted into.

See the drop down menu for the full range of standard sizes.

They come in three standard colours: white, brown and stainless steel.

Special sizes and colours can be quoted on request. Please contact us on 01752 690997

You can choose between a louvred grille or a slotted grille. The slotted grilles provide more ventilation, whereas the louvres make it more invisible. Each slot gives 6cm² and louvre 3.2cm² free ventilation area.

We can also provide plain plates if necessary. Please contact us to order these.

Fire testing:

Tested to BS476 Parts 20 and 22 (1987), achieving 66 minutes on one side only.

Tested to BS476 Part 22 (1987), achieving an integrity of 73 minutes.

Tested to EN1363-1 (2000).

Application Instructions:

Two types of plates can be supplied: the /D version is for use in situations in which the risk is double-sided (that is, the opening could be vulnerable to fire from either side); and the /S version is for use in situations in which it has been clearly identified that only a single side of the opening is at risk and a plain plate is needed.

When fitting the /S version, ensure the intumescent plate is on the risk side and the plain plate is placed on the opposite side of the opening.

Both the single and double grilles are available in 15 standard sizes. Select a grille size which is at least 50mm larger than the opening size.

Grilles MUST be fitted in the orientation shown e.g. height = vertical / width = horizontal measurements.

Materials:

The intumescent material used in these grilles is made from:

• Mineral wool fibre (20-70% by weight)
• Exfoliating graphite (20-60% by weight)
• Organic binder (including adhesive binder) (5-30% by weight)

To view Envirograf’s block grilles, which provide a 90% free ventilation area, click here.

We can also provide technical advice on 01752 690997.