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ISL Brand

ISL Therm-A-Grille | Intumescent Air Transfer Grille

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There is often a requirement for a ventilation aperture to be cut into a fire resisting compartment wall or door, as a penetration within the wall or door breaches the integrity so it is necessary to fit a suitable fire resistant intumescent ventilator unit. Therm-A-Grille provides a suitable solution for this, as applications could include vertical apertures in fire resisting doors, compartment walls. If you are looking for an intumescent grille, Therm-A-Grille offers a specially designed solution that provides a light weight intumescent ventilator core with excellent airflow characteristics and rapid activation in the event of a fire.

Consisting of two sheets, the intumescent grille has been made from steel mesh that has been coated with a graphite based intumescent material, which activates at approximately 180°C and expands to fill the ventilation holes in the grille thus providing the required fire resistance. The twin plate construction provides fire insulation performance in addition to fire integrity and the coating thickness has been optimized to ensure rapid activation, whilst maintaining a high free area and a good air flow rate of over 50% of the face area to create the ideal intumescent air transfer grille.

The intumescent air transfer grille does not require any additional mastic sealant to its perimeter and fixing should be by 2″” No. 8 steel screws at 150mm centres through the mesh forming the flange. The grille should be fitted centrally within the thickness of the fire resisting element. For stud and plaster walls or any element where a void is present, a steel sleeve should be provided to line the full depth of the aperture to it’s perimeter. Facia or louvre plates (not supplied as standard) may be fitted to the substrate surface. Apertures in fire resisting door leaves should only be formed by suitably qualified door converters to ensure that the fire integrity of the door is not compromised.

Therm-A-Grilles provide a flange for fixing and are 38mm thick to fit to any 30 minute or 60 minute fire door. The intumescent fire grille is held in position by means of 50mm No.8 size steel screws (not supplied) through the unit’s frame at 150mm centres.

The fire performance of the Therm-A-Grille intumescent air vent has been proved in tests carried out to BS 476 Part 22 1987, where a grille measuring 570 x 570mm obtained an integrity and insulation rating of 66 minutes when mounted in a fire door panel. The free area of the grille is over 50%, so the 600mm x 600mm size vent has an effective ventilation aperture of 185,000mm².

Therm-A-Grille is available in stock sizes ranging from 100 x 100mm up to 600 x 600mm, in 50mm steps, in any combination of width and height. It can also be produced to special order in any intermediate size. Please call or email Firewise at +44 (0) 1223 839 727 or [email protected] to discuss Therm-A-Grille from the intumescent vents range.

Brand: ISL

Use Case: Fire

Applications: Doors, Walls

Test Certification: Fire Tested to BS 476: Part 22: 1987

Fire Rating: 30 Minutes, 60 Minutes

Material: Steel Frame, Graphite Based Intumescent

Finish: Black

Fixing: Screw Fixed (not supplied)

Included: 1x ISL Therm-A-Grille Intumescent Air Transfer Grille

Length mm: 75mm, 85mm 115mm, 150mm 200mm, 225mm, 300mm, 350mm, 400mm, 450mm, 495mm, 600mm

Width mm: 75mm, 85mm 115mm, 150mm, 200mm, 225mm, 300mm, 350mm, 400mm, 450mm, 495mm, 600mm

Depth mm: 38mm

Date Added
ISL Therm-A-Grille Technical Data Sheet
17 October 2022
Technical Data Sheet
ISL Therm-A-Grille Fire Test Report
17 October 2022
Technical Data Sheet

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