Ductwork Fire-Prevention Systems are essential in providing fire protection and thermal and acoustic insulation for steel ductwork, and can provide up to 120 minutes of fire protection for stability, integrity, and insulation. There are four types of fire resistant ductwork: Ventilation fire ductwork: This needs to be fire rated where it passes from a fire compartment, an escape corridor or an outside area. Smoke extract fire ductwork: This is for removing smoke from the building. Non-domestic kitchen extract fire ductwork: This is sometimes called grease ducting and prevents flammable grease from catching fire when it passes through an adjacent area. Pressurisation ductwork: This restricts the penetration of smoke into critical areas of a building by ensuring the air is at a higher pressure than in adjacent areas, in particular, protected stairways, lobbies, and corridors.