. Fire stopping and penetration seals, cavity barriers, ductwork and dampers and the building envelope Flashcards
Question 18 a) Explain the purpose of fire stopping. (2 marks) b) State four factors to be considered when selecting and installing fire stopping in a building. (4 marks)
Fire-stopping is used for sealing apertures and imperfections of fit, or design tolerance between fire resisting walls, floors and ceilings to restrict the passage of fire and smoke. Fire-stopping products should generally have at least the same fire resistance as the separating elements into which they are installed and contain a fire within the originating compartment for given period.
B Surrounding construction, Floor, wall, junction, floor type wall type, loadbearing if in floor
Fire resistance period
Service type, material, size, wall thickness
Does the firestopping have to cater for movement
Aperture size
Question 19 In relation to the construction and design of the building envelope, describe how the use of cladding can affect fire resistance. (4 marks)
Correct selection of materials used in cladding systems should have a reaction to fire classification of A2S1D0 unless exempted by reg 7(3) Cladding and insulation should have this reaction to fire classification.
Cladding systems should have an appropriate cavity barrier installed to prevent the spread of fire inside the leaves to prevent external spread of fire between compartments.
Poor design and installation of cladding systems can contribute to external vertical fire spread within the cavity of the cladding system, this type of spread can go undetected.
Question 20 Describe the factors to be considered when carrying out the installation of dampers. (4 marks)
The selection and installation of dampers should be carried out by competent persons.
Maintenance requirements – dampers require access for maintenance
Orientation – separate test evidence is required for vertical and horizontal use
Correct for the purpose i.e. smoke control or compartmentation
Surrounding construction- test evidence supporting the use in rigid or flexible walls or composite walls
Selection of the correct supporting system – should be installed according to manufacturer’s instructions
Should be installed in the plane of the compartment wall
Question 21 Describe the differences between a fire damper and a smoke control damper. (6 marks)
Smoke control dampers are connected to a smoke detection system and are used to remove smoke and combustion gasses in the event of a fire. The smoke detection system actuates the blade/s to the open position when smoke is detected and is in the closed position to maintain compartmentation. They do not have a thermal release mechanism and are single or multi-bladed.
Fire dampers are usually open to allow the ductwork to operate as normal in non – fire conditions. In the event of a fire, fire dampers close to maintain compartmentation. Fire dampers can be thermally activated by thermal release or thermally activated by the use of intumescent materials. Fire dampers can be of curtain, single or multi blade
