Option 3: Fire stopping and penetration seals, cavity barriers, ductwork and dampers and the building envelope

Question 1

a) Explain the purpose of fire stopping. (3 marks)
b) State three situations where fire stopping would be required. (3 marks)

Answer 1

To maintain compartmentation. 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 have at least the same fire resistance as the separating elements into which they are installed.

B

• Penetration seals
  Where services pass through fire separating elements and/or compartment walls or floors
• Linear joint seals
  Between fire resisting elements of building construction, for example the junction between a
  wall and a floor.
  Consideration may also be needed if movement accommodation is required.
• Small cavity barriers
  At imperfections in the building process, for example at the junctions of walls/floors with
  cladding/curtain walling, between separating walls and a roof, over and between leaves of
  masonry walls
• Large cavity barriers
  The subdivision of large roof spaces and under floor voids
• Open state cavity barriers
  Between elements of a building, for example rain screen cladding, where the cavity barrier is
  open in the cold state to allow for the free movement of air for ventilation. In a fire situation,
  the cavity barrier closes preventing the spread of fire.

Question 2

a) State three fire stopping/sealing systems that could be used in relation to fire barriers
including cavity barriers.
(3 marks)
b) Describe three fire stopping/sealing systems that could be used in relation to Movement
joints.

Answer 2

• Coated batts
• Mineral wool curtains
• Woven textiles
• Ridged boards

B

Intumescent Sealants

Description: Intumescent sealants expand when exposed to heat, sealing gaps in movement joints to prevent fire and smoke passage.
Use: Applied in linear joints and small gaps where flexibility is required.
Advantages: Provides effective fire resistance while allowing minor structural movement.

Fire-Resistant Expansion Joints

Description: Pre-formed fire-resistant joint strips made of materials like mineral wool, graphite, or silicone-based compounds/elastomeric.
Use: Installed in larger movement joints where significant expansion and contraction occur.
Advantages: Offers both fire protection and high movement capability.

Fire-Rated Foam Systems

Description: Special fire-rated polyurethane or silicone-based foams that expand and harden to fill movement joints.
Use: Used in irregular or wider gaps where standard sealants may not be effective.
Advantages: Provides flexibility, sound insulation, and fire resistance.

Question 3

a) Explain the purpose of pipe closures (2 marks)
b) Describe how pipe closure systems work and give two examples of such systems. (6
marks)

Answer 3

Pipe closures are designed to preserve the integrity of a fire resistant compartment where various
plastic pipes, plastic trunking, steel pipes with insulation or plastic pipes with insulation pass through
floors or walls.
Unlike metal or cable service penetrations, these service penetrations soften and collapse under
heating, therefore some means of preventing the passage of fire is required. This is achieved by
compressing the cross-section of the softened pipe or trunking. High pressure exerting graphite is used, this expands when exposed to the heat of a fire.

Examples are pipe collars, pipe wraps, intumescent insulated pipe sleeves and HPE sealants

Question 4

a) Explain the purpose of a fire damper. (1 marks)
b) Describe the operation of multi-blade fire dampers. (3 marks)

Answer 4

The purpose of a fire damper is to maintain compartmentation where ductwork passes a compartment wall or floor by preventing the passage of fire and combustion products.
Multi-blade fire dampers are constructed with a number of linked pivoting blades contained within a
frame. The blades are released from their open position by means of a thermal release mechanism
normally rated at 72°C ± 4°C.
When the release mechanism is activated the blades pivot and move to close the airway to prevent
the passage of fire. Test results or assessments are required for plane of installation (e.g. horizontal
and vertical) and the method of installation.

Question 5

a) State three purposes of cladding. (3 marks)
b) Explain how cladding can affect external fire spread. (3 marks)

Answer 5

Protection – It acts as a shield against external elements such as rain, wind, UV radiation, and temperature changes, helping to prevent structural deterioration.

Aesthetic Enhancement – Cladding improves the visual appeal of a building by providing a range of textures, colors, and styles to suit different architectural designs.

Thermal and Sound Insulation – Certain cladding materials enhance insulation, reducing heat loss or gain and minimizing external noise penetration.

B

Poorly fitted cladding provides a route for vertical fire spread within the cavities between inner and outer leaves. This spread can also be unseen. Cladding materials and insulation added for insulation values without considering fire, often retro-fitted, are a considerable risk for fire spread