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

Question 1

Describe the situations where each of the following would be used to achieve fire stopping
and give two examples of the fire stopping products that would be used:

a) penetration seals
(4 marks)
b) linear joint seals
(4 marks)

Answer 1

• Penetration seals
  Where services pass through fire separating elements and/or compartment walls or floors

Intumescent pipe collars can be used where plastic pipes penetrate a wall or floor.

Intumescent acrylic mastic can be used where a cable penetrates a wall or floor

• 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.

Examples of products

Pre formed elastomeric strips
Pre formed mineralwool strips with an acrylic capping

Question 2

One method of fire stopping is bags/pillows.

a) Describe this method of fire stopping and explain the installation process.
(4 marks)
b) Describe the circumstances when this would be an appropriate option and state why this
is the case.
(2 marks)

Answer 2

Bags/pillows or cushions are available in various sizes and shapes and are specified for use in
temporary or permanent fire-stopping situations where services such as cables pass through walls and
floors. Bags/pillows are made from non-combustible fabrics and enclose a filling material which may
incorporate an intumescent material.
Areas of Use
Bags/pillows can be used wherever services, such as cables, penetrate a fire resistant element. Since
they are easily removed, they are particularly useful where services are frequently re-routed, and can
be used as adaptable protection during construction work.
Bags/pillows must be placed into the opening(s) using the correct orientation, packing density and
overlap (staggered joints), to achieve the desired fire resistance. For wall penetrations, bags/pillows
are normally self-supporting, but large openings with few penetrating services may require a steel
retaining mesh for support on both sides of the penetration.
Usually the whole length of the bag is designed to be encapsulated within the substrate.

Question 3

Describe the factors to be considered when carrying out the installation of dampers.
(4 marks)

Answer 3

manufacturers
installation instructions should be followed; details may be different for different types of
walls or floors; securely fixed in place; access to the fire damper for maintainance

Question 4

Describe the differences between a fire damper and a smoke control damper.
(6 marks)

Answer 4

Differences Between a Fire Damper and a Smoke Control Damper:

Purpose:

Fire Damper: Designed to prevent the spread of fire through ductwork by closing when high temperatures are detected.

Smoke Control Damper: Designed to control or block the movement of smoke within a building, often as part of a smoke ventilation system.

Activation Mechanism:

Fire Damper: Typically activated by a fusible link that melts at a set temperature (e.g., 72°C), triggering closure.

Smoke Control Damper: Operated by electric or pneumatic actuators, controlled by smoke detectors or a building management system (BMS).

Function During a Fire:

Fire Damper: Closes completely to compartmentalize fire and protect escape routes.

Smoke Control Damper: May open or close selectively to channel smoke towards extraction points or away from evacuation routes.

Regulatory Requirements:

Fire Damper: Must comply with fire resistance ratings and often tested to BS EN 1366-2.

Smoke Control Damper: Must meet both air leakage and control performance standards, often tested to BS EN 12101-8.

Typical Locations:

Fire Damper: Installed in walls or floors where ductwork passes through fire-rated barriers.

Smoke Control Damper: Installed in ducts of smoke ventilation systems, stairwells, lobbies, or smoke shafts.

Maintenance and Testing:

Fire Damper: Requires periodic manual testing and inspection for operational readiness.

Smoke Control Damper: Requires functional testing as part of the smoke control system, usually integrated into the fire alarm system.