Fire and fire protection Flashcards
a) State the primary function of passive fire protection. (2 marks)
b) Explain how passive fire protection measures contribute to limiting the spread of fire. (4
marks)
The primary function of PFP is to contain a fire and products of combustion within a compartment for a given period of time.
Passive fire protection measures are built in to the fabric of the building and require no activation. PFP materials have a low reaction to fire so do not contribute to fire load within a compartment. Sealants are used to seal imperfections where building materials meet and prevent flames, heat smoke and gasses leaving the compartment. Combustible pipe collars and HPE sealants are used to close the voids left when a plastic pipe combusts or melts/distorts containing the fire within the compartment.
Question 2
Describe the process of smouldering combustion. (4 marks)
mouldering occurs in porous materials producing a solid carbonaceous char. Smouldering has no visible flame and a lower rate of heat release than flaming combustion. Smouldering combustion can change to flaming combustion when sufficient heat has been released or airflow is increased. Smouldering combustion produces smoke and gasses that can combust in the gas phase. Smouldering combustion has weak combustion characteristics and is slow to spread and releases a low amount of heat.
Question 3
Describe the fire tetrahedron and explain the implications for extinguishing a fire. (6 marks)
The fire tetrahedron consists of four elements required to sustain a fire, the four elements are:
Oxygen, Heat, Fuel (which make up the fire triangle) and Chemical chain reaction.
Removing any of the elements (oxygen, heat and fuel) interrupts the chemical chain reaction needed to maintain a fire. Oxygen can be removed by smothering e.g. with a fire blanket. Heat can be removed/lowered by cooling with water. Fuel can be removed by cutting off a gas supply, for example
In relation to fire development, explain what is meant by the term ‘flashover’ (4 marks)
Flashover is the term used to describe the point in a fire’s development where a fire transitions from the growth phase to fully developed involving all flammable materials within a room/compartment. At the flashover stage temperature rises rapidly and materials and gasses released from combustion can ignite without direct contact with flame, flashover usually occurs at around 600 degrees C.
Question 5 In terms of product testing, assessment and certification, explain the following: a) Certification from a Third-Party Certification body. (4 marks) b) An assessment from an accredited fire test laboratory or suitable qualified fire consultant. (4 marks)
Third party certification provides evaluation of performance from a range of tests, not just a single test, these are then used to provide a scope of certification for the product/s, a scope and limitations of use. Tests are carried out by a certified ukas laboratory. Third party certification requires ongoing inspection of products and manufacturing process to ensure that the products tested continue to have the same characteristics as that tested. Manufacturers have to declare changes to products and provide traceability in case of problems and undertake product verification at predetermined intervals.
An assessment from an accredited fire test laboratory or qualified consultant provides a similar level of evaluation of a products performance to third party testing without the ongoing quality control aspects of third party certification.
Question 6 Good housekeeping is essential to maintain the fire protection provisions. Describe the steps that building managers can take to ensure that provisions are maintained. (4 marks)
To ensure that fire protection provisions are maintained building managers can:
Regularly inspect fire protection systems, signage and fire safety provisions and rectify any issues promptly. Ensure all signage, exits and firefighting equipment are free from obstructions.
Maintain/inspect/test fire protection systems, test smoke alarms, dampers, sprinklers, fire doors and emergency lighting.
Hold regular fire drills.
Maintain compartmentation should a contractor introduce new penetrations
Re evaluate the fire strategy if the building has a change of use.
Question 7 Explain how signage can be used to improve fire safety in a building. (4 marks)
Signage improves fire safety by providing information to building users, these include:
Fire escape route signs that show unfamiliar users of a building the route to exit in the event of a fire. Escape equipment signs that show how to use equipment such as fire exit door device.
Assembly point signs identify a safe point of assembly that allows wardens to account for people that may still be in the building
Prohibition signs alert users to hazards and prevent poor/risky actions being taken that can cause a fire.
Firefighting equipment signs that identify the location of portable extinguishers and hoses.
Warning signs to identify nearby dangers.
Mandatory Notices which can be a number of signs.
Wayfinding signage to assist firefighters to find a location/floor within a building and designed to be seen in poor light
wo different types of sprinkler system are wet pipe and dry pipe.
Wet pipe sprinkler systems are used/required in multi storey buildings and for life safety as well as building protection. Wet pipe sprinkler systems are used where ther is no risk of freezing.
Dry pipe sprinkler systems are used in buildings where freezing conditions may be an issue. Such buildings include unheated warehouses and any building or area exposed to freezing conditions. The pipes are filled with air under pressure and only filled with water when a control valve is activated.
