A beginner’s guide to passive fire protection

What is passive fire protection?

Passive fire protection (PFP), also known as Built Fire Protection, is an important component of any fire safety strategy. It plays a vital, and increasingly significant, role in safeguarding people, as well as limiting damage to buildings and their contents from fire and smoke.

How does passive fire protection work? 

Passive fire protection works by:

• Using fire-resistant walls and floors to limit the spread of fire, heat, and smoke by containing it in a single compartment in its area of origin
• Protecting escape routes and providing vital escape time for occupants
• Protecting a building’s critical structural members
• Protecting a building’s assets

Passive fire protection works in conjunction with active fire prevention, such as sprinkler systems, suppression systems and extinguishers, and fire safety education of building occupants.

Whose responsibility is passive fire protection? 

In the UK, passive fire protection must meet Building Regulations that ensure people can escape safely from a building that will itself not collapse in the event of fire.

Legislation places responsibility on building owners, managers, occupiers, and designers, to carry out regular fire risk assessments, which should include evaluation of the PFP provided.

Experts advise that the original building specification should incorporate a clear fire protection strategy, including the installation of certified passive fire components.  The number of people who then have the authority to alter the specification should be limited to guard against compromising fire protection. A competent third party should be asked to revise the fire protection strategy if a large number of changes are made.

Firestopping

Firestopping best practice should always be followed from the start of any building design and its construction, as explained here in our nine-step guide to firestopping in new buildings. It is imperative that any gaps in new installations from refurbishments also have an appropriate firestop in place, as building fire protection systems could be compromised if not carried out.

The national standard for electrical installations, BS 7671 requires the installer wiring systems are properly sealed to provide an efficient firestop. The responsibility depends on the size of the projects. For small-scale projects, the electrical installer might be the only person involved and so the responsibility is on them. Larger projects might involve a specialist contractor, rather than the main contractor.

Fire Protection Surveys

A Fire Protection Survey takes the findings of a Fire Risk Assessment to and develops a plan of works required throughout the property, protecting residents or employees in a building by removing potential hazards, making the escape routes clearer and proving equipment where needed, e.g. fire hoses and extinguishers. Particular attention should be paid to the safety of children, elderly and the physically challenged or impaired.

The owner of the building usually performs the Fire Protection Survey. However, it’s often the case that the work is given to a trained employee or an accredited third-party.

Passive Fire Protection products

The demands placed on passive fire protection have become increasingly complex in recent years, partly because of pressures to improve thermal insulation and reduce energy costs.

PFP products that are installed in a building to improve its fire safety include:

• Fire doors
• Fire-resisting walls, floors, ceilings, and ducts
• Firestopping and fire protection for structural members
• Fire-resistant epoxy coatings that can be spray applied
• PFP sheet
• Fire-protective boxes or wardrobes
• Protection for vital equipment such as first-aid boxes, oil or gas tanks, or other volatile sites to prevent the risk of explosion.

And also, as supplied by the The Association for Specialist Fire Protection (ASFP):

• Fire protection to the structural frame of the building
• Fire-resisting doors and fire door furniture
• Fire shutters
• Compartment walls and floors
• Fire-resisting walls and partitions
• Suspended ceilings
• Fire-resisting glazing
• Fire doors and hardware
• Industrial fire shutters and curtains
• Fire fighting shafts and stairwells
• Fire-resisting dampers (mechanical or intumescent) used in horizontal or vertical air distribution ducts
• Fire-resisting ductwork
• Fire-resisting service ducts and shafts
• Linear gap seals
• Penetration seals for pipes, cables and other services
• Cavity barriers
• Fire-resisting air transfer grilles (mechanical or intumescent)
• The building envelope, e.g. fire-resisting external walls, curtain walls etc.
• Reaction to fire coatings
• Hydrocarbon structural fire protection system

Passive fire protection systems may be part of the fabric of a building, or added after it is constructed. PFP products should be fit for purpose and properly maintained. They must have been tested, assessed, and certified by third party certification, to independently verify the competency and quality of the workmanship of companies manufacturing, installing, and maintaining them.

Fire doors

A fire door is a door with a fire-resistance or fire-protection rating. It is used to reduce the spread of fire or smoke between compartments, and to give occupants enough time to enable safe escape from a building.

Find out more with our beginners guide to fire doors.

Fire dampers

Fire and smoke dampers are used in heating, ventilation, and air conditioning ducts to prevent the spread of fire inside the ductwork, closing automatically if the temperature rises. They can also be linked to fire alarm systems.

Firewalls

A firewall is a fireproof barrier used to prevent the spread of fire between or through buildings or structures.

Coatings

Spray-applied epoxy intumescent and subliming coatings are the most frequently used, although cementitious materials were extensively used in the past. Other available types of PFP coatings include phenolic foam, glass fibre, and elastomer rubber.

Epoxy intumescent and subliming materials begin to degrade at temperatures above 80 degrees C, limiting their use on very hot surfaces. However, new dual layer systems are now available using phenolic foam bonded directly to the hot surface to provide an insulating layer, with a second layer of material bonded to it.

• e.g. fire doors, firestopping, intumescent coatings, intumescent material, etc.

You can find more guidance and information about passive fire protection from the Association for Specialist Fire Protection (ASFP).

Why is accreditation important for the products used?

Independent, third-party accredited products will give the user a vital assurance that key standards are being met. Moreover, using an accredited fire protection company also guarantees that installing these products will be done to the required standard by appropriately trained staff, and third-party inspections will take place to verify that.

A further benefit is that the user will be able to see a ‘chain of traceability’ of the documents that an accredited company is required to keep, including audits and company records. Finally, you will receive a ‘Certificate of Conformity’ on completion of the work.

The difference between passive and active fire protection

A comprehensive fire protection plan requires the implementation of both Active Fire Protection and Passive Fire Protection. While Passive Fire Protection is, as described above, a series of built-in fire resistant features, Active Fire Protection is essentially a collection of manual or automatic elements that need intervention to work – for example; fire detection and alarms, sprinklers (triggered by a sensor) and extinguishers (manual), gaseous suppression, door release mechanisms, dynamic fire shutters, etc.

The choice between active and passive systems, or a combination of the two, is influenced by the likely size and type of fire, the duration of protection required, the equipment or structure requiring protection, water availability, and the time required for evacuation.

With AFP you are taking action to out a fire. PFP stops that fire from spreading. Their combined result means that people inside a building are alerted of a fire, safely containing that fire and allowing people to suppress the fire and/or evacuate.