Passive Fire Protection in commercial buildings is vital for FM's to contain fires to the point of origin and prevent flames and smoke from spreading, writes Richard Nichols.
13 November 2015 | By Richard Nichols
Concrete Fire Protection, or Passive Fire Protection (PFP), as it's known in FM, is an integral component of structural fire protection in a building.
PFP systems do not seek to extinguish a blaze. Instead their role is to contain the fire at its point of origin and prevent flames and smoke from spreading throughout the building, through the use of fire-resistant walls, floors, doors and stopping materials. This is achieved through compartmentalisation, which means that every room or section of the building is effectively a sealed unit. In many instances the blaze will burn itself out within the contained unit, without spreading to other areas of the building.
Passive fire protection products and systems are named as such because they are considered to be always 'switched on' and do not require activating in order to fulfill their role. In contrast, active fire protection devices require some form of response and/or motion in order to work. A further distinction being that active fire protection systems are added to the building after construction, as opposed to being part of the building itself.
All buildings with segregated zones are divided by fire partitions. Where services pass through these partitions the connection between the service and the construction materials is infilled with fire stopping products rated equal to the fire resistance of the partition, as set out in the Fire Reform Act 2005. This passive fire stopping is a critical element of a building's fire prevention strategy and warrants careful design consideration.
Stopping the spread
Fire stopping is made up of three methods: insulated panels, which separate one fire zone from another; fire collars, which wrap around a pipe and expand when fire occurs to fill the hole when a fire penetrates; and infill mastic, which fills the void when a fire breaks out, and stops it spreading from one void to another. These techniques must be designed by a competent contractor and documented and signed off as part of the fire strategy for the particular building.
Good practice denotes that all fire penetrations have a unique numbering system, which specifies when it was installed, the unique reference number, the material used and whether it is 90-minute or 60-minute stopping material. These identification numbers linked to locations should be listed as part of the fire strategy. In an environment such as a hospital, this is critical as the fire stopping buys time to evacuate the building and to tackle the fire in selected zones. If there is no passive fire protection, a fire will spread through the ceiling void, which will make the whole facility go into alarm mode.
Contractors do not always provide the information on day one, and it can be overlooked at the handover stage of a project. Commonly a plethora of contractors are looking after a building, with different teams responsible for different areas. There is seldom one health and safety file that covers it all, which can make it complicated when contractors come along and do minor works, and the 'stopping', for example, maybe not resealed. If this happens, the building is
at risk of breaching its health and safety.
Operating and maintenance (O&M) manuals and/or the installed drawings often fall short of providing sufficient detail. The information can be out of date, as the fire stopping has been disturbed/removed (if it was there in the first instance) by trades during the final commissioning period.
Unfortunately, quality inspections and sign off are usually a percentage of the total installation and thus cannot be relied upon. The situation is further exacerbated by variation works post service commencement date, undertaken by the FM organisation or client, that passes though the fire stopping without remedial repairs - reducing the system's efficiency.
It is not uncommon in older buildings that through a progressive works programme and/or deterioration of the materials used, the fire stopping can no longer provide the resistance as designed. Products have a shelf life and thus require regular inspection to ensure there is no shrinkage of materials.
Photographic evidence should be taken of each fire penetration, to show the state of the fire 'stopping' at any given date. This should then be linked back to the strategy design, where it can be double checked that all is in order. Also materials can be analysed to confirm that materials used independently give greater confidence in the overall structure. This process is often overlooked, which makes compliance difficult. Any works, no matter who commissioned it, need to be managed, so that this element is controlled and signed off, every time someone penetrates a fire partition.
Whilst it cannot be stressed enough just how important passive fire protection systems are, obviously they should not be viewed as an alternative to active systems. Providing effective fire protection requires both elements working in unison.This combined approach, building occupants have the greatest chance of exiting the building safely and damage to the property will be minimised.
Richard Nichols is technical services director at G4S Facilities Management