What needs to be considered in the construction process to ensure adequate passive fire protection in buildings?
Passive fire protection; it is really not that exciting a term and I am sometimes envious of our colleagues in the active area, as the word ‘active’ makes ‘active fire protection’ somehow sound much more dynamic and exciting. And yet, passive fire protection is critically important in providing fire safety in buildings.
What needs to be considered in the construction process to ensure adequate passive for protection in buildings? One message that needs to be stressed is that passive fire protection is not something that can be ‘bolted-on’ at the end or half way through a project; it needs to be considered from when the development is still in concept form right through all the stages until maintenance of the completed building.
What is Passive Fire Protection?
Passive fire protection makes buildings safe when fire occurs; by ensuring the building does not collapse and by subdividing it to prevent the spread of smoke and fire. Passive fire protection comprises those elements, for example fire doors, walls, protection to the structural frame and protection to services passing through walls/floors, which are specifically engineered to fulfil this function. In some cases, this may be in addition to their normal function in a building.
It is vital that all passive fire protection measures are correctly designed, specified and installed if the building is to behave as expected should fire break out. By their nature they are ‘passive’ until there is a fire and only then will their fire performance in-situ be demonstrated. The occupants of a building will attend to their daily business; visitors will shop, be entertained, or enjoy recreation without any knowledge of the passive fire protection measures that will protect them in fire. So it is essential that these measures will work if an emergency occurs.
What Defines the Passive Fire Protection that is used in a Building?
Building Regulations usually deal with life safety standards for the design and construction of domestic, commercial, residential and industrial buildings. The provisions are often expanded in Statutory Guidance Documents (for example, Approved Document B in England and Wales) which give detailed guidance on how to meet the Building Regulations. Depending on local or national regulations, alternative ways to satisfy Building Regulations can use less prescriptive methods, including the engineered approaches embodied in, for example, ISO/TR 13387-1, BS 9999 and DD 7974, which are increasingly used as designers seek more freedom to innovate in building design.
Building Regulations will also usually only consider life safety. Other issues such as; protecting the building fabric/contents, business interruption, heritage, functionality and environmental protection may also be applicable. These also need to be considered in the fire strategy at the design stage and therefore impact on the need for increased passive fire protection or other measures.
How are Passive Fire Protection Products Evaluated?
The performance of passive fire protection products is ‘proven’ by their undergoing fire tests in specialist independent laboratories. The scope of the performance may be further enhanced by assessments (engineering judgements) undertaken by the fire laboratories or fire consultants.
However, the best guarantee of the quality of passive fire protection products is by third-party product certification, which links the tested/assessed product to the actual factory production and ensures traceability from raw material to finished product. It is strongly recommended that wherever possible, passive fire protection products should be supported by third-party certification and that clients/developers, main contractors and specifiers should always require third-party certification.
While legislation does not generally cover installation of passive fire protection products, installers have an obligation to install products correctly so that they will work as intended in the building. The best way of guaranteeing this is to use a third-party certificated installer whose skills, training and competence will have been validated by a third-party organisation backed up by random inspection of completed works. The Association for Specialist Fire Protection always recommends the use of third-party certificated installers and this is a mandatory requirement for any contractor member of the association.
The procurement strategy for the building may be designer-led, which sees the client/developer appoint an architect in the early stages of the project to seek planning consent for the building and produce designs and specifications according to the regulations and the client needs.
Alternatively, the project may involve Management Contracting. This differs from the traditional designer-led process, in that the management contractor/construction manager, who takes responsibility for delivering the construction of the project, is brought into the process at a much earlier stage, as are other key specialists. This type of procurement is most commonly used for complex or fast track projects where risks tend to be high.
Increasingly, the option of design and build is the preferred approach. Under this option a client will offer the basic concept, or a brief, to construction companies that will undertake to deliver the completed building largely to performance-based requirements. This system requires the contractor responsible for designing all aspects of the project to meet the performance needs of the client within the agreed budget. It can also give rise to some of the worst examples of installation of different types of passive fire protection because the installations are not designed appropriately in advance and the fire stopping contractor is often required to design something ‘on the hoof’. Budget and time constraints often mean that the resulting installation is not covered by appropriate fire test evidence and may not work satisfactorily.
The ultimate responsibility for fire safety of the building as-constructed rests with the client and/or developer and consequently it is essential that the basic fire strategy for any project should be agreed as early as possible in the design process so that the activities of all sectors involved in the process may be co-ordinated. Any safety objectives that go beyond life safety must be agreed at an early stage. ‘Best practice’ in passive fire protection will be achieved by setting out the requirements at the start of the project.
The building designer has a range of techniques available to protect occupants against fire and smoke. These include:
- Passive fire protection measures to physically limit the spread and effects of the fire, protect escape routes against heat and smoke and stop the building collapsing.
- Detection and alarm systems, to quickly alert occupants and ensure a rapid response.
- Smoke control systems to limit the spread of smoke, or contain it so that it does not hinder escape.
- Suppression systems, such as sprinklers or water mist, to either put the fire out or limit its growth.
- Use of passive and active fire protection measures to ‘protect in place’, for example, where occupants are immobile or by the use of refuges.
- Facilities designed into the building to assist the fire service in its efforts to extinguish or control the fire and to rescue trapped occupants.
The design specification will be based on the agreed fire strategy. For the different elements of the building, this specification may show a required performance, or may identify a specific proprietary product. The design needs to specify passive fire protection systems that can actually be constructed properly within the building. It is not sufficient merely to require a fire resisting wall that might contain a mixture of ducts, dampers, cable trays and pipes without some thought as the design of the division, the supports for the services and justifying the fire performance that is required.
Consequently, it is important that the design specification is adhered to during the procurement and construction of the building, despite pressures of time, money and availability. It is strongly recommended that only a limited and controlled number of parties be authorised to change the passive fire protection specification and that any changes be carefully monitored and recorded.
It should be noted that the design considerations outlined above apply just as much to buildings designed using fire engineering techniques as to those designed using conventional code complaint approaches; perhaps even more so, as the engineered solution might rely on less passive fire protection, which is why ensuring it is correctly designed, specified and installed is even more important.
- Main contractors commissioning passive fire protection.
The main contractor is responsible for co-ordinating all the work on the project. In relation to passive fire protection, this includes:
- Selecting specialist subcontractors for passive fire protection installation:
As the objective of passive fire protection material installation is to protect the life of the building occupants, the work should not be allocated to contractors that cannot prove their competency to install such products. Main Contractors should select sub-contractors that carry third-party certification wherever possible.
- Programming activities:
It is crucially important that the installation of passive fire protection, including the correct and timely scheduling of all the sub-contractor work is included as part of the main work programme. This will ensure that the passive fire protection measures are installed in the correct order, preventing unnecessary rework later which, in turn, may lead to an unsatisfactory ad-hoc solution being applied.
Subcontractors Installing Passive Fire Protection
Specialist sub-contractors will be identified for many sections of the work in a building and passive fire protection should be one of the specialist trades with which separate contracts are placed. By placing this work with specialists, and with careful programming, it is much more likely that the correct materials will be specified and installed, avoiding damage and rework. The Association for Specialist Fire Protection strongly recommends that all contractors installing passive fire protection hold third-party certification for the products they install.
Inspection of completed works either by the installer, or preferably the main contractor, or best of all a third-party is recommended to ensure adequate installation of passive fire protection. Irrespective of any Building Control inspection, a specific project-based systematic approach involving the actual installer, his/her supervisor, the main contractor and an inspection agency (which may be a third-party certification body) is essential to ensure passive fire protection is installed correctly before other parts of the building are constructed and fit-out takes place. Attempting to inspect and remedy deficient passive fire protection at a late stage is often impossible and/or time consuming, since passive fire protection is often hidden or inaccessible once the building is complete.
When the construction programme is completed the main contractor must hand over to the client/occupier the relevant fire safety information, including certificates of conformity from passive fire protection subcontractors. Such information is required to be able to not only operate and maintain the building appropriately, but to be available for any fire risk assessor who is undertaking a fire risk assessment under applicable legislation.
Information on installed passive fire protection will also need to be included in the building’s fire safety manual, which should be compiled by the designer for the occupier.
Most passive fire protection products are robust in nature and require only limited maintenance during their life, which can often be the life of the building. However, there are some exceptions and some products, for example, fire doors, fire/smoke dampers and some fire resisting ducts that require inspection/maintenance/cleaning on a regular basis. Provision must be made for this in the building’s maintenance programme.
Inspection of those parts of passive fire protection that are not in plain view, for example, fire-stopping of services above suspended ceilings, is also vital to ensure that completed passive fire protection has not been breached by follow on trades that have not made-good after their work. It is imperative that any breaches in compartmentation – however caused – are made-good as soon as possible. Care must be taken in selecting an appropriately rated repair solution that is compatible with the original installation.
Facilities managers have a key role to play in the management of breaches in passive fire protection. They are often empowered to plan and supervise the installation of new services on behalf of building owners and occupiers and yet also to fulfil duties in respect of fire safety compliance. The facilities manager must use care in the planning and control of new works in order to have minimal impact on the passive fire protection measures in the building. By specifying third-party certificated contractors to undertake maintenance work, the facilities manager can be assured that works undertaken will use appropriate materials which will be installed correctly.
The correct installation of high quality passive fire protection products is essential to achieving fire safety in buildings. Passive fire protection needs to be considered from project inception through to maintenance of the completed building; it should not be added as a ‘bolt-on’ after or during the project. All the players in the construction process have a role to play to ensure that passive fire protection is designed, commissioned and installed correctly.
The Association for Specialists Fire Protection has just revised its Guide to Ensuring Best Practice for passive fire protection in buildings that elaborates on the themes included in this article. The ASFP Guide contains everything you need to know about the installation specification commissioning and purchasing of passive fire protection. It will be launched at the FIREX International exhibition in ExCel, London from the 17th to the 19th June.
For further information, go to www.asfp.org.uk