Lawrence Webster Forrest (LWF), Fire Engineering and Fire Risk Management Consultants
Lawrence Webster Forrest (LWF), Fire Engineering and Fire Risk Management Consultants



Navigation

Client login
Forgotten password
Follow us on Twitter Follow us on Facebook Subscribe to our blog

Lawrence Webster Forrest
Legion House
Lower Road
Kenley
Surrey
CR8 5NH

Tel: +44 (0)20 8668 8663 Fax: +44 (0)20 8668 8583
E-mail: fire@lwf.co.uk

Types of Fire precautions, their use as Compensation Features

Fire precautions are often categorised into two groups, active and passive.  A fire safety design will rarely rely on only one or the other categories, usually a combination of fire precautions will be necessary to achieve a safe design.

Active Fire Precautions:

Active fire precautions are those installations that usually monitor for the presence of a fire or smoke /or interact with a fire when it occurs.  The most common example of active fire precautions is AFD (Automatic Fire Detection).  This installation is constantly reviewing the condition in the building and effectively reporting back a 'no fire' / 'fire' condition.  Similarly, suppression systems, such as sprinklers, monitor the conditions, should a fire occur, the extinguishing media will be used to control / extinguish the fire.

Passive Fire Precautions:

In contrast to active systems, passive fire precautions, typically lie dormant until a fire starts and then they stay in that condition.  A common example of a passive fire precaution is compartmentation, i.e. fire walls.  A wall is constructed using appropriate materials, with part of its purpose to prevent fire spread from one area to another, usually for a specified time.  The wall does not act or monitor the fire condition and does not normally change during the fire condition.

The examples above a very simplistic.  For example there are some precautions that act in a passive manner until they are heated, then their properties alter to achieve the desired objective.

Which precautions to choose?

As previously discussed, it is unlikely that a safe design will be achieved via one category of precautions, for example a building fully compartmentalised is unlikely to be safe without any automatic fire detection and vice versa.

There is rarely a clear cut right or wrong answer in terms of what precautions to adopt, however, as with most projects, costs will be an important factor.  It may be possible to specify systems that achieve life safety compliance based on an optimal cost basis.  However, pure costing is often more complicated, with some precautions, such as a fire wall only really attracting a 'capital cost', whereby once the precaution is built, it will require little in terms of maintenance / testing and is unlikely to require updating or modification.  However, active systems, by virtue of their very nature will require testing, servicing and maintenance and are likely to have a lifespan in which time they may need to be replaced.

Code Compliance / Compensation Features:

Understanding the types of fire precautions available will enable alterations to be made to code compliant solutions.  For example, should fire compartmentation (passive precautions) be required by codes of practice, but deemed prohibitive to the design, active precautions could be offered as a compensation feature.  Compartmentation is usually required to protect escape routes, thus reducing the time occupants spend in a potentially dangerous environment.  The use of comprehensive AFD, ensuring that occupants receive early warning of a fire, will also ensure persons spend a reduced time in the same environment.  This example highlights that two very different fire precautions can achieve the same goal.

It is noted that the example provided is again, very simplistic, it is the understanding of the approach to selecting fire precautions that is important.  Fire Engineers must ensure they understand the functional objectives of the code, which form the benchmark for life safety.  This coupled with the project objectives will ensure that the fire safety installations compliment the design rather that suppress it.

We very much look forward to hearing from you and helping you select the optimal fire safety measures for your individual needs.

If you would like to know more – or would like to arrange an appointment with one of our senior fire safety advisers – simply call Peter Gyere on 020 8668 8663.

Subscribe to our fire safety blogs

Bulletins
Email Format
* indicates required

FIRE SAFETY BLOGS

  • Fire Engineering Design and Risk Assessment - Firefighting & External Water Supplies - Part 22

    In LWFs fire engineering blog series for Architects and others involved in building design, we have been looking at the subject of firefighting. In part 21, the issue of whether a building needs to supply a source of water for the Fire Service to use upon attending a fire was discussed. In part 22, we continue looking at the regulations dealing with water hydrants.In the UK, BS 5306:1 was published in 1976 (and withdrawn...

    Read more...

  • Fire Safety for Healthcare Premises - Access & Facilities for the Fire Service - Part 56

    In LWF’s blog series for healthcare professionals, the aim is to give information on best practice of fire safety in hospitals and other healthcare premises. In part 55 of this series, we began looking at the importance of access by road for the Fire Service and which entrances should be used for their access. In part 56, LWF will continue looking at those measures which should be taken to ensure the Fire Service has access...

    Read more...

  • Facilities Management & Fire Safety - Fire Safety Objectives - Part 3

    In LWFs blog series for those who work in Facilities Management, or who have an interest in or responsibility for fire safety, we have been looking at property protection and the insurer. In part 2, it was ascertained that while there is a legal requirement for buildings to be fire safe in order to ensure the safe evacuation of the building occupants, there is no legal requirement for precautions which are designed for the protection...

    Read more...

  • Fire Engineering Design and Risk Assessment - Firefighting & External Water Supplies - Part 21

    In LWF’s fire engineering blog series for Architects and others involved in building design we have been looking at firefighting. In part 20, an outline of how the water carried by a fire engine is used with the hoses to provide a limited time supply of water to fight a fire. In part 21, we continue from that point.As a fire engine can only carry a limited amount of water, a large fire will...

    Read more...

  • Fire Safety for Healthcare Premises - Access & Facilities for the Fire Service - Part 55

    In LWFs blog series for healthcare professionals, the aim is to give information on best practice of fire safety in hospitals and other healthcare premises. In part 54 of this series, we finished our discussion on ventilation for car parks as part of healthcare buildings. In part 55, we move on to look at the provision of access and facilities for the Fire Service both in terms of general requirements and those particular to healthcare...

    Read more...

Case Studies

The Wohl Neuroscience Institute - Fire Safety, Strategy & Engineering
Key Facts: Client: King’s Clinical Neuroscience Institute Project Manager: MACE Ltd Designers: Devereux Architects/Allies and Morrison Approximate Size: 7,400m2 Description of the Project:...

Read more..

General Bulletins

Fire - The External Risk
When we consider fire safety, our focus is normally from within, what can we do to prevent the occurrence of fire and how we can limit its damage.  Whilst this is the correct stance to take, we m...

Read more..

Technical Bulletins

Evacuation Modelling - Factor in Human Behaviour
Evacuation of buildings can be analyzed in different ways. Approved Document B (ADB) which provides guidance on meeting the requirements of the England and Wales Building Regulations with regard to fi...

Read more..

Site map | Web development London