By Michael van Niekerk, CEO of ASP Fire
Inhaling just five breaths in a smoke-filled room can lead to death. It is therefore imperative for buildings to be designed to allow for safe escape and the control of fire and smoke, as a minor design flaw could potentially put people, equipment, and property at risk.
All buildings in South Africa need to comply with the requirements of the National Building Regulations and Building Standards Act, 1977 (Act No. 103 of 1977), Fire Protection, as set out in SANS 10400 Part T: 2011.
A deemed-to-satisfy fire safety solution is one where the dimensions and construction of the building, the materials used in the construction, the occupancy, and the storage of items in the building all fall within the prescriptive requirements or limitations set out in SANS 10400-T.
Any deviation from the prescriptive requirements or limitations, requires a rational design to be completed in accordance with the fire engineering methodology framework requirements of BS 7974 – Application of fire safety engineering principles to the design of buildings, supported by the published documents that form part of the BS 7974 framework. Johannesburg-based ASP Fire is a specialist in this field.
A rational design is the detailed design of fire safety and prevention mechanisms and strategies in a building to comply with the National Building Regulations, where prescriptive requirements cannot be met. This process is not elective, inasmuch as that only certain parts of the framework may be used, or that the results of the process are subjective or optional.
Rational design begins with a fire risk consultant visiting the premises, or reviewing a set of new building plans, for a comprehensive evaluation of all areas of the property — looking at all areas of fire safety and risk in detail. Sound fire engineering principles are applied to ensure that the design complies with the life, building, fire behavioural, and environmental fire safety objectives required by law.
When undertaking a rational design, the framework that is set out in the internationally recognised BS 7974 British fire safety standard is used. Many designers in South Africa do not follow this methodology, either because they do not fully understand it, or because they elect to apply only certain elements of the framework — completely oblivious that they are putting people’s lives and assets at risk.
Often, consultants copy and paste from previous rational design reports, unaware that they are including errors or mistakes in evaluating or applying fire engineering principles, sometimes even including errata in formulae or fire safety designs.
One needs to avoid under-designing for a particular fire risk, resulting in an inadequate fire protection system, or over-designing, leading to overly expensive fire safety solutions.
The three main causes of fire are electrical faults, arson, and faulty or unattended heating equipment. In the event of a major fire resulting in immense damage and the possible death of occupants, the fire engineer will be held liable. Rational design considers the behaviour of a building during a fire, thereby minimising the potentially devastating impact it might have.
The structure of the building, the fire load of products stored or manufactured in the building, the occupants of the building, and the built and natural environments are also analysed. Other aspects to consider include how people will respond to a fire, based on their level of alertness and familiarity with their surroundings.
A fundamental basic is that the building should be designed to withstand fire so that occupants, including disabled persons, can escape safely, and appropriate fire equipment must be in an adequate and easily accessible area. Access must be provided for firefighters to enter the building, and suitable fire detection and suppression equipment must be installed for the particular fire risks. The building structure should be able to remain intact so that it contains the fire and does not threaten surrounding buildings in the event that it collapses.
Fires can be dealt with through three main actions. The first is controlling the growth of the fire to prevent it from spreading. The next is suppression, which involves rapidly cooling the fire. Finally, extinguishing the fire means that there is no heated substance remaining. Evacuation should also be safe and easy while allowing unrestricted access for emergency services. The installed fire detection system must be able to detect the fire as soon as possible, so that it can warn occupants and allow them to escape before untenable conditions are reached.
Rational design process
Rational design begins with a qualitative design review, which includes an architectural review of the building, fire safety objectives, fire hazards and risks, trial fire safety designs, and worst-case fire scenarios for analysis. Consultants, for example, may ignore the building roof’s geometry and the required substitute rectangular volume used in smoke fill formulae, resulting in inaccurately calculated smoke fill times and average gas layer temperatures.
“One needs to avoid under-designing for a particular fire risk, resulting in an inadequate fire protection system, or over-designing, leading to overly expensive fire safety solutions.”
The next step is quantitative analysis according to BS 7974 published documents. Here, the main focus is on the development of fire within the building, spread of smoke within the building, the building’s structural response and fire spread beyond the origin of the fire, detection of fire and activation of fire protection systems, fire services intervention, and evacuation of occupants.
Assessment against criteria is the final step, where the fire safety design developed during the engineering analysis is assessed to ensure that the objectives established at the beginning of the process are in fact met.
After the completion of the fire risk assessment and the drafting of the rational design report, companies such as ASP Fire provide the client with a report with practical actions to follow. This report comprises a detailed and documented objective fire risk assessment, as well as fire engineering calculations and analysis where required, covering all aspects of fire risk and safety.
This factual report provides guides to the client in protecting its business, employees, and customers by providing prioritised recommendations for action, in order to rectify problem areas and strengthen existing fire safety procedures. This also ensures that the client complies with fire safety regulations for the protection of life, property, and the environment.
The company also works closely with insurance brokers and underwriters to address a client’s fire risk based on the outcomes of the fire safety risk assessment report. This assists in preventing damage to property and products, loss of life, monetary loss, consequential loss of profit, loss of productivity, and insurance repercussions.
About ASP Fire
ASP Fire operates across the entire African continent from its Gauteng base, providing professional, accredited fire risk management and support to its clients. ASP Fire designs, installs, and maintains a full range of fire detection and suppression equipment suited to clients’ needs.
