Expert of the Week   for  23 Apr - 06 May 2018

Mr. Charles, greetings.

Another excellent question from you.

While a fire risk assessment of buildings could take a standard approach, the purpose and use of the different types of buildings and structures, would determine the extent and associated factors needed to be considered, to adequately prepare a fire risk assessment. A fire risk assessment of a gas station or the associated convenience store would vary from the fire risk assessment of a Hotel, while the fire risk assessment of a school would vary from that of a manufacturing building or a restaurant. Moreover, preventative, mitigation and control measures of addressing a fire, would also vary based on the type of building and the type of fire that would be ignited. A water base solution to extinguish a fire in a school or a wooden building would be ideal; however, it would not be the same approach and solution to be used to address a fire at a gas station or in the kitchen of a restaurant.

In common terms, a fire risk assessment is the analysis of the factors and conditions that would increase the risk and possibility of the occurrence of a fire. A fire therefore needs a source and an agent to be ignited and to survive (or spread), it requires a third constant, oxygen. Keeping these conditions away from each other will greatly reduce the possibilities of a fire and the spread thereof. These conditions may also take many forms and would vary between the different types and functions of the buildings and structures that are in operations.

Let’s consider the following;
• A gas station - Sources and agents; petrol and cigarettes and any form of sparks, lightning, etc.
• Domestic house - Sources and agents; matches and paper, clothes, gas, children, etc.
• Factory building - Sources and agents; oil and fuel spills, cigarettes and any form of sparks, malfunctioning tools, plants and equipment
• Restaurant building - Sources and agents; oil spills, leaking gas pipes, unattended stoves, fire, clothing, etc.
• School building - Sources and agents; expose electrical connections, metal objects (spoons), children, malfunctioning tools and equipment, matches, papers, etc.

In identifying any and all probable sources and agents that may increase the risk of a fire, the assessment would then move to the stage of mitigating one or both of the conditions. Because some conditions such as spills from gas stations or the presences of fire in the kitchen of a restaurant will always be present and may be unavoidable, additional considerations will be necessary. However, eliminating conditions that may lend themselves to promoting the risk of a fire are most times fundamental while some control measures that could be employed are equally as easy.

Let’s consider the fire risk assessment for a machine welding shop, especially those which may not have been constructed to design standards. I am addressing those machine welding shops that were created below domestic dwelling houses or on the premises of a domestic building; a scenario quiet prevalent in the Caribbean and third world countries. However, the application of a fire assessment for this type of structure is also applicable to machine welding shops that were designed and constructed against standards and regulations.

The first approach would be to identify the sources and agents that are likely to increase the risk of a fire at such operation; explosions, sparks, gas/fumes, petrol and electric shock. While the presence of one condition may be more than adequate to ignite a fire, others would require an agent to develop and oxygen to maintain its vitality; an explosion could be fatal while petrol would require an agent to be ignited.

Next approach would be to completely eliminate, if not possible, then reduce the exposure of such conditions to a minimum that any contact with each other would be of minimum to zero threat. A fire is likely after any explosion. Therefore, it is necessary to ensure that all equipment, tools, plants and all operations be strictly executed under control environments and with regards to necessary safety, health and operational rules and standards to avoid an explosion. This therefore means that if any equipment requires routine maintenance at specific periods (i.e., 40 hours after operation), then this is essential to reduce the possibility of self-failure and possible explosion due to increase wear and tear beyond manufacture’s recommendations.

Sparks emitted from the welding plant can cover an estimated distance of 30 feet. This therefore means that no agent of a combustible nature should be in close proximity to the welding arc when in use. Storage and use of petrol should be kept in a confined but not concealed location where any spills or leak can be controlled. It should definitely be separated from the welding arc and away from any source of heat, inclusive of direct contact with the sun. Containers used to store fuel must also be of appropriate and the recommended made.

Once the identified sources and agents have been identified and addressed as best as possible during the fire risk assessment, control measures that can be applied to reduce the impact and the spread of the fire, in the machine welding shop would require a combination of methods. Fire extinguishers or suppression methods are categorize; 
• Class A - fires involving solid materials such as wood, paper or textiles.
• Class B - fires involving flammable liquids such as petrol, diesel or oils.
• Class C - fires involving gases.
• Class D - fires involving metals.
• Class E - fires involving live electrical apparatus.

Therefore, classes B, C & D should always be on the premises of this operation.

Equally important as using the correct fire control measure on a potential fire, is the training and knowledge required in its application.

Repetition is a best friend to memory and therefore, routine practice of attending to potential fires will be of tremendous benefit to all.

Please feel free to make any and future contact with me, should you require further information or guidance on this subject.

Amsterdam K
Chartered Construction Manager
Guyana, South America

Greetings Mr. Chishiri.

Your follow up question is one that is greatly overlooked by many in authority and with such responsibilities.

I am not sure there is a code of practice for designers with regards to specific design requirements for buildings and structures, to consider emergency evacuation for disable persons.

I would rather suspect such considerations and requirements rest with the respective statutory bodies and organisations who may have vested interest in accomplishing such. The National Fire Protection Agency (NFPA) has a planning guide on evacuation measures for disable persons, The Americans with Disabilities Act (ADA), Title III (Public Accommodations) which was amended in 2008, and became effective January 1, 2009 made it law, that design considerations should be given for disable persons to access public and private (commercial) buildings while The Building Regulation Act 2000 (Fire Safety), of the United Kingdom, stated that evacuation requirements from public buildings by disable persons are limited. This regulation was however replaced by Regulation 2010. Health and safety organisations such as NEBOSH and OSHA along with institutions such as IFE (Institute of Fire Engineers) would be entities with vested interest in evacuation of persons with disabilities from buildings.

International lending organisations may require borrowing countries who request loans for structural/building developments, to consider access and may be, evacuation measures for persons with disabilities who are likely to utilize such buildings. Recently, (Guyana, South America) one of our completed (but not fully completed) developmental projects, five overhead pedestrian walk bridges, which was funded by the Inter-American Development Bank, had required the installation of elevators to be used by the elderly and those who may have mobility challenges, as part of the design and construction of the project. I cannot therefore, confirm the existence of a code of practice for design evacuations from buildings for disable persons. This would require further research.

When considering evacuation from buildings for disable persons, designers may restrict access to services to such buildings, to the ground floor of the structure. This is an easy and fundamental approach/option for achieving successful evacuations in an emergency situations. However, considerations must also be given to the purpose and function of the building in achieving this. A building to be designed as a learning institution, catering for children and adults with disabilities, should allow for specific classrooms for such disable persons to be on the ground floor of the building.

It is therefore important to know and note, the function of the building, so as to cater for disable persons during the design stage.  Of further importance also, is to note that persons with disabilities are not just persons restricted to mobility challenges; we must consider persons with challenges in visual, speech, hearing and cognitive impairments, along with those affected by emotional, psychiatric, arthritis, asthma and even significant allergies. Anyone needing extra assistances or considerations during an evacuation can therefore be classified as having some form of disability.

Additional design considerations for successful evacuation from buildings for disable persons will consider the following;
• Door openings- These should be wider than your standard doors with the swing directions outwards.
• Access - The use of locks and handles/knobs on doors should be avoided. Push bar doors which can only be accessed from within are ideal.
• Additional (exit) doors positioned in strategic locations
• Handrails along corridors
• Use of ramps and
• Exit stairs – catering for slow and fast lane, if permitted.

For buildings with more than one floor and for high rise buildings, where evacuation out of the building by the disable may be challenging, then specific areas within the building (on each or identified floors) could be designed and designated as safe zones for disable persons. This is termed horizontal evacuation and may be outfitted with an emergency/exit door. Designated safe zones within buildings requires special construction techniques.

The use of lifts (or specially designed elevators), which can be manually operated would also be a consideration that would allow for disable persons to be lowered from upper floors to floors below. Standard elevators should not to be used during fires.

It is therefore achievable for buildings to be designed with considerations for evacuation of disable persons. But this is a special factor that has to be taken into account early in the design stages. It is not the same as catering for ingress to buildings for disable persons as compared to considering egress from the building.

It was a pleasure responding to your post. Please feel free to ask further questions if you require additional information.

Amsterdam K
Chartered Construction Manager
Guyana, South America

Greetings Mr. Chishiri.

Much thanks for the question you posted.

The design plan for evacuation from public buildings must consider the following;
• The movement of people from one location (hazard/threat) to another location (safety) within the same building or the exterior of the building
• The time factor to move the affected persons from the area of danger, to an area of safety
• The space available to move the volume of persons from point A to point B
• The location of the area of safety; whether within the building or on the exterior of the building
• Placement of strategic doors, windows  and stairs to allow for evacuations
• The openings and use of identified doors, windows and stairs to be used for evacuations
• The materials and constructions technologies employed  during the construction; both can either hinder evacuation approach or aid in timely escape
• The capacity of the structure
• Location, environment and community where the structure is to be constructed
• Purpose of the building (primary function)
• Number (maximum, at worst case) of persons that are likely to be within the building at any given time
• Cost for construction and operation
• Type of occupants within the buildings

It is therefore possible with the above factors (which could further be expanded) taken into account, that it would pose a challenge for the designer to produce a design fit for purpose and in keeping with the client’s budget, purpose and objectives. This is quite evident in third world countries and for projects where size (land and building), along with project costs are restricted.

Let’s look at two examples in focus;
A client (government) requires a design for a public school in an existing community due to demands for the growing children population in that community. The identified land available, when all other factors such as classroom size, number of children, play area and outdoor facilities are considered, only allows for a maximum of 200 children. However, the feasibility study conducted revealed a total of 350 children of school age within that community.

Consider also, a supermarket with a capacity of 100 customers at any given time. However, on a particular day, there was an influx of an additional 55 persons within the building due to a promotion or blow out sale. Even if we consider that the supermarket or any structure meeting satisfactorily evacuation measures, an increase in capacity of persons within the structure is a threat to safe and timely evacuation.
Evacuation measures when considered and incorporated into the design of buildings, caters for a specific amount of persons within that building at a given time, who can safely and in a timely manner, exit that building. Consider again, a semi or high rise building that has become the subject of a pending hazard (fire or riot), if no taught was given to the isolations of specific floors within the structure during the design and construction stages, then, safe and timely evacuation will be compromised.
In the design of public buildings, regardless of the type and use, whether be it for supermarkets, restaurants, libraries, hospitals, schools, etc., the above factors must be given careful considerations at all times. Unfortunately, because many parties would have vested interest in the purpose and function of a particular project (buildings), this will pose a challenge to the designer in trying to produce a design which provides timely exit out of such buildings.

Evacuation measures in buildings must consider the number of persons within, the use of space, movements and information that are available.

I hope I have answered your question with clarity. Please feel free to ask further questions if you require additional information.

Amsterdam K
Chartered Construction Manager
Guyana, South America