30 Jul Picking up the pieces
Part 1 – Post Fire Damage Decontamination
PETER STEPHENSON, Associate Director, BuroHappold Engineering
As professionals in the fire industry we can influence fire safety in the built environment in many ways including building design, product specification & performance, system commissioning & testing, management systems & training and ultimately with the decommissioning of a building. Throughout these different stages we are looking to protect employees, members of the public, plant/assets, the environment and company/city brands.
A well-developed fire strategy will ensure the building design and safety regime is accurately recorded through the design and occupied phases and will consider the following key objectives, namely;
• Life safety
• Property protection
• Business protection, and
• Environmental protection
A fire strategy is an important document throughout the complete life cycle of a building and will assist in reinforcing confidence in the design of a building and operational efficiency. A fire strategy should include but not be limited to the following key outputs:
• Fire Strategy Statement
• Management of the Fire Strategy
• Evacuation Strategy
• Fire & Smoke Control Strategy
• Firefighting Strategy
• Fire Protection Strategy
Fire safety management plays a major part in building safety following occupation. Inadequate fire safety management is often the root cause of a fire incident which leads to business disruption and often results in failure to meet contractural obligations, orders and service delivery etc. In the case of a serious incident this could lead to loss of market share, reduced cash flow with increased costs, possible job redundancies and demotivated staff which could ultimately result in complete business failure.
Picking up the pieces
Following a fire incident and subsequent investigation some of the common fire safety issues that are often identified include poor fire safety governance where roles and responsibilities are not clearly defined, no identified responsible or competent person, no fire risk assessment and a `tick in the box’ culture. It is no surprise that there is often no fire strategy or emergency plan. Depending on the severity of a fire incident some or all of the following may be required, all resulting in huge costs:
• Fire Investigation – Forensic Analysis
• Building Damage Assessment
• Reconstruction Costs
• Project programme delays
• Loss of plant and equipment Loss of Brand Confidence
• Fire Department Response and Enforcement
Unfortunately, safety risks from fire do not end once the flames are extinguished. Fire damage can linger for years unless properly addressed. Adequate safety equipment (respiratory, skin, and eye protection) are essential in reducing possible exposure to dangerous smoke and soot, and quite possibly water and mould related health issues resulting from firefighting efforts. Proper ventilation practices are also possibly necessary to protect and restore indoor air quality following a fire, including HEPA filtration and adsorption (activated carbon) to preserve air quality.
Cleaning up the soot and the smoke damage after a fire is just as important factor in the building rehabilitation. In order to prevent health issues, the removal of soot and smoke should be done by people who are suitably trained to undertake the fire and smoke damage restoration. They have the experience and the proper equipment needed to undertake the clean up safely.
The hidden dangers of soot
What is Soot? Smoke is the result of incomplete combustion, which produces tiny particles of carbon in the air. When deposited, these particulates are identified as soot. Put simply, the particle size of smoke residue on a surface can present a respiratory hazard. The particle size of soot is approximately 2.5 microns, a size that is associated with deep lung penetration. Particles that are approximately 10 microns or larger get trapped in the upper respiratory tract. Particles that are 5 microns or smaller can make it down to the lower lung where the gas exchange occurs in the alveoli. In order to offer some perspective on the size of these particles, the dust you see flying in the light coming through a window is about 40 microns in size. Airborne soot present within the breathing zone of workers is too small to be seen with the naked eye and can easily be inhaled.
Soot will usually adhere to a wall or any other surface that is cooler than the heart of the fire. In fire investigations, a wall free from soot may be an indicator of where the fire began because the fire would burn at a higher temperature in this area. As a fire dies down, the smoke it has caused will disperse leaving behind a residue of quickly cooling particles which is generally referred to as soot.
All materials involved in a fire cause odours. Typically, soot is representative of what has burned, but may include by-products that at first seem unrelated to the original material. Each fire is different based on the contents of what has burned during the event. Organic and inorganic materials produce different types of smoke residue or soot. These residues may be present on surfaces that conservators may be tasked with treating. Burnt organic material produces soot that is hard to see and often has a very pungent odour. This is known as protein smoke. It can discolour paints and varnishes. Protein smoke can disperse over large areas and attach itself to everything.
How the fire burns and how much moisture is in the air while the fire burns, plays a role in soot deposition on articles. The amount of moisture in the air is a key component in whether the smoke that is produced is wet or dry.
There are several types of smoke or soot, which may be present on a surface that conservators might be tasked with treating:
Can present as a sticky residue or soot, and is often associated with a smouldering type of fire and often will have a strong odour.
Associated with a fast-burning fire and occurs at high temperatures.
Often present in soot, usually invisible, it can discolour paints and varnishes and often has a very pungent odour. Protein odours could be caused by food on the stove burning slowly or other sources. The slow burn allows the protein to disperse and attach itself to everything, producing a strong odour.
Potential exposures soot
Is in the general category of airborne particulate matter. While we would not expect most volatile organic compounds (VOC) to survive a fire and still be present on the soot, there may be metals present as well as some chlorinated compounds. It is important to note that soot is not simply
a form of dirt that needs to be removed from an article. Soot can be a respiratory or skin irritant, and there may be chemicals or metals riding on the soot particles that are small enough to enter into your lungs.
Homeowners and companies are often devastated by the damage caused by a fire. Unfortunately the fire damage ends up being a small part of the issues. The smoke, soot, char and mould are the major issues to be taken into consideration after such an incident. Smoke is an acidic product, capable of corroding and staining surfaces such as metal, joinery, walls and counters. Due to the high levels of humidity and heat in U.A.E. after extinguishing a fire by water, mould and microorganisms and rapid growth adds to the damage and cost repair, with the possibly of affecting human health.
A thorough damage assessment to determine the extent of soot contamination should be made. Where possible a dry vacuum and dry wipe initial clean-up should be undertaken. Specialist contractors, such as Snag & Inspect can undertake a fogging process that kills smoke and smell enzymes, mould spores and microorganisms that are known to be by-products of a fire. Fogging can penetrate areas that cannot be reached
by conventional cleaning such as ceiling voids, ducts and shafts. These microorganisms are harmful and in some cases deadly to young persons, people with lung conditions and the elderly. Specialist cleaning agents kill mould spores, neutralise mycotoxins, and are effective against microorganisms and neutralise the smell of smoke completely. Systems approved by the Ministry of Health in U.A.E. and Dubai Municipality are suitable for use in Office Buildings, Hotels, Hospital and Homes. It is safe for use around electric equipment, A/C systems, without impact on painted surfaces, ceilings or furniture.
Depending on the restoration methodology proposed, pressure washing, either high or low pressure may be implemented. Water temperature along with pressure is a key factor depending on the surface to be cleaned as incorrect application can cause the soot to be driven into a porous surface.
Fire can damage and affect a business or home structure in unexpected ways. When faced with the aftermath of a fire, business or home owners may find a location and concentration of smoke, smell and soot residue perplexing and astonishing. Fire is not the only problem people face, burned areas are just a small part of the problem. Smoke, soot and char are also by-products of such unfortunate events, and they are equally dangerous to a person’s health. These by-products carry with them toxic substances that can irritate the skin, eyes, and if inhaled, can cause respiratory and nasal problems. Some soot even have cancer-inducing chemicals in them.
Pressure Washing and Fogging are two inter-related and vital elements of a professional and complete Fire Restoration process.
Without each application the cleaning process could be compromised. While fogging is a biological technique used to kill microorganisms and smell, the pressure washing is a mechanical technique that eliminates soot, char, fibre glass, petroleum, etc.
A combination of pressure washing and fogging can be used to avoid the danger of mould, micro-organisms, smoke, soot and char damage and ensure a full clean of the exterior/interior surfaces of a premises is carried out to expedite the restoration process. Initial fogging to eliminate the soot odours, followed by the pressure washing with a second fogging application is found to provide optimum results.
By applying Pressure Washing combined with a Fogging system, outstanding results in killing moulds, eliminating smell, soot and char after a fire can reduce the impact of a fire incident in a building.
Part 2: Peter Stephenson will be looking in more detail at the effects of fire in the next issue.