There has never been a tougher time for fire professionals to make decisions about which type of foam they should use and how they should apply it to their flammable liquid risks. With the changes in environmental legislation, larger and larger storage tanks, the increasing use of geodesic tank roofs with internal floating roofs and new foams reaching the market every month, it is not surprising that making the correct choices can be a daunting task.
Bulk Flammable Liquid Storage Tanks
This year marks the 10-year anniversary of the Buncefield (UK) emergency, 7 years since Jaipur, and 3 years since the Banksmeadow incident in Sydney. All of these incidents had major impacts on the lives of the people affected by these events, both locally and globally, and each of them required a very specific type of emergency response.
Crude oil contains every oil derived product from bitumen to butane and as a result any fire is a very complex scenario. Careful planning, a well maintained system and the most applicable foam choice is paramount. Open top floating roof tanks can reach diameters in excess of 110m and require significant fixed protection systems. Lightning strikes within a tank farm which contains processed or blended products such as petrol or gasoline, can result in catastrophic consequences. Boil overs in a crude oil storage tank can escalate rapidly into multi-tank fires and the protection of a bund is especially important as the surface area is much larger than that of a tank.
Traditionally, the ideal foams for these extreme hydrocarbon fire scenarios are the fluorine containing foams such as AR-AFFFs or fluoroproteins. Angus Fire manufactures a number of high performing foams in these categories such as TridolC6 ATF Ultra 1-3%, FP70C6 and TankmasterC6, which are the preferred choice in many international high risk sectors.
In recent years the foam manufacturers have invested heavily in reformulating firefighting foam concentrates to increase their environmental credentials. Today, the introduction of the so-called C6 foams, which are based on very pure C6 short chain telemore chemistry instead of the long chain C8 chemistry, has radically improved the environmental aspects of these foams without sacrificing their fire-fighting performance.
In terms of equipment used to apply foam concentrates, there is a range of fixed foam equipment specifically designed for storage tanks. Open top floating roof tanks, have traditionally only had their rimseal area protected through manually activated rimseal foam pourers. Angus Fire manufactures an automatic system called Floatafoam, which comprises a number of fully automatic foam delivery modules designed to detect and extinguish floating roof tank rimseal fires in their infancy. Recent developments have brought the introduction of full surface pourers and full surface nozzles for targeting the total surface area of these tanks. In addition, many users have invested in mobile Big Flow systems involving pump sets, extra-large diameter feed hose and high capacity monitors giving them the confidence of being able to fight a full surface fire remotely.
Some tank owners are investing in both fixed and mobile protection for their tanks, for maxiumum security.
The use of medium expansion foam systems to protect the bunds around the tanks is also a new suppression and firefighting technique which prevents the fire-fighters being put at risk, should the tank be breached or the feed lines rupture.
Municipal Fire Departments
The challenge in selecting the right foam for a municipal fire department is especially complex.
Municipal firefighters can be faced with any kind of flammable liquid fire and are best served with a multi-purpose foam concentrate. An alcohol resistant, fluorine containing foam will give the best firefighting performance. In terms of equipment some of the biggest challenges for municipal firefighters come from ensuring the foam concentrate is induced correctly into the water lines. Many alcohol resistant foams contain high levels of polymer which make correct induction difficult particularly with portable foam equipment. A solution to this is the use of a polymer free foam such as Angus NIAGARAC6 which overcome these issues and ensure correct mixing.
In addition, municipal firefighters are under great pressure to consider the total environmental impact of firefighting. It is vital that a foam concentrate is selected with the best fire-fighting performance, but today there is also significant drive to choose a foam concentrate with as lower an environmental impact as possible. When the main objective is to minimise the effect of the foam on the environment, then there are fluorine free, alcohol resistant products on the market with good fire performance (such as Angus Respondol). These foam concentrates are welcomed by the environmental bodies as they contain no fluorosurfactants. However, it should not be forgotten that these products too have environmental issues in terms of aquatic toxicity.
The preservation of life is paramount at any aviation emergency, considering the likelihood of rapid escalation into a major incident and the certainty that there will be people inside. So much so that aerodrome firefighters are tasked with creating a survivable environment within, or around, any aircraft to enable self-evacuation or rescue of passengers. Fuels used in this industry are highly combustible and release tremendous amounts of heat when they are burnt (due to their high calorific value). Jet-A and Jet-A1 aviation fuel is stored in large quantities in tanks, tankers and aeroplanes themselves at various locations around the airport. Film-forming foams such as Angus Fire’s PetrosealC6 and TridolC6 are ideally suited for this application achieving Level B or C passes against the ICAO (International Civil Aviation Organisation) performance test criteria. (ICAO sets three levels of performance, A, B and C with C being the most demanding).
However, today airports are under ever increasing pressure to control their environmental footprint. In these cases, consideration should be given to a fluorine free product such as Angus Fire’s JetFoam (1%, 3% or 6%) which is a fluorine free alternative with ICAO level B certification.
Training is a critical part of the aviation fire-fighter’s role and where the majority for foam is used. For these situations specifically formulated training products exist such as Angus Trainol or TF foams.
Key to buying a foam concentrates is to ensure that the correct approvals are in place for the risk being covered. Foams can be approved to EN, ICAO,Mil-F, Lastfire and UL, as well as many more. UL links the foam to the equipment being used to give a system approval.
All these approvals focus on different criteria and may give greater priority to certain aspects of performance. In aviation, the focus needs to be on rapid extinction to free passengers from the aeroplane. In large storage tank fires, a foam with better heat resistance and post-fire security is essential. If the foam breaks down quickly post fire and needs to be continually topped up to ensure no re-ignition takes place, it has a significant impact on resources and logistics.
Every test/accreditation focuses slightly differently on knockdown or burnback resistance so it is important to look out for the approval which is going to be most applicable to individual risks.
Approvals play a vital role in the selection of foam concentrates. In most cases they represent not just an indication of quality but may be user specific. That is why manufacturers strive to obtain a wide range of approvals, to support as many markets and end-users as possible.
What should be the decision making process?
Professional firefighters often ask which foam they should be using. Regardless of what the manufacturers promote, the right choice should always be based on the user’s risk profile. Risk isn’t just the fire, risk needs to include how much emphasis is placed on knock-down, burn back resistance, post-fire security and the environment (air, soil and water). Talking with manufacturers and being informed of the latest developments is important. Manufacturers know about their products and have a tremendous amount of information to share, which can then be augmented this with feedback from fellow firefighters and experienced professionals.
What is the future for foam?
The primary consideration in an emergency is to protect life. The environment comes next and then assets. Foam manufacturers, response agencies, approval bodies all work hard to find the best balance between high performance and minimal environmental impact. The last few years has seen an unrivalled investment by the foam manufacturers in product development. This is likely to continue for the foreseeable future as attempts are made to produce fluorine free products that match the fire-fighting performance of C6 fluorine containing foams. This day is still some way off. So far, no fluorine free foam manufacturer has discontinued their fluorinated foam production. In fact, recently a key advocate of fluorine free foams, launched a new AFFF foam concentrate with Mil-F approval. To achieve this approval a foam concentrate currently requires fluorosurfactants.
With all this level of research, undoubtedly new and novel solutions to the current foam issues will appear over the forthcoming years.
As a responsible manufacturer Angus Fire continues to research, develop and bring the best possible products to the markets. In addition Angus Fire offers a variety of services to support the fire industry. Emergency Foam Service, Foam Testing Service and Firefighting Foam School.
To request a copy of the latest Foam Brochure and the Tank Protection Brochure please email [email protected]
For more information, go to www.angusuk.co.uk