FOAMSPEX - Large Scale Foam Application-Modelling of Foam Spread and Extinguishment

Although tank fires are rare, they present a real challenge when they occur. For extinguishment of tank fires, the use of fire fighting foam is the only practicable method. However, there is still need for improved knowledge about foams and foam equipment and therefore the EC-funded project FOAMSPEX - Large Scale Foam Application-Modelling of Foam Spread and Extinguishment, was launched in 1998. The project is now completed and the findings were presented at the FOAMSPEX seminar on September 20, 2001.

The project is summerised in a hard bound final report and in a project video.

Objective
Project summary
Consortium
Sponsors and reference group
FOAMSPEX seminar
FOAMSPEX final report
Project video
More information

Objective

Large scale tank fires present a huge challenge to fire fighters, oil companies, and to the environment. For such large fire risks the costs of fire protection and prevention are high, and optimising cost effectiveness is an important and difficult task. An improved understanding of the extinguishment mechanisms and limitations of fire fighting foams is essential to make such judgements.

The aim of the FOAMSPEX project is to provide this information by comprehensive theoretical and experimental work resulting in engineering models to predict foam spread under fire conditions.

Project summary

The FOAMSPEX project have addressed three main areas:

  • practical scale characterisation of the foam jets including the effect of thermal updraft
  • laboratory and small scale characterisation of the rheological and surface properties of various types of foam
  • modelling of foam spread on the burning fuel surface to enable prediction of extinguishment in full scale application

The project is almost completed and here follows a short summary of the work which includes modelling work and a large number of experiments.

The efficiency of foam monitors in directing foam towards the target area (e.g. a burning tank top) plus the characteristics of the foam jet are believed to be of critical importance in fighting storage tank fires. Measurement methods using the latest digital techniques have been developed by TRI and used during full scale field trials conducted to characterise jets of foam produced by foam monitors in terms of their main features, such as size and velocity distribution of foam flakes, effect of thermal up-draft, etc.

Foam characterisation tests have been conducted by TRI at the Angus test field in Bentham. A video recording equipment, taking 500 pictures per second was developed by TRI and was used to record the foam stream just above the impact point. Nozzles having a flow from 11 l/min to 1800 l/min were tested. Some tests were also made recording the impact of the initial foam flakes onto an open fuel surface.


From the pictures, foam flake sizes, speed and direction, etc. have been determined.


TRI and SP have measured the influence of thermal updaught as a base for the modelling.

Basic laboratory measurements of foam parameters have been pereformed by Angus Fire in order to provide basic data for use in the interpretation of the results from the foam jets experiments and for use in the modelling work. Various methods for measuring the foam rheology are being evaluated in order to be used for creating input data for the foam spread modelling. A literature study has been performed.

Pipe flow measurements have been performed and the shear stress machine developed by UK Fire Research Station has been partly modified and used. Various flow behaviour of the foams have been recorded, such as shear flow, plug flow and slip flow. Evaluation of the results obtained are now in progress. Rheological measurements have been carried out on a range of foams.Surface and interfacial tension and small scale fuel pick up have been measured.

SP has developed models predicting foam spreading on fuel surfaces with gentle foam application. Engineering models have been developed to predict foam spread under fire conditions in order to estimate the times for foam coverage of a fuel surface under various conditions.

At SP a large number of foam flow tests have been conducted. The test series have included tests in channel, in half circular geometry and in circular geometry. A number of different liquids were used for the foam spread tests and tests were performed both in cold conditions and during fire conditions. Two types of foam, one "fluid" and one "stiff", have been tested using various application rate, fuel depth, etc. Foam spread and foam layer thickness were recorded with video cameras.

   
 The cold tests with channels were performed indoor and the channels used were 1 m wide and 5 m and 15 m long, respectively. To simulate the radiation from a fire affecting the foam layer, a special radiation panel was constructed and used in som of the indoor channel tests.  
   
Outdoor foam spread tests with fire were performed in the 15 m channel.  
   
The half circular tests were performed in an indoor basin with an radius of 10 m.    
The circular tests have been performed in various scales ranging from 17 m2 up to 140 m2. In the 17 m2 tests the position of application was varied:  
  1) All foam applicated in the centre of the pool.
   
2) All foam applicated at the rim of the pool. 3) The foam applicated at three different positions along the rim of the pool.

The experimental results have been analysed and used for the correlation of the foam spread model.

A series of outdoor full scale fire experiments of 140 m2 have been performed to validate the foam spread model under fire conditions. Results from the foam spread model have also been compared with observations from real tank fires. Unfortunately, the available information from real fires is often limited and therefore another research project was started after the completion of FOAMSPEX. The aim of this project is to create a data base with information from tank fires and large-scale foam-spread tests.

The developed models have been used to study the influences of different parameters and define possible limitations for the use of foam, such as a maximum practical spreading distance.The models have also been used to predict foam spread and fire extinction for typical full scale storage tanks.

 
Photo: © Fortum Oil & Gas Resources Oy

The calulations try as far as possible to reflect the arrangements mentioned in the NFPA 11 standard. The scenarios used in the calculations range from the simple conditions with gentle application, central inlet and no drainage (1A) to the most complex condition with over-the top application on a fire (4C).

 

 

The influences of different parameters are illustrated and the overall accuracy of the models analysed in order to show the potential for using the overall work as a basis for possible revisions of existing guidelines.

One of the main findings from the FOAMSPEX project is that the application rate (6 L/m2 min) has to be increased, for  larger fuel surfaces. This means that an already today large amount of foam has to be increased even further. This can lead to practical and logistical problems which have to be dealt with.

The overall work and findings of the project are summarised in a final report, which have been published as a book. A seminar has been arranged at which the project was presented to world experts in the protection of large scale storage tanks. The experimental part of the project is also described in a video.

Consortium

The project consortium consists of three partners:

SP Technical Research Institute of Sweden-Bror Persson (project co-ordinator)
T.R.I.-Tecsa Ricerca e Innovazione srl in Italy- Antonio Lancia
ANGUS FIRE Ltd in UK- Dave Mulligan

Each partner has created a special project team to conduct the FOAMSPEX project. The scientists above are the project leaders for each partner, respectively

As project co-ordinator, SP will be responsible for overall management of the project and will provide the main links with the sponsors throughout the duration of the project.

Recently, a M&T project "FAIRFIRE-Fire Fighting Foams: Small Scale Fire Test Procedure" was successfully completed by the same consortium. The aim with the FAIRFIRE project was to develop a small scale fire test which could be used for quality control tests of foams.

Sponsors and reference group

The total project costs are approximately 1100 kECU

Almost half of the total costs, about 450 kECU, are funded by the European Commission through the Environment and Climate programme. The remaining funding has to be raised by external sponsors and the partners themselves.

The project is sponsored by the following organisations:

European Commission, Environment and Climate programme, DG IIV

  • Swedish Environmental Protection Agency (SNV)
    Swedish Rescue Service Agency (SRV)
    Swedish Fire Research Board (BRANDFORSK)
    Swedish Defence Material Administration (FMV)
    Swedish Petroleum Institute (SPI)
    3M Belgium N.V.
FOAMSPEX seminar

A seminar on the use of fire fighting foam for extinguishing tank fires was arranged on Sept 20 2001 in connection with the INTERFLAM´01 symposium in Edinburg, Scotland. Besides the presentations of FOAMSPEX, Niall Ramsden from Resource Protection International (UK), Eric Lavergne from Williams Fire and Hazard Control (USA) and Joel Rogard from GESIP (France) participated and gave their views on fire fighting of tank fires.

FOAMSPEX final report

A hard bound copy of the FOAMSPEX report containing experimental data, description of the models, and examples of modelling on full scale tanks can be obtained from SP for a cost of SEK 1500 (about USD 150, EUR 160).

Please download and use this form for your order.

Project video

A video giving an overview of the experimental work within the project is also available and can be ordered for a cost of  SEK 750 (about USD 75, EUR 80). Also available as DVD.

Please download and use this form for your order.

 

The scientific project leaders for each project team within the consortium are


Henry Persson
SP Technical Research Institute of Sweden
Fire Technology
Box 857
S-501 15 BORÅS
Sweden
Phone.: +46 10-516 51 98; Fax: +46 33-41 77 59; E-Mail: henry.persson@sp.se

Dr. Antonio Lancia
TRI - Tecsa Ricerca e Innovazione srl
Via A. Moro 1, 20420 Scanzorosciate (BG)
Italy
Tel.: +39-35-66 8084; Fax: +39-35-656598; E-Mail: antonio.lancia@mediacom.it

Mr. Dave Mulligan
ANGUS FIRE Ltd
Station Road
Bentham, Near Lancaster
LA2 7NA United Kingdom
Tel.: +44-15242-61611; Fax: +44-15242-61947; E-Mail: dave.mulligan@angusuk.co.uk

Related Information

Contact Persons

Henry Persson

Phone: +46 10 516 51 98

RISE Research Institutes of Sweden, Phone 010-516 50 00, E-mail info@ri.se

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