Surface spreading

Fire safety Class P not easily ignitable to BS 476 Part 5. Can achieve Class 1 surface spread of flame to BS 476 Part 7 when faced with aluminum foil. 

Antifoams and defoamer surfactants must possess a good surface spreading action (spreading coefficient). 

A description is given of the initiatives carried out within the European Community for the harmonization of fire testing. The technical and economic reasons are explained for such initiatives, which are taken in order to remove barriers to trade from the European internal market. Of the various fire aspects, only fire reaction testing is taken into consideration here, because it appears as a major technical obstacle to the free circulation of construction materials. All possible approaches are considered for the attainment of such a harmonization and one, the so called interim solution, is fully described. The proposed interim solution, is based on the adoption of three fundamental test methods, i.e. the British "Surface Spread of Flame", the French "Epiradiateur" and the German "Brandschacht", and on the use of a rather complicated "transposition document", which should allow to derive most of the national classifications from the three test package. 

British "Surface Spread of Flame" BS 476 Part. 7 (Figure 3)... 

The number of small scale test methods, used for classification purposes, should be limited and based on ISO tests, presumably the Cone Calorimeter /10/ (see Fig. 8) and possibly the ISO Surface Spread of Flame test /11/. 

Surface spread of flame test. The 13 materials listed in Table I were tested in the IMO and ISO surface spread of flame tests. 

Table I. Results from the Surface Spread of Flame Test and the Cone Calorimeter... 

Figure 1. Surface spread of flame test for particle board.

Examine data taken under a natural convection lateral vertical surface spread for a particle board as shown in Figures 8.12(a) and (b) [17]. The correlation of these data based on Equation (8.29) suggests that the critical flux for ignition is... 

Gas Temperature Approximate Scale EC) Figure 11.22 Surface spread fire growth... 

Figure 3.30. Schematic showing the impact phenomena of multiple droplets on a substrate surface spreading pattern at low impact velocities (fop) and splashing mechanism at high impact velocities (bottom).

Holt and Bernstein [3] conducted a second monitoring exercise to determine LAS along with linear alkyl benzene in sludge-amended soils. Analyses of the anionic surfactant followed the previously established method [2], The agricultural lands sampled had all been surface spread with primary or anaerobically digested sludge. In seven out of nine soil samples collected from fields with sludge application in previous years, the mean LAS level was below... 

Table 1 summarises the features of equipment design which influence the risks of odour problems arising from surface spreading. There are numerous combinations of these features to be found in slurry tankers however, tanker design is often directed more to productivity in terms of speed of operating and area of ground covered rather than to minimising odour and aerosol production. 

The control of ammonia loss by injection has been measured directly and indirectly through crop yields. Hoff et al (21) measured the proportion of applied NH4+-N lost as NH3-N from pig manure over a 3.5 day sampling period. Losses were 14.0, 12.2 and 11.2% from 90, 135 and 180m3/ surface spread respectively. Only 2.5% was lost from 90 and 180 m3/ha injected. 

Soil injection of farm slurries and sewage sludges eliminates the odour and visual problem associated with surface spreading, it can control surface run-off and help prevent watercourse pollution. It can avoid crop taint and pathogen transfer on pastures and can provide soil loosening with better nutrient management. 

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