,oad and workshop by Handyman
Page 45
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ombustibles and spontaneous heating
afe and unsafe storage (2)
The tendency to generate heat is ist marked where a material is finely ided, as the surface area of the aerial exposed to the air and oxidation very large due to this fine division; this particularly so with certain metal wd ars.
A powder that by its composition and ely divided state is found to glow or lite on contact with air is known as rophoric. An example of the action of a rophoric powder on contact with air I be demonstrated when iron is formby reducing iron oxide with hydrogen, the metal produced is spontaneously mbustible.
Aluminium is now in common use; in e powder form it can heat up rapidly d under certain conditions can ignite if posed to pure air after manufacture. Care is taken during transport and storage to keep the powder intact, and away from air streams—any torn or split containers should be sealed at once, and any spillage in a storehouse should be covered with sand and disposed of clear of the building.
Sulphur or sulphur-containing gases in contact with iron can form pyrophoric iron sulphide, and if conditions are such that air is excluded at the time, the iron sulphide becomes particularly reactive and can glow strongly when in contact with normal air; the danger here is that if any petrol, coal gas or other inflammable liquid or gas is nearby it can ignite. It pays at all times to be knowledgeable about the materials being transported, especially if it is intended to store them among other merchandise. Even certain solids can be prone to spontaneous combustion by their formation, and note should be taken of any labels to this effect before storing. An example is freshly made charcoal; and while this is not a particularly commonly transported commodity, where it is prepared by the retort method and especially where it is made from hardwood the risk of spontaneous combustion on contact with air is considerable.
Considering the vast range of inflammable substances that are transported today, it pays to note all labels, as some are carried in seemingly innocent cartons and can be overlooked. Metal polish, lighter fuels and oils for lubrication and cooking are examples: if damaged and spilled these can form the other substances that will bring ignition from spontaneous heating.