What is piloted ignition of a solid?
Introduction. Piloted ignition of solids and liquids occurs when a discrete source of energy such as a flame, spark, electrical arc, or glowing wire initiates combustion of the gases and vapors liberated by the condensed phase.
What is a piloted ignition?
▪ Piloted ignition – Ignition of a combustible or flammable material in the. presence of a pre-existing flame (the “pilot” flame)
What is the difference between piloted ignition and autoignition?
Ignition by piloted ignition occurs when the rate of pyrolysis is sufficient to allow the establishment of a diffusion flame, when a spark or small pilot flame is introduced into the boundary layer close to the irradiated surface (Silcock 1995). Autoignition requires very high intensities to occur.
How is ignition of solids done?
The Process of Ignition When a solid material, initially at ambient temperature, is subject to an external source of energy the temperature of the exposed surface starts to increase. A series of physical and chemical phenomena are initiated as the energy reaches the surface of the material.
What is an example of piloted ignition?
The accidental initiation of combustion by means of contact of gaseous material with an external high-energy source, such as a flame, spark, electrical arc, or glowing wire.
What is the piloted ignition temperature?
Ignition to Flaming Combustion: 1. A temperature of 520 °F to 750 °F (270 °C to 400 °C) is necessary for piloted ignition of most organic solids.
Why do we need to know the different ignition sources?
To maximise safety and minimise the risk of a fire, all sources of ignition should be identified and accounted for when a fire risk assessment is being carried out, and employees should be trained in the risks and hazards they face in their day-to-day work.
What is done in an ignition process chemistry?
Ignition is the process of providing the energy that is required to initiate a combustion process. When hydrocarbons interact with molecular oxygen to combust, it requires what is known as activation energy to do so – the minimum energy needed to “activate” a chemical reaction.
What is external source of ignition?
An external ignition source is classified as anything that can deliver enough energy in the form of heat to ignite a substance. This category includes sources such as open flames, electric arcs and sparks and mechanical sparks.
Do solid fuels combust directly?
Combustion of a solid or liquid fuel takes place above the fuel surface in a region of vapors created by heating the fuel surface. Some solid materials can undergo a charring reaction where oxygen reacts directly with solid material. Charring can be the initial or the final stage of burning.
What are the types of combustible solids?
There are two categories of flammable solids: category 1 materials are rapidly burning metals and compounds very resistant to being extinguished by water; category 2 materials are slower burning metals and compounds that are susceptible to extinguishment by water.
What are the different sources of ignition?
Type of ignition sources
- Hot surfaces.
- Flames and hot gases.
- Mechanically produced sparks.
- Electrical equipment.
- Transient currents.
- Static electricity.
- Lightning strikes.
- Electromagnetic waves.