ISO TR 10093:2018 pdf free
ISO TR 10093:2018 pdf free.Plastics一Fire tests一Standard ignition sources
To form a diffusion flame ignition source, a gas (usually propane, methane or butane) flows through metallic tubes without ingress of air prior to the base of the flame. These flames simulate natural flames well but they often fluctuate and are not convenient to direct if it is necessary to point any angular presentation toward the specimen.
To form a premixed flame source, a gas burner (usually using propane, methane or butane) fitted with air inlet ports or an air intake manifold is used. Premixed flame sources are typically more directional than diffusion flame sources and are generally hotter than diffusion flame sources.
Gas burners are always set up to conform to precise gas flow rates and/or flame heights. Periodic checks of flame temperature or heat flux precede the setup, but criteria on these parameters are not necessarily an essential part of the laboratory procedure. After setting up the burner for a particular test (i.e. often at an acute angle to the test specimen), it is desirable to leave the burner in this orientation throughout a series of experiments. This objective is conveniently satisfied if the operator simply maintains the gas flow constant to the burner.
The gas burners are connected to the gas supply by flexible tubing via a cylinder regulator providing an outlet pressure, on-off valve, fine-control valve and flowmeter.
Difficulties sometimes occur with the supply and measurement of butane or propane when the cylinders have been stored in an environment cooler than the defined test conditions and/or some distance from the test rig. When difficulties occur, a sufficient length of tubing is used inside the controlled environment (15 °C to 30 °C) to ensure that the gas equilibrates to the appropriate temperature before flow measurement.
NOTE 1 One way to facilitate this equilibration is to pass the gas (before flow measurement) through a metal tube immersed in water maintained at 25 °C.ISO TR 10093 pdf download.
