The behaviour of polymeric diphenyl methane-4,4′-diisocyanate (PMDI) is described when examined i... more The behaviour of polymeric diphenyl methane-4,4′-diisocyanate (PMDI) is described when examined in a laboratory small-scale test for its reaction to fire (ease of ignition; heat release and toxic gas production). Full-scale real fire scenarios have also been staged to predict events if (1) drumstock PMDI and (2) sizeable pools of liquid PMDI become enveloped in a fire. PMDI requires a stimulus (e.g. heat) before it will ignite from an applied flame. It then burns in a self-sustaining manner for a few minutes, during which main emissions take place. Then a polymerization reaction begins, producing a low density non-burning residue, which progressively dampens down the burning events by blanket action. Residues of 30–80% sample weight were recorded. The major toxic gas produced is carbon monoxide, though free isocyanate is to be expected in the early stages of the fire, and hydrogen cyanide could be important, especially in well-developed fire conditions. Firefighters should therefore wear full protective clothing and fresh-air breathing equipment. Events when drums of PMDI are exposed to fire depend heavily on the characteristics of the containers, with some rupture steps proceeding with considerable violence. Drumstock PMDI should be stored separately from easily ignitable materials.
Several -i-isocyanates have become commercially important materials, used as intermediates in the... more Several -i-isocyanates have become commercially important materials, used as intermediates in the manufacture of a wide variety of polyurethane products, yet little is recorded on their behaviour if involved in fire. This paper describes a series of programmes carried out under the auspices of the International Isocyanate Institute Inc. First, a small-scale laboratory investigation of the ignition, heat release, smoke and toxic gas production characteristics of di-isocyanates was carried out. Second, their behaviour in drumstock and pool fires, respectively, was examined, using full-sized samples and selected real-fire scenarios. Part 1 records the results for toluene di- isocyanate (TDI) showing the need for a modest energy input to ignite it from a pilot flame. It then burns in a steady rather than vigorous manner, leaving no residues. Toxic gases evolved are mainly carbon monoxide, while free isocyanate is likely in the early stages of the fire, and hydrogen cyanide may be important in well-developed fires. Drumstock material behaviour in a fire is dictated mainly by the rupture characteristics of the containers, which can be violent. A series of simple guidelines is suggested, which includes the need for firefighters to wear full protective clothing and fresh-air breathing equipment. It is also recommended that drumstock TDI should be stored away from easily ignitable materials.
ABSTRACT The Heat Release Rate (HRR) is a critical parameter to characterise a fire. Different me... more ABSTRACT The Heat Release Rate (HRR) is a critical parameter to characterise a fire. Different methods have been developed to estimate it. The most widespread techniques are based on mass balance. If the heat of combustion of the fuel is known, the measure of the mass loss ...
ABSTRACT Oxygen consumption (OC) calorimetry and carbon dioxide generation (CDG) calorimetry are ... more ABSTRACT Oxygen consumption (OC) calorimetry and carbon dioxide generation (CDG) calorimetry are usual methods to determine the heat release rate (HRR) in bench-scale and large-scale fire tests. The paper emphasises on measuring problems associated with fires releasing large amounts of soot. Until now, the soot-related energy transfer was hardly ever taken into consideration in practical applications of HRR calculations. From standard CDG calorimetry, a generalised relationship is introduced in order to take into account the soot generation in the accurate determination of the heat release produced in sooty fires. The analysis of the significance of this correction factor is discussed by theoretical consideration as well as from results of lab-scale experiments recently carried out on chemicals by means of the INERIS fire calorimeter.
ABSTRACT Bare-bead thermocouples are widely used for measuring temperature fields in compartment ... more ABSTRACT Bare-bead thermocouples are widely used for measuring temperature fields in compartment fires. It is well-known that temperature readings using such a device can be significantly affected by radiation errors, the apparent thermocouple junction temperature being thus different from the true gas temperature. However, a probe consisting of two thermocouples of unequal diameters, but made of the same material can be used for estimating the gas temperature in a fire environment. Using a steady-state heat transfer model applicable to a bare-bead thermocouple, a very simple rule is proposed for the estimation of radiation errors when temperatures are measured by use of two thermocouples of different diameters. Radiation errors obtained from this simple rule are compared and discussed with experimental results involving a compartment fire with pyridine as the fuel.
The behaviour of polymeric diphenyl methane-4,4′-diisocyanate (PMDI) is described when examined i... more The behaviour of polymeric diphenyl methane-4,4′-diisocyanate (PMDI) is described when examined in a laboratory small-scale test for its reaction to fire (ease of ignition; heat release and toxic gas production). Full-scale real fire scenarios have also been staged to predict events if (1) drumstock PMDI and (2) sizeable pools of liquid PMDI become enveloped in a fire. PMDI requires a stimulus (e.g. heat) before it will ignite from an applied flame. It then burns in a self-sustaining manner for a few minutes, during which main emissions take place. Then a polymerization reaction begins, producing a low density non-burning residue, which progressively dampens down the burning events by blanket action. Residues of 30–80% sample weight were recorded. The major toxic gas produced is carbon monoxide, though free isocyanate is to be expected in the early stages of the fire, and hydrogen cyanide could be important, especially in well-developed fire conditions. Firefighters should therefore wear full protective clothing and fresh-air breathing equipment. Events when drums of PMDI are exposed to fire depend heavily on the characteristics of the containers, with some rupture steps proceeding with considerable violence. Drumstock PMDI should be stored separately from easily ignitable materials.
Several -i-isocyanates have become commercially important materials, used as intermediates in the... more Several -i-isocyanates have become commercially important materials, used as intermediates in the manufacture of a wide variety of polyurethane products, yet little is recorded on their behaviour if involved in fire. This paper describes a series of programmes carried out under the auspices of the International Isocyanate Institute Inc. First, a small-scale laboratory investigation of the ignition, heat release, smoke and toxic gas production characteristics of di-isocyanates was carried out. Second, their behaviour in drumstock and pool fires, respectively, was examined, using full-sized samples and selected real-fire scenarios. Part 1 records the results for toluene di- isocyanate (TDI) showing the need for a modest energy input to ignite it from a pilot flame. It then burns in a steady rather than vigorous manner, leaving no residues. Toxic gases evolved are mainly carbon monoxide, while free isocyanate is likely in the early stages of the fire, and hydrogen cyanide may be important in well-developed fires. Drumstock material behaviour in a fire is dictated mainly by the rupture characteristics of the containers, which can be violent. A series of simple guidelines is suggested, which includes the need for firefighters to wear full protective clothing and fresh-air breathing equipment. It is also recommended that drumstock TDI should be stored away from easily ignitable materials.
ABSTRACT The Heat Release Rate (HRR) is a critical parameter to characterise a fire. Different me... more ABSTRACT The Heat Release Rate (HRR) is a critical parameter to characterise a fire. Different methods have been developed to estimate it. The most widespread techniques are based on mass balance. If the heat of combustion of the fuel is known, the measure of the mass loss ...
ABSTRACT Oxygen consumption (OC) calorimetry and carbon dioxide generation (CDG) calorimetry are ... more ABSTRACT Oxygen consumption (OC) calorimetry and carbon dioxide generation (CDG) calorimetry are usual methods to determine the heat release rate (HRR) in bench-scale and large-scale fire tests. The paper emphasises on measuring problems associated with fires releasing large amounts of soot. Until now, the soot-related energy transfer was hardly ever taken into consideration in practical applications of HRR calculations. From standard CDG calorimetry, a generalised relationship is introduced in order to take into account the soot generation in the accurate determination of the heat release produced in sooty fires. The analysis of the significance of this correction factor is discussed by theoretical consideration as well as from results of lab-scale experiments recently carried out on chemicals by means of the INERIS fire calorimeter.
ABSTRACT Bare-bead thermocouples are widely used for measuring temperature fields in compartment ... more ABSTRACT Bare-bead thermocouples are widely used for measuring temperature fields in compartment fires. It is well-known that temperature readings using such a device can be significantly affected by radiation errors, the apparent thermocouple junction temperature being thus different from the true gas temperature. However, a probe consisting of two thermocouples of unequal diameters, but made of the same material can be used for estimating the gas temperature in a fire environment. Using a steady-state heat transfer model applicable to a bare-bead thermocouple, a very simple rule is proposed for the estimation of radiation errors when temperatures are measured by use of two thermocouples of different diameters. Radiation errors obtained from this simple rule are compared and discussed with experimental results involving a compartment fire with pyridine as the fuel.
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Papers by Guy MARLAIR