Carbon dioxide generation calorimetry—Errors induced by the simplifying assumptions in the standard test methods

Abstract

SUMMARYCarbon dioxide generation (CDG) calorimetry is commonly used for measuring heat release rates of materials. Calorimetric equation provided in the ASTM E 2058 and the NFPA code 287 is a simplified equation since the water content in the ambient air and the fumes as well as the expansion factor of the combustion gases are neglected. This paper provides general equation for CDG calorimetry based on the Tewarson formulation. A comparison is proposed between the Standard test methods (simplified equation) and the general one. It is shown that the errors induced by the simplifying assumptions are negligible for oxygen depletion factor values commonly encountered in the Fire Propagation Apparatus (where large dilution factors of the combustion gases are used before the measurements of species concentrations).

Calorimetry

“…Modified equations to address specific circumstances or problems, such as heat release rate measurements during suppression experiments, from fires with significant soot yields, or during experiments conducted in a vitiated (reduced O 2 ) environment, can also be found in the literature [26][27][28]. Derivation of detailed equations for carbon oxide calorimetry, a technique that is used extensively by FM Global, can also be found in the literature [29,30]. Carbon oxide calorimetry is discussed in section "Carbon Oxide Calorimetry".…”

Combustion Characteristics of Materials and Generation of Fire Products

“…One more example is a scenario where a fire is suppressed by water (i.e., a sprinkler) and a large amount water vapor is present in the combustion-product-air mixture. Some correction procedures are available (e.g., [106]) to account for these effects.…”

Experimental determination of fire heat release rate with OC and CDG calorimetry for ventilated compartments fire scenario

“…This formulation explicitly introduces ṁ fuel O 2 , the total mass rate of oxygen for the oxidation of the hydrocarbon (C n H m ), and the mass rates of CO 2 , CO, and C generated (ṁ The combustion enthalpies for the known oxidation reactions (Equations (2b) and (2c)) are E O2 CO = 17.6 MJ/kg of O 2 [18] and E O2 C = 12.3 MJ/kg of O 2 [18] when referring to the mass of OC, and E CO2 CO = 6.4 MJ/kg of CO 2 and E CO2 C = 8.9 MJ/kg of CO 2 when referring to the mass of carbon dioxide produced (the equivalent enthalpies indicated in the second relation of Equation (4) are E CO CnHm = 10.8 MJ/kg of CO and E C CnHm = 15.8 MJ/kg of C) [18,20]. The combustion enthalpies of fuel per mass of OC (E O2 CnHm ) or per mass of CDG (E CO2 CnHm ) depend on the nature of the fuel.…”

“…Combined with the mechanical method, this method allows the heat of combustion to be determined. Numerous contributions have discussed specific aspects of chemical methods: the uncertainties [13][14][15][16][17], the effect of soot [18,19], and the discrepancy between several formulations [20][21][22][23]. Some contributions have also pointed out the need for corrections for special applications, for example, the effect of water spray [24] or building scale experiments [25].…”