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The MQH analysis has an enduring presence in design guidance.Using semi-empirical dimensionless expressions derived over 30 years ago, the MQH analysis enables one to predict pre-flashover peak/steady hot gas temperatures in compartment fires, given specific (or limiting) values of heat output,vent parameter and lining thermal inertia.Conversely, it may be used to suggest limiting conditions of fuel areas, vent parameters and lining thermal characteristics to prevent hot gas temperature from exceeding a chosen limit.MQH analysis also purports to enable estimation of the likelihood of flashover.Fresh regression analyses using modern data sets are also available in the literature, which have benefit for lining materials with extreme values of thermal inertia but otherwise confirm the reliability of the original MQH analysis.Practical use of these relationships for design purposes is illustrated and discussed.Limiting conditions to achieve 90% confidence in avoiding flashover are derived.Philosophical objections to the use of MQH analysis to estimate the likelihood of flashover are considered.In particular, the impact of omitting recorded temperatures greater than 600℃C from the various analyses is discussed.A further statistical analysis is presented that first demonstrates the facility of error for use with preflashover fires and which then attempts to illustrate the effect of incorporating higher temperature (and therefore, most probably post-flashover results).