The life safety hazard issues associated with flaming fires of mattress and up- holstered furniture are explored. It is shown that full-scale heat release rate (HRR) is the dominant variable which needs to be controlled. This can be determined directly by full-scale measurement. In many cases, full-scale tests are not convenient to conduct. Thus, it is desirable that bench-scale procedures be available which can be used to predict some of the important features of the full-scale test. Such procedures have been developed at NIST for upholstered furniture during several prior studies. In the present work, differences between the behavior of mattresses and of upholstered furniture are explored. Mattresses and upholstered chairs are soft goods which are constructed in a somewhat similar way: both use padding foams or battings, covered by upholstery fabric. There are differences in construction, however. Mattresses are flat, whereas upholstered chairs normally have seats, backs, and side arms. Also, an upholstered chair is constructed normally on a wood frame, whereas a mattress has no structural components, or else has steel innersprings. The quantitative knowledge of mattress behavior is still not as advanced as that for upholstered furniture. Nonetheless, based on a recent set of tests, the behavior of mattress fires can be quantified initially. Especially, data are now available to predict whether or not a particular mattress construction will lead to a propagating fire. Similarly as for upholstered furniture, such a limit value can be used to determine whether certain regulatory pass/fail criteria are met. The relationship obtained is incomplete, however, because the known roles of ignition source power level (that is, kilowatts output) and geometrical configuration are not yet quantified. Also, there is not yet a detailed explanation for differences between the observed relationships for mattresses and for uphol- stered chairs. Thus, future work will need to be done to address and further quantify these effects.