NISTIR 7341

An Assessment of a Possible Bench 

Scale Screening Protocol For

Predicting Full-Scale Mattress Fire

Behavior

Thomas J. Ohlemiller

 

NISTIR 7341

An Assessment of a Possible Bench 

Scale Screening Protocol For

Predicting Full-Scale Mattress Fire

Behavior

Thomas J. Ohlemiller 

Fire Research Division 

Building and Fire Research Laboratory 

September 2006

U.S. Department of Commerce 

Carlos M. Gutierrez, Secretary 

Technology Administration 

Robert Cresanti, Under Secretary of Commerce for Technology 

National Institute of Standards and Technology 

 William Jeffrey, Director 

 
 1 
An Assessment of a Possible Bench Scale Screening Protocol 

For Predicting Full-Scale Mattress Fire Behavior 

T. J. Ohlemiller 

National Institute of Standards and Technology 

Building and Fire Research Laboratory 

Abstract 

This report summarizes a study of the feasibility of developing a bench-scale protocol for possible use in 

Code of Federal Regulations (CFR) 1633 (open flame) compliance testing of commercial mattress 

designs. It was shown that local resistance to the CFR 1633 gas burner exposure could successfully be

done in one step with a composite consisting of a mattress top panel, tape edge seam and side panel (or

analogous components for a foundation), rather than with separate tests for each component. A second 

type of test (with a different apparatus) is indicated for assessing resistance to commonly encountered, 

persistent mattress/foundation crevice flames which represent a different mode of mattress design

vulnerability. An apparatus for this was developed but not systematically applied. Other vulnerability 

modes may require other tests. The real goal of bench-scale testing, faster and more economical

assessments, is thus unlikely to be achieved and the best approach appears to be full-scale testing. 

Introduction

The Consumer Product Safety Commission (CPSC) recently instituted a regulation (CFR 1633) 

that limits the consequences of open-flame ignition of beds. While the flaming ignition source 

most commonly encountered is small, i.e., match or candle size, the material ignited, bed 

clothing, results in a large fire insult to the mattress and foundation, which contain the bulk of 

the combustible materials. Thus the focus of the regulation is a pair of gas burners, mimicking 

the intensity of burning bed clothes, which are applied to the mattress and foundation. The 

regulation limits the ensuing peak heat release rate from this mattress/foundation combination 

within a particular time frame after ignition (30 min). 

Enforcement of a national regulation of this nature implies both a considerable testing burden 

and the availability of specialized testing facilities. Compliance assessment is usually achieved 

by testing of random purchases of products from the open market. The enforcement process 

could potentially be appreciably facilitated by a small scale screening procedure that, at a 

minimum, cuts down on the full-scale testing burden. 

Ideally the small scale screening procedure would produce results which correlate perfectly with 

the full-scale results of CFR 1633. Thus bench-scale measure(s) made on mattress and 

foundation materials or assemblies would quantitatively predict the peak heat release rate and the 

time to that peak when the mattress/foundation is subjected to the pair of gas burners. 

Experience to date with the myriad subtleties which lead to mattress/foundation fires of varying 

sizes suggests that this ideal goal is simply not achievable both because of the nature of the fullscale test and because of the nature of the objects tested. However, a useful assessment of the 

1 
fire resistance of some aspects of a given design can be achieved and this could reduce the 

amount of full scale testing required. Whether the use of bench-scale testing is ultimately more 

practical and economical is the subject of this study. 

Although nearly all mattress designs responsive to CFR 1633 use barrier layers of varied types to 

obtain passing behavior, it is not sufficient to simply test the barrier itself for resistance to a CFR 

1633 flame exposure. Other layers of the mattress are sometimes factored into the design to 

create passing behavior and, of course, seams are also essential elements. 

The screening procedure originally proposed by NIST consisted of four separate steps. It is 

tacitly assumed that the mattress is a box spring design and the ultimate threat is flaming in the 

space defined by the springs. The first three steps looked for vulnerabilities in the panels and 

seams which form the outer envelope of a mattress or foundation. The fourth step attempted to 

assess the consequences of any vulnerability that is found. In the first two steps, material 

assemblies from each exposed1

 surface or seams bonding two surfaces were subjected to small 

gas burners providing the virtual equivalent of the CFR 1633 burner flame exposures. Seams 

which pass by showing no flame penetration were still to be tested for residual strength in a third 

step. This step was prompted by early experience with a Sleep Products Safety Council (SPSC) 

mattress design which showed a marked tendency for a strong internal over-pressurization in 

full-scale tests with burning bed clothes; this over-pressure split its seams and led to a substantial 

fire [1]. Residual seam strength was intended as a measure of ability to resist such seam 

splitting. Finally, any surface or seam failure (indicated by flame penetration) in the first two gas 

burner exposure steps would prompt a fourth step. This step was intended to provide a measure 

of the peak size of fire the complete mattress/foundation assembly could yield. This utilized 

sections (roughly 30 cm wide2

) of both mattress and foundation assemblies within a special 

holder. Peak heat release rate was to be measured approximately by peak mass loss rate from the 

combined assembly as it burned. 

Had this multi-step screening procedure proved feasible, it would have implied a considerable 

testing burden of its own. Several changes and developments subsequently reduced it to two 

steps. Tests with several mattress designs, described in this report, have shown that substantially 

similar results can be obtained by combining steps one and two such that all mattress surfaces (or 

all foundation surfaces) are subjected to a gas burner in one step3

. The requirement for step three 

(residual seam strength measurement) was obviated by the observation that no other mattress 

design tested by NIST in the last three years has exhibited the strong over-pressurizations shown 

by that early SPSC design4

. The value of step four, burning of sections of the mattress and 

foundation assemblies, was called into question by the present author’s limited attempts to 

implement it and the observation that its results were very likely to be strongly influenced by 

 

1

 “Exposed” here means a surface that would plausibly see flames from burning bed clothes. This includes the 

mattress top and sides as well as the foundation sides and a small upper peripheral portion of its top. 2 The size was dictated by the goal of keeping the maximum fire heat release rate below about 50 kW, an estimate of

what could be handled safely by an overhead laboratory fume hood. 3 What one gives up here is exposure of a substantial length of a tape edge seam. Instead, the tape edge is tested 

only along a length equal to the narrow width of the burner flames. 4

 Numerous weak over-pressurizations have been seen in full-scale tests with the CFR 1633 burners; none appeared

to split any seams. The original SPSC design that was prone to strong over-pressurizations was not a practical 

commercial design for other reasons. 

2 
subtle assembly and/or procedural details which could not be adequately controlled. In 

particular, the edges of the mattress and foundation sections were clearly going to pose very 

difficult-to-control fire paths that would strongly affect the fire size and thus invalidate the goal 

of the tests. Thus only the first two of the above four steps, which are combinable into one step, 

can be viewed as useful to mattress design flammability assessment. 

The results of a comparison between the original two step procedure and the single step 

procedure for testing mattress or foundation surfaces and seams are presented in this report. 

Also presented is a comparison of the results of the single step procedure with full-scale CFR 

1633 tests on eleven mattress designs. 

An additional observation, made repeatedly in full-scale tests [2, 3] with more recent

mattress/foundation designs responsive to CFR 1633 requirements, is that flame persistence in 

the mattress/foundation crevice is an indicator of potential failure. Small flames can persist at a 

given location along the crevice for times that exceed ten minutes and even longer at corners. 

This far exceeds the gas burner duration (70 s on the top of the mattress). What these flames 

lack in intensity (or heat flux imposed on adjacent surfaces), they can more than make up for in 

duration, provoking eventual burn-through of otherwise flame-resistant layers. This prompted 

the development of an additional test that seeks to mimic the threat from these weak, long-lived 

flames in the crevice. That test is also described here. 

Rationale and Limitations of Bench-Scale Mattress Tests. The goal of these tests is to 

ascertain whether burn-through occurs in the mattress/foundation surfaces or seams being tested, 

either during the burner exposure or in any subsequent persistent burning of the sample

materials. In the original four step procedure, each surface or seam was tested individually and 

so any weakness in each emerged in isolation. In the abbreviated, composite testing, the weakest 

surface or seam burns through first and stops the test; the test lasts no longer than the weakest 

component of the assembly. 

In actual usage by CPSC, the test sample would have been cut from a mattress/foundation 

purchased from the open market. The bench-scale test seeks to determine how that 

mattress/foundation would perform if it were subjected to the CFR 1633 burners in a full scale 

test situation. A key issue is whether flames penetrate to the interior side of the sample during or 

after the burner exposure. To make this as realistic as possible, all layers of organic materials in 

the mattress/foundation construction are included as part of the tested sample. The interior of 

the sample then essentially represents the interior, typically spring-filled volume of the mattress 

or foundation. Flaming within either of these volumes in the full-scale mattress/foundation 

usually leads to a growing fire and probable ultimate failure of any reasonable mattress 

flammability criterion. (An exception to this is noted in the test results.) 

This approach essentially assumes that all manufacturers will rely on fire barrier-like materials to 

protect the largely unchanged cushioning materials within their mattress/foundation designs. 

This has been the case for essentially all designs tested thus far. However, this approach, as 

developed here at least, would not work for designs which, instead of barriers, utilize flameretarded versions of the cushioning materials to limit fire growth. Burn-through of such 

3 
materials could be a tolerable condition that did not lead to a large fire (if the materials were 

sufficiently fire-retarded). 

Note that this particular type of bench-scale test can only follow what happens locally as a result 

of this type of burner exposure. The test is over when all burning of sample materials has 

ceased, typically in a few minutes. If this localized burning has not produced any flame 

penetration, the sample is, by this measure, evidently adequate to pass a CFR 1633 type test, 

regardless of the duration criterion that may apply in that type of full-scale test. 

In a full-scale CFR 1633 type of test, the burner application is again local but the fire typically 

continues to spread to other areas of the mattress/foundation5

. Frequently the early flames are 

minimal in size but remarkably persistent in time (especially in more adiabatic locations like the 

mattress/foundation crevice). Some of the heat from these flames accumulates within the 

mattress and foundation interior volumes. Often a consequence of that accumulation is a gradual 

strengthening of the fire continuing to spread elsewhere on the mattress or foundation. 

Subsequent fire development and the ultimate peak heat release rate of such a fire (within some

time period) are highly dependent on details of materials and construction and are not predictable 

from the behavior exhibited during the burner exposure. The supplemental crevice test can at 

least pick up the vulnerability to burn-through after extended, low level flame exposure. This 

result again does not foretell the size of any subsequent fire but it does imply a greater likelihood 

of a fire of some significance.

Description of the Test Apparatuses 

Surface Burner. Figure 1 is an overall view of the bench-scale gas burner assembly. Figure 2 

is a schematic of the flow system that supplies propane to the burner head. 

The burner head consists of a pair of T-burners, each made from 0.95 cm OD by 16.5 cm long 

stainless steel tubing having a straight-line series of 18 holes (nominally 0.13 cm diameter) for 

gas jets. The pair of tubes is held 5.4 cm apart with their gas jets pointed toward each other at an 

approximately 45o angle. This pair of burner tubes serves the same function as the single 

horizontal burner tube in the CFR 1633 apparatus. Two tubes were used here because of the 

need to more uniformly expose the protrusive shape of a mattress or foundation tape edge in the 

original four step screening procedure6

. The burner pair is held at a fixed distance (20.3 mm) 

above the test surface by means of a pair of stand-off feet. This distance, in combination with 

the gas flow rate to the burner pair, determines the heat flux which the burners impose on the test 

surface. Figure 3 shows the measured peak heat flux to the test surface as a function of 

transverse distance along a line near the center of the pair of burner tubes. The flux is measured 

with a 6 mm diameter, water-cooled, Schmidt-Boelter gage that yields a cold-wall total heat flux 

(convection plus radiation). Such flux measurements are generally accurate to better than ± 5 % 

 

5

 In an actual bed fire the flames continue to spread elsewhere with more speed and vigor because of burning bed 

clothes. 6

 In the original four step procedure, the tape edge seams were tested with the seam parallel to the pair of burner 

tubes and halfway between (but below) them. The gas jets thus impinged on both sides of the tape edge as it

protruded upward from the sample as it was laid out flat with mattress/foundation top and side surfaces in the same

plane. One burner tube would suffice for the simplified test procedure discussed later in this report but a switchover 

to one tube would require extensive re-calibration of the heat flux from the burner. 

4 
but the flux has a substantial high frequency noise level due to eddies in the turbulent diffusion 

flame provided by the gas burner. The flux tends to peak in the neighborhood of the 

impingement points of individual gas jets and a longitudinal scan along the burner assembly 

centerline shows three or four localized peaks (ca. 5 mm wide) near the burner center that are 10 

% higher than the (78 to 80) kW/m2

 peak in Fig. 3. These fluxes (particularly the localized 

peaks) are higher than the nominal average flux of about 73 kW/m2

 reported for the horizontal 

CFR 1633 gas burner in Ref. 1. However, considerably more effort was put into flux vs. position 

characterization and spatial resolution in the present study7

, as compared to Ref. 1; it is quite 

probable that these localized, jet-induced heat flux peaks exist also with the CFR 1633 burner. 

The spatial average of the peaks along the burner centerline, near the burner center, is about 75 

kW/m2

. 

This horizontal burner assembly lays atop the test surface with nominally the same downward 

force that is exerted by the horizontal burner in CFR 1633 (i.e., 170 g to 230 g, 6 oz to 8 oz, 

applied on a total support foot area of 6.5 cm2 , 1 in2

). This force is applied so that the burner 

will follow any shrinkage of the heated test surface (in much the same manner burning bed 

clothes on top of a bed would do so). Here this is accomplished mechanically by mounting the 

burner assembly on a vertical guide rail and counterbalancing most of the burner assembly 

weight with a brass weight attached via a pair of cables running over a pulley system. There is 

more friction in this system than is desirable. To eliminate its effect on the net downward force 

of the burner, an electro-mechanical vibrator is attached to the support framework to prevent any 

sticking. 

The duration of the flux impingement is determined by a time delay relay operating a solenoid 

valve in the gas supply line to the burner (Fig. 2). As with the CFR 1633 horizontal burner, the 

duration is set to 70 s, a value inferred from burning bed clothes measurements in Ref. 1. 

In the original four step mattress screening procedure described in the Introduction, horizontal 

mattress or foundation surfaces were tested in a horizontal position with the above burner 

assembly. Vertical surfaces, however, were tested with a separate, much simpler vertical burner 

assembly using nominally the same heat flux conditions as those applied in CFR 1633 to such 

surfaces. A single T burner (same dimensions as the pair above) was rigidly mounted in a 

vertical orientation and positioned relative to the test surface with a single stand-off foot. Scans 

of this burner showed that it gave peak heat fluxes slightly higher than the nominal vertical 

burner values in Ref. 1 (ca. 58 kW/m2

 vs ca. 53 kW/m2) along the upper 50 % to 60 % of its 

length. However, it gave quite high localized (few mm2

) heat flux peaks due to non-diffused 

gas jets on its lower portion so that the section of the sample that would have been impinged by 

this lower portion of the burner was masked to preclude exposure to these excessive heat fluxes. 

As in CFR 1633, the vertical tests utilized only a 50 s exposure to the burner. As in the 

horizontal seam tests, a vertical seam was tested with that seam aligned parallel to the long 

 

7

 A 6 mm diameter, Schmidt-Boelter, total heat flux gage was embedded flush into the surface of a water-cooled 

aluminum plate mounted, in turn, on a two-axis mechanical stage for scanning the gage position relative to the gas 

burner flames. The gage and plate were cooled with hot water to preclude false readings from water condensation. 

Flux measurements were made at a variety of gas flow and burner positioning conditions to find a combination

nearest to the nominal results of Ref. 1

5 
direction of the burner so that several cm of the seam length were exposed to the 58 kW/m2

 flux 

peak. 

As noted in the Introduction, tests were also performed using composite assemblies of all 

mattress or foundation surfaces. In this case a test sample consisted of a rectangular patch 

removed from the top and side of a mattress or foundation so as to include a section of the top, 

the tape edge seam and a portion of the side. The side portion in some cases included a vertical 

side seam. This assembly was laid out horizontally and tested flat using the horizontal burner. 

In such tests, the sample was rotated 90 degrees so that the burner flames were perpendicular to 

the tape edge seam but were parallel to and coincident with the “vertical” seam, if present. The 

tape edge is thus exposed only along a short section equal to the width of the burner flame (and 

to the peak flux only at one spot; see Fig. 3). Note that this achieves the goal of testing some

portion of all elements of interest in a single exposure. However, the side surface (and its seam, 

if present) now sees the higher flux, longer duration condition seen in the alternative procedure 

above only by horizontal surfaces. This aspect of this composite test procedure is thus more 

severe than CFR 1633. 

The emphasis on burn-through (or flame appearance on the interior side of the material 

assembly) as the ultimate outcome of these tests points to a need to assure against false flame 

penetrations as a result of a bypass around the sample edges. This issue is addressed by the 

design of the sample holder. 

Sample Holder. The samples themselves are 38 cm by 23 cm while the flame exposed area is 

only about 16 cm by 7 cm to 8 cm. The extra sample area serves two purposes. First, some of 

the additional peripheral material allows persistent localized flaming as in CFR 1633 and this 

may result in burn-through of materials weakened by the burner exposure. Second, the outer 

periphery of the sample provides a region intended to be a barrier to flames trying to work their 

to the sample rear side via the sample edges (an unrealistic path peculiar to testing sections of a 

mattress rather than the full mattress). 

Figures 4a and 4b show two views of the sample holder. It is essentially a metal box with two 

compartments. The upper compartment holds the sample in its interior and, on its exterior, a 

simple pulley system for applying a fixed tension force (typically 2.0 kg) in the plane of the 

sample. The sample rests on a peripheral, stainless steel “shelf” that is approximately 5 cm wide 

by 0.6 cm thick. The thickness is chosen to provide thermal heat sinking mass as part of the 

effort to suppress sample edge bypass flames. 

The sample itself poses a substantial challenge here since it is not of uniform thickness in any 

embodiment that includes portions from two different surfaces of a mattress or foundation. The 

difference in thickness between a mattress top and mattress side can be many centimeters since 

the former includes cushioning layers of indefinite, but potentially large thickness8

. As noted 

previously, the goal in the test is to lay the outer surface of the sample in a plane so that it bears a 

constant spatial relationship to the gas burner flames, thus fixing the heat flux this surface sees. 

The thin side of a non-uniform sample (e.g., the portion from the mattress side panel) is therefore 

 

8

 The upper portion of the sample holder can accommodate sample thicknesses up to 15 cm (6 in). 

6 
supported underneath by an appropriate thickness of rigid fiberglass batt on its periphery so the 

top surface of the test piece is flat across its full dimensions. 

No pillowtop designs were included in any of the testing. It is not clear how one should apply 

the approach used here to the more complex geometry of a pillowtop though laying the pillow 

edge convolutions out flat may be the only viable alternative with this apparatus. 

The top of the sample is covered on its periphery by a stainless steel frame, again about 5 cm

wide, intended to be a heat sink to any flames moving toward the sample periphery. One straight 

side of the frame is a separate piece to accommodate the application of the tension force in the 

plane of the top surface of the sample. Thus opposite sides of this frame, unconnected to each 

other, each grip the sample top by means of thin spikes (1.3 mm dia by 13 mm long) protruding 

from their lower surfaces. A pair of cables attached near opposite ends of the straight frame side 

applies the tension weight evenly to the sample top. 

The above system is well-suited to prevent flaming bypass of the sample edges provided that the 

sample top itself is in continuous contact with the upper peripheral frame. However, mattresses 

provide top surfaces of quite variable top surface relief, depending on the depth of the quilt layer. 

For most mattress designs tested it was necessary to supplement this system with pieces of 

ceramic wool filling, as much as possible, any gaps (due to the quilt pattern relief) between 

mattress surface and frame. Even so, mattress designs including a sacrificial layer of fiberfill 

above the barrier in the quilt layer could still allow flames to bore though the sample periphery 

and attempt to reach the sample rear by going around the sample edge. Adequate protection in 

this regard was a learning process that continued to adapt as new mattress designs were 

encountered. A fraction of the data obtained in this study was probably affected by this bypass 

burning problem; suspect data are flagged below.

The goal of the test is to see whether flames penetrate through the sample (not around its edges) 

to the lower portion of the sample holder box. Two redundant means of detecting flames are 

used. A pair of silicon photodiodes views this volume from opposite sides of the lower box. 

Their output is recorded by a computer. Alternatively, flame penetration can be seen visually by 

the test operator using a mirror that provides a wide view of the underside of the sample. To 

facilitate either detection mode, smoke accumulation in the box (caused by pyrolyzing sample 

materials) is kept to a minimum by a weak flow out an exhaust duct on the side of the lower 

section of the box. The time from the onset of the burner flame to first detection of flames in the 

lower portion of the box is recorded to the nearest second. Visual observation of burn-though 

times are accurate to about ± 1 s. Due to the uneven nature of the lower surface of samples that 

include, for example, a portion of a mattress top and side, one or both of the photodiodes may 

not have a good view of penetrating flames. Visual observations by an experienced operator are 

more reliable once some of the pitfalls of this test are learned.9

 

Crevice Test. Figure 5 shows a picture of the crevice test assembly. Its goal is to subject 

sections of the mattress and adjacent foundation to the same level of flame intensity as was found 

in persistent crevice flames during full-scale mattress tests (38 kW/m2 ± 6 kW/m2 ; Ref. 3) for ten 

 

9

 These include light coming through the sample when flames do not. This can happen in panel areas as well as at 

seams. 

7 
minutes or more to ascertain whether this yields flaming on the mattress or foundation interior 

surfaces. The set-up recreates a crevice as follows. The material assemblies from mattress and 

foundation are each clamped over a basic shape-fixing structure that consists (for each assembly) 

of a piece of expanded stainless steel (0.013 cm thick by 32 cm wide by 39 cm long with 

diamond-shaped openings 7 cm by 3 cm) bent at 90o so as to form a 16 cm high surface for a 

mattress or foundation side panel and a 23 cm deep section of mattress or foundation “top” 

surface. The various layers of materials are assembled in proper order and clamped onto the 

expanded metal to create 32 cm wide, appropriately-shaped sections of mattress and foundation. 

The mattress section is then clamped on top of the foundation section to create the desired 

crevice. When these two sections are clamped together, a 1.0 cm diameter tube, porous along 

one half of its circumference, is inserted ca. 5 cm into the crevice. This porous tube provides a 

means to inject a low flow of propane into the crevice which recreates the persistent, weak 

flames seen in full-scale mattress tests. Proper adjustment of the propane flow rate creates 

flames that hover inside the “mouth” of the crevice (after the ticking and any sacrificial layer 

outside the barrier layer are burned out). This propane substitutes for the unknown fuel gases 

coming from deeper layers in real mattress/foundation crevices. The crevice flame duration can 

then be made to be any desired value. 

The crevice assembly is mounted on a simple framework that supports it above the bench top. 

The frame also supports two mirrors that allow the test operator to see the rear surfaces of both 

the mattress and foundation assemblies to detect any flame penetration. 

As with the assemblies used in the preceding tests, there is a threat that flames will make their 

way to the “interior” by going around the periphery of the assembly. Here that problem is dealt 

with by using ceramic wool in the crevice area and aluminum foil wrapped over the outer edges.

Test Materials. Eleven mattress/foundation designs, previously tested with the CFR 1633 

protocol, have been tested in the bench-scale burner exposure apparatus. These include three of 

the Sleep Products Safety Council (SPSC) designs described in Ref. 1, two other SPSC designs 

tested by the California Bureau of Home Furnishings, and 6 designs built for CPSC for which the 

full scale results are reported in Ref. 3. In the case of the SPSC designs, separate panels for 

bench-scale testing were made at the same time as the mattresses. For the CPSC designs the 

bench-scale samples were cut from spare mattress/foundation pairs. 

All of these designs are based on the use of barrier materials between the external fabric layer 

(ticking) and the mattress/foundation interior. In most cases this barrier is a relatively thin layer 

just under the ticking. In some cases it is more diffuse, perhaps consisting of alternating layers 

of a charring fiber and normal polyurethane foam. The first three SPSC designs are summarized 

in Table 1, the second two in Table 2 and the six CPSC designs are summarized in Table 3. In 

this report, the SPSC designs will be referred to as M1, M3, etc. and the CPSC designs as D1, 

D2, etc. 

Table 4 summarizes the full scale peak heat release rate and time to that peak as found with the 

CFR 1633 test protocol for all of the above designs. 

Results and Discussion

8 
Surface Burner Tests. Comparison of Results for Two Sample Testing Modes. Recall that

the original bench-scale testing mode called for testing each surface and seam separately while 

the revised protocol calls for testing all surfaces from a mattress or foundation at one time, as a 

composite that incorporates top and side surfaces held together by the manufacturer’s original 

seams. In all cases mattresses and foundations are tested separately. Table 5 shows a 

comparison of the test results from these two testing modes for the five M designs. 

In Table 5 the two columns on the left are results from the original protocol. Thus there are data 

reported for the measured burn-through times of each component (mattress top panel, mattress 

tape edge seam, mattress side panel plus the same three items for the foundation). A value of 

“none” means that no burn-through occurred over the burner exposure time plus a post exposure 

time that lasted out to 5 min or more (by which time all materials on the exposed surface -out to 

the sample holder frame- had usually self-extinguished). 

In Table 5 the two columns on the right are the results for the testing of the composite (top panel, 

tape edge seam, side panel) from the mattress or foundation. 

Comparison of the two modes of testing shows that there is never perfect agreement in the burnthrough times. Such agreement (even of replicate test averages) is not to be expected given the 

nature of the materials and the limited number of replicates. With the exception of the M3 

design, there is however a general tendency for the results from the two testing modes to be 

similar in that both modes give roughly similar values for the shortest times to a burn-through. 

In looking at the data from the original protocol (left side of Table 5) it is the shortest time for 

any given component that is to be compared to the composite value on the right hand side. Thus 

the composite testing clearly gives much less data on the vulnerability of specific aspects of a 

design. The large savings in testing time in the composite tests is their main virtue. 

The behavior of the M3 mattress composite in Table 5 is scattered but both modes of testing 

suggest a vulnerability of the design. In actual full scale tests this design generally looked much 

better than the Table 5 results imply. It gave large fires only late in tests in cases where the 

foundation wood got involved. The particular barrier used here, which is also the ticking in this 

design, can remain intact (no holes except a 2 mm to 3 mm gap along the tape edge seam) and 

still permit ignition of materials in the mattress interior. This intact barrier tends to limit the air 

supply to an internal fire (in a mattress; not necessarily so in a foundation) and keeps it very 

much limited in heat release rate. For such barriers, either test protocol used in Table 5 would 

raise questions. This simply means that the test, in these circumstances, is conservative and 

suggests a need for a full-scale test as a check. 

Overall, the results in Table 5 indicate that the composite test is about as effective as the more 

time consuming tests of individual components of a design, That said, there is limited 

information in the Table 5 results. If one takes the conservative position that any indication of a 

burn-through is a sign of a need for further testing, then all of the designs in Table 5 need such 

testing; all gave at least one burn-through in both individual component and in composite tests. 

In fact the designs in Table 5 gave widely-varying full-scale performance in CFR 1633 tests; see 

Table 4. The time to burn-through seems to offer some hint about this, as discussed below. 

9 
Table 6 summarizes composite test results for the six CPSC designs (D1 through D6 described in 

Table 3). All of these designs included a flame barrier and, except for D4, all did generally well 

in full-scale CFR 1633 testing (see Table 4). It should be noted here that designs D1 through D5 

had continental foundations which means that the materials of the sidewall of the foundation 

continue unbroken onto the foundation top for 5 or more centimeters. This usually puts the 

foundation top panel materials so far back into the mattress/foundation crevice that they do not 

see the gas burner flames. Thus their poor performance (Designs D4 and D5) in the bench scale 

test is not likely to have an effect on full-scale performance. 

Note that several of the burn-throughs listed in Table 6 appeared to be due to flame penetration 

around the edges of the sample assembly (denoted as a “frame bypass”). Again, precluding this 

type of misbehavior in the test is a learning process and it is most problematical with deeply 

quilted samples. One mattress failure of Design D3 was through the seam on the side panel; its 

wide opening suggests a failure to use the proper flame-resistant thread in that particular sample. 

At least one and possibly two of the failures of a Design D4 mattress sample (the first) was due 

to defective construction of the barrier layer; the relatively poor performance of this design in 

full-scale tests could have had the same cause, though its late occurrence argues against this. 

Figures 6 and 7 show the full-scale peak heat release rate values obtained with the M series and 

D series designs (data from Table 4). The data are arranged in the order of smallest average 

value (over the replicates) to the largest. In Fig. 8 is a plot of a bench-scale measure on the M 

series – the time to sample burn-through. Comparison of Fig. 6 with Fig. 8 does suggest an 

approximate inverse correlation between peak heat release rate (HRR) and bench-scale burnthrough time. However, there is no sensible way to make a similar attempt at a correlation with 

the D series data in Table 6, especially after one removes the several points for which burnthrough occurred via a frame bypass. In fact, given that most current mattress designs 

employing flame barriers show greatly delayed heat release rate peaks that occur tens of minutes 

after gas burner exposure in CFR 1633, there is no physical reason to expect the burn-through 

time (if any) should correlate with peak HRR. The bench-scale burner exposure really only 

gives a measure of whether a mattress design is immediately vulnerable to local gas burner 

exposure. If it is, of course, the design is fatally flawed. This bench-scale test cannot predict the 

ultimate fate of a mattress tens of minutes later as it is subjected to persistent propagating flames, 

especially persistent flames in the mattress/foundation crevice. 

Other Tests. The crevice test (Fig. 5) was conceived as a complement to the above test. It 

attempts to pick up the most likely (based on several years of test experience) longer term

vulnerability of a mattress design, i.e., one that shows up after ten or more minutes of persistent 

weak flaming in the mattress/foundation crevice. It is certainly a preferable alternative to the 

original fourth test proposed as part of a screening protocol. That fourth test, mentioned in the 

Introduction, attempted to reconstruct and burn a section of the mattress and foundation to get a 

measure (via rate of weight loss) of the potential peak HRR that the sample materials could give 

after local failure of a seam or barrier layer. Only limited work was done with that test because it 

was evident that the burning process in the test apparatus was influenced entirely too much by 

the fact that the sample was a finite section (roughly 30 cm wide) whose edges were strongly 

affecting the fire behavior. The results would thus reflect more of the interaction of the materials 

10 
with the apparatus rather than giving a true measure of expected behavior from a full-scale 

mattress/foundation fire test. 

The crevice test has a more modest goal – to ascertain whether internal ignition will occur 

through either the mattress or foundation outer layers as a result of an extended weak flame 

exposure. The test was developed to the point where it appeared to be capable of achieving its 

goal. However, it was not systematically applied to any set of mattress designs before this study 

was ended. Thus its viability in this regard must be viewed as unproven. 

Summary and Conclusions. 

The goal of a bench-scale test protocol which predicts the CFR 1633 behavior of a 

mattress/foundation design must be viewed as somewhat quixotic. The actual behavior of real 

mattresses, especially those with some level of flaming resistance built in, is highly varied and 

prone to evolve slowly tens of minutes after the brief gas burner exposure. At this point it is 

clear that not all of the physical processes that dictate ultimate fire size are fully understood. The 

test procedures developed here aimed at looking first at the immediate response of the assembly 

of mattress or foundation materials to gas burner exposure – the possibility that the burner flames 

will yield a local penetration to the interior where they could be expected to cause a serious fire. 

Tests of several designs were ambiguous about the relation between local burn-through time and 

overall full-scale mattress fire behavior. Furthermore, most of the designs with fire barriers did 

not yield any burn-throughs; sporadic “frame bypass” events in the tests added an element of 

unreliability that could only be overcome by re-testing with ever greater precautions and 

protections of the sample edges. Experience with full-scale mattresses points to the need for a 

complementary crevice test to ascertain the vulnerability to a separate mode of potential failure. 

More recent experience with certain full-scale mattress designs points to yet another potential 

failure mode – barrier splitting due to shrinkage. It is impractical and uneconomical to develop 

separate bench-scale tests for all possible failure modes in mattress designs. Thus, at this point, 

it appears that the only practical solution for assessing the compliance of mattress designs with 

CFR 1633 is full-scale testing. 

11 
Acknowledgements 

Randy Shields of NIST was instrumental in all of the set-up and testing of the apparatuses 

discussed here. Gail Stafford and Drew Bernatz of CPSC became very proficient with the panel 

testing apparatus and provided most of the mattress design test work reported here. 

This work was sponsored by the Consumer Product Safety Commission. The content of this 

report does not necessarily reflect the views of the Commission nor does the mention of trade 

names, commercial products or organizations imply endorsement by the Commission or the 

USFA. 

References

1) Ohlemiller, T., Shields, J., McLane, R. and Gann, R., “Flammability Assessment 

Methodology for Mattresses,” National Institute of Standards and Technology NISTIR 

6497, June, 2000 

2) Ohlemiller, T. and Gann, R., “Effect of Bed Clothes Modifications on Fire Performance 

of Bed Assemblies,” NIST Technical Note 1446, February, 2003 

3) Ohlemiller, T., “Flammability Tests of Full-Scale Mattresses: Gas Burners versus 

Burning Bed Clothes,” NISTIR 7006, July, 2003 

12 
Table 1. Component Materials in SPSC Mattress Designs 

(Refer to Figure 5 for Component Locations)

M 1 M 3 M 5 

Ticking Std. Damask Combined

fabric/barrier

MVSS 302 damask

Quilt 19 mm (3/4 in) 

std. PU10 foam 

(19.2 kg/m3

, 

1.2 lb/ft3) in 

quilt 

Same as Mattress 

#1 

19 mm (3/4 in) TB 

117 PU foam in 

quilt 

Topper Pad 25.4 mm (1 in) 

std. PU foam 

(19.2 kg/m3

, 

1.2 lb/ft3

) 

Same as Mattress 

#1 

12.7 mm (0.5 in) 

TB 117 PU foam

(19.2 kg/m3

, 1.2 

lb/ft

3

) over 1.1 

kg/m2

 (3.5 oz/ft2) 

boric acid treated 

cotton batt 

Insulator Thermo-plastic 

Mesh Pad 

Thermo-plastic

Mesh Pad 

Thermo-plastic

Mesh Pad 

Spring Unit Twin 

Innerspring 

Twin Innerspring Twin Innerspring 

Mattress 

Border 

 6 mm (1/4 in) 

std. PU foam 

(19.2 kg/m3

, 

1.2 lb/ft3

) 

under std. 

Damask 

Same as Mattress 

#1 

Boric acid treated 

cotton batt under 

MVSS 302 damask 

Thread Standard Combustion

modified 

Standard

Foundation 

Border 

Same as 

mattress 

Same as mattress Same as mattress

Foundation 

Top Pad 

0.62 kg/m2

 (2 

oz/ft2

) 

polyester fiber 

pad 

0.62 kg/m2

 (2 

oz/ft2

) polyester 

fiber pad 

0.62 kg/m2

 (2 

oz/ft2

) polyester 

fiber pad 

 

10 PU = polyurethane 

13 
Table 2. Second Set of SPSC Designs 

M6 M7

Ticking Class “B” Class “B” 

Quilt Charring fiber A over 1 oz 

PE11 fiber over 2.5 cm (1 in) 

PU foam

Charring fiber B over 2.5 cm

(1 in) PU foam

Upholstery 2.5 cm (1 in) PU foam (1.2 

pcf) 

2.5 cm (1 in) PU foam (1.4 

pcf) 

Insulator Std Shoddy Pad Std Shoddy Pad 

Spring Unit Steel Coil Spring Steel Coil Spring 

Border Charring fiber A under 

Ticking 

Charring fiber layer plus

Charring fiber B 

Thread Aramid Combustion modified

Closing Tape Std PE Std PE 

Fdn Ticking Same as mattress Same as mattress

Fdn Filler Cloth Non-Skid Non-Skid

Fdn Spring Unit Semi-flex on wood frame 

w/slats 

Semi-flex on wood frame 

w/slats 

Fdn Thread Aramid Combustion modified

Fdn Border Style Continental border Continental border 

 

11 PE = polyester 

14 
Table 3. Nominal Composition of CPSC Mattress/Foundation Designs12

Design 1 Design 2 Design 3 Design 4 Design 5 Design 6 

Mattress 

Ticking Class B 

damask 1 

Class B 

damask 2

Class B 

Class B 

PE/Cotton 

65 %

Cotton/35 %

PE 

PE, PP, 

cotton 

blend 

Quilt Layer Charring 

barrier 

fabric A 

over 19 

mm (0.75 

in) PU 

foam

Charring 

barrier 

fabric B 

over 19 

mm (0.75 

in) PU 

foam

FR cotton

over 13 

mm (0.5 

in) PU 

foam

Charring 

barrier 

fabric D

over 25 

mm (1 in) 

soft PU 

foam

Fiberfill 

over 

composite 

barrier layer

over 6 mm

(0.25 in) PU 

foam

Charring 

fiberfill 

blend over 

9.5 mm

(0.38 in) 

PU foam

Layers on 

Springs 

25 mm (1 

in) PU 

foam over 

PP net 

25 mm (1 

in) PU 

foam over 

PP net 

FR cotton

over 25 

mm (1 in) 

PU foam

over 

needled 

FR cotton

(6 mm) 

19 mm

(0.75 in) 

PU foam in 

two layers 

over 

shoddy pad 

Two 25 mm

layers of 

undescribed 

materials 

FR cotton

over 13 

mm (0.5 in) 

PU foam

over 

blended 

fiber pad

Mattress 

Border 

Same as 

quilt layer 

but 

without 

PU foam

Same as 

quilt layer 

but 

without 

PU foam

Quilted 

FR cotton

Lighter 

weight 

charring 

barrier 

fabric D

inside 

ticking 

Composite 

barrier layer

inside 

ticking; 6

mm PU 

foam behind 

barrier 

Lighter 

weight 

charring 

fiberfill 

blend under 

ticking 

Foundation 

Top 

Std nonskid fabric 

over 

charring 

barrier 

fabric C

Std nonskid fabric 

over 

charring 

barrier 

fabric C

Cover 

fabric 

over two 

6 mm 

layers of 

FR cotton

Cover 

fabric over 

“std 2 oz 

insulator” 

pad 

Composite 

barrier layer

under cover 

fabric

Cover 

fabric over 

FR cotton 

over 

blended 

fiber pad

Foundation 

Border 

Same as 

mattress 

border; ca. 

95 mm

wide 

Cont’l 

Same as 

mattress 

border; ca. 

95 mm

wide 

Cont’l

Same as 

mattress 

border; 

ca. 70 

mm wide 

Cont’l

Same as 

mattress 

border; ca. 

90 mm

wide 

Cont’l

Composite 

barrier layer

under 

ticking; ca 

65 mm

Cont’l

Same as 

mattress 

border (but

barrier is 

apparently

lighter)

Seams All fire 

resistant 

thread 

All fire 

resistant 

thread

All fire 

resistant 

thread

All fire 

resistant 

thread

All fire 

resistant 

thread

All fire 

resistant 

thread

 

12 Abbreviations: PU = polyurethane; PP = polypropylene; PE = polyester; FR = fire-retarded; Cont’l =

continental border. All fire resistant features indicated in italics. 

15 
Table 4. Summary of Average Peak HRR and Time to Peak 

In Full-Scale CFR 1633 Tests of Mattress/Foundations 

Matt/Fdn Designation Peak HRR (kW)13 Time to HRR Pk (s) 

M1 93014 200 

M3 35 0

M5 42015 970 

M6 ca. 200016 1900 

M7 22 30

D1 0,0,0 0, 0, 0 

D2 20, 35, 20 N. A.17, 1200, N. A. 

D3 455, 20, 20 3525, N. A., N. A. 

D4 1245, 995, 870 3250, 3310, 3545 

D5 50, 20, 20 900, N. A., N. A. 

D6 20, 490, 20 N. A., 2780, N. A. 

 

13 For all of the M series designs, the results for peak HRR and time to peak are the average of two tests

(M1, M3, M5) or three tests (M6 except as noted below and M7). For the D designs, individual test results 

are listed. 14 Data obtained at a commercial testing lab. There were indications from later NIST tests of this design

that the peak HRR here was probably about 50 % larger than this but was underestimated due to smoke

spillage from the hood. 15 This design was quite variable in performance in various tests and could give two appreciable heat

release peaks, sometimes as large as 600 kW 16 Tested in a room at CBHF. These tests had to be terminated before they peaked but one of three 

exceeded 2.6 MW; the other two were stopped before reaching 1 MW. The room environment can be 

expected to have boosted the peak HRR values above those to be seen in an open hood, which was the 

condition for all of the other tests reported here. 17 N. A. here means that no time to peak could be measured since the peak, reported as 20 kW, was below 

the sensitivity of the hood system used. 

16 
Table 5 

Comparison of Test Results for Two Sampling Modes 

Left Two Columns: Surfaces/Seams Tested Individually

Right Two Columns: Top/Seam/Side Tested as Unit 

Design and 

Component 

Surface 

Time to Any Burn -

Through (s)18

Design, Mattress 

or 

Foundation 

Time to Any Burn -

Through (s)19

M1 Matt Top 

Panel 

42, 44, 53 

M1 Matt Tape 

Edge

40, 44, 45 M1 Mattress 10, 10 

M1 Matt Side 

Panel

5, 4 

M1 Fdn Top 

Panel

45, 61, 70 

M1 Fdn Tape 

Edge 

none, 32, 50 M1 Foundation 7, 8 

M1 Fdn Side 

Panel 

8, 5 

M3 Matt Top 

Panel

177, 156, none 

M3 Matt Tape 

Edge

none, 41, 66 M3 Mattress 100, 115,

 68 with side seam

M3 Matt Side 

Panel 

none, none 

M3 Matt Side 

Seam

none, none 

M5 Matt Top 

Panel 

320, none, 241 

M5 Matt Tape 

Edge 

17, 18 M5 Mattress 33, 28,

28 with side seam

M5 Matt Side 

Panel 

none, none 

M5 Matt Side 

Seam

none, none 

 

18 Horizontal surfaces tested at higher flux for 70 s; Vertical surfaces tested at lower flux for 50 s 

19 All assemblies tested at higher flux for 70 s 

17 
Design and 

Component 

Surface 

Time to Any Burn -

Through (s)20

Design, Mattress 

or 

Foundation 

Time to Any Burn -

Through (s)21

M5 Fdn Top 

Panel

58, 53, 75 

M5 Fdn Tape 

Edge 

20, 12, none M5 Foundation 31, 21

M5 Fdn Side 

Panel 

none, none 

M5 Fdn Side 

Seam

none, none 

 

20 Horizontal surfaces tested at higher flux for 70 s; Vertical surfaces tested at lower flux for 50 s 21 All assemblies tested at higher flux for 70 s 

18 
19 

Table 5, Cont’d 

Comparison of Test Results for Two Sampling Modes 

Left Two Columns: Surfaces/Seams Tested Individually 

Right Two Columns: Top/Seam/Side Tested as Composite 

Design and 

Component 

Surface 

Time to Any Burn 

Through22 (s) 

Design, Mattress 

or 

Foundation 

Time to Any Burn -

Through (s)23

M6 Matt Top 

Panel 

378, none, none 

M6 Matt Tape 

Edge 

97, 99 M6 Mattress 75, 71, 

77 with side seam 

M6 Matt Side 

Panel 

none, none 

M6 Matt Side 

Seam 

135, none 

M7 Matt Top 

Panel 

(406), none, none 

M7 Matt Tape 

Edge 

none, none M7 Mattress none, none, 

158 with side seam 

M7 Matt Side 

Panel 

none, none, 

M7 Matt Side 

Seam 

none, none 

M7 Fdn Top 

Panel

39, 39, 35 

M7 Fdn Tape 

Edge 

75, 13, 9 M7 Foundation 31, 32 

M7 Fdn Side 

Panel 

none, none 

M7 Fdn Side 

Seam 

none, none 

 

 

 

22 Horizontal surfaces tested at higher flux for 70 s; Vertical surfaces tested at lower flux for 50 s 

23 All assemblies tested at higher flux for 70 s 
Table 6. Summary of Composite Bench-Scale Test Results for D Series24

Matt/Fdn Design Time to Any Burn-Through (s) Comment 

D1 Mattress (78) post-exposure burn-through was possible D1 Mattress No Burn Through all flaming out at 4 min 30 s; smoke/smol. D1 Mattress No Burn Through all flaming out at 4 min 15 s 

D1 Mattress 

With Vertical Seam No Burn Through all flaming out at 1 min 26 s; smoke/smol. 

D1 Foundation No Burn Through all flaming out at 2 min 39 s D1 Foundation No Burn Through all flaming out at 2 min 50 s; smoke/smol. D1 Foundation No Burn Through all flaming out at 5 min 53 s; smoke/smol. 

 D1 Foundation 

With Vertical Seam No Burn Through all flaming out at 2 min 46 s; smoke/smol. 

D2 Mattress No Burn Through all flaming out at 3 min 50 s; matt smolder D2 Mattress No Burn Through all flaming out at 7 min 31 s; matt smolder uD2 Mattress No Burn Through all flaming out at 4 min 43 s; side smolder 

D2 Mattress 

With Vertical Seam 190 

post-exposure flames penetrated vertical se

stitching intact across the sea

D2 Foundation No Burn Through all flaming out at 3 min 58 s; side smolder D2 Foundation No Burn Through all flaming out at 3 min 41 s; side smolder D2 Foundation No Burn Through all flaming out at 4 min 12 s; side smolder 

24 Burner exposure, in all cases, was 70 seconds. 

20 
Table 6, Cont’d. Summary of Composite Bench-Scale Test Results for D Series25

Matt/Fdn Design Time to Any Burn-Through (s)

Comment 

D3 Mattress No Burn Through all flaming out at 7 min 30s; smoke/smol. uD3 Mattress (200 s) post-exposure burn through was probably 

D3 Mattress No Burn Through all flaming out at 6 min 19 s; smoke/smol. 

D3 Mattress 

With Vertical Seam 67 vertical seam opened wide 

D3 Foundation No Burn Through all flaming out at 1 min 32 s; smoke/smol. D3 Foundation No Burn Through all flaming out at 2 min 1 s; smoke/smol. D3 Foundation No Burn Through all flaming out at 2 min 6 s; smoke/smol. 

D3 Foundation 

With Vertical Seam No Burn Through all flaming out at 3 min; smoke/sm

ol. unt

D4 Mattress (143) post-expos. flames penetrated m

attress top; pos

D4 Mattress 185 post-expos. flames thru m

attress side; barr

D4 Mattress 240 post-exposure flames penetrated m

att side by 

D4 Mattress 

With Vertical Seam No Burn Through 

PU foa

m layer extended from top onto m

all flames out at 6 min 26 s; smoke/smol. u

D4 Foundation3 2

5

p

e

n

etratio

n thro

u

g

h both seam and sh

D4 Foundation 76 post-exposure flames penetrated fD4 Foundation No Burn Through all flaming out at 4 min 33 s; smoke/smol. 

D4 Foundation 

With Vertical Seam No Burn Through all flaming out at 3 min 28 s; smoke/smol. u

25 Bur

ner e

xpos

ure, i

n all cases, was 70 seconds. 3 Shoddy pad e

xten

ds o

ver fou

n

dation top a

nd sides i

n t

his design, at least on po

21 
22 

Table 6, Cont’d. Summary of Composite Bench-Scale Test Results for D Series

Matt/Fdn Design Time to Any Burn-Through (s) Comment 

D5 Mattress No Burn Through all flames out at 4 min 9 s; smoke/smol. uD5 Mattress (100 s) post-exposure burn through was probably 

D5 Mattress No Burn Through all flames out at 4 min 17 s; smoke/smol. u

D5 Mattress 

With Vertical Seam (320) post-exposure burn through was probably 

D5 Foundation4 (62) burner flames apparently penetrated fdn 

D5 Foundation (91) post-exposure flames apparently penetrated D5 Foundation No Burn Through all flames out at 3 min 29 s; smoke/smol. 

D5 Foundation 

With Vertical Seam No Burn Through 

all flames out at 5 min 30 s; smoke/smol. u

vertical seam showed partial sepa

D6 Mattress (125) post-exposure flames penetrated around shD6 Mattress No Burn Through all flames out at 5 min 40 s; smoke/smol. to 

D6 Mattress No Burn Through all flames out at 6 min 45 s; smoke/smol. u

D6 Mattress 

With Vertical Seam No Burn Through all flames out at 5 min 23 s; smoke/smol. u

D6 Foundation No Burn Through all flames out at 4 min 1 s; smoke/smol. uD6 Foundation No Burn Through all flames out at 3 min 13 s; smoke/smol. uD6 Foundation (20) flames penetrated past short side b

D6 Foundation 

With Vertical Seam No Burn Through all flames out at 7 min 15 s; smoke/smol. u

4 Shoddy pad extends under both fdn top and sides for this design, at least for portion
Figure 1. Overview of gas burner exposure apparatus. The propane gas control panel is 

at the left. Immediately to its right, between the two vertical structural beams, is the 

counterweight for the gas burner assembly to control the downward force the burner 

exerts on the sample top. The sample itself is in the bottom of the upper, dark gray 

section of the box to the right of center. The double gas burner is at the base of the dark 

rectangular, foil covered object above the sample box; it rides on a vertical rail within the 

foil covered area. 

23 
VERTICAL

BURNER

CP PROPANE

FROM BOTTLE

AND LOW PRESSURE

REGULATOR

PILOT

NI SU

L

A

T

E

D

E

N

C

L

OSU

R

E

O

V

E

R

B

U

R

N

E

R

R

AIL

AIR PURGEFOR COOLING

TIMER

PILOT

H

O

USE

A

RI

DUAL

 HEAD

 BURNER

v

v

v

v

v

v

v

v

v v v

v

v

v

v

v

v

v

 FIGURE 2. SCHEMATIC OF GAS CONTROL SYSTEM 

 -24- 

24 
0

20

40

60

80

100

50 100 150 200 250 300 350 400 450

Figure 3

Transverse Scan of Horizontal Burner Pair

Approximately 2.5 cm Left of Center of Tee Heads

Total He

at Fl

u

x t

o G

a

g

e (kW/

m2

)

Time in File (s)

Total Scan Length = 2.5 cm

25 
Figure 4a. Close-up of sample holder and double gas burner. Note that three of the four 

walls of the sample box are made of air permeable stainless steel wire mesh. The fourth 

wall, on the right, holds the apparatus for applying a uniform tension in the plane of the 

top of the sample by means of the weight seen in the lower right. One of the photocells 

for sensing flame penetration of the sample is immediately below the apparatus for 

applying the tension and is hidden by it in this view. 

26 
Figure 4b. View of the sample box. The lower part of the box is vented through the 

flexible duct to the left of center. The second photocell used to sense flame penetration 

of the sample is box next to the vent. The mirror for seeing the underside of the sample is 

visible on the lower right. The vertical burner used in the earliest versions of this test

protocol is visible at the left, in front of the vent duct. 

27 
Figure 5. Overview of the crevice test apparatus. The mattress side panel is seen on top 

with the foundation side panel beneath it. Only the ends of the propane burner are visible 

protruding from each side of the mattress/foundation crevice. The mirrors giving the 

operator a view of the “interior” surfaces of the test pieces are evident above and below 

the sample 

28 
0

500

1000

1500

2000

2500

3000

M7 M3 M5 M6 M1

Figure 6

Full Scale Tests of SPSC Beds With Gas Burners

(Arranged in Order of Avg Peak HRR)

Pe

a

k HRR (

kW)

Mattress Design Designation

M1, M3, M5 tested at NIST in open hood

M6 and M7 tested at CBHF in a room

M6 extinguished before peak HRR

29 
0

200

400

600

800

1000

1200

1400

D1 D2 D5 D3 D6 D4

Figure 7

Full Scale Tests of CPSC Beds With Gas Burners

(Arranged in Order of Average Peak Heat Release Rate)

Pea

k Heat R

elease Rat

e (

k

W)

Mattress Design Designation

30 
0

50

100

150

200

250

300

350

M7 M3 M5 M6 M1

Figure 8

Bench-Scale Tests of SPSC Bed Designs

(Arranged in Order of Full Scale Peak HRR)

(Smallest to Largest)

Time to 

B

urn-Throug

h in Ben

ch S

cale 

E

xposur

e (s)

Mattress Design Designation

No Burn-Through Cases

Assigned Time of 300 s

31