[Code of Federal Regulations]
[Title 16, Volume 2]
[Revised as of January 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 16CFR1633.7]
[Page 738-746]
TITLE 16--COMMERCIAL PRACTICES
CHAPTER II--CONSUMER PRODUCT SAFETY COMMISSION
PART 1633_STANDARD FOR THE FLAMMABILITY (OPEN FLAME) OF MATTRESS
SETS--Table of Contents
Subpart A_The Standard
Sec. 1633.7 Mattress test procedure.
(a) Apparatus and test materials--(1) Calorimetry. The rate of heat
release must be measured by means of oxygen consumption calorimetry. The
calibration should follow generally accepted practices for calibration.
The calorimetry system shall be calibrated
[[Page 739]]
at a minimum of two (2) calibration points--at 75 kW and 200 kW.
(2) Test area. The test area must have either Test Configuration A
or B. The test area conditions shall be maintained at a temperature
greater than 15 [deg]C (59 [deg]F) and less than 27 [deg]C (80.6 [deg]F)
and a relative humidity less than 75 percent.
(i) Test configuration A. (an open calorimeter (or furniture
calorimeter)). In this configuration, the specimen to be tested is
placed under the center of an open furniture calorimeter. Figure 1 of
this part shows the test assembly atop a bed frame and catch surface.
The specimen shall be placed under an open hood which captures the
entire smoke plume and is instrumented for heat release rate
measurements. The area surrounding the test specimen in an open
calorimeter layout shall be sufficiently large that there are no heat
re-radiation effects from any nearby materials or objects. The air flow
to the test specimen should be symmetrical from all sides. The air flow
to the calorimeter hood shall be sufficient to ensure that the entire
fire plume is captured, even at peak burning. Skirts may be placed on
the hood periphery to help assure this plume capture, if necessary,
though they must not be of such an excessive length as to cause the
incoming flow to disturb the burning process. Skirts must also not heat
up to the point that they contribute significant re-radiation to the
test specimen. The air supply to the hood shall be sufficient that the
fire is not in any way limited or affected by the available air supply.
The fire plume should not enter the hood exhaust duct. Brief (seconds)
flickers of flame that occupy only a minor fraction of the hood exhaust
duct inlet cross-section are acceptable since they do not signify
appreciable suppression of flames.
(ii) Test configuration B. The test room shall have dimensions 10
ft. by 12 ft. by 8 ft. (3048 mm x 3658 mm x 2438 mm) high. The specimen
is placed within the burn room. All smoke exiting from the room is
caught by a hood system instrumented for heat release rate measurements.
The room shall have no openings permitting air infiltration other than a
doorway opening 38 in 0.25 in by 80 in 0.25 in (965 mm 6.4 mm x 2032 mm
6.4 mm) located as indicated in Figure 2 of this
part and other small openings as necessary to make measurements. The
test room shall be constructed of wood or metal studs and shall be lined
with fire-rated wallboard or calcium silicate board. An exhaust hood
shall be positioned outside of the doorway so as to collect all of the
combustion gases. There shall be no obstructions in the air supply to
the set-up.
(3) Location of test specimen. The location of the test specimen is
shown in Figure 2 of this part. The angled placement is intended to
minimize the interaction of flames on the side surfaces of the test
specimen with the room walls. One corner of the test specimen shall be
13 centimeters (cm) to 17 cm from the wall and the other corner shall be
25 cm to 30 cm from the wall. The test room shall contain no other
furnishings or combustible materials except for the test specimen.
(4) Bed frame. (i) Frame dimensions. The specimen shall be supported
around its perimeter by the bed frame. For twin size mattresses, the
specimen shall be placed on top of a welded bed frame 1.90 m by 0.99 m
(75 in by 39 in) made from 40 mm (1.50 in) steel angle. If testing a
size other than twin, the bed frame shall similarly match the dimensions
of the specimen.
(ii) Frame height. The frame shall be 115 mm (4.5 in) high, except
if adjustments are necessary to accommodate the required burner position
in paragraph (h)(2)(ii) of this section. The height of the frame shall
also be adjusted, as necessary, so that the burner is no less than 25mm
(1 in) above the supporting surface.
(iii) Frame crosspieces. The frame shall be completely open under
the foundation except for two crosspieces, 25 mm wide (1 in) at the \1/
3\ length points, except when sagging of the specimen between the
crosspieces exceeds 19 mm (\3/4\ in) below the frame. Minimal additional
crosspieces shall then be added to prevent sagging of the specimen.
(5) Catch pan. The bed frame feet shall rest on a surface of either
calcium silicate board or fiber cement board, 13 mm (0.5 in) thick, 2.11
m by
[[Page 740]]
1.19 m (83 in by 47 in). The board serves as a catch surface for any
flaming melt/drip material falling from the bed assembly and may be the
location of a pool fire that consumes such materials. This surface must
be cleaned between tests to avoid build-up of combustible residues.
Lining this surface with aluminum foil to facilitate cleaning is not
recommended since this might increase fire intensity via reflected
radiation.
(6) Ignition source--(i) General. The ignition source shall consist
of two T-shaped burners as shown in Figures 3 and 4 of this part. One
burner impinges flames on the top surface of the mattress. The second
burner impinges flames on the side of the mattress and on the side of
the foundation. Each of the burners shall be constructed from stainless
steel tubing (12.7 mm diameter with 0.89 0.5 mm
wall thickness; 0.50 in diameter with 0.035 0.002
in wall). Each burner shall incorporate a stand-off foot to set its
distance from the test specimen surface (Figure 5 of this part). Both
burners shall be mounted with a mechanical pivot point but the side
burner is locked in place to prevent movement about this pivot in normal
usage. The top burner, however, is free to rotate about its pivot during
a burner exposure and is lightly weighted so as to exert a downward
force on the mattress top through its stand-off foot so that the burner
follows a receding top surface on the test specimen (Figure 6 of this
part). The combination of burner stand-off distance and propane gas flow
rate to the burners determines the heat flux they impose on the surface
of the test specimen so that both of these parameters are tightly
controlled.
(ii) Top surface burner. The T head of the top surface burner
(horizontal burner, Figure 3 of this part) shall be 305 2 mm (12 0.08 in) long with gas
tight plugs in each end. Each side of the T shall contain 17 holes
equally spaced over a 135 mm length (8.5 mm 0.1 mm
apart; 0.333 0.005 in). The holes on each side
shall begin 8.5 mm (0.33 in) from the centerline of the burner head. The
holes shall be 1.45 mm to 1.53 mm (0.058 in to 0.061 in) in diameter
(which corresponds to Grade 10 machining practice with a well formed
53 drill bit). The holes shall point 5[deg] out of the plane of
the diagram in Figure 3. This broadens the width of the heat flux
profile imposed on the surface of the test specimen.
(iii) Side surface burner. The T head of the side surface burner
(vertical burner) shall be constructed similarly to the top surface
burner, as shown in Figure 4 of this part, except that its overall
length shall be 254 2 mm (10 0.08 in). Each side of the burner head shall contain 14
holes spaced evenly over a 110 mm length (8.5 mm 0.1 mm apart; 0.333 0.005 in). The
holes shall be 1.45 mm to 1.53 mm (0.058 in to 0.061 in) in diameter
(which corresponds to Grade 10 machining practice with a well formed
53 drill bit). The holes shall point 5[deg] out of the plane of
the diagram in Figure 4.
(iv) Burner stand-off. The burner stand-off on each burner shall
consist of a collar fixed by a set screw onto the inlet tube of the
burner head (Figure 5 of this part). The collar shall hold a 3 mm
diameter stainless steel rod having a 12.7 mm by 51 mm by (2-2.5 mm)
thick (0.5 in by 2 in by (0.08-0.10 in) thick) stainless steel pad
welded on its end with its face (and long axis) parallel to the T head
of the burner. The foot pad shall be displaced about 10 mm to 12 mm from
the longitudinal centerline of the burner head so that it does not rest
on the test specimen in an area of peak heat flux. A short section (9.5
mm outer diameter (``OD''), about 80 mm long; \3/8\ in OD, about 3.2 in
long) of copper tubing shall be placed in the inlet gas line just before
the burner to facilitate making the burner nominally parallel to the
test specimen surface (by a procedure described below). The copper tube
on the top surface burner should be protected from excessive heat and
surface oxidation by wrapping it with a suitable layer of high
temperature insulation to protect the equipment. Both copper tubes are
to be bent by hand in the burner alignment process. They must be
replaced if they become work-hardened or crimped in any way. The gas
inlet lines (12.7 mm OD stainless steel tubing; 0.50 in) serve as arms
leading back to the pivot points and beyond, as shown in Figure 6 of
this part. The length to the pivot for the top burner shall be
approximately 1000 mm (40 in).
[[Page 741]]
(v) Frame. Figure 6 of this part shows the frame that holds the
burners and their pivots, which are adjustable vertically in height. All
adjustments (burner height, burner arm length from the pivot point,
counterweight positions along the burner arm) are facilitated by the use
of knobs or thumbscrews as the set screws. The three point footprint of
the burner frame, with the two forward points on wheels, facilitates
burner movement and burner stability when stationary.
(vi) Arms. The metal arms attached to the burners shall be attached
to a separate gas control console by flexible, reinforced plastic
tubing.\1\ The gas control console is mounted separately so as to
facilitate its safe placement outside of the test room throughout the
test procedure. The propane gas lines running between the console and
the burner assembly must be anchored on the assembly before running to
the burner inlet arms. A 1.5 m 25 mm (58 in 1 in) length of flexible, reinforced tubing between the
anchor point and the end of each burner inlet allows free movement of
the top burner about its pivot point. The top burner arm shall have a
pair of moveable cylindrical counterweights that are used, as described
below, to adjust the downward force on the stand-off foot.
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\1\ Fiber-reinforced plastic tubing (6 mm ID by 9.5 mm OD; 3 inch ID
by inch OD) made of PVC should be used.
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(vii) Burner head. Each burner head shall have a separate pilot
light consisting of a 3 mm OD (\1/8\ in OD) copper tube with an
independently-controlled supply of propane gas. The tube terminates
within 10 mm of the center of the burner head. Care must be taken to set
the pilot flame size small enough so as not to heat the test specimen
before the timed burner exposure is begun.
(viii) Flow control system. Each burner shall have a flow control
system of the type shown in Figure 7 of this part. Propane gas from a
source such as a bottle is reduced in pressure to approximately 70
kilopascals (``kPa'') (20 pounds per square inch gage (``psig'')) and
fed to the system shown in Figure 8 of this part. The gas flow to the
burner is delivered in a square-wave manner (constant flow with rapid
onset and termination) by means of the solenoid valve upstream of the
flowmeter. An interval timer (accurate to 0.2 s)
determines the burner flame duration. The pilot light assures that the
burner will ignite when the solenoid valve opens.\2\ The gas flow shall
be set using a rotameter type of flowmeter, with a 150 mm scale,
calibrated for propane. When calibrating the flowmeter, take into
account that the flow resistance of the burner holes causes a finite
pressure increase in the flowmeter above ambient. (If a calibration at
one atmosphere is provided by the manufacturer, the flowmeter reading,
at the internal pressure existing in the meter, required to get the flow
rates listed below must be corrected, typically by the square root of
the absolute pressure ratio. This calls for measuring the actual
pressure in the flow meters when set near the correct flow values. A
value roughly in the range of 1 kPa to 3 kPa--5 in to 15 in of water--
can be expected.) See information on calibration in paragraph (b) of
this section.
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\2\ If the side burner, or more commonly one half of the side
burner, fails to ignite quickly, adjust the position of the igniter,
bearing in mind that propane is heavier than air. The best burner
behavior test assessment is done against an inert surface (to spread the
gas as it would during an actual test).
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(ix) Gas flow rate. Use propane gas: The propane shall be minimum
99% pure (often described by suppliers as CP or ``chemically pure''
grade, but this designation should not be relied on since the actual
purity may vary by supplier). Each burner has a specific propane gas
flow rate set with its respective, calibrated flowmeter. The gas flow
rate to the top burner is 12.9 liters per minute (``L/min'') 0.1 L/min at a pressure of 101 5
kPa (standard atmospheric pressure) and a temperature of 22 3 [deg]C. The gas flow rate to the side burner is 6.6
0.05 L/min at a pressure of 101 5 kPa (standard atmospheric pressure) and a temperature
of 22 3 [deg]C. The total heat release rate of the
burners is 27 kW.
(b) Calibration of Propane Flowmeters--(1) Preparation. Once the
assembly of the burner is completed and all the connecting points are
checked for gas leakage, the most critical task is ensuring the exact
flow rates of propane
[[Page 742]]
into the top and side burners, as described in the test protocol. The
gas flow rates are specified at 12.9 Liters per minute (LPM) 0.1 LPM and 6.6 LPM 0.05 LPM for
the top and side burners (Burners 1 and 2), respectively, at a pressure
of 101 5 kiloPascal (kPa) (standard atmospheric
pressure) and a temperature of 22 3 [deg]C. The
rotameters that are installed in the control box of the burner assembly
need to be calibrated for accurate measurement of these flow rates.
(i) The most practical and accurate method of measuring and
calibrating the flow rate of gases (including propane) is use of a
diaphragm test meter (also called a dry test meter). A diaphragm test
meter functions based on positive displacement of a fixed volume of gas
per rotation and its reading is therefore independent of the type of the
gas being used. The gas pressure and temperature, however, can have
significant impact on the measurement of flow rate.
(ii) The gas pressure downstream of the rotameters that are
installed in the control box of the burner assembly should be maintained
near atmospheric pressure (only a few millimeters of water above
atmosphere). Therefore, the best location to place the diaphragm test
meter for gas flow calibration is right downstream of the control box.
The pressure at the propane tank must be set at 20 0.5 pounds per square inch gage (psig).
(2) Calibration Procedure. Install the diaphragm test meter (DTM)
downstream of the control box in the line for the top burner. Check all
connecting points for gas leakage. Open the main valve on the propane
tank and set a pressure of 20 0.5 psig. Set the
timers in the control box for 999 seconds (or the maximum range
possible). Record the barometric pressure. Turn the ``Burner 1'' switch
to ON and ignite the top burner. Allow the gas to flow for 2-3 minutes
until the DTM is stabilized. Record the pressure and temperature in the
DTM. Use a stopwatch to record at least one minute worth of complete
rotations while counting the number of rotations.\3\ Calculate the
propane gas flow rate using the recorded time and number of rotations
(total flow in that time). Use the pressure and temperature readings to
convert to standard conditions. Repeat this measurement for two
additional meter setting to allow for calibrating the flowmeter
throughout the range of interest. Plot the flow versus meter reading,
fit a best line (possibly quadratic) through these points to find the
meter setting for a flow of 12.9 LPM at the above ``standard
conditions.'' Repeat this procedure for ``Burner 2'' using three meter
readings to find the setting that gives a flow rate of 6.6 LPM at the
standard conditions. After completion of the calibration, re-set the
timers to 70 and 50 seconds.
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\3\ With a diaphragm test meter well-sized to this application, this
should be more than five rotations. A one liter per rotation meter will
require 10 to 15 rotations for the flow measurements and greater than
the minimum of one minute recording time specified here.
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(c) Conditioning. Remove the specimens from any packaging prior to
conditioning. Specimens shall be conditioned in air at a temperature
greater than 18 [deg]C (65 [deg]F) and less than 25 [deg]C (77 [deg]F)
and a relative humidity less than 55 percent for at least 48 continuous
hours prior to test. Specimens shall be supported in a manner to permit
free movement of air around them during conditioning.
(d) Test preparation--(1) General. Horizontal air flow at a distance
of 0.5 m (20 in) on all sides of the test specimen at the mattress top
height shall be 0.5 m/s. If there is any visual evidence that the burner
flames are disturbed by drafts during their exposure durations, the
burner regions must be enclosed on two or more sides by at least a
triple layer of screen wire. The screens shall be at least 25 cm tall.
The screen(s) for the top burner shall sit on the mattress top and shall
be wide enough to extend beyond the area of the burner impingement. All
screens shall be far enough away (typically 30 cm or more) from the
burner tubes so as not to interfere or interact with flame spread during
the burner exposure. The screen for the side burner will require a
separate support from below. All screens shall be removed at the end of
the 70 second exposure interval.
[[Page 743]]
(2) Specimen. Remove the test specimen from the conditioning room
immediately before it is to be tested. Testing shall begin within 20
minutes after removal from the conditioning area. Be sure the bed frame
is approximately centered on the catch surface. Place the specimen on
the bed frame. Carefully center them on the bed frame and on each other.
The mattress shall be centered on top of the foundation (see Figure 1 of
this part). However, in order to keep the heat flux exposure the same
for the sides of the two components, if the mattress is 1 cm to 2 cm
narrower than the foundation, the mattress shall be shifted so that the
side to be exposed is in the same plane as the foundation. Refer to
Figure 8 of this part. A product having an intended sleep surface on
only one side shall be tested with the sleeping side up so that the
sleeping surface is exposed to the propane burner.
(e) Burner flow rate/flow timer confirmation. Just prior to moving
the burner adjacent to the test specimen, briefly ignite each burner at
the same time, and check that the propane flow to that burner is set at
the appropriate level on its flowmeter to provide the flows listed in
Sec. 1633.7(a)(6)(ix). Check that the timers for the burner exposures
are set to 70 seconds for the top burner and 50 seconds for the side
burner. For a new burner assembly, check the accuracy of the gas flow
timers against a stop watch at these standard time settings. Set pilot
flows to a level that will not cause them to impinge on sample surfaces.
(f) Location of the gas burners. Place the burner heads so that they
are within 300 mm (1 ft) of the mid-length of the mattress. If there are
unique construction features (e.g., handles, zippers) within the burner
placement zone, the burner shall impinge on this feature. The general
layout for the room configuration is shown in Figure 2 of this part. For
a quilted mattress top the stand-off foot pad must alight on a high,
flat area between dimples or quilting thread runs. The same is to be
true for the side burner if that surface is quilted. If a specimen
design presents a conflict in placement such that both burners cannot be
placed between local depressions in the surface, the top burner shall be
placed at the highest flat surface.
(g) Burner set-up. The burners shall be placed in relation to the
mattress and foundation surfaces in the manner shown in Figure 9 of this
part, i.e., at the nominal spacings shown there and with the burner
tubes nominally parallel \4\ to the mattress surfaces on which they
impinge. Since the heat flux levels seen by the test specimen surfaces
depend on burner spacing, as well as gas flow rate, care must be taken
with the set-up process.
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\4\ The top burner will tend to be tangential to the mattress
surface at the burner mid-length; this orientation will not necessarily
be parallel to the overall average mattress surface orientation nor will
it necessarily be horizontal. This is a result of the shape of the
mattress top surface.
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(h) Burner alignment procedure--(1) Preparation. Complete the
following before starting the alignment procedure:
(i) Check that the pivot point for the mattress top burner feed tube
and the two metal plates around it are clean and well-lubricated so as
to allow smooth, free movement.
(ii) Set the two burners such that the 5[deg] out-of-plane angling
of the flame jets makes the jets on the two burners point slightly
toward each other.
(iii) Check the burner stand-off feet for straightness and
perpendicularity between foot pad and support rod and to see that they
are clean of residue from a previous test.
(iv) Have at hand the following items to assist in burner set-up:
The jig, shown in Figure 10 of this part, for setting the stand-off feet
at their proper distances from the front of the burner tube; a 3 mm
thick piece of flat stock (any material) to assist in checking the
parallelness of the burners to the mattress surfaces; and a 24 gage
stainless steel sheet metal platen that is 30 mm (12 in) wide, 610 mm
(24 in) long and has a sharp, precise 90[deg] bend 355 mm (14 in) from
one 30 mm wide end. Refer to Figure 8 of this part.
(2) Alignment. (i) Place the burner assembly adjacent to the test
specimen. Place the sheet metal platen on the mattress with the shorter
side on top. The location shall be within 30 cm (1 ft) of the
longitudinal center of the mattress. The intended location of the
[[Page 744]]
stand-off foot of the top burner shall not be in a dimple or crease
caused by the quilting of the mattress top. Press the platen laterally
inward from the edge of the mattress so that its side makes contact with
either the top and bottom edge or the vertical side of the mattress.\5\
Use a 20 cm (8 in) strip of duct tape (platen to mattress top) to hold
the platen firmly inward in this position.
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\5\ Mattresses having a convex side are treated separately since the
platen cannot be placed in the above manner. Use the platen only to set
the top burner parallelness. Set the in/out distance of the top burner
to the specification in paragraph (h)(1)(iii). Set the side burner so
that it is approximately (visually) parallel to the flat side surface of
the foundation below the mattress/foundation crevice once its foot is in
contact with the materials in the crevice area. The burner will not be
vertical in this case. If the foundation side is also non-flat, set the
side burner vertical (3 mm, as above) using a
bubble level as a reference. The side surface convexities will then
bring the bowed out sections of the specimen closer to the burner tube
than the stand-off foot.
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(ii) With both burner arms horizontal (pinned in this position),
fully retract the stand-off feet of both burners and, if necessary, the
pilot tubes as well.\6\ (Neither is to protrude past the front face of
the burner tubes at this point.) Move the burner assembly forward
(perpendicular to the mattress) until the vertical burner lightly
contacts the sheet metal platen. Adjust the height of the vertical
burner on its vertical support column so as to center the tube on the
crevice between the mattress and the foundation. (This holds also for
pillow top mattress tops, i.e., ignore the crevice between the pillow
top and the main body of the mattress.)\7\ Adjust the height of the
horizontal burner until it sits lightly on top of the sheet metal
platen. Its burner arm should then be horizontal.
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\6\ The pilot tubes can normally be left with their ends just behind
the plane of the front of the burner tube. This way they will not
interfere with positioning of the tube but their flame will readily
ignite the burner tubes.
\7\ For tests of the mattress alone, set the center of the side
burner at the lower edge of the mattress OR the top (upper tip) of the
side burner 25 mm (1 in) below the top edge of the mattress, whichever
is lower. This prevents inappropriate (excessive) exposure of the top
surface of the mattress to the side burner.
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(iii) Move the horizontal burner in/out (loosen the thumb screw near
the pivot point) until the outer end of the burner tube is 13 mm to 19
mm (\1/2\ in to \3/4\ in) from the corner bend in the platen (this is
facilitated by putting a pair of lines on the top of the platen 13 mm
and 19 mm from the bend and parallel to it). Tighten the thumb screw.
(iv) Make the horizontal burner parallel to the top of the platen
(within 3 mm, \1/8\ in over the burner tube length) by bending the
copper tube section appropriately. Note: After the platen is removed (in
paragraph (h)(2)(vii) of this section), the burner tube may not be
horizontal; this is normal. For mattress/foundation combinations having
nominally flat, vertical sides, the similar adjustment for the vertical
burner is intended to make that burner parallel to the sides and
vertical. Variations in the shape of mattresses and foundations can
cause the platen section on the side to be non-flat and/or non-vertical.
If the platen is flat and vertical, make the vertical burner parallel to
the side of the platen (3 mm) by bending its
copper tube section as needed. If not, make the side burner parallel to
the mattress/foundation sides by the best visual estimate after the
platen has been removed.
(v) Move the burner assembly perpendicularly back away from the
mattress about 30 cm (1 ft). Set the two stand-off feet to their
respective distances using the jig designed for this purpose. Install
the jig fully onto the burner tube (on the same side of the tube as the
stand-off foot), with its side edges parallel to the burner feed arm, at
about the position where one end of the foot will be. Loosen the set
screw and slide the foot out to the point where it is flush with the
bottom end of the jig. Tighten the set screw. Make sure the long axis of
the foot is parallel to the burner tube. It is essential to use the
correct side of the spacer jig with each burner. Double check this. The
jig must be clearly marked.
(vi) Set the downward force of the horizontal burner. Remove the
retainer pin near the pivot. While holding the burner feed arm
horizontal using a
[[Page 745]]
spring scale \8\ hooked onto the thumbscrew holding the stand-off foot,
move the small and/or large weights on the feed tube appropriately so
that the spring scale reads 170 g to 225 g (6 oz to 8 oz).
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\8\ An acceptable spring scale has a calibrated spring mounted
within a holder and hooks on each end.
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(vii) Remove the sheet metal platen (and tape holding it).
(viii) Hold the horizontal burner up while sliding the burner
assembly forward until its stand-off foot just touches the mattress and/
or the foundation,\9\ then release the horizontal burner. The outer end
of the burner tube should extend at least 6 mm to 12 mm (\1/4\ in to \1/
2\ in) out beyond the uppermost corner/edge of the mattress so that the
burner flames will hit the edge. (For a pillow top mattress, this means
the outer edge of the pillow top portion and the distance may then be
greater than 6 mm to 12 mm.) If this is not the case, move the burner
assembly (perpendicular to the mattress side)--not the horizontal burner
alone--until it is. Finally, move the vertical burner tube until its
stand-off foot just touches the side of the mattress and/or the
foundation. (Use the set screw near the vertical burner pivot.)
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\9\ The foot should depress the surface it first contacts by no more
than 1 mm to 2 mm. This is best seen up close, not from the rear of the
burner assembly. However, if a protruding edge is the first item
contacted, compress it until the foot is in the plane of the mattress/
foundation vertical sides. The intent here is that the burner be spaced
a fixed distance from the vertical mattress/foundation sides, not from
an incidental protrusion. Similarly, if there is a wide crevice in this
area which would allow the foot to move inward and thereby place the
burners too close to the vertical mattress/foundation sides, it will be
necessary to use the spacer jig (rather than the stand-off foot) above
or below this crevice to set the proper burner spacing. Compress the
mattress/foundation surface 1 mm to 2 mm when using the jig for this
purpose.
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(ix) Make sure all thumbscrews are adequately tightened. Care must
be taken, once this set-up is achieved, to avoid bumping the burner
assembly or disturbing the flexible lines that bring propane to it.
(x) If there is any indication of flow disturbances in the test
facility which cause the burner flames or pilot flames to move around,
place screens around the burners so as to minimize these
disturbances.\10\ These screens (and any holders) must be far enough
away from the burners (about 30 cm or more for the top, less for the
side) so that they do not interact with the flames growing on the
specimen surfaces. For the top surface burner, at least a triple layer
of window screen approximately 30 cm high sitting vertically on the
mattress top (Figure 9 of this part) has proved satisfactory. For the
side burner at least a triple layer of screen approximately 15 cm wide,
formed into a square-bottom U-shape and held from below the burner has
proved satisfactory. Individual laboratories will have to experiment
with the best arrangement for suppressing flow disturbances in their
facility.
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\10\ The goal here is to keep the burner flames impinging on a fixed
area of the specimen surface rather than wandering back and forth over a
larger area.
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(i) Running the test. (1) Charge the hose line to be used for fire
suppression with water.
(2) Burner Preparation. (i) Turn AC power on; set propane pressure
to 20 psig at bottle; set timers to 70 s (top burner) and 50 s (side
burner); with burner assembly well-removed from test specimen, ignite
burners and check that, WHEN BOTH ARE ON AT THE SAME TIME, the
flowmeters are set to the values that give the requisite propane gas
flow rates to each burner. Turn off burners. Set pilot tubes just behind
front surface of burners; set pilot flow valves for ca. 2 cm flames.
Turn off pilots.
(ii) Position burner on test specimen and remove sheet metal platen.
(iii) Place screens around both burners.
(3) Start pilots. Open pilot ball valves one at a time and ignite
pilots with hand-held flame; adjust flame size if necessary being very
careful to avoid a jet flame that could prematurely ignite the test
specimen (Note that after a long interval between tests the low pilot
flow rate will require a long time to displace air in the line and
achieve the steady-state flame size.)
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(4) Start recording systems. With the calorimetry system fully
operational, after instrument zeroes and spans, start the video lights
and video camera and data logging systems two minutes before burner
ignition (or, if not using video, take a picture of the setup).
(5) Initiate test. Start test exposure by simultaneously turning on
power to both timers (timers will turn off burners at appropriate
times). Also start a 30 minute timer of the test duration. Check/adjust
propane flow rates (DO THIS ESSENTIAL TASK IMMEDIATELY. Experience shows
the flow will not remain the same from test-to-test in spite of fixed
valve positions so adjustment is essential.) If not using video, one
photo must be taken within the first 45 seconds of starting the burners.
(6) End of burner exposure. When the burners go out (after 70
seconds for the longer exposure), carefully lift the top burner tube
away from the specimen surface, producing as little disturbance as
possible to the specimen. Turn off power to both timers. Remove all
screens. Turn off pilots at their ball valves. Remove the burner
assembly from the specimen area to facilitate the video camera view of
the full side of the specimen. In the case of the room-based
configurations, remove the burner assembly from the room to protect it.
(j) Video Recording/Photographs. Place a video or still frame camera
so as to have (when the lens is zoomed out) just slightly more than a
full-length view of the side of the test specimen being ignited,
including a view of the flame impingement area while the burner assembly
is present. The view must also include the catch pan so that it is clear
whether any melt pool fire in this pan participates significantly in the
growth of fire on the test specimen. The camera shall include a measure
of elapsed time to the nearest 1 second for video and 1 minute for still
frame within its recorded field of view (preferably built into the
camera). For the room-based configuration, the required full-length view
of the sample may require an appropriately placed window, sealed with
heat resistant glass, in one of the room walls. Place the camera at a
height just sufficient to give a view of the top of the specimen while
remaining under any smoke layer that may develop in the room. The
specimen shall be brightly lit so that the image does not lose detail to
over-exposed flames. This will require a pair or more of 1 kW photo
flood lights illuminating the viewed side of the specimen. The lights
may need to shine into the room from the outside via sealed windows.
(k) Cessation of Test. (1) The heat release rate shall be recorded
and video/photographs taken until either 30 minutes has elapsed since
the start of the burner exposure or a fire develops of such size as to
require suppression for the safety of the facility.
(2) Note the time and nature of any unusual behavior that is not
fully within the view of the video camera. This is most easily done by
narration to a camcorder.
(3) Run the heat release rate system and datalogger until the fire
has been fully out for several minutes to allow the system zero to be
recorded.
(l) Use of alternate apparatus. Mattress sets may be tested using
test apparatus that differs from that described in this section if the
manufacturer obtains and provides to the Commission data demonstrating
that tests using the alternate apparatus during the procedures specified
in this section yield failing results as often as, or more often than,
tests using the apparatus specified in the standard. The manufacturer
shall provide the supporting data to the Office of Compliance, Recalls &
Compliance Division, U.S. Consumer Product Safety Commission, 4330 East
West Highway, Bethesda, Maryland 20814. Staff will review the data and
determine whether the alternate apparatus may be used.