CPSC open flame mattress standard part 1633.

Purpose, scope and who must comply

Section 1633.1(a) says the part "establishes flammability requirements that all mattress sets must meet before sale or introduction into commerce. The purpose of the standard is to reduce deaths and injuries associated with mattress fires by limiting the size of the fire generated by a mattress set during a thirty minute test." Under (b), "all mattress sets ... manufactured, imported, or renovated on or after the effective date of this standard are subject to the requirements," and one-of-a-kind sets may be exempted under 1633.13(c). The part applies to each manufacturer of mattress sets made for sale in commerce, and importers and renovators are considered manufacturers (1633.2(k)).

A "mattress set" is "either a mattress and foundation labeled by the manufacturer for sale as a set, or a mattress labeled by the manufacturer for sale without any foundation" (1633.2(c)). A "mattress" is a resilient material enclosed by ticking and intended or promoted for sleeping upon, including adult, youth and crib mattresses, bunk bed mattresses, futons, flip chairs without a permanent back or arms, sleeper chairs, and water beds or air mattresses if they contain upholstery material between the ticking and the core; it also includes mattresses in upholstered furniture such as convertible sofa bed mattresses. It excludes mattress pads, mattress toppers, sleeping bags, pillows, liquid and gaseous filled tickings with no upholstery, upholstered furniture without a mattress, and juvenile product pads such as car bed pads, stroller pads and crib bumpers.

The two criteria

The test "measures the flammability (fire test response characteristics) of a mattress specimen by exposing the specimen to a specified flaming ignition source and allowing it to burn freely under well-ventilated, controlled environmental conditions" (1633.3(a)). The ignition source is a pair of propane burners, one on the top surface and one on the side of the mattress and foundation. Heat release is measured by oxygen consumption calorimetry, calibrated at 75 kW and 200 kW (1633.7(a)(1)).

The specimen must comply with both criteria in 1633.3(b)(1): "the peak rate of heat release shall not exceed 200 kilowatts ('kW') at any time within the 30 minute test; and the total heat release shall not exceed 15 megajoules ('MJ') for the first 10 minutes of the test." Those are written as limits that may not be exceeded, so exactly 200 kW or 15 MJ is within them. The operator should stop and record a failure if the fire gets large enough to require suppression for safety (1633.3(b)(2)). The checker above applies both numbers.

How the test is run

The burners expose the specimen for set times: the burner timers are confirmed at 70 seconds for the top burner and 50 seconds for the side burner (1633.7(e)). The specified propane flow is 12.9 liters per minute (plus or minus 0.1) to the top burner and 6.6 liters per minute (plus or minus 0.05) to the side burner. Specimens are conditioned in air greater than 18 and less than 25 degrees C (65 to 77 F) at less than 55 percent relative humidity for at least 48 continuous hours, and testing begins within 20 minutes of removal. The test area is held between 15 and 27 degrees C with relative humidity under 75 percent. The specimen sits on a bed frame 115 mm (4.5 in) high over a calcium silicate or fiber cement catch board. The burner and assembly figures (Figures 1 to 9) are images in the eCFR.

All tests use specimens "no smaller than a twin size, unless the largest size mattress set produced is smaller than a twin size" (1633.4(c)). Twin size is 38 by 74.5 inches (965 by 1892 mm), with each dimension allowed to vary by plus or minus 1/2 inch (1633.2(u)).

Prototypes, pooling and quality assurance

Before selling a mattress set, each manufacturer must have "three specimens of each prototype" tested under 1633.7 and obtain passing results on both criteria, unless it complies with the pooling and confirmation rules (1633.4(a)). If each of the three meets both criteria the prototype is qualified; "if any one (1) specimen fails to meet the test criteria," it is not (1633.4(d)(1)). A mattress intended for sale with a foundation is a separate prototype from one intended for sale without.

A manufacturer may sell a set that is untested if it differs from a qualified or confirmed prototype only in length and width (not depth), in ticking (unless the prototype ticking was designed to improve test performance), or in a component, material or design "so long as the manufacturer can demonstrate on an objectively reasonable basis that such differences will not cause the mattress set to exceed the test criteria" (1633.4(b)). Under prototype pooling (1633.5), a manufacturer can rely on another manufacturer's or developer's qualified prototype if it makes the same materials, components, design and assembly and runs a confirmation test on at least one specimen; a failed confirmation test stops sales until corrected and requires notice to the prototype's manufacturer. Section 1633.6 requires a quality assurance program with incoming inspection, defined production lots and inspection of finished sets, and stopping production and distribution if a test or other evidence shows a lot does not meet the criteria.

Labels, records and the physician exemption

Each mattress set needs a permanent, conspicuous, legible English label giving the manufacturer (and, for imports, the foreign manufacturer and importer), the address, month and year of manufacture, model identification, prototype identification number, a certification statement that the mattress meets "the requirements of 16 CFR part 1633 (federal flammability (open flame) standard for mattresses)" with the foundation identity if sold with one, and a statement of whether it is intended to be used with or without a foundation (1633.12). The label is 2 3/4 inches wide, white with black text, and the minimum font sizes are in the section. Records are kept for as long as sets based on the prototype are in production and for 3 years after (1633.11(e)).

A mattress set made to a physician's written prescription for a named individual is a "one of a kind mattress" exempt from testing if it carries a label beginning "WARNING: This mattress set may be subject to a large fire if exposed to an open flame." The label must be at least 40 square inches with no linear dimension under 5 inches and the word WARNING in letters of no less than 0.5 inch, and the maker retains the prescription for three years from manufacture (1633.13(c)).

Worked example

Three specimens of a new foam mattress and its foundation are tested. Specimen 1 peaks at 140 kW with 9 MJ at 10 minutes; specimen 2 peaks at 190 kW with 14.5 MJ; specimen 3 peaks at 205 kW with 11 MJ. Specimen 3 exceeds 200 kW, so it fails the first criterion and, under 1633.4(d)(1), the prototype is not qualified, even though the other two pass both. A redesigned prototype would need three new passing specimens. A queen size version of the qualified design that differs only in length and width may be sold without its own test under 1633.4(b)(1).

Limits of this page

The tool compares two readings with two limits. It cannot run the calorimetry test, judge whether a design change is "objectively reasonable" or confirm a pooling arrangement. The Commission's published findings in 1633.8 estimate net benefits and discuss alternatives that were considered and are not restated here. This page quotes the CFR and is not a determination about any mattress.

Sources

Sources opened and read November 2, 2026.

• eCFR: 16 CFR part 1633, flammability, open flame, mattress sets (current through October 29, 2026) (read November 2, 2026)