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Three and a half seconds is a pass

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The standard classifies a fabric by how long a flame takes to travel And it is Class 3 when the flame spreads faster than that So one number separates acceptable from prohibited The parenthesis is the detail worth keeping Across this library that kind of drafting is unusual Raised surface fabrics get a different pass mark entirely Which means the surface decides which test applies And the rule spends a page on how to tell Six special cases, and the rule says the list is not closed None of which reaches anything in this group References

The whole boundary is one number. With the edge case settled in brackets.

The standard classifies a fabric by how long a flame takes to travel

A plain surface textile fabric is Class 1, Normal Flammability, and acceptable for use in clothing, when the burn time is 3.5 seconds or more.

And it is Class 3 when the flame spreads faster than that

Class 3, Rapid and Intense Burning, applies when the time of flame spread is less than 3.5 seconds. Such textiles are described in the rule as dangerously flammable and shall not be used for clothing.

So one number separates acceptable from prohibited

Which puts a great deal of weight on the boundary, and the summary table resolves it explicitly rather than leaving it to be read off the words.

The parenthesis is the detail worth keeping

Table 1 records the Class 1 criterion as burn time is 3.5 seconds or more, acceptable, and then adds in brackets that 3.5 seconds is a pass.

Across this library that kind of drafting is unusual

Most thresholds are stated once and the boundary case is left to the words or more, or not more than, or exceeds. Here the rule writes the answer out a second time in a table, in case the first way was ambiguous.

Raised surface fabrics get a different pass mark entirely

Class 1 for a raised surface fabric requires a burn time of more than 7.0 seconds, or a rapid surface flash between 0.0 and 7.0 seconds, provided the intensity of the flame is so low as not to ignite or fuse the base fabric.

Which means the surface decides which test applies

Not the fiber, not the weight, not the use. Whether a fabric is plain surface or raised surface determines both the procedure and the number it is measured against.

And the rule spends a page on how to tell

Flocked overall is raised. Flock printed is plain. Cut velvet with a patterned construction is raised. Metallic thread is plain provided the base fabric is smooth. A burn-out pattern on a flat woven construction is plain.

Six special cases, and the rule says the list is not closed

The guidance is given as examples along with guidelines, with a note that the information is not intended to be all-inclusive. Which is honest about what a list of fabric constructions can cover.

None of which reaches anything in this group

Part 1610 classifies fabric. A binding clip, a quilt pin, a rotary blade and a template part are not fabric, and nothing on these pages says the standard applies to them.

References

16 CFR 1610.4. Class 1, Normal Flammability, for a plain surface textile fabric, applies "when the burn time is 3.5 seconds or more", and Table 1 to 1610.4 records it as "Burn time is 3.5 seconds or more. ACCEPTABLE (3.5 seconds is a pass)". For a raised surface fabric Class 1 applies "when the burn time is more than 7.0 seconds, or when they burn with a rapid surface flash (0.0 to 7.0 seconds), provided the intensity of the flame is so low as not to ignite or fuse the base fabric". Paragraph (b)(1) reads in full: "Plain surface textile fabric. Class 2 is not applicable to plain surface textile fabrics." Class 3, Rapid and Intense Burning, applies to a plain surface fabric "when the time of flame spread is less than 3.5 seconds", and such textiles "are dangerously flammable and shall not be used for clothing". law.cornell.edu

16 CFR 1610.6(a)(1), which gives guidelines for fabrics that "require extra attention when preparing test specimens because of their particular construction characteristics", noting that the list "is not intended to be all-inclusive". Fabrics flocked overall "are treated as raised surface textile fabrics"; flock printed fabrics "shall be treated as plain surface textile fabrics"; cut velvet with a patterned construction "shall be considered a raised surface textile fabric"; metallic thread fabrics "shall be considered plain surface textile fabrics provided the base fabric is smooth", with specimens cut so that "the test flame impinges on a metallic thread"; and flat woven constructions with burn-out patterns "shall be considered plain surface textile fabrics". Paragraph (a)(1)(vi): "Narrow fabrics and loose fibrous materials manufactured less than 50 mm (2 in) in width in either direction shall not be tested. If a 50 mm by 150 mm (2 in by 6 in) specimen cannot be cut due to the nature of the item, i.e. hula skirts, leis, fringe, loose feathers, wigs, hairpieces, etc., do not conduct a test." law.cornell.edu

Written from 16 CFR part 1610 and from the catalog as it stood on 19 October 2026. Part 1610 is the Standard for the Flammability of Clothing Textiles and it classifies fabric by how fast a flame spreads across a test specimen; it does not govern clips, pins, blades or templates, and nothing here says it does. No container on this shelf is described as fire resistant, flame retardant or rated for anything, and no liner is described by what it will achieve in any particular use. This shelf is a subset of the store-small-dry shelf and the sewing notions property enumerates that shelf in full.