CPSC flammability standards for children's sleepwear apply to garments in sizes 0 through 14. Importers of boys' pajamas must ensure products either meet the flame-resistance standard or are tight-fitting and labeled accordingly. Adult men's nightwear is not subject to the same mandatory standard, though voluntary compliance is common.

CBP considers design features, marketing, and intended use: nightwear is designed primarily for sleeping, while loungewear or casual separates are intended for general indoor wear. Garments marketed or labeled as sleepwear, constructed of typical nightwear fabrics, and styled accordingly are generally classified as nightwear. Importers should retain product documentation supporting the intended use to defend classification on audit.