24 CFR § 3280.207 - Requirements for thermal insulating materials.

---
identifier: "/us/cfr/t24/s3280.207"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "24 CFR § 3280.207 - Requirements for thermal insulating materials."
title_number: 24
title_name: "Housing and Urban Development"
section_number: "3280.207"
section_name: "Requirements for thermal insulating materials."
chapter_name: "OFFICE OF ASSISTANT SECRETARY FOR HOUSING—FEDERAL HOUSING COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT"
part_number: "3280"
part_name: "MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "15 U.S.C. 2697, 42 U.S.C. 3535(d), 5403, and 5424."
regulatory_source: "40 FR 58752, Dec. 18, 1975, unless otherwise noted. Redesignated at 44 FR 20679, Apr. 6, 1979."
cfr_part: "3280"
---


# 3280.207 Requirements for thermal insulating materials.

(a) *General.* Except for foam plastic materials and as provided in this section, exposed and concealed thermal insulating materials, including any facings, must be tested in accordance with NFPA 255-96, Standard Method of Test of Surface Burning Characteristics of Building Materials (incorporated by reference, see § 3280.4) and must have a flame spread index of 25 or less and a smoke developed index of 450 or less. The flame spread and smoke developed limitations do not apply to:

(1) Coverings and facings of insulation batts or blankets installed in concealed spaces when the facings are in substantial contact with the unexposed surface of wall, floor, or ceiling finish; or

(2) Cellulose loose-fill insulation that complies with paragraph (b) of this section.

(b) *Loose-fill insulation.* (1) Cellulose loose-fill insulation that is not spray-applied or self-supporting must comply with, and each package must be labeled in accordance with the Consumer Product Safety Commission requirements in 16 CFR parts 1209 and 1404.

(2) Other loose-fill insulation that cannot be mounted in the NFPA 255-96, test apparatus without a screen or other artificial support must be tested in accordance with CAN/ULC S102.2-M88, Standard Method of Test for Surface Burning Characteristics of Floor Coverings and Miscellaneous Materials and Assemblies (incorporated by reference, see § 3280.4), and must have a flame spread index of 25 or less and a smoke developed index of 450 or less.

(c) *Attic locations.* Exposed insulation installed on the floor or ceiling forming the lower boundary of the attic must be tested in accordance with NFPA 253-2000, Standard Method of Test for Critical Radiant Flux of Floor Covering Systems Using a Radiant Heat Energy Source (incorporated by reference, see § 3280.4) and must have a critical radiant flux of not less than 0.12 watt/cm
<sup>2</sup>.