Summary of Topics

This new Third Edition of ULC 703 dated July 14, 2025 includes the following changes in requirements:

– Revision of the definition for cellulose fibre insulation

– Addition of a definition for “fibre”

– Clarification of intended uses for Type 1 in the Classification section

– The moisture vapour sorption test is replaced with a reference to ASTM C739

– Replacement of the open flammability test (critical radiant flux) with a reference to ASTM C1485

– The smoulder resistance test clarifies conditions that require a new specimen to be prepared (mandatory language)

– Removal of statement favouring ASTM C177 in case of dispute

– Reporting and Labelling sections are updated to remove references to “sub-type” to be consistent with the Classification section

– Rewriting of Annex A and addition of Annex B

– Editorial changes throughout the document

1 Scope

1.1 This Standard specifies requirements for treated cellulose fibre intended for use as thermal insulation (Cellulose Fibre Insulation, CFI) in new and existing buildings within the temperature range of -60 °C to 90 °C

1.2 This document does not purport to address all the health and safety aspects associated with its use. Anyone using this Standard has the responsibility to consult the appropriate authorities and to establish appropriate health and safety practices in conjunction with any existing applicable regulatory requirements prior to its use.

1.3 The methods used in this Standard to measure and describe the properties of materials, products or assemblies in response to heat and flame under controlled laboratory conditions do not describe or appraise the fire hazard or fire risk of materials and products under actual fire conditions. Results of these tests are meant to be used as elements in a fire risk assessment that takes into account all of the factors that are pertinent to an assessment of the fire hazard of a particular end use.