*Voluntary Practice for Assessment of Frame Deflection When Using One Component Polyurethane Foams for Air-Sealing Rough Openings of Fenestration InstallationsThis practice identifies pressure build and dimensional stability as the key attributes that contribute to deflection of fenestration products resulting from the use of one component polyurethane foams and provides test protocols for assessing these key attributes. Assessment of toxicity and precautions for safe use are excluded from the scope of this document.