Smoke-developed index

Smoke-developed index (abbreviated SDI) is a measure of the concentration of smoke a material emits as it burns.{{cite web |url=http://www.kydex.com/briefs/143.pdf |title=Archived copy |accessdate=2008-11-16 |url-status=dead |archiveurl=https://web.archive.org/web/20070923155439/http://www.kydex.com/briefs/143.pdf |archivedate=2007-09-23 }} Like the Flame Spread Index, it is based on an arbitrary scale in which asbestos-cement board has a value of 0, and red oak wood has 100. The SDI is measured using a horizontal test specimen, according to the Steiner tunnel test protocol.

The ASTM standard E84 defines a standard test method for surface flame spread and smoke density measurements.{{cite web | url=http://www.astm.org/Standards/E84.htm | title=Standard Test Method for Surface Burning Characteristics of Building Materials }} A smoke-developed index of less than 450 is required by IBC section 803.1 at interior walls and ceilings for all surface materials except trim.