BS 2742:2009 PDF Download

BS 2742:2009 is a standard that provides guidance on the use of the Ringelmann and miniature smoke charts to assess smoke emissions from unregulated processes. These charts compare the darkness of smoke with standard shades of grey placed in a suitable position. The charts are placed at a distance from the observer where the black lines merge into the white background and produce a uniform grey for each shade.

It is important to note that BS 2742 is not suitable for calibrating Continuous Emissions Monitoring Systems and is not applicable to processes whose emissions are regulated by EU Directives with stated Uncertainty. The standard should be used in conjunction with the specific Ringelmann and miniature smoke charts provided in BS 2742C and BS 2742M respectively.

In terms of changes from the 1958 version, the 1972 Addendum has been removed as it was only applicable to a limited number of coal burning chain grate stoker appliances which are now rare. The technical requirements remain the same, but the values are now expressed in metric terms.

It is important to use the BS charts provided and discard them when they become soiled or discoloured, as a soiled chart may give a lower observed Ringelmann number than the true value. The format of the Ringelmann charts is either standard or miniature, with the standard chart consisting of four sections and the miniature chart consisting of five paint swatches mounted on a card.

The contents of BS 2742 include an introduction, scope, normative references, guidance on the use of the charts, the format of the charts, chart holders, and a bibliography. The standard also includes figures depicting suitable holders for the charts and the method of use.

BS 2742:2009 replaces the previous version from 1969.