BS 2742, BS2742, bs 4742, BSI, British Standard, smoke chart, smoke charts, chimney, chimneys, chimney testing, Ringelmann, ringelman, ringelmann charts, using ringelman charts, 2742
To be read in conjunction with BS 2742C, BS 2742M ; Gives guidance on the use of BS Ringelmann charts to assess smoke emissions from unregulated processes.
