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</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link="#467886" vlink="#96607D" style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal>Hello all!<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I’m modelling an extract system for a rail maintenance depot (RMD). It’ll be sucking about 50m3/s (106,000 cfm).<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The client wishes to investigate solutions regarding intake air louvres. The main resulting variable is the zone’s resulting internal pressure. I’ve calculated, based on their stock louvre selection, and based on many assumptions (e.g., leakiness, backflow through non-operable fans, etc) that this will be in the <b>range of minus 10 to 25 Pa</b>.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Does this sound reasonable? I’m unaware of any standards relating to maintenance sheds anywhere.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Also, considering the range 10 to 25 Pa, what discharge coefficients and flow exponents would be normally considered? I’ve usually worked to Cd ~ 0.62 and ~ 0.5 respectively, but this could be more variable as the pressure increases.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Many thanks<o:p></o:p></p><p class=MsoNormal><br>Chris<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>PS. X-posted in AIVC linkedin group<o:p></o:p></p></div></body></html>