1、August 2014Translation by DIN-Sprachendienst.English price group 9No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 9
2、1.010.30!%:= 20 000 kN/m2Figure D.2 Critical distance L for a smooth straight pipe or duct (for D see D.4.2(2) (2) In order to keep the pressure during deflagration less than 17 kN/m2for an explosion of propane, the maximum distance between vents is given in Figure D.3. DIN EN 1991-1-7/A1:2014-08EN
3、1991-1-7:2006/A1:2014 (E) 10 Propane and Dusts with KSt 30 000 kN/m2initial velocity between 2 m/s and 20 m/s Figure D.3 L/D-values during a deflagration to comply with a maximum pressure of propane explosion of 17 kN/m2(see D.4.2(2) for D; to apply only when the initial flow velocity is between 2 m
4、/s and 20 m/s) (3) For gases other than propane, the critical distance between vents may be calculated using Formula (D.10): Lx= LP(Su,P/ Su,x)2(D.10) where Lxis the critical distance between vents for gas X in m; LPis the critical distance between vents for propane in m. D.4.4 Design pressure (1) T
5、he design pressure pdin the vented pipe for dust may be determined from Figure D.4. NOTE Values of pdare given for three different KStvalues, For dusts with other values of KSt, interpolation is allowed. Figure D.4 Design pressure pdfor vented pipe containing dust (2) The design overpressure pdfor t
6、he pipe for a gas having a fundamental burning velocity of less than 0,60 m/s may be determined from Figure D.5. DIN EN 1991-1-7/A1:2014-08EN 1991-1-7:2006/A1:2014 (E) 11 Figure D.5 Design value of the overpressure pdfor gases with fundamental burning velocity of less than 0,60 m/s (3) For gases oth
7、er than propane, the maximum pressure and the distance between vents may be calculated using Formula (D.11): pd,X= pd,P(Su,X/ Su,P)2(D.11) where pd,Xis the maximum explosion overpressure of the gas X in kN/m2; pd,Pis the maximum explosion overpressure of propane in kN/m2; Su,Xis the fundamental burn
8、ing velocity for gas X in m/s, see Table D.2; Su,Pis the fundamental burning velocity for propane in m/s. (4) For gases with fundamental burning velocities greater than 0,60 m/s (see Table D.2) additional vent area is required by using multiple vent locations to decrease the spacing between the vent
9、s determined for propane. Table D.2 Fundamental burning velocity SuType of gas Sum/s Acetone 0,54 Acetylene 1,66 Benzene 0,48 Butane 0,45 Ethane 0,47 Ethylene 0,80 Gasoline 0,40 Heptane 0,46 Hydrogen 3,12 Jet fuel, grade JP-1 0,40 Methane 0,40 Pentane 0,46 Propane 0,46 Toluene 0,41 “. DIN EN 1991-1-7/A1:2014-08
