Calculations

Basic calculations 7 Basic calculations

7.1 Factors influencing pipe system design

Type of influence Outside diameter Inside diameter Internal pressure External pressure Underpressure Reference stress Creep modulus Operating temperatures Lowest operating temperature Highest operating temperature Highest ambient temperature Average installation temperature Safety factor for load class I = 1.3 for load class II = 1.8 for load class III = 2.0 for stability N = 2.0 Calculated pipe wall temperature TW = 0,9 . TFlow medium Maximum occurring temperature difference max '- = Tu - Ti T0 = upper maximum value Tu = lower maximum value Load period: Load h/a (= hours per annum) for min Tw for max Tw for Ui for Ua Calculated service life for calculation of creep strength Reduction factors Time dependence (if applying appendix A1, this factor has already been taken into account) Reduction factor (influence of ambient medium) according to DVS 2205 - Part 1 Reduction factor Temperature dependence (if applying appendix A1, this factor has already been taken into account!) Reduction factor (influence of specific resilience) DVS 2205 - Part 1 (See table 7.12) Flow medium Pressure loss per m pipe Flow velocity Flow volume Short symbol de di pi pex pu Vref EcR Ti min Ti max Ta max Tins S S S S TW min TW max '°C Unit mm mm bar bar bar N/mm2 N/mm2 °C °C °C °C Type of influence Pressure Surge Welding factors Short-term welding factor Long-term welding factor (The abbreviations fs and fl indicated here have been freely chosen by Akatherm. In the DVS 2205 Part 1 guideline they are shown as fz (short-term welding factor) and fl (longterm welding factor)! Connection method - detachable connection - unions - couplings - plug-in connections - flange connections - compression connections - permanently attached connections - welding o electrofusion o butt-welding o hot gas extrusion welding o hot gas hand welding o hot gas speed welding Types of installation - above ground with linear...