Stopples Eq. Length Stopples Eq. Length cheme2016 (Chemical) (OP) 28 Sep 16 15:41 For pressure drop calculation- what would be resistance coefficient and equ. length for stopples? Would be the same as the pipe size? RE: Stopples Eq. Length Latexman (Chemical) 28 Sep 16 16:05 I don't think I understand your question, because a stopple (a stopper or plug) has infinite resistance or equivalent length. Is this a joke? Good luck, Latexman To a ChE, the glass is always full - 1/2 air and 1/2 water. RE: Stopples Eq. Length MikeClay (Chemical) 28 Sep 16 16:46 Once the stopple is removed, I'd treat it as a run tee. I can't be much worse than that. --Mike-- RE: Stopples Eq. Length LittleInch (Petroleum) 28 Sep 16 16:52 I think he means stople and bypass Remember - More details = better answers Also: If you get a response it's polite to respond to it. RE: Stopples Eq. Length cheme2016 (Chemical) (OP) 28 Sep 16 22:31 Thanks for the responses Wrong symbols were used on the drawings! They are not stopples. I found out they are check valves not stopples but called out that way. RE: Stopples Eq. Length georgeverghese (Chemical) 29 Sep 16 03:26 There are many types of check valves- wafer checks, swing checks, plate checks, lift checks, piston checks, nozzle checks, etc. Which one are you after? RE: Stopples Eq. Length cheme2016 (Chemical) (OP) 29 Sep 16 21:56 Swing check valves. RE: Stopples Eq. Length georgeverghese (Chemical) 30 Sep 16 00:21 If you are working with the classic K value method, then K = 2.0, while L/D = 135 for a swing check. Pls note that the Fanning friction factor to be used for this classic approach for fittings pressure drop must always range between 0.016 to 0.02, regardless of what the computed flow regime friction factor is. If are using the 3-K method, then K = (2025/Nre) + 0.621 [1 + 4.0 (25.4/ID)^0.3], where ID = pipe id in mm, Nre = piping Reynolds number. I've had to extrapolate this myself from other known info, since there is no literature for swing checks in the 3-K docs. Pls also note there is a minimum velocity which must be exceeded for swing / dual plate checks to enable stable flow - you may glean this off the internet - but be careful to cross check this against other guidance.