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The firewater pump discharge is already provided with ARV but it doesnt help much in dumping overpressure during pump start-up. I've also tried to use a proper check valve setting but still, it wont open fast enough. Plus, in case of blocked discharge and there is high pressure from the other...

Thanks Gerhadl, Yes, your explanation of the situation is correct. And i believe this kind of situation of pump start-up is typical for all firewater system in offshore platform where we have the pump outlet with ARV, PRV and Check Valve in sequence. in PIPENET, there are 3 types of check...

thanks Stanier, From pump discharge to the check valve is a dry section and the PRV is located just before the check valve. During pump start-up, the pump flow will be higher than rated flow (steady state). As per my understanding, when the pump start it will fill-up the column (since this is...

Thanks MortenA. Yeah, manufacturer can only say that the valve can open fast. But the question is how fast? Back to my case, it is actually a self modulating pressure relief valve and it's an auto pilot valve. The size is 8". Ive tried the time constant of 1second but the surge is still...

I have a submersible firewater pump (offshore) with a rated capacity of 1050 m3/hr@12barg. There is a pressure relief valve (PRV) located at the discharge header just before the check valve and the valve is sized based on NFPA 20. As per my transient study, during pump start-up (pump is...

i have done my simulation, normal combination air valve will definitely gives high pressure surge in my system. this is due to the fast water speed filling up the pipeline. i need to get this thing right, do you guys know something about a non-slam vacuum breaker?

Ok, i need to change the principle to use the large orifice as venting. The only concern is, large orifice will cause the speed of water rise too fast and probability of surge happens is high. Do you know how to calculate the optimum orifice size during pipe filling?

Thank you guys, Im agree with cvg, i think its called double orifice isnt it? Ive read about it somewhere but i dont know whether this criteria is a typical for all type of combination air valves. This is important for me since im doing the transient surge analysis. And at the moment, i use...

Hi guys, currently im in the middle of selecting ARV for firewater system. I believe at high points a combination air valve shall be used. can someone explain to me on how this combination air valve works? im confuse with the small orifice. is this small orifice will be used to discharge...

Hi all, Im still new in designing firewater system on offshore platform. regarding the ARV, may i know what is the typical type of air release valve for the submersible pump? ive read some technical data from some manufacturers. there is an ARV with small orifice and some with large orifice...

I want to restrict the flow. My client dont want the flow passing through the deluge valve exceeds 1000m3/hr due to dificulty in reaching steady state condition. Currently, the flow is at about 1200 m3/hr. Im just curious what people normally do when facing something like this. Btw, 4 bar...

Hi all, Im doing the static hydraulic calculation for sprinkler firewater system on offshore platform. I need to kill the flow/pressure that going into the sprinkler system (downstream of deluge valve) after deluge valve is opened. However the valve cannot kill the pressure/flow as required...

Thanks mjcronin, Ive got your point saying that MAOP means MAOP. however the word "operating" itself means operating condition which i think is continuous operation pressure that is permissible. And that is not the same as surge pressure where it only happened due to pump start/ failed or...

I have 2 cases for the same system. The ARV location and size shall be the same for both cases (ofcourse because its the same system on the same platform). However, based on my calculation in pipenet, the first case need larger size and the 2nd case need smaller size. Its impossible to have the...

So youre saying that i need to follow b31.3? Just to make you clear with my situation. Im doing the transient surge analysis for firewater system on offshore platform. The main objective is to check the integrity of copper nickel pipe when surge happened due to pump start, stop, deluge valve...

thanks BigInch for the reply, Yes you are right. Hydrotest pressure is not aplicable for the transient surge analysis since the maximum surge for the case that im working on right now is only last about 0.2 second! (where it exceed design pressure). So far from what ive got from reading, the...

Hi all, Currently for my transient surge analysis, my basis for the maximum allowable pressure during surge is 150% of the design pressure of the pipe. (im using Cu-Ni where design pressure is 18 bar). so my maximum limit for the surge pressure is 1.5 x 18 = 27 bar. This 150% value is actually...

Hi all, Im currently doing a transient analysis pressure surge for firewater system. I have problem in sizing the right Air Release Valve at the highest point of the system. Comparing 2 cases, Case 1 when the deluge valve for the largest fire zone is opened, there are large amount of water...