How to calculate the fire water consumption in process units in gas&oil plant?

[taoxianwen123]

hello,everybody,
How to calculate the fire water consumption in process units in gas&oil plant?
anybody has the handbook of calculation?
normally,the worse case will happen in the crude oil tank farm,the fire water consumption of fixed roof crude oil tanks for exposure protection shall be according to API 2030,4.1L/m2/min for min. 6 hours.
but, how to calculate the fire water consumption in process units?according to NFPA 15,the application rate of fire water for exposure protection for process units shall be 4.1~20.4L/min/m2, but how to group the equipments? if group each process unit together,the total fire water consumption will be very large,the water consumption may be 5 times of that used in tank farms, how to group the equipments(like 3 phase separators and desalters etc.)is a problem.and in NFPA codes,there are not very clear definition of it.
for storage tanks,if the space(shell to shell) between the fired tank and adjacent tanks is bigger than one time diameter,then the adjacent tanks may not be cooled.so the fire water consumption will be lowed down.
but for the process units,which is the space requirements?I have not gotten it from the NFPA codes,if all of the equipments need to be cooled, the fire water consumption may be very big.I don't want to cool all the equipments at the same time.

[Raj indo]

Hi taoxianwen123

Hope you are doing good, did you get any information on above subject, if so pls send any information on above subject, i am also struggle to get the information
rajindo@gmail.com

Thanks

[f81aa]

Hi taoxianwen123:

Firewater consumption can be large in process areas, even larger than in storage areas. If you can support your numbers, they will prevail.

Traditionally we have used prescriptive codes and standards and ended up with fire protection systems that sometimes have been underestimated. And plants that look "identical" are not necessarily so in terms of the fire protection requirements. Designers might fail to consider operating manpower levels, environmental concerns, potential for business interruption and facility reputation, among others, which could have an impact.

In recent years, performance-based means of protection are gaining acceptance and designers have now more tools to give them certitude that their protection systems designs really achieves the objectives.

You should consider performing a fire risk assessment. I´ll share the SHELL Design and Engineering Practice titled "Assessment of the Fire Safety of Onshore Installations", which is part of the SHELL DEP (Design and Engineering Practice). I think it explains very well the methodology. The download link is:

[link Point to another website Only the registered members can access]
You will have to consider Loss of Containment Scenarios and Fire Scenarios and carry out many calculations. It will take some time. You won´t cool all the equipment simultaneously, just the ones that need it.

By the way, the Forum thread link for the whole set of SHELL DEP (Design and Engineering Practice) is:

[link Point to another website Only the registered members can access]
Thanks polaris 44.

Well, these are my comments. Other members are still expected to share theirs.

Regards