Dear All,
I am currently looking after a project where the sizing of our vents for and emergency case, such as, fire engulfment has to be checked against methods provided in either NFPA 30 or API 2000. We store ethanol at various strengths ranging from 40% v/v up to 94% v/v.
I have completed the calculations set out by both standards above and determined that the majority of our vents are undersized! I am now at the stage where I am engaging with contractors to resolve this issue. I feel there is various ways in which the venting capacity required can be achieved and would like some of your views?
We currently have 6 inch goose-neck type vents installed in the majority of tanks. However we require the vents to be around 12 inch. The following options are what we are exploring in terms of install:
- Preferred option would be to utilize unused spare flanges on the tanks to install an additional 6 inch vent? would this be acceptable both vents serving as normal condition venting and emergency relief? (this options would save the operational headache of having to empty tanks to cut and weld new vents)
- The second option is to cut and weld new vents to the tanks at the appropriate size.
- Could man-ways be used? I have came across designs for man-ways to this effect?
The additional caveat which I also have to deal with is also the issue of flame arrestors. These are installed throughout the whisky industry as best practice and we do have them installed on the majority of our exiting vents. Would this mean that any new vents (i.e. if option 1 above was carried forward) that the vents would also have to have flame arrestors fitted or could we define the new vent lines as if for emergency relief only? I personally would assume both would be required to have flame arrestors fitted, as per best practice.
Any help is appreciated.
Regards,
The Whisky Guy .