Flammable Storage tank - N2 blanket? 1

[cougarfan]

Is there any regulation which requires a nitrogen blanket into atmospheric storage tanks that contain flammable liquids? I could not find anything in NFPA - but there might be - typically these tanks are aound 10000 gallons each.... Help....

 

[Montemayor]

cougarfan (Mechanical):

I always stress the use of N2 padding or "blankets" on flammable storage fluids (normally stored in API 650 tanks).

The reasons are manifold:

1) Local fire/safety codes;
2) Local environmental emissions regulations;
3) Your own Company's standard safety guidelines;
4) Loss of vaporized low boilers;
5) positive containment and control of flammable fluids.
6) the constraints and guidelines mandated by your plant's insurance carrier.

Number 6 is usually one of the more practical reasons for applying the technique; I would optimistically expect that Number 3 be at the forefront and leading the pack. It just makes good, safety sense to use the N2 blanket on volatile and flammable storage fluids. I don't believe you'll find any guidelines or recommendations in the NFPA.

I hope these points help you out.


Art Montemayor
Spring, TX

 

[Guidoo]

Although application of a N2 blanketing system is certainly recommended, I do not think that it is required by international regulations.
Reason why I think this, is that the international standards on Hazardous Area Classification (i.e. API RP 500, IEC 60079-10, IP15) classify the volume in a fixed roof storage tank above the flammable liquid level as Class I, division 1 (API) or zone 0 (IEC, IP). This classification means that a flammable mixture is expected to be normally present there.
With a N2 blanketing system you would expect a lower classification (e.g. zone 2), since a flammable mixture would only be present in case the blanketing system fails.