5 replies to this topic

[kkala]

A new boiler will burn heavy fuel oil of min flash point 66 0C (sg approx 1.0). The fuel oil is stored in a heated cone roof tank (30 m3, temp 61-94 0C, blanketed with N2) and a pump transfers it to burners, after having passed from a steam heater (temp about 150 0C). Meanway there is filter, control valve, meter,shutoff valve, drain.
Although I am not specialist in area classification, I had thought that this fuel oil circuit shall create a hazardous area around it, since its temperature is above its flash point. The transferring pipe is welded (not flanged), but the equipment / instruments are supposed flanged and there are valves too. Area around fuel oil tank would be also classified. Let us assume API RP500 as applicable code (has not yet defined).
A consultant has the opinion that above fuel oil handling circuit shall not create a classified area. It is difficult for me to accept it, especially for the fuel oil tank. But I may be wrong, or it may be a "gray" area. Can you advise?
With best regards

Edited by kkala, 20 January 2010 - 11:37 AM.

[gvdlans]

Your system can result in flammable atmospheres, e.g. because of a flange leak. It shall therefore have an area classification.

[breizh]

Hi ,
This link may support your query .

http://www.hse.gov.u...easareaclas.htm

To me too , should be classified as hazardous .
Hope it helps
Breizh

[Whit123]

Area Classification is a risk management technique. How often do you think that you would have a leakage of flammable vapors/other substances in this area? If you can answer this question with some amount of precision, you will get your answer. If you refer to the IEC area classification standards, it talks about Zone 0, Zone 1 and Zone 2. If the amount of time that these vapors would be present is less than that which is below the limits of Zone 2, then you may have a "safe area". Contrary to popular opinion, a "safe area" of a plant is not "100 % safe" (like say the inside of a forest with respect to the probability of having a flammable vapor cloud), but rather the area is safer than other areas in the plant.
This is why even in a safe area, in a plant, it is always advisable to do a gas test before starting any "hot work".

[S.AHMAD]

A new boiler will burn heavy fuel oil of min flash point 66 0C (sg approx 1.0). The fuel oil is stored in a heated cone roof tank (30 m3, temp 61-94 0C, blanketed with N2) and a pump transfers it to burners, after having passed from a steam heater (temp about 150 0C). Meanway there is filter, control valve, meter,shutoff valve, drain.
Although I am not specialist in area classification, I had thought that this fuel oil circuit shall create a hazardous area around it, since its temperature is above its flash point. The transferring pipe is welded (not flanged), but the equipment / instruments are supposed flanged and there are valves too. Area around fuel oil tank would be also classified. Let us assume API RP500 as applicable code (has not yet defined).
A consultant has the opinion that above fuel oil handling circuit shall not create a classified area. It is difficult for me to accept it, especially for the fuel oil tank. But I may be wrong, or it may be a "gray" area. Can you advise?
With best regards

Dear kkal
Based on IP 15 (3rd Edition), with volume in excess of 200 liters and stored above its flash point, the fuel oil falls under Class III(2) and fluid category C that requires HAC. See attached.

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[kkala]

Based on IP 15 (3rd Edition), with volume in excess of 200 liters and stored above its flash point, the fuel oil falls under Class III(2) and fluid category C that requires HAC. See attached.

Thanks for the hint. Searching API RP 500, I have found that mentioned fuel oil is a Class III liquid heated above its flash point. API RP 500 does not give specific instructions for radii of hazardous areas when reports Class III liquids (para 5.2.4), but it gives much more in Appendix D (informative annex - an alternative method for area classification). I assume suppliers should be instructed to apply Appendix D of API RP 500 (as a minimum) for the radii of hazardous areas created.