6 replies to this topic

[process En]

Dear All:
Maximum allowable personnel exposure time to particular heat radiation level proposed in API RP 521 .
for personal continuous exposure Heat radiation at any location shall be limited to 1.58 kW/m2.


my question:
Is like this limitation also for equipment installation?
It was requested to install one hydrocarbon condensate storage tank in the area which impacted by flare radiation.
Introducing useful document are highly appreciated.

[kkala]

Radiation allowable for equipment is different, as indicated by http://www.nao.com/T...tion_Levels.htm. In safety (Seveso-II) studies we apply different max allowable radiation levels for people and equipment, more or less like the reference in Web.
Additional safety criterion for a liquid hydrocarbon storage tank (assumed to be a drum, ie a pressure vessel) exposed to radiation (from flare + sun simultaneously) can be as follows:
The vessel should have a PRV directed to flare header and covering the fire case. If heat input due to fire per API RP 520 is higher than heat input due to radiation, the vessel fire protection will cover the case of incident radiation letting some vapor go through the PRV. This is expected to be the valid case in the plurality of cases; fire can be close to drum, while flare gases are burnt at a height. In case that incident radiation is higher than fire heat input, PRV has to be sized accordingly.
In case of max 1.58 kW/m2 at ground level (value rather small, compare to max solar radiation = 1 kW/m2) no tank shelter to protect workers near the drum from flare radiation seems necessary.

[loupurdie]

The increased ionized solar wind can cause increased aurora activity, if the flare also ejects a CME that intersects the Earth it can cause damage to satellite electronics and can cause some reconnection electrical feedback into our power grid system.solar flares happen all the time. As a matter of fact, there have been at least half a dozen solar flares, including a major one, in the past two days. Did you notice anything happening? I certainly didn't. Most solar flares are completely harmless.
volvo parts

Hi There,

Would have been more helpful to know if you are designing or constructing around that area. Usually up to 1500 btu/h/ft2 (please convert to SI) is permitted in design but if your personnel are uncomfortable then put a shield and work. Though the deisgn says 1,500 btu/h/ft2 normally there is only purge gas through the flare and its not hot around that place to work. You have about 10 to 20 minutes for escape if soemthing blows out and the flare goes boom !

Maditha

[kkala]

Damages of thermal radiation on equipment or human beings are summarized on the attached "radiation.xls", taken from a book dealing with safety studies.

Attached Files

•  radiation.xls   13.5KB   436 downloads

[chemsac2]

Process EN,

API 2218 for fireproofing practices in its appendix C, section C.3 has following on radiation flux for equipments:

"Q: What is the allowable heat flux exposure for equipment?
A: While no single number can be used for all equipment, one company uses a value of 300°C (572°F) as a safe operating maximum for steel structures and process equipment. They then calculate acceptable radiation guidelines. Computer modeling equates 300°C to an exposure of approximately 12.5 kW/m2 (4000 BTU/hr-ft2) for exposure without fireproofing or water spray; for vulnerable structures they lower this to as little as 8 kW/m2 (2500 BTU/hr-ft2). They require fireproofing for any case where the fire scenario envisions direct fire impingement."

Shell DEP 80.45.10.10, section 6.3.2 suggests 6.3 kW/m2 radiation flux for equipments in flare within sterile area.

This radiation flux criteria can be used to decide surface temperature of equipment. Design temperature of equipment should be more than calculated surface temperature.

Irrespective of radiation flux, it is this surface temperature that would decide flare stack height (in addition to other criteria like flux for human exposure, dispersion of combustion products etc).

Regards,

Sachin

[Root]

Dear All:
Maximum allowable personnel exposure time to particular heat radiation level proposed in API RP 521 .
for personal continuous exposure Heat radiation at any location shall be limited to 1.58 kW/m2.


my question:
Is like this limitation also for equipment installation?
It was requested to install one hydrocarbon condensate storage tank in the area which impacted by flare radiation.
Introducing useful document are highly appreciated.

You need to calculate the Stack hight and Mditha already give you clue, 'ie' 1500BTU/hr/Ft² , Henceforth you can estimate the limitation for equipment installation.
Toor