Interesting to see a link to my postings (as gvdlans) in the cheresources forum! The link to the BASF website doesn't work anymore though. It showed a picture of a steam curtain employed at the ethylene cracker heaters at the BASF plant in Port Arthur, Texas.
For these applications, what the steam curtain (as well as water curtains) are used for is to generate an air flow (wind). In case of no or low wind conditions this helps to disperge/dillute the flammable gas cloud so that it does not reach the ignition source (the heater).
Both steam and water...
25362,
You do not even have to register to read the chapters. On the subject they write:
"4.2 Explosion Limits
Same meaning as flammable limits, i.e. UEL = UFL and LEL = LFL. We recommend using the term flammability limit instead of explosion limit."
I want to add that I am not familiar with the definition of explosion limits as given in the link from 25362 (http://www.galcit.caltech.edu/EDL/public/flammability.html) where they say that explosion limits refer to properties such as AIT (Auto Ignition Temperature). Apart from that it is a...
LFL/UFL and LEL/UEL can be used interchangeably. If prefer LFL/UFL since for many flammable mixtures to result in an explosion (rapid reaction causing overpressures) it doesn't only need an ignition source but also some form of confinement.
For example, ignition of a flammable methane/air...
Looking back at my previous posts in this tread, I see that I used the word "control room", where I should have used "control building". If you would design the control building to act as a safe refuge, I agree with epoisses that there should be another room apart from the control room that has...
A search with keywords "control room" on http://www.hse.gov.uk gave some very interesting hits. For example: http://www.hse.gov.uk/comah/sragtech/techmeascontrol.htm , http://www.hse.gov.uk/comah/sragtech/casepasadena89.htm and http://www.hse.gov.uk/comah/sragtech/caseflixboroug74.htm
I agree that offshore is a special kind of workplace (mainly because of the expensive and therefore limited space available). Onshore best approach may be to simply move away from the hazard (taking wind direction into account). Offshore this is obviously not so simple.
However, there is a...
As a starting point for a literature search you could consider Frank P. Lees "Loss Prevention in the Process Industries". It covers topics such as survivability of escape routes and shelters with many cross references.
Not having the control room inside the plant doesn't mean that it is at an unreachable distance. It can be ~200 m from the plant.
You could have 2 or more mustering areas (primary and alternatives) in the open air at opposite locations. Personnel moves to one of these areas depending on the...
Good point. I have not seen this being considered in control room design (although this may be covered in control room design standards).
For modern plants I would anyway prefer to have the control room at some distance from the actual plant, also because you do not have to make it blast...
Good question.
I do not have the answer, but would like to add that the exact height varies per standard. NFPA 15 (A 4-5.1) mentions a height of 30 or 40 feet (say 9 or 12 m) where water spray cooling is to be considered for destillation columns, API 521 (3.15.1.1) mentions a height of 25 feet...
If there is a possibility of having toxic smoke or gases near the control room, I normally specify that air intakes of HVAC system are provided with toxic/smoke/flammable gas detection that close dampers in the air intake, so that HVAC goes into internal circulation. As a rule of thumb, one...
In chapter 6 of the Relief Systems Handbook by Cyril F. Parry, a flow scheme is shown. According to this flow scheme, a thermal relief valve is recommended for LNG (being a cryogenic liquid) if the trapped volume of liquid is more than a significant volume of 0.01 m3 (10 liters).
He further...
Thank you Phil, I was getting curious after CJKrugers reply...
From what you write I understand that the referenced interpretation can mean that the user states that the internal failure scenario "tube leakage" (e.g. leakage through a 1 mm diameter hole) is considered a credible scenario, while...
The logical about the "test pressure/design pressure rule", formerly known as the "2/3 rule" is that:
1) Full tube rupture is a rare event
2) In case a full tube rupture does happen, it is unlikely that it will result in loss of containment (release of the contents to atmosphere) when the low...
For vapor filled vessels, you want to depressurize in case of an external fire. There is no boiling liquid inside the vessel that provides cooling, and therefore a relief valve will not do the job. The API guideline (depressurize to half design pressure or 7 barg whichever is lower in 15...
To me, the most worrying about the report is the fact that the explosion overpressures found at Buncefield were much higher than one would predict for such an unconfined Vapor Cloud Explosion. This may have considerable impact on similar storage sites where there are other buildings nearby.
Look also at: http://www.total.gb.com/media/mediatool.cfm?page=3
The tanks involved in the fire are most of the tanks in HOSL west (most of which are fixed roof) plus the big one in the lower left hand corner of the picture owned by British Pipeline Association (also fixed roof) plus one of the...
