Re: Flame Arrester

Sajit,

Based on what you describe, except at startup it is impossible to have a fire from the inside. No mixture I have ever encountered or can imagine can sustain a flame at 3% oxygen. Even 6%.

I can readily imagine situations where an external fire should be arrested. However, unless there can be controls put in place to assure safety at startup (and after extended shutdown), perhaps BOTH units could be used. Such measures would include purge cycle(s) to fill the pipe with nitrogen (or other "inert" gas), and use of an O2 monitor in the system. In a 1" line, neither flame arrestor is prohibitively costly. However, I would tend to go with only the deflagration type. Also, please assure that a proper PHA is done on the system before commissioning!

... Bruce D. Bullough ...
Lead Process Engineer
Foth Production Systems, LLC
8550 Hudson Boulevard North, Suite 100
Lake Elmo, MN 55042
Direct: +651-288-8598 Fax: +651-288-8551 <a href="http://www.foth.com">http://www.foth.com</a>

IMPORTANT NOTICE
This communication including any attachments, (E-mail) is confidential and may be proprietary, privileged or otherwise protected from disclosure. If you are not the intended recipient, please notify the sender, permanently delete this E-mail from your system and destroy any copies. Any use of the E-mail, including disclosure, distribution or replication, by someone other than its intended recipient is prohibited.

This E-mail has the potential to have been altered or corrupted due to transmission or conversion. It may not be appropriate to rely upon this E-mail in the same manner as hard copy materials bearing the author's original signature or seal.

<a href="/group/PipingDesign/post?postID=NAp84KVKs6Jlz8R9qevK0lshrMn0zWmNuBlWXNJxwNdjGvQXLDRWisZs0_vfLl2NX0r3WGokT04oLjE_">sviswan@technip.com</a> Sent by: <a href="/group/PipingDesign/post?postID=AijlNqcKJ1wPopppcCBkjhjKj2K14jemh2te7aV3KI2r-CQTLadv5E0XUys-qqiSweh5K4bpGstM8yObAYtUl4aUI_-bNQ">PipingDesign@yahoogroups.com</a> 02/08/2007 01:01 AM
Please respond to
<a href="/group/PipingDesign/post?postID=AijlNqcKJ1wPopppcCBkjhjKj2K14jemh2te7aV3KI2r-CQTLadv5E0XUys-qqiSweh5K4bpGstM8yObAYtUl4aUI_-bNQ">PipingDesign@yahoogroups.com</a>

To
<a href="/group/PipingDesign/post?postID=AijlNqcKJ1wPopppcCBkjhjKj2K14jemh2te7aV3KI2r-CQTLadv5E0XUys-qqiSweh5K4bpGstM8yObAYtUl4aUI_-bNQ">PipingDesign@yahoogroups.com</a> cc

Subject
Re: [PipingDesign] Flame Arrester

Bruce,

The vent is a 1" line, between 2 to 3 mts, from an inert gas generator unit, a packaged equipment. The unit uses fuel gas (MW 21). The vent gas stream is a varying mixture of fuel gas vapour and nitrogen with 3% oxygen.
The equipment is on an FPO (floating production and off loading) topside.

The BS EN 12874 groups arresters according to the gas group. Each of the gas groups has a corresponding MESG (maximum experimental safe gap, the gap
between the plates of the arrester) under which an arrester is type tested under a series of deflagration and detonation tests.

The vendor selects the stream as of IIA.

The standard defines IIA as propane of purity by vol% >= 95, Gas in air vol% = 4.2.

Sajit Viswan
Piping Materials Engineer
Technip Abu Dhabi
UAE Save a tree...please don't print this e-mail unless you really need to. Received on Thu Feb 08 09:27:00 2007